Tri-functional Fe2O3-encased Ag-doped ZnO nanoframework: magnetically retrievable antimicrobial photocatalyst

NASA Astrophysics Data System (ADS)

Karunakaran, Chockalingam; Vinayagamoorthy, Pazhamalai

2016-11-01

Fe2O3-encased ZnO nanoframework was obtained by hydrothermal method and was doped with Ag through photoreduction process. Energy dispersive x-ray spectroscopy, transmission electron microscopy (TEM), high resolution TEM, selected area electron diffractometry, x-ray diffractometry and Raman spectroscopy were employed for the structural characterization of the synthesized material. While the charge transfer resistance of the prepared nanomaterial is larger than those of Fe2O3 and ZnO the coercivity of the nanocomposite is less than that of hydrothermally obtained Fe2O3 nanostructures. Although Fe2O3/Ag-ZnO exhibits weak visible light absorption its band gap energy does not differ from that of ZnO. The photoluminescence of the fabricated nanoframework is similar to that of ZnO. The radiative recombination of charge carriers is slightly slower in Fe2O3/Ag-ZnO than in ZnO. The synthesized Fe2O3-encased Ag-doped ZnO, under UV A light, exhibits sustainable photocatalytic activity to degrade dye and is magnetically recoverable. Also, the Fe2O3/Ag-ZnO nanocomposite disinfects bacteria effectively in absence of direct illumination.

Iron Sulfide Attenuates the Methanogenic Toxicity of Elemental Copper and Zinc Oxide Nanoparticles and their Soluble Metal Ion Analogs

PubMed Central

Gonzalez-Estrella, Jorge; Gallagher, Sara; Sierra-Alvarez, Reyes; Field, Jim A.

2016-01-01

Elemental copper (Cu0) and zinc oxide (ZnO) nanoparticle (NP) toxicity to methanogens has been attributed to the release of soluble metal ions. Iron sulfide (FeS) partially controls the soluble concentration of heavy metals and their toxicity in aquatic environments. Heavy metals displace the Fe from FeS forming poorly soluble metal sulfides in the FeS matrix. Therefore, FeS may be expected to attenuate the NP toxicity. This work assessed FeS as an attenuator of the methanogenic toxicity of Cu0 and ZnO NPs and their soluble salt analogs. The toxicity attenuation capacity of fine (25–75 µm) and coarse (500 to 1200 µm) preparations of FeS (FeS-f and FeS-c respectively) was tested in the presence of highly inhibitory concentrations of CuCl2, ZnCl2 Cu0 and ZnO NPs. FeS-f attenuated methanogenic toxicity better than FeS-c. The results revealed that 2.5× less FeS-f than FeS-c was required to recover the methanogenic activity to 50% (activity normalized to uninhibited controls). The results also indicated that a molar FeS-f/Cu0 NP, FeS-f/ZnO NP, FeS-f/ZnCl2, and FeS-f/CuCl2 ratio of 2.14, 2.14, 4.28, and 8.56 respectively, was necessary to recover the methanogenic activity to >75%. Displacement experiments demonstrated that CuCl2 and ZnCl2 partially displaced Fe from FeS. As a whole, the results indicate that not all the sulfide in FeS was readily available to react with the soluble Cu and Zn ions which may explain the need for a large stoichiometric excesses of FeS to highly attenuate Cu and Zn toxicity. Overall, this study provides evidence that FeS attenuates the toxicity caused by Cu0 and ZnO NPs and their soluble ion analogs to methanogens. PMID:26803736

EFFECT OF Mg AND TEMPERATURE ON Fe-Al ALLOY LAYER IN Fe/(Zn-6%Al-x%Mg) SOLID-LIQUID DIFFUSION COUPLES

NASA Astrophysics Data System (ADS)

Liang, Liu; Liu, Ya-Ling; Liu, Ya; Peng, Hao-Ping; Wang, Jian-Hua; Su, Xu-Ping

Fe/(Zn-6%Al-x%Mg) solid-liquid diffusion couples were kept at various temperatures for different periods of time to investigate the formation and growth of the Fe-Al alloy layer. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD) were used to study the constituents and morphology of the Fe-Al alloy layer. It was found that the Fe2Al5Znx phase layer forms close to the iron sheet and the FeAl3Znx phase layer forms near the side of the melted Zn-6%Al-3%Mg in diffusion couples. When the Fe/(Zn-6%Al-3%Mg) diffusion couple is kept at 510∘C for more than 15min, a continuous Fe-Al alloy layer is formed on the interface of the diffusion couple. Among all Fe/(Zn-6%Al-x%Mg) solid-liquid diffusion couples, the Fe-Al alloy layer on the interface of the Fe/(Zn-6% Al-3% Mg) diffusion couple is the thinnest. The Fe-Al alloy layer forms only when the diffusion temperature is above 475∘. These results show that the Fe-Al alloy layer in Fe/(Zn-6%Al-x%Mg) solid-liquid diffusion couples is composed of Fe2Al5Znx and FeAl3Znx phase layers. Increasing the diffusing temperature and time period would promote the formation and growth of the Fe-Al alloy layer. When the Mg content in the Fe/(Zn-6%Al-x%Mg) diffusion couples is 3%, the growth of the Fe-Al alloy layer is inhibited. These results may explain why there is no obvious Fe-Al alloy layer formed on the interface of steel with a Zn-6%Al-3%Mg coating.

Application of iron and zinc isotopes to track the sources and mechanisms of metal loading in a mountain watershed

USGS Publications Warehouse

Borrok, D.M.; Wanty, R.B.; Ian, Ridley W.; Lamothe, P.J.; Kimball, B.A.; Verplanck, P.L.; Runkel, R.L.

2009-01-01

Here the hydrogeochemical constraints of a tracer dilution study are combined with Fe and Zn isotopic measurements to pinpoint metal loading sources and attenuation mechanisms in an alpine watershed impacted by acid mine drainage. In the tested mountain catchment, ??56Fe and ??66Zn isotopic signatures of filtered stream water samples varied by ???3.5??? and 0.4???, respectively. The inherent differences in the aqueous geochemistry of Fe and Zn provided complimentary isotopic information. For example, variations in ??56Fe were linked to redox and precipitation reactions occurring in the stream, while changes in ??66Zn were indicative of conservative mixing of different Zn sources. Fen environments contributed distinctively light dissolved Fe (<-2.0???) and isotopically heavy suspended Fe precipitates to the watershed, while Zn from the fen was isotopically heavy (>+0.4???). Acidic drainage from mine wastes contributed heavier dissolved Fe (???+0.5???) and lighter Zn (???+0.2???) isotopes relative to the fen. Upwelling of Fe-rich groundwater near the mouth of the catchment was the major source of Fe (??56Fe ??? 0???) leaving the watershed in surface flow, while runoff from mining wastes was the major source of Zn. The results suggest that given a strong framework for interpretation, Fe and Zn isotopes are useful tools for identifying and tracking metal sources and attenuation mechanisms in mountain watersheds. ?? 2009 Elsevier Ltd.

Insights into the effect of iron and cobalt doping on the structure of nanosized ZnO.

PubMed

Giuli, Gabriele; Trapananti, Angela; Mueller, Franziska; Bresser, Dominic; d'Acapito, Francesco; Passerini, Stefano

2015-10-05

Here we report an in-depth structural characterization of transition metal-doped zinc oxide nanoparticles that have recently been used as anode materials for Li-ion batteries. Structural refinement of powder X-ray diffraction (XRD) data allowed the determination of small though reproducible changes in the unit cell dimensions of four ZnO samples (wurtzite structure) prepared with different dopants or different synthesis conditions. Moreover, large variations of the full width at half-maximum of the XRD reflections indicate that the crystallinity of the samples decreases in the order ZnO, Zn0.9Co0.1O, Zn0.9Fe0.1O/C, and Zn0.9Fe0.1O (the crystallite sizes as determined by Williamson-Hall plots are 42, 29, 15, and 13 nm, respectively). X-ray absorption spectroscopy data indicate that Co is divalent, whereas Fe is purely trivalent in Zn0.9Fe0.1O and 95% trivalent (Fe(3+)/(Fe(3+) + Fe(2+)) ratio = 0.95) in Zn0.9Fe0.1O/C. The aliovalent substitution of Fe(3+) for Zn(2+) implies the formation of local defects around Fe(3+) such as cationic vacancies or interstitial oxygen for charge balance. The EXAFS (extended X-ray absorption fine structure) data, besides providing local Fe-O and Co-O bond distances, are consistent with a large amount of charge-compensating defects. The Co-doped sample displays similar EXAFS features to those of pure ZnO, suggesting the absence of a large concentration of defects as found in the Fe-doped samples. These results are of substantial importance for understanding and elucidating the modified electrochemical lithiation mechanism by introducing transition metal dopants into the ZnO structure for the application as lithium-ion anode material.

Light-controlled resistive switching characteristics in ZnO/BiFeO3/ZnO thin film

NASA Astrophysics Data System (ADS)

Liang, Dandan; Li, Xiaoping; Wang, Junshuai; Wu, Liangchen; Chen, Peng

2018-07-01

ZnO/BiFeO3/ZnO multilayer was fabricated on silicon (Si) substrate by radio-frequency magnetron sputtering system. The resistive switching characteristics in ZnO/BiFeO3/ZnO devices are observed, and the resistive switching behavior can be modulated by white light.

Enriching rice with Zn and Fe while minimizing Cd risk

PubMed Central

Slamet-Loedin, Inez H.; Johnson-Beebout, Sarah E.; Impa, Somayanda; Tsakirpaloglou, Nikolaos

2015-01-01

Enriching iron (Fe) and zinc (Zn) content in rice grains, while minimizing cadmium (Cd) levels, is important for human health and nutrition. Natural genetic variation in rice grain Zn enables Zn-biofortification through conventional breeding, but limited natural Fe variation has led to a need for genetic modification approaches, including over-expressing genes responsible for Fe storage, chelators, and transporters. Generally, Cd uptake and allocation is associated with divalent metal cations (including Fe and Zn) transporters, but the details of this process are still unknown in rice. In addition to genetic variation, metal uptake is sometimes limited by its bioavailability in the soil. The availability of Fe, Zn, and Cd for plant uptake varies widely depending on soil redox potential. The typical practice of flooding rice increases Fe while decreasing Zn and Cd availability. On the other hand, moderate soil drying improves Zn uptake but also increases Cd and decreases Fe uptake. Use of Zn- or Fe-containing fertilizers complements breeding efforts by providing sufficient metals for plant uptake. In addition, the timing of nitrogen fertilization has also been shown to affect metal accumulation in grains. The purpose of this mini-review is to identify knowledge gaps and prioritize strategies for improving the nutritional value and safety of rice. PMID:25814994

In-Situ Crafting of ZnFe₂O₄ Nanoparticles Impregnated within Continuous Carbon Network as Advanced Anode Materials.

PubMed

Jiang, Beibei; Han, Cuiping; Li, Bo; He, Yanjie; Lin, Zhiqun

2016-02-23

The ability to create a synergistic effect of nanostructure engineering and its hybridization with conductive carbonaceous material is highly desirable for attaining high-performance lithium ion batteries (LIBs). Herein, we judiciously crafted ZnFe2O4/carbon nanocomposites composed of ZnFe2O4 nanoparticles with an average size of 16 ± 5 nm encapsulated within the continuous carbon network as anode materials for LIBs. Such intriguing nanocomposites were yielded in situ via the pyrolysis-induced carbonization of polystyrene@poly(acrylic acid) (PS@PAA) core@shell nanospheres in conjunction with the formation of ZnFe2O4 nanoparticles through the thermal decomposition of ZnFe2O4 precursors incorporated within the PS@PAA nanospheres. By systematically varying the ZnFe2O4 content in the ZnFe2O4/carbon nanocomposites, the nanocomposite containing 79.3 wt % ZnFe2O4 was found to exhibit an excellent rate performance with high capacities of 1238, 1198, 1136, 1052, 926, and 521 mAh g(-1) at specific currents of 100, 200, 500, 1000, 2000, and 5000 mA g(-1), respectively. Moreover, cycling performance of the ZnFe2O4/carbon nanocomposite with 79.3 wt % ZnFe2O4 at specific currents of 200 mA g(-1) delivered an outstanding prolonged cycling stability for several hundred cycles.

In situ synthesis of water-soluble magnetic graphitic carbon nitride photocatalyst and its synergistic catalytic performance.

PubMed

Zhang, Shouwei; Li, Jiaxing; Zeng, Meiyi; Zhao, Guixia; Xu, Jinzhang; Hu, Wenping; Wang, Xiangke

2013-12-11

Water-soluble magnetic-functionalized graphitic carbon nitride (g-C3N4) composites were synthesized successfully by in situ decorating spinel ZnFe2O4 nanoparticles on g-C3N4 sheets (CN-ZnFe) through a one-step solvothermal method. The magnetic properties of CN-ZnFe can be effectively controlled via tuning the coverage density and the size of ZnFe2O4 nanoparticles. The results indicate that the CN-ZnFe exhibits excellent photocatalytic efficiency for methyl orange (MO) and fast separation from aqueous solution by magnet. Interestingly, the catalytic performance of the CN-ZnFe is strongly dependent on the loading of ZnFe2O4. The optimum activity of 160CN-ZnFe photocatalyst is almost 6.4 and 5.6 times higher than those of individual g-C3N4 and ZnFe2O4 toward MO degradation, respectively. By carefully investigating the influence factors, a possible mechanism is proposed and it is believed that the synergistic effect of g-C3N4 and ZnFe2O4, the smaller particle size, and the high solubility in water contribute to the effective electron-hole pairs separation and excellent photocatalytic efficiency. This work could provide new insights that g-C3N4 sheets function as good support to develop highly efficient g-C3N4-based magnetic photocatalysts in environmental pollution cleanup.

Facile synthesis of magnetic ZnFe2O4-reduced graphene oxide hybrid and its photo-Fenton-like behavior under visible iradiation.

PubMed

Yao, Yunjin; Qin, Jiacheng; Cai, Yunmu; Wei, Fengyu; Lu, Fang; Wang, Shaobin

2014-06-01

A magnetic ZnFe2O4-reduced graphene oxide (rGO) hybrid was successfully developed as a heterogeneous catalyst for photo-Fenton-like decolorization of various dyes using peroxymonosulfate (PMS) as an oxidant under visible light irradiation. Through an in situ chemical deposition and reduction, ZnFe2O4 nanoparticles (NPs) with an average size of 23.7 nm were anchored uniformly on rGO sheets to form a ZnFe2O4-rGO hybrid. The catalytic activities in oxidative decomposition of organic dyes were evaluated. The reaction kinetics, effect of ion species and strength, catalytic stability, degradation mechanism, as well as the roles of ZnFe2O4 and graphene were also studied. ZnFe2O4-rGO showed to be a promising photocatalyst with magnetism for the oxidative degradation of aqueous organic pollutants and simple separation. The combination of ZnFe2O4 NPs with graphene sheets leads to a much higher catalytic activity than pure ZnFe2O4. Graphene acted as not only a support and stabilizer for ZnFe2O4 to prevent them from aggregation, largely improving the charge separation in the hybrid material, but also a catalyst for activating PMS to produce sulfate radicals at the same time. The ZnFe2O4-rGO hybrid exhibited stable performance without losing activity after five successive runs.

Fenton-like oxidation of 4-chlorophenol using H2O2 in situ generated by Zn-Fe-CNTs composite.

PubMed

Liu, Yong; Fan, Qing; Liu, Yanlan; Wang, Jianlong

2018-05-15

In this paper, a zinc-iron-carbon nanotubes (Zn-Fe-CNTs) composite was prepared, characterized and used to develop a Fenton-like system of Zn-Fe-CNTs/O 2 for the degradation of 4-chlorophenol (4-CP), in which H 2 O 2 was generated in situ from zinc-carbon galvanic cells and oxygen in aqueous solution was activated by iron attached on the surface of CNTs to produce ·OH radicals for the oxidation of 4-CP. The experimental results showed that the particles of Zn and Fe in Zn-Fe-CNTs composite were adhered to the surface of CNTs, which accelerated the electron transfer process. The BET area of Zn-Fe-CNTs composite was 32.9 m 2 /g. The contents of Zn and Fe (% w) in the composite were 44.7% and 4.2%, respectively. The removal efficiency of 4-CP and TOC in Zn-Fe-CNTs/O 2 system was 90.8% and 52.9%, respectively, with the initial pH of 2.0, O 2 flow rate of 800 mL/min, Zn-Fe-CNTs dosage of 1.0 g/L, 4-CP concentration of 50 mg/L and reaction time of 20 min. Based on the analysis of the degradation intermediate products with LC-MS and IC, a possible degradation pathway of 4-CP in Zn-Fe-CNTs/O 2 system was proposed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Structural classification of RAO3( MO) n compounds ( R =Sc, In, Y, or lanthanides; A =Fe(III), Ga, Cr, or Al; M =divalent cation; n = 1-11)

NASA Astrophysics Data System (ADS)

Kimizuka, Noboru; Mohri, Takahiko

1989-01-01

A series of new compounds RAO3( MO) n ( n = 1-11) having spinel, YbFe 2O 4, or InFeO 3(ZnO) n types of structures were newly synthesized ( R =Sc, In, Y, Lu, Yb, Tm, or Er; A =Fe(III), Ga, Cr, or Al; M =Mg, Mn, Fe(II), Co, Ni, Zn, or Cd) at elevated temperatures. The conditions of synthesis and the lattice constants for these compounds are reported. The stacking sequences of the InO 1.5, (FeZn)O 2.5, and ZnO layers for InFeO 3(ZnO) 10 and the TmO 1.5, (AlZn)O 2.5, and ZnO layers for TmAlO 3(ZnO) 11 are presented, respectively. The crystal structures of the( RAO3) m( MO) n phases ( R =Sc, In, Y, or lanthanide elements; A =Fe(III), Ga, Cr, or Al; M =divalent cation elements; m and n =integer) are classified into four crystal structure types (K 2NiF 4, CaFe 2O 4, YbFe 2O 4, and spinel), based upon the constituent cations R, A, and M

Improving the selective cancer killing ability of ZnO nanoparticles using Fe doping.

PubMed

Thurber, Aaron; Wingett, Denise G; Rasmussen, John W; Layne, Janet; Johnson, Lydia; Tenne, Dmitri A; Zhang, Jianhui; Hanna, Charles B; Punnoose, Alex

2012-06-01

This work reports a new method to improve our recent demonstration of zinc oxide (ZnO) nanoparticles (NPs) selectively killing certain human cancer cells, achieved by incorporating Fe ions into the NPs. Thoroughly characterized cationic ZnO NPs (∼6 nm) doped with Fe ions (Zn(1-x )Fe (x) O, x = 0-0.15) were used in this work, applied at a concentration of 24 μg/ml. Cytotoxicity studies using flow cytometry on Jurkat leukemic cancer cells show cell viability drops from about 43% for undoped ZnO NPs to 15% for ZnO NPs doped with 7.5% Fe. However, the trend reverses and cell viability increases with higher Fe concentrations. The non-immortalized human T cells are markedly more resistant to Fe-doped ZnO NPs than cancerous T cells, confirming that Fe-doped samples still maintain selective toxicity to cancer cells. Pure iron oxide samples displayed no appreciable toxicity. Reactive oxygen species generated with NP introduction to cells increased with increasing Fe up to 7.5% and decreased for >7.5% doping.

Zn-Fe-CNTs catalytic in situ generation of H2O2 for Fenton-like degradation of sulfamethoxazole.

PubMed

Liu, Yong; Fan, Qin; Wang, Jianlong

2018-01-15

A novel Fenton-like catalyst (Zn-Fe-CNTs) capable of converting O 2 to H 2 O 2 and further to OH was prepared through infiltration fusion method followed by chemical replacement in argon atmosphere. The catalyst was characterized by SEM, EDS, TEM, XRD and XPS. The reaction between Zn-Fe-CNTs and O 2 in aqueous solution could generate H 2 O 2 in situ, which was further transferred to OH. The Fenton-like degradation of sulfamethoxazole (SMX) using Zn-Fe-CNTs as catalyst was evaluated. The results indicated that Zn-Fe-CNTs had a coral porous structure with a BET area of 51.67m 2 /g, exhibiting excellent adsorption capacity for SMX, which enhanced its degradation. The particles of Zn 0 and Fe 0 /Fe 2 O 3 were observed on the surface of Zn-Fe-CNTs. The mixture of Zn 0 and CNTs could reduce O 2 into H 2 O 2 by micro-electrolysis and Fe 0 /Fe 2 O 3 could catalyze in-situ generation of H 2 O 2 to produce OH through Fenton-like process. When initial pH=1.5, T=25°C, O 2 flow rate=400mL/min, Zn-Fe-CNTs=0.6g/L, SMX=25mg/L and reaction time=10min, the removal efficiency of SMX and TOC was 100% and 51.3%, respectively. The intermediates were detected and the possible pathway of SMX degradation and the mechanism of Zn-Fe-CNTs/O 2 process were tentatively proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

Third generation biosensing matrix based on Fe-implanted ZnO thin film

NASA Astrophysics Data System (ADS)

Saha, Shibu; Gupta, Vinay; Sreenivas, K.; Tan, H. H.; Jagadish, C.

2010-09-01

Third generation biosensor based on Fe-implanted ZnO (Fe-ZnO) thin film has been demonstrated. Implantation of Fe in rf-sputtered ZnO thin film introduces redox center along with shallow donor level and thereby enhance its electron transfer property. Glucose oxidase (GOx), chosen as model enzyme, has been immobilized on the surface of the matrix. Cyclic voltammetry and photometric assay show that the prepared bioelectrode, GOx/Fe-ZnO/ITO/Glass is sensitive to the glucose concentration with enhanced response of 0.326 μA mM-1 cm-2 and low Km of 2.76 mM. The results show promising application of Fe-implanted ZnO thin film as an attractive matrix for third generation biosensing.

Effect of NaFeEDTA-fortified soy sauce on zinc absorption in children.

PubMed

Li, Min; Wu, Jinghuan; Ren, Tongxiang; Wang, Rui; Li, Weidong; Piao, Jianhua; Wang, Jun; Yang, Xiaoguang

2015-03-01

NaFeEDTA has been applied in many foods as an iron fortificant and is used to prevent iron deficiency in Fe-depleted populations. In China, soy sauce is fortified with NaFeEDTA to control iron deficiency. However, it is unclear whether Fe-fortified soy sauce affects zinc absorption. To investigate whether NaFeEDTA-fortified soy sauce affects zinc absorption in children, sixty children were enrolled in this study and randomly assigned to three groups (10 male children and 10 female children in each group). All children received daily 3 mg of (67)Zn and 1.2 mg of dysprosium orally, while the children in the three groups were supplemented with NaFeEDTA-fortified soy sauce (6 mg Fe, NaFeEDTA group), FeSO₄-fortified soy sauce (6 mg Fe, FeSO₄ group), and no iron-fortified soy sauce (control group), respectively. Fecal samples were collected during the experimental period and analyzed for the Zn content, (67)Zn isotope ratio and dysprosium content. The Fe intake from NaFeEDTA-fortified and FeSO₄-fortified groups was significantly higher than that in the control group (P < 0.0001). The daily total Zn intake was not significantly different among the three groups. There were no significant differences in fractional Zn absorption (FZA) (P = 0.3895), dysprosium recovery (P = 0.7498) and Zn absorption (P = 0.5940) among the three groups. Therefore, NaFeEDTA-fortified soy sauce does not affect Zn bioavailability in children.

High-Performance Epoxy-Resin-Bonded Magnets Produced from the Sm2Fe17Nx Powders Coated by Copper and Zinc Metals

NASA Astrophysics Data System (ADS)

Noguchi, Kenji; Machida, Ken-ichi; Adachi, Gin-ya

2001-04-01

Fine powders of Sm2Fe17Nx coated with copper metal reduced from CuCl2 and/or zinc metal subsequently derived by photo-decomposition of diethylzinc [Zn(C2H5)2] were prepared, and their magnetic properties were characterized in addition to those of epoxy-resin-bonded magnets produced from the coated powders (Cu/Sm2Fe17Nx, Zn/Sm2Fe17Nx and Zn/Cu/Sm2Fe17Nx). The remanence (Br) and maximum energy product [(\\mathit{BH})max] of double metal-coated Zn/Cu/Sm2Fe17Nx powders were maintained at higher levels than those of single Zn metal-coated Sm2Fe17Nx ones (Zn/Sm2Fe17Nx) even after heat treatment at 673 K since the oxidation resistance and thermal stability were effectively improved by formation of the thick and uniform protection layer on the surface of Sm2Fe17Nx particles. Moreover, the epoxy-resin-bonded magnets produced from the Zn/Cu/Sm2Fe17Nx powders possessed good corrosion resistance in air at 393 K which it resulted in the smaller thermal irreversible flux loss than that of uncoated and single Zn metal-coated Sm2Fe17Nx powders in the temperature range of above 393 K.

UV Light-Driven Photodegradation of Methylene Blue by Using Mn0.5Zn0.5Fe2O4/SiO2 Nanocomposites

NASA Astrophysics Data System (ADS)

Indrayana, I. P. T.; Julian, T.; Suharyadi, E.

2018-04-01

The photodegradation activity of nanocomposites for 20 ppm methylene blue solution has been investigated in this work. Nanocomposites Mn0.5Zn0.5Fe2O4/SiO2 have been synthesized using coprecipitation method. The X-ray diffraction (XRD) pattern confirmed the formation of three phases in sample Mn0.5Zn0.5Fe2O4/SiO2 i.e., Mn0.5Zn0.5Fe2O4, Zn(OH)2, and SiO2. The appearance of SiO2 phase showed that the encapsulation process has been carried out. The calculated particles size of Mn0.5Zn0.5Fe2O4/SiO2 is greater than Mn0.5Zn0.5Fe2O4. Bonding analysis via vibrational spectra for Mn0.5Zn0.5Fe2O4/SiO2 confirmed the formation of bonds Me-O-Si stretching (2854.65 cm-1) and Si-O-Si asymmetric stretching (1026.13 cm-1). The optical gap energy of Mn0.5Zn0.5Fe2O4/SiO2 was smaller (2.70 eV) than Mn0.5Zn0.5Fe2O4 (3.04 eV) due to smaller lattice dislocation and microstrain that affect their electronic structure. The Mn0.5Zn0.5Fe2O4/SiO2 showed high photodegradation ability due to smaller optical gap energy and the appearance of SiO2 ligand that can easily attract dye molecules. The Mn0.5Zn0.5Fe2O4/SiO2 also showed high degradation activity even without UV light radiation. The result showed that photodegradation reaction doesn’t follow pseudo-first order kinetics.

Understanding the role of iron in the magnetism of Fe doped ZnO nanoparticles.

PubMed

Beltrán, J J; Barrero, C A; Punnoose, A

2015-06-21

The actual role of transition metals like iron in the room temperature ferromagnetism (RTFM) of Fe doped ZnO nanoparticles is still an unsolved problem. While some studies concluded that the Fe ions participate in the magnetic interaction, others in contrast do not believe Fe to play a direct role in the magnetic exchange interaction. To contribute to the understanding of this issue, we have carefully investigated the structural, optical, vibrational and magnetic properties of sol-gel synthesized Zn1-xFexO (0 < x < 0.10) nanoparticles. No Fe(2+) was detected in any sample. We found that high spin Fe(3+) ions are substitutionally incorporated at the Zn(2+) in the tetrahedral-core sites and in pseudo-octahedral surface sites in ZnO. Superficial OH(-) was observed in all samples. For x ≤ 0.03, an increment in Fe doping concentration decreased a and c lattice parameters, average Zn-O bond length, average crystallite size and band gap; while it increased the degree of distortion and quadrupole splitting. Undoped ZnO nanoparticles exhibited very weak RTFM with a saturation magnetization (Ms) of ∼0.47 memu g(-1) and this value increased to ∼2.1 memu g(-1) for Zn0.99Fe0.01O. Very interestingly, the Ms for Zn0.99Fe0.01O and Zn0.97Fe0.03O increased by a factor of about ∼2.3 by increasing annealing for 1 h to 3 h. For x ≥ 0.05, ferrimagnetic disordered spinel ZnFe2O4 was formed and this phase was found to become more ordered with increasing annealing time. Fe does not contribute directly to the RTFM, but its presence promoted the formation of additional single charged oxygen vacancies, zinc vacancies, and more oxygen-ended polar terminations at the nanoparticle surface. These defects, which are mainly superficial, altered the electronic structure and are considered as the main sources of the observed ferromagnetism.

Dopant concentration dependent growth of Fe:ZnO nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sahai, Anshuman; Goswami, Navendu, E-mail: navendugoswami@gmail.com

2016-05-23

Systematic investigations of structural properties of 1-10% Fe doped ZnO nanostructure (Fe:ZnO NS) prepared via chemical precipitation method have been reported. Structural properties were probed thoroughly employing scanning electron microscope (SEM) and transmission electron microscope (TEM), energy dispersive X-ray (EDAX) analysis and X-ray diffraction (XRD). Morphological transformation of nanostructures (NS) with Fe incorporation is evident in SEM/TEM images. Nanoparticles (NP) obtained with 1% Fe, evolve to nanorods (NR) for 3% Fe; NR transform to nanocones (NC) (for 5% and 7% Fe) and finally NC transform to nanoflakes (NF) at 10% Fe. Morover, primary phase of Zn{sub 1-x}Fe{sub x}O along withmore » secondary phases of ZnFe{sub 2}O{sub 4} and Fe{sub 2}O{sub 3} were also revealed through XRD measurements. Based on collective XRD, SEM, TEM, and EDAX interpretations, a model for morphological evolution of NS was proposed and the pivotal role of Fe dopant was deciphered.« less

Anemia induced by high zinc intake in chicks: Mechanisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pimentel, J.L.; Greger, J.L.; Cook, M.E.

1991-03-15

The mechanisms by which excess Zn induced anemia in chickens was assessed in 8 studies in which chicks were randomly assigned to a 2 {times} 2 factorial arrangement of treatments with 60 or 2,000 {mu}g Zn and 10 or 250 {mu}g Cu/g diet. Less Fe-59 appeared in the plasma 1 hour after a labeled meal when chicks were fed excess Zn in 1 of 2 studies but less Fe-59 appeared in livers of chicks fed excess Zn in both studies. The decrease of Fe-59 uptake into tissues paralleled a decrease in Fe concentrations in livers and tibiotarsi. These differences inmore » tissue Fe did not reflect differences in Fe excretion because excretion and incorporation into tissues of injected Fe-59 was not affected by high Zn intake. Although excess Zn decreased tissue Cu concentrations, excess Zn, per se, did not affect cytosolic superoxide dismutase activity, the in vivo t 1/2 of erythrocytes, or erythrocyte hemolysis in vitro. The decrease in body weight of chicks fed excess Zn indicated that protein synthesis and/or degradation could be affected. Increased incorporation of C-14 tyrosine into liver and bone marrow of chicks fed excess Zn suggested increased protoporphyrin synthesis or metallothionein synthesis. These results indicated that decreased Fe absorption was the primary mechanism by which excess Zn induced anemia.« less

Fe{sub 3}O{sub 4}/CuO/ZnO/Nano graphene platelets (Fe{sub 3}O{sub 4}/CuO/ZnO/NGP) composites prepared by sol-gel method with enhanced sonocatalytic activity for the removal of dye

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hendry, Tju; Taufik, Ardiansyah; Saleh, Rosari, E-mail: rosari.saleh@gmail.com, E-mail: rosari.saleh@ui.ac.id

2016-04-19

In this study, an attempt has been made to synthesize nanographene platelets coupled with Fe3O4/CuO/ZnO (Fe3O4/CuO/ZnO/NGP) with various ZnO loadings using a two step methods, sol-gel followed by hydrothermal method. Characterization was carried out by X-ray diffraction, energy-dispersive X-ray spectroscopy and vibrating sample magnetometer. The sonocatalytic performance was evaluated by degradation of methylene blue under ultrasonic irradiation.The Fe3O4/CuO/ZnO/NGP showed superior sonocatalytic activity than the Fe3O4/CuO/ZnO materials. They also showed high stability and can be easily separated from the reaction system for recycling process.

Different copolymer films on ZnFeCo particles: Synthesis and anticorrosion properties

NASA Astrophysics Data System (ADS)

Ozyilmaz, A. Tuncay; Avsar, Busra; Ozyilmaz, Gul; Karahan, İ. Hakkı; Camurcu, Taskin; Colak, Fatma

2014-11-01

Zinc-iron-cobalt (ZnFeCo) particles were electrochemically deposited on carbon steel (CS) electrode applying current of 3 mA with chronopotentiometry technique. ZnFeCo particles had homogenous, smooth with prismatic structure. It was shown that the ZnFeCo particles exhibited important barrier effect on CS substrate. Poly(aniline-co-o-anisidine), poly(aniline-co-pyrrole), poly(aniline-co-N-methylpyrrole) and poly(o-anisidine-co-pyrrole) copolymer films were obtained on CS/ZnFeCo electrode. Evaluation of anticorrosion performance of copolymer coatings in 3.5% NaCl solution was investigated by using AC impedance spectroscopy (EIS) technique, anodic polarization and the Eocp-time curves. Copolymer films exhibited significant physical barrier behavior on ZnFeCo plated carbon steel, in longer exposure time.

Iron, copper, and zinc status: response to supplementation with zinc or zinc and iron in adult females.

PubMed

Yadrick, M K; Kenney, M A; Winterfeldt, E A

1989-01-01

Response of iron, copper, and zinc status to supplementation with Zn or a combination of Zn and Fe was assessed in adult females in a 10-wk study. Group Z received 50 mg Zn/d as Zn gluconate; group F-Z received 50 mg Fe as ferrous sulfate monohydrate in addition to the Zn. For Group Z, serum ferritin, hematocrit, and erythrocyte Cu,Zn-superoxide dismutase (ESOD) were significantly lower (p less than 0.05) after 10 wk supplementation compared with pretreatment levels. Serum Zn increased (p less than 0.01) but no change occurred in serum ceruloplasmin, hemoglobin, or salivary sediment Zn with treatment. For Group F-Z ESOD decreased with treatment as did salivary sediment Zn (p less than 0.05). Serum ferritin and serum Zn increased significantly, but hemoglobin, hematocrit, and ceruloplasmin were not affected by this treatment. Supplementation with Zn poses a risk to Fe and Cu status. Inclusion of Fe with Zn ameliorates the effect on Fe but not on Cu status.

Ferrate(VI) oxidation of zinc-cyanide complex.

PubMed

Yngard, Ria; Damrongsiri, Seelawut; Osathaphan, Khemarath; Sharma, Virender K

2007-10-01

Zinc-cyanide complexes are found in gold mining effluents and in metal finishing rinse water. The effect of Zn(II) on the oxidation of cyanide by ferrate(VI) (Fe(VI)O(4)(2-), Fe(VI)) was thus investigated by studying the kinetics of the reaction of Fe(VI) with cyanide present in a potassium salt of a zinc cyanide complex (K(2)Zn(CN)(4)) and in a mixture of Zn(II) and cyanide solutions as a function of pH (9.0-11.0). The rate-law for the oxidation of Zn(CN)(4)(2-) by Fe(VI) was found to be -d[Fe(VI)]/dt=k[Fe(VI)][Zn(CN)(4)(2-)](0.5). The rate constant, k, decreased with an increase in pH. The effect of temperature (15-45 degrees C) on the oxidation was studied at pH 9.0, which gave an activation energy of 45.7+/-1.5kJmol(-1). The cyanide oxidation rate decreased in the presence of the Zn(II) ions. However, Zn(II) ions had no effect on the cyanide removal efficiency by Fe(VI) and the stoichiometry of Fe(VI) to cyanide was approximately 1:1; similar to the stoichiometry in absence of Zn(II) ions. The destruction of cyanide by Fe(VI) resulted in cyanate. The experiments on removal of cyanide from rinse water using Fe(VI) demonstrated complete conversion of cyanide to cyanate.

Layered Double Hydroxides: Potential Release-on-Demand Fertilizers for Plant Zinc Nutrition.

PubMed

López-Rayo, Sandra; Imran, Ahmad; Bruun Hansen, Hans Chr; Schjoerring, Jan K; Magid, Jakob

2017-10-11

A novel zinc (Zn) fertilizer concept based on Zn-doped layered double hydroxides (Zn-doped Mg-Fe-LDHs) has been investigated. Zn-doped Mg-Fe-LDHs were synthesized, their chemical composition was analyzed, and their nutrient release was studied in buffered solutions with different pH values. Uptake of Zn by barley (Hordeum vulgare cv. Antonia) was evaluated in short- (8 weeks), medium- (11 weeks), and long-term (28 weeks) experiments in quartz sand and in a calcareous soil enriched with Zn-doped Mg-Fe-LDHs. The Zn release rate of the Zn-doped Mg-Fe-LDHs was described by a first-order kinetics equation showing maximum release at pH 5.2, reaching approximately 45% of the total Zn content. The Zn concentrations in the plants receiving the LDHs were between 2- and 9.5-fold higher than those in plants without Zn addition. A positive effect of the LDHs was also found in soil. This work documents the long-term Zn release capacity of LDHs complying with a release-on-demand behavior and serves as proof-of-concept that Zn-doped Mg-Fe-LDHs can be used as Zn fertilizers.

Preparation of a nanosized as(2)o(3)/mn(0.5)zn(0.5)fe(2)o(4) complex and its anti-tumor effect on hepatocellular carcinoma cells.

PubMed

Zhang, Jia; Zhang, Dongsheng

2009-01-01

Manganese-zinc-ferrite nanoparticles (Mn(0.5)Zn(0.5)Fe(2)O(4), MZF-NPs) prepared by an improved co-precipitation method and were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). Then thermodynamic testing of various doses of MZF-NPs was performed in vitro. The cytotoxicity of the Mn(0.5)Zn(0.5)Fe(2)O(4) nanoparticles in vitro was tested by the MTT assay. A nanosized As(2)O(3)/Mn(0.5)Zn(0.5)Fe(2)O(4) complex was made by an impregnation process. The complex's shape, component, envelop rate and release rate of As(2)O(3) were measured by SEM, EDS and atom fluorescence spectrometry, respectively. The therapeutic effect of nanosized As(2)O(3)/Mn(0.5)Zn(0.5)Fe(2)O(4) complex combined with magnetic fluid hyperthermia (MFH) on human hepatocelluar cells were evaluated in vitro by an MTT assay and flow cytometry. The results indicated that Mn(0.5)Zn(0.5)Fe(2)O(4) and nanosized As(2)O(3)/Mn(0.5)Zn(0.5)Fe(2)O(4) complex were both prepared successfully. The Mn(0.5)Zn(0.5)Fe(2)O(4) nanoparticles had powerful absorption capabilities in a high-frequency alternating electromagnetic field, and had strong magnetic responsiveness. Moreover, Mn(0.5)Zn(0.5)Fe(2)O(4) didn't show cytotoxicity in vitro. The therapeutic result reveals that the nanosized As(2)O(3)/Mn(0.5)Zn(0.5)Fe(2)O(4) complex can significantly inhibit the growth of hepatoma carcinoma cells.

Calculation of phase diagrams for the FeCl2, PbCl2, and ZnCl2 binary systems by using molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Seo, Won-Gap; Matsuura, Hiroyuki; Tsukihashi, Fumitaka

2006-04-01

Recently, molecular dynamics (MD) simulation has been widely employed as a very useful method for the calculation of various physicochemical properties in the molten slags and fluxes. In this study, MD simulation has been applied to calculate the structural, transport, and thermodynamic properties for the FeCl2, PbCl2, and ZnCl2 systems using the Born—Mayer—Huggins type pairwise potential with partial ionic charges. The interatomic potential parameters were determined by fitting the physicochemical properties of iron chloride, lead chloride, and zinc chloride systems with experimentally measured results. The calculated structural, transport, and thermodynamic properties of pure FeCl2, PbCl2, and ZnCl2 showed the same tendency with observed results. Especially, the calculated structural properties of molten ZnCl2 and FeCl2 show the possibility of formation of polymeric network structures based on the ionic complexes of ZnCl{4/2-}, ZnCl{3/-}, FeCl{4/2-}, and FeCl{3/-}, and these calculations have successfully reproduced the measured results. The enthalpy, entropy, and Gibbs energy of mixing for the PbCl2-ZnCl2, FeCl2-PbCl2, and FeCl2-ZnCl2 systems were calculated based on the thermodynamic and structural parameters of each binary system obtained from MD simulation. The phase diagrams of the PbCl2-ZnCl2, FeCl2-PbCl2, and FeCl2-ZnCl2 systems estimated by using the calculated Gibbs energy of mixing reproduced the experimentally measured ones reasonably well.

Crop acquisition of phosphorus, iron and zinc from soil in cereal/legume intercropping systems: a critical review

PubMed Central

Xue, Yanfang; Xia, Haiyong; Christie, Peter; Zhang, Zheng; Li, Long; Tang, Caixian

2016-01-01

Background Phosphorus (P), iron (Fe) and zinc (Zn) are essential elements for plant growth and development, but their availability in soil is often limited. Intercropping contributes to increased P, Fe and Zn uptake and thereby increases yield and improves grain nutritional quality and ultimately human health. A better understanding of how intercropping leads to increased plant P, Fe and Zn availability will help to improve P-fertilizer-use efficiency and agronomic Fe and Zn biofortification. Scope This review synthesizes the literature on how intercropping of legumes with cereals increases acquisition of P, Fe and Zn from soil and recapitulates what is known about root-to-shoot nutrient translocation, plant-internal nutrient remobilization and allocation to grains. Conclusions Direct interspecific facilitation in intercropping involves below-ground processes in which cereals increase Fe and Zn bioavailability while companion legumes benefit. This has been demonstrated and verified using isotopic nutrient tracing and molecular analysis. The same methodological approaches and field studies should be used to explore direct interspecific P facilitation. Both niche complementarity and interspecific facilitation contribute to increased P acquisition in intercropping. Niche complementarity may also contribute to increased Fe and Zn acquisition, an aspect poorly understood. Interspecific mobilization and uptake facilitation of sparingly soluble P, Fe and Zn from soil, however, are not the only determinants of the concentrations of P, Fe and Zn in grains. Grain yield and nutrient translocation from roots to shoots further influence the concentrations of these nutrients in grains. PMID:26749590

Disinfection of Multidrug Resistant Escherichia coli by Solar-Photocatalysis using Fe-doped ZnO Nanoparticles.

PubMed

Das, Sourav; Sinha, Sayantan; Das, Bhaskar; Jayabalan, R; Suar, Mrutyunjay; Mishra, Amrita; Tamhankar, Ashok J; Stålsby Lundborg, Cecilia; Tripathy, Suraj K

2017-03-07

Spread of antibiotic resistant bacteria through water, is a threat to global public health. Here, we report Fe-doped ZnO nanoparticles (Fe/ZnO NPs) based solar-photocatalytic disinfection (PCD) of multidrug resistant Escherichia coli (MDR E. coli). Fe/ZnO NPs were synthesized by chemical precipitation technique, and when used as photocatalyst for disinfection, proved to be more effective (time for complete disinfection = 90 min) than ZnO (150 min) and TiO 2 (180 min). Lipid peroxidation and potassium (K + ) ion leakage studies indicated compromisation of bacterial cell membrane and electron microscopy and live-dead staining confirmed the detrimental effects on membrane integrity. Investigations indicated that H 2 O 2 was the key species involved in solar-PCD of MDR E. coli by Fe/ZnO NPs. X-ray diffraction and atomic absorption spectroscopy studies showed that the Fe/ZnO NPs system remained stable during the photocatalytic process. The Fe/ZnO NPs based solar-PCD process proved successful in the disinfection of MDR E. coli in real water samples collected from river, pond and municipal tap. The Fe/ZnO NPs catalyst made from low cost materials and with high efficacy under solar light may have potential for real world applications, to help reduce the spread of resistant bacteria.

ZIF-8 derived hexagonal-like α-Fe2O3/ZnO/Au nanoplates with tunable surface heterostructures for superior ethanol gas-sensing performance

NASA Astrophysics Data System (ADS)

Chen, Ying; Li, Hui; Ma, Qian; Che, Quande; Wang, Junpeng; Wang, Gang; Yang, Ping

2018-05-01

A series of hexagonal-like α-Fe2O3/ZnO/Au nanoplate heterostructures with tunable morphologies and superior ethanol gas-sensing performance were successfully synthesized via the facile multi-step reaction processes. Hexagonal-like α-Fe2O3 nanoplates with uniform size around 150 nm are employed as new sensor substrates for loading the well-distributed ZnO and Au nanoparticles with adjustable size distribution on the different surfaces. Brunauer-EmmeQ-Teller (BET) surface areas of α-Fe2O3 and α-Fe2O3/ZnO samples are evaluated to be 37.94 and 61.27 m2/g, respectively, while α-Fe2O3/ZnO/Au composites present the highest value of 79.08 m2/g. These α-Fe2O3-based functional materials can exhibit outstanding sensing properties to ethanol. When the ethanol concentration is 100 ppm, the response value of α-Fe2O3/ZnO/Au composites can reach up to 170, which is 14.6 and 80.3 times higher than that of α-Fe2O3/ZnO and pure α-Fe2O3, respectively. The recycling stability and long-time effectiveness can be availably maintained within 30 days, as well as the response and recovery times are shortened to 4 and 5 s, respectively. Significantly, the response value of α-Fe2O3/ZnO/Au composite is still up to 63 at an operating temperature of 280 °C even though the ethanol concentration decreases to 10 ppm. The enhanced gas sensing mechanism would be focused on the synergistic effects of phase compositions, surface heterogeneous structures, large specific surface area, and the selective depositions of Au nanoparticles in α-Fe2O3/ZnO/Au sensors. The synergistic effect of different surface heterostructures referring to α-Fe2O3/Au and α-Fe2O3/ZnO/Au and their novel electron transport processes on the surfaces are first investigated and discussed in details. It is expected that hexagonal-like α-Fe2O3/ZnO/Au nanoplate heterostructures with excellent sensing performance can be the promising highly-sensitive materials in the actual application for monitoring and detecting ethanol.

Effect of surfactant amount on the morphology and magnetic properties of monodisperse ZnFe{sub 2}O{sub 4} nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Haitao, E-mail: zht95711lunwen@163.com; Liu, Ruiping; Zhang, Qiang

2016-03-15

Graphical abstract: Polyol process to monodisperse ZnFe{sub 2}O{sub 4} nanoparticles. - Highlights: • An one-step, facile and inexpensive synthetic route to monodisperse ZnFe{sub 2}O{sub 4} nanoparticles is described. • The sodium citrate stabilized ZnFe{sub 2}O{sub 4} nanoparticles with a diameter in the 5–8 nm size range can be easily dispersed in water. • The synthesis is very robust in terms of variations of experimental parameters. • ZnFe{sub 2}O{sub 4} nanoparticles present ferrimagnetic behavior at room temperature with a small hysteresis. - Abstract: The spinel ZnFe{sub 2}O{sub 4} ferrites with sodium citrate as a surfactant were fabricated by polyol process. Themore » effect of surfactant amount on the structure, morphology and magnetic properties of ZnFe{sub 2}O{sub 4} ferrites were investigated by X-ray diffraction(XRD), transmission electron microscope (TEM), thermogravimetric and differential scanning calorimetry (TG–DSC) and vibrating sample magnetometry (VSM), respectively. The results indicate that the structure of ZnFe{sub 2}O{sub 4} ferrites is a pure cubic spinel structure with a particle size of 5–8 nm. The dispersion of the synthesized ZnFe{sub 2}O{sub 4} is enhanced when the mole ratio of Fe(acac){sub 3} to sodium citrate decreases. The synthesized particles present ferrimagnetic behavior with a small hysteresis at room temperature. The increase of surfactant amount conversely leads to the decrease in the saturation magnetization value (Ms) especially when the mole ratio of Fe(acac){sub 3} to sodium citrate decreases to 8:3. Its Ms value is drastically reduced to 18.97 emu/g.« less

In-situ synthesized ZnFe2O4 firmly anchored to the surface of MWCNTs as a long-life anode material with high lithium storage performance

NASA Astrophysics Data System (ADS)

Yang, Tianbo; Zhang, Wanxi; Li, Linlin; Jin, Bo; Jin, Enmei; Jeong, Sangmoon; Jiang, Qing

2017-12-01

Because of two different metal cations in the crystal structures, binary transition metal oxides possess a lot of unique properties. ZnFe2O4 emerges from these transition metal oxides on account of its high theoretical capacity (1072 mAh g-1). One-dimensional multi-walled carbon nanotubes (MWCNTs) would be a desirable conductive additive for ZnFe2O4, thereby improving the electrochemical performance of ZnFe2O4. In this work, we prepare ZnFe2O4/MWCNTs by solvothermal method with further heat-treatment. ZnFe2O4 nanoparticles are firmly anchored to the surface of MWCNTs. ZnFe2O4/MWCNTs nanocomposite displays high specific capacity (1278 mAh g-1 at a current density of 200 mA g-1 after 200 cycles, and 565 mAh g-1 at a current density of 1500 mA g-1 after 500 cycles), and good rate performance (367 mAh g-1 even at a current density of 6000 mAh g-1 after 80 cycles). The superior electrochemical performance may promote ZnFe2O4 to be a promising alternative anode in lithium-ion batteries.

Surface complexation and precipitate geometry for aqueous Zn(II) sorption on ferrihydrite I: X-ray absorption extended fine structure spectroscopy analysis

USGS Publications Warehouse

Waychunas, G.A.; Fuller, C.C.; Davis, J.A.

2002-01-01

"Two-line" ferrihydrite samples precipitated and then exposed to a range of aqueous Zn solutions (10-5 to 10-3 M), and also coprecipitated in similar Zn solutions (pH 6.5), have been examined by Zn and Fe K-edge X-ray absorption spectroscopy. Typical Zn complexes on the surface have Zn-O distances of 1.97(0.2) A?? and coordination numbers of about 4.0(0.5), consistent with tetrahedral oxygen coordination. This contrasts with Zn-O distances of 2.11(.02) A?? and coordination numbers of 6 to 7 in the aqueous Zn solutions used in sample preparation. X-ray absorption extended fine structure spectroscopy (EXAFS) fits to the second shell of cation neighbors indicate as many as 4 Zn-Fe neighbors at 3.44(.04) A?? in coprecipitated samples, and about two Zn-Fe neighbors at the same distance in adsorption samples. In both sets of samples, the fitted coordination number of second shell cations decreases as sorption density increases, indicating changes in the number and type of available complexing sites or the onset of competitive precipitation processes. Comparison of our results with the possible geometries for surface complexes and precipitates suggests that the Zn sorption complexes are inner sphere and at lowest adsorption densities are bidentate, sharing apical oxygens with adjacent edge-sharing Fe(O,OH)6 octahedra. Coprecipitation samples have complexes with similar geometry, but these are polydentate, sharing apices with more than two adjacent edge-sharing Fe(O,OH)6 polyhedra. The results are inconsistent with Zn entering the ferrihydrite structure (i.e., solid solution formation) or formation of other Zn-Fe precipitates. The fitted Zn-Fe coordination numbers drop with increasing Zn density with a minimum of about 0.8(.2) at Zn/(Zn + Fe) of 0.08 or more. This change appears to be attributable to the onset of precipitation of zinc hydroxide polymers with mainly tetrahedral Zn coordination. At the highest loadings studied, the nature of the complexes changes further, and a second type of precipitate forms. This has a structure based on a brucite layer topology, with mainly octahedral Zn coordination. Amorphous zinc hydroxide samples prepared for comparison had a closely similar local structure. Analysis of the Fe K-edge EXAFS is consistent with surface complexation reactions and surface precipitation at high Zn loadings with little or no Fe-Zn solid solution formation. The formation of Zn-containing precipitates at solution conditions two or more orders of magnitude below their solubility limit is compared with other sorption and spectroscopic studies that describe similar behavior. Copyright ?? 2002 Elsevier Science Ltd.

Zinc abundances in Galactic bulge field red giants: Implications for damped Lyman-α systems

NASA Astrophysics Data System (ADS)

Barbuy, B.; Friaça, A. C. S.; da Silveira, C. R.; Hill, V.; Zoccali, M.; Minniti, D.; Renzini, A.; Ortolani, S.; Gómez, A.

2015-08-01

Context. Zinc in stars is an important reference element because it is a proxy to Fe in studies of damped Lyman-α systems (DLAs), permitting a comparison of chemical evolution histories of bulge stellar populations and DLAs. In terms of nucleosynthesis, it behaves as an alpha element because it is enhanced in metal-poor stars. Abundance studies in different stellar populations can give hints to the Zn production in different sites. Aims: The aim of this work is to derive the iron-peak element Zn abundances in 56 bulge giants from high resolution spectra. These results are compared with data from other bulge samples, as well as from disk and halo stars, and damped Lyman-α systems, in order to better understand the chemical evolution in these environments. Methods: High-resolution spectra were obtained using FLAMES+UVES on the Very Large Telescope. We computed the Zn abundances using the Zn i lines at 4810.53 and 6362.34 Å. We considered the strong depression in the continuum of the Zn i 6362.34 Å line, which is caused by the wings of the Ca i 6361.79 Å line suffering from autoionization. CN lines blending the Zn i 6362.34 Å line are also included in the calculations. Results: We find [Zn/Fe] = +0.24 ± 0.02 in the range -1.3 < [Fe/H] < -0.5 and [Zn/Fe] = + 0.06 ± 0.02 in the range -0.5 < [Fe/H] < -0.1, whereas for [Fe/H] ≥ -0.1, it shows a spread of -0.60 < [Zn/Fe] < + 0.15, with most of these stars having low [Zn/Fe] < 0.0. These low zinc abundances at the high metallicity end of the bulge define a decreasing trend in [Zn/Fe] with increasing metallicities. A comparison with Zn abundances in DLA systems is presented, where a dust-depletion correction was applied for both Zn and Fe. When we take these corrections into account, the [Zn/Fe] vs. [Fe/H] of the DLAs fall in the same region as the thick disk and bulge stars. Finally, we present a chemical evolution model of Zn enrichment in massive spheroids, representing a typical classical bulge evolution. Observations collected both at the European Southern Observatory, Paranal, Chile (ESO programmes 71.B-0617A, 73.B0074A, and GTO 71.B-0196).Table 6 is available in electronic form at http://www.aanda.org

Structural classification of RAO/sub 3/(MO)/sub n/ compounds (R = Sc, In, Y, or lanthanides; A = Fe(III), Ga, Cr, or Al; M = divalent cation; n = 1-11)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimizuka, N.; Mohri, T.

A series of new compounds (RAO/sub 3/MO)/sub n/ (n = 1-11) having spinel, YbFe/sub 2/O/sub 4/, or InFeO/sub 3/(ZnO)/sub n/ types of structures were newly synthesized (R = Sc, In, Y, Lu, Yb, Tm, or Er; A = Fe(III), Ga, Cr, or Al; M = Mg, Mn, Fe(II), Co, Ni, Zn, or Cd) at elevated temperatures. The conditions of synthesis and the lattice constants for these compounds are reported. The stacking sequences of the InO/sub 1.5/, (FeZn)O/sub 2.5/, and ZnO layers for InFeO/sub 3/(ZnO)/sub 10/ and the TmO/sub 1.5/, (AlZn)O/sub 2.5/, and ZnO layers for TmAlO/sub 3/(ZnO)/sub 11/ are presented,more » respectively. The crystal structures of the (RAO/sub 3/)/sub m/(MO)/sub n/ phases R = Sc, In, Y, or lanthanide elements; A = Fe(III), Ga, Cr, or Al; M = divalent cation elements; m and n = integer are classified into four crystal structure types (K/sub 2/NiF/sub 4/, CaFe/sub 2/O/sub 4/, YbFe/sub 2/O/sub 4/, and spinel), based upon the constituent cations R, A, and M.« less

Adsorption of multi-heavy metals Zn and Cu onto surficial sediments: modeling and adsorption capacity analysis.

PubMed

Li, Shanshan; Zhang, Chen; Wang, Meng; Li, Yu

2014-01-01

Improved multiple regression adsorption models (IMRAMs) was developed to estimate the adsorption capacity of the components [Fe oxides (Fe), Mn oxides (Mn), organic materials (OMs), residuals] in surficial sediments for multi-heavy metal Zn and Cu. IMRAM is an improved version over MRAM, which introduces a computer program in the model developing process. As MRAM, Zn(Cu) IMRAM, and Cu(Zn) IMRAM again confirmed that there is significant interaction effects that control the adsorption of compounded Zn and Cu, which was neglected by additional adsorption model. The verification experiment shows that the relative deviation of the IMRAMs is less than 13%. It is revealed by the IMRAMs that Mn, which has the greatest adsorption capability for compounded Zn and Cu (54.889 and 161.180 mg/l, respectively), follows by interference adsorption capacity of Fe/Mn (-1.072 and -24.591 mg/l respectively). Zn and Cu influence each other through different mechanisms. When Zn is the adsorbate, compounded Cu mainly affects the adsorption capacities of Fe/Mn and Fe/Mn/OMs; while when Cu is the adsorbate, compounded Zn mainly exerts its effect on Mn, Fe/Mn, and Mn/OMs. It also shows that the compounded Zn or Cu weakened the interference adsorption of Fe/Mn, and meanwhile, strengthened the interference adsorption of Mn/OMs.

Effect of thermal annealing on the structure and magnetism of Fe-doped ZnO nanocrystals synthesized by solid state reaction

NASA Astrophysics Data System (ADS)

Wang, Dong; Chen, Z. Q.; Wang, D. D.; Gong, J.; Cao, C. Y.; Tang, Z.; Huang, L. R.

2010-11-01

High purity Fe 2O 3/ZnO nanocomposites were annealed in air at different temperatures between 100 and 1200 °C to get Fe-doped ZnO nanocrystals. The structure and grain size of the Fe 2O 3/ZnO nanocomposites were investigated by X-ray diffraction 2θ scans. Annealing induces an increase of the grain size from 25 to 195 nm and appearance of franklinite phase of ZnFe 2O 4. Positron annihilation measurements reveal large number of vacancy defects in the interface region of the Fe 2O 3/ZnO nanocomposites, and they are gradually recovered with increasing annealing temperature. After annealing at temperatures higher than 1000 °C, the number of vacancies decreases to the lower detection limit of positrons. Room temperature ferromagnetism can be observed in Fe-doped ZnO nanocrystals using physical properties measurement system. The ferromagnetism remains after annealing up to 1000 °C, suggesting that it is not related with the interfacial defects.

Development and optimization of iron- and zinc-containing nanostructured powders for nutritional applications.

PubMed

Hilty, F M; Teleki, A; Krumeich, F; Büchel, R; Hurrell, R F; Pratsinis, S E; Zimmermann, M B

2009-11-25

Reducing the size of low-solubility iron (Fe)-containing compounds to nanoscale has the potential to improve their bioavailability. Because Fe and zinc (Zn) deficiencies often coexist in populations, combined Fe/Zn-containing nanostructured compounds may be useful for nutritional applications. Such compounds are developed here and their solubility in dilute acid, a reliable indicator of iron bioavailability in humans, and sensory qualities in sensitive food matrices are investigated. Phosphates and oxides of Fe and atomically mixed Fe/Zn-containing (primarily ZnFe2O4) nanostructured powders were produced by flame spray pyrolysis (FSP). Chemical composition and surface area were systematically controlled by varying precursor concentration and feed rate during powder synthesis to increase solubility to the level of ferrous sulfate at maximum Fe and Zn content. Solubility of the nanostructured compounds was dependent on their particle size and crystallinity. The new nanostructured powders produced minimal color changes when added to dairy products containing chocolate or fruit compared to the changes produced when ferrous sulfate or ferrous fumarate were added to these foods. Flame-made Fe- and Fe/Zn-containing nanostructured powders have solubilities comparable to ferrous and Zn sulfate but may produce fewer color changes when added to difficult-to-fortify foods. Thus, these powders are promising for food fortification and other nutritional applications.

Improvement of in vitro corrosion and cytocompatibility of biodegradable Fe surface modified by Zn ion implantation

NASA Astrophysics Data System (ADS)

Wang, Henan; Zheng, Yang; Li, Yan; Jiang, Chengbao

2017-05-01

Pure Fe was surface-modified by Zn ion implantation to improve the biodegradable behavior and cytocompatibility. Surface topography, chemical composition, corrosion resistance and cytocompatibility were investigated. Atomic force microscopy, auger electron spectroscopy and X-ray photoelectron spectroscopy results showed that Zn was implanted into the surface of pure Fe in the depth of 40-60 nm and Fe2O3/ZnO oxides were formed on the outmost surface. Electrochemical measurements and immersion tests revealed an improved degradable behavior for the Zn-implanted Fe samples. An approximately 12% reduction in the corrosion potential (Ecorr) and a 10-fold increase in the corrosion current density (icorr) were obtained after Zn ion implantation with a moderate incident ion dose, which was attributed to the enhanced pitting corrosion. The surface free energy of pure Fe was decreased by Zn ion implantation. The results of direct cell culture indicated that the short-term (4 h) cytocompatibility of MC3T3-E1 cells was promoted by the implanted Zn on the surface.

Synthesis and characterization of Mn-ZnFe2O4 and Mn-ZnFe2O4/rGO nanocomposites from waste batteries for photocatalytic, electrochemical and thermal studies

NASA Astrophysics Data System (ADS)

Mylarappa, M.; Venkata Lakshmi, V.; Vishnu Mahesh, K. R.; Nagaswarupa, H. P.; Raghavendra, N.

2017-11-01

In the present paper, Mn-ZnFe2O4 and Mn-ZnFe2O4/rGO composites recovered from waste batteries using acid dissolution and ferrite processing were studied. The recovered Mn-ZnFe2O4 nanocomposites were decorated onto rGO using the facile hydrothermal method. The recovered material was characterized using x-ray powder diffraction to study the particle size and crystallinity. The morphology of the composites was analyzed using scanning electron microscopy, and elements present in the materials were studied using energy dispersive x-ray analysis. The functional groups attached were observed using a Fourier transform infrared spectrometer. Furthermore, the recovered composites were evaluated in thermal studies using thermal gravimetric analysis, differential scanning calorimetry and dynamic thermal analysis. The material was used as a photocatalyst for the removal of acid orange 88 dye, and as an electrocatalyst. The decreased band gap energy for the Mn-ZnFe2O4/rGO composite was displayed in better photocatalytic activity for a given reaction. The electrochemical properties of Mn-ZnFe2O4 and Mn-ZnFe2O4/rGO have been investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) with a paste-type electrode. The CV indicated the reversibility of the electrode reaction, and the EIS revealed that a decrease in the charge transfer resistance increases the double layer capacitance of the rGO/Mn-ZnFe2O4 electrode.

Hierarchical heterostructures of p-type bismuth oxychloride nanosheets on n-type zinc ferrite electrospun nanofibers with enhanced visible-light photocatalytic activities and magnetic separation properties.

PubMed

Sun, Yucong; Shao, Changlu; Li, Xinghua; Guo, Xiaohui; Zhou, Xuejiao; Li, Xiaowei; Liu, Yichun

2018-04-15

P-type bismuth oxychloride (p-BiOCl) nanosheets were uniformly grown on n-type zinc ferrite (n-ZnFe 2 O 4 ) electrospun nanofibers via a solvothermal technique to form hierarchical heterostructures of p-BiOCl/n-ZnFe 2 O 4 (p-BiOCl/n-ZnFe 2 O 4 H-Hs). The density and loading amounts of the BiOCl nanosheets with exposed {0 0 1} facets were easily controlled by adjusting the reactant concentration in the solvothermal process. The p-BiOCl/n-ZnFe 2 O 4 H-Hs exhibited enhanced visible-light photocatalytic activities for the degradation of Rhodamine B (RhB). The apparent first-order rate of the p-BiOCl/n-ZnFe 2 O 4 H-Hs and its normalized constant were about 12.6- and 8-fold higher than pure ZnFe 2 O 4 nanofibers. This suggests that both the improved charge separation efficiency from the uniform p-n heterojunctions and the enlarged active surface sites from the hierarchical structures increase the photocatalytic performances. Furthermore, the p-BiOCl/n-ZnFe 2 O 4 H-Hs could be efficiently separated from the solution with an external magnetic field via the ferromagnetic behavior of ZnFe 2 O 4 nanofibers. The magnetic p-BiOCl/n-ZnFe 2 O 4 H-Hs with enhanced visible-light photocatalytic performances might have potential applications in water treatment. Copyright © 2018. Published by Elsevier Inc.

Oxygen vacancy induced by La and Fe into ZnO nanoparticles to modify ferromagnetic ordering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verma, Kuldeep Chand, E-mail: kuldeep0309@yahoo.co.in; Kotnala, R.K., E-mail: rkkotnala@gmail.com

We reported long-range ferromagnetic interactions in La doped Zn{sub 0.95}Fe{sub 0.05}O nanoparticles that mediated through lattice defects or vacancies. Zn{sub 0.92}Fe{sub 0.05}La{sub 0.03}O (ZFLaO53) nanoparticles were synthesized by a sol–gel process. X-ray fluorescence spectrum of ZFLaO53 detects the weight percentage of Zn, Fe, La and O. X-ray diffraction shows the hexagonal Wurtzite ZnO phase. The Rietveld refinement has been used to calculate the lattice parameters and the position of Zn, Fe, La and O atoms in the Wurtzite unit cell. The average size of ZFLaO53 nanoparticles is 99 nm. The agglomeration type product due to OH ions with La resultsmore » into ZnO nanoparticles than nanorods that found in pure ZnO and Zn{sub 0.95}Fe{sub 0.05}O sample. The effect of doping concentration to induce Wurtzite ZnO structure and lattice defects has been analyzed by Raman active vibrational modes. Photoluminescence spectra show an abnormal emission in both UV and visible region, and a blue shift at near band edge is formed with doping. The room temperature magnetic measurement result into weak ferromagnetism but pure ZnO is diamagnetic. However, the temperature dependent magnetic measurement using zero-field and field cooling at dc magnetizing field 500 Oe induces long-range ferromagnetic ordering. It results into antiferromagnetic Neel temperature of ZFLaO53 at around 42 K. The magnetic hysteresis is also measured at 200, 100, 50 and 10 K measurement that indicate enhancement in ferromagnetism at low temperature. Overall, the La doping into Zn{sub 0.95}Fe{sub 0.05}O results into enhanced antiferromagnetic interaction as well as lattice defects/vacancies. The role of the oxygen vacancy as the dominant defects in doped ZnO must form Bound magnetic polarons has been described. - Graphical abstract: The long-range ferromagnetic order in Zn{sub 0.92}Fe{sub 0.05}La{sub 0.03}O nanoparticles at low temperature measurements involves oxygen vacancy as the medium of magnetic interactions. - Highlights: • The La and Fe doping into ZnO nanoparticles induce defects in terms of oxygen vacancy. • The La ions in Fe substituted ZnO formed nanoparticles than nanorods. • Antiferromagnetic interactions are observed at room temperature magnetic measurement. • Rietveld analysis evaluated structural deformation in the Wurtzite ZnO lattice.« less

Monodisperse Zn-doped Fe3O4 formation and photo-Fenton activity for degradation of rhodamine B in water

NASA Astrophysics Data System (ADS)

Cen, Huoshi; Nan, Zhaodong

2018-10-01

Zn-doped Fe3O4 can be used as a catalyst in the photo-Fenton process to degrade dye molecules dissolved in water, in which cluster-shaped Zn-doped Fe3O4 (CSZnFe) was synthesized. To enhance the catalytic activity, monodisperse Zn-doped Fe3O4 (MZnFe) was facilely synthesized by a modified solvothermal method through replacement of sodium acetate by urea as a base. The particle size of MZnFe was about 9-16 nm. MZnFe exhibits a larger surface area and higher photo-Fenton catalytic activity for degradation of rhodamine B in water than CSZnFe. Additionally, MZnFe exhibits high saturation magnetization (about 80 emu/g), which is very convenient for separation of MZnFe from solution by a magnet. The growth processes for MZnFe were proposed on the basis of results from in situ calorimetry and other techniques, which indicated different formation mechanisms for MZnFe and CSZnFe.

Extremely High Phosphate Sorption Capacity in Cu-Pb-Zn Mine Tailings.

PubMed

Huang, Longbin; Li, Xiaofang; Nguyen, Tuan A H

2015-01-01

Elevated inorganic phosphate (Pi) concentrations in pore water of amended tailings under direct revegetation may cause toxicity in some native woody species but not native forbs or herb species, all of which are key constituents in target native plant communities for phytostabilizing base metal mine tailings. As a result, Pi sorption capacity has been quantified by a conventional batch procedure in three types of base metal mine tailings sampled from two copper (Cu)-lead (Pb)-zinc (Zn) mines, as the basis for Pi-fertiliser addition. It was found that the Pi-sorption capacity in the tailings and local soil was extremely high, far higher than highly weathered agricultural soils in literature, but similar to those of volcanic ash soils. The Langmuir P-sorption maximum was up to 7.72, 4.12, 4.02 and 3.62 mg P g-1 tailings, in the fresh tailings of mixed Cu-Pb-Zn streams (MIMTD7), the weathered tailings of mixed Cu-Pb-Zn streams (MIMTD5), EHM-TD (fresh Cu-stream, high magnetite content) and local soil (weathered shale and schist), respectively. Physicochemical factors highly correlated with the high Pi-sorption in the tailings were fine particle distribution, oxalate and dithionite-citrate-bicarbonate extractable Fe (FeO and Fed), oxalate-extractable Al and Mn, and the levels of soluble Cd and Zn, and total S and Fe. Large amounts of amorphous Fe oxides and oxyhydroxides may have been formed from the oxidation of pyritic materials and redox cycles of Fe-minerals (such as pyrite (FeS2), ankerite (Ca(Fe Mg)(CO3)2 and siderite (FeCO3), as indicated by the extractable FeO values. The likely formation of sparingly soluble Zn-phosphate in the Pb-Zn tailings containing high levels of Zn (from sphalerite ((Zn,Fe)S, ZnS, (Zn,Cd)S)) may substantially lower soluble Zn levels in the tailings through high rates of Pi-fertiliser addition. As a result, the possibility of P-toxicity in native plant species caused by the addition of soluble phosphate fertilizers would be minimal.

Extremely High Phosphate Sorption Capacity in Cu-Pb-Zn Mine Tailings

PubMed Central

Huang, Longbin; Li, Xiaofang; Nguyen, Tuan A. H.

2015-01-01

Elevated inorganic phosphate (Pi) concentrations in pore water of amended tailings under direct revegetation may cause toxicity in some native woody species but not native forbs or herb species, all of which are key constituents in target native plant communities for phytostabilizing base metal mine tailings. As a result, Pi sorption capacity has been quantified by a conventional batch procedure in three types of base metal mine tailings sampled from two copper (Cu)-lead (Pb)-zinc (Zn) mines, as the basis for Pi-fertiliser addition. It was found that the Pi-sorption capacity in the tailings and local soil was extremely high, far higher than highly weathered agricultural soils in literature, but similar to those of volcanic ash soils. The Langmuir P-sorption maximum was up to 7.72, 4.12, 4.02 and 3.62 mg P g-1 tailings, in the fresh tailings of mixed Cu-Pb-Zn streams (MIMTD7), the weathered tailings of mixed Cu-Pb-Zn streams (MIMTD5), EHM-TD (fresh Cu-stream, high magnetite content) and local soil (weathered shale and schist), respectively. Physicochemical factors highly correlated with the high Pi-sorption in the tailings were fine particle distribution, oxalate and dithionite-citrate-bicarbonate extractable Fe (FeO and Fed), oxalate-extractable Al and Mn, and the levels of soluble Cd and Zn, and total S and Fe. Large amounts of amorphous Fe oxides and oxyhydroxides may have been formed from the oxidation of pyritic materials and redox cycles of Fe-minerals (such as pyrite (FeS2), ankerite (Ca(Fe Mg)(CO3)2 and siderite (FeCO3), as indicated by the extractable FeO values. The likely formation of sparingly soluble Zn-phosphate in the Pb-Zn tailings containing high levels of Zn (from sphalerite ((Zn,Fe)S, ZnS, (Zn,Cd)S)) may substantially lower soluble Zn levels in the tailings through high rates of Pi-fertiliser addition. As a result, the possibility of P-toxicity in native plant species caused by the addition of soluble phosphate fertilizers would be minimal. PMID:26295582

Zinc-Containing Magnetic Oxides Stabilized by a Polymer: One Phase or Two?

PubMed

Baird, Nicholas; Losovyj, Yaroslav; Yuzik-Klimova, Ekaterina Yu; Kuchkina, Nina V; Shifrina, Zinaida B; Pink, Maren; Stein, Barry D; Morgan, David Gene; Wang, Tianhao; Rubin, Mikhail A; Sidorov, Alexander I; Sulman, Esther M; Bronstein, Lyudmila M

2016-01-13

Here we developed a new family of Zn-containing magnetic oxides of different structures by thermal decomposition of Zn(acac)2 in the reaction solution of preformed magnetite nanoparticles (NPs) stabilized by polyphenylquinoxaline. Upon an increase of the Zn(acac)2 loading from 0.15 to 0.40 mmol (vs 1 mmol of Fe(acac)3), the Zn content increases, and the Zn-containing magnetic oxide NPs preserve a spinel structure of magnetite and an initial, predominantly multicore NP morphology. X-ray photoelectron spectroscopy (XPS) of these samples revealed that the surface of iron oxide NPs is enriched with Zn, although Zn species were also found deep under the iron oxide NP surface. For all the samples, XPS also demonstrates the atom ratio of Fe(3+)/Fe(2+) = 2:1, perfectly matching Fe3O4, but not ZnFe2O4, where Fe(2+) ions are replaced with Zn(2+). The combination of XPS with other physicochemical methods allowed us to propose that ZnO forms an ultrathin amorphous layer on the surface of iron oxide NPs and also diffuses inside the magnetite crystals. At higher Zn(acac)2 loading, cubic ZnO nanocrystals coexist with magnetite NPs, indicating a homogeneous nucleation of the former. The catalytic testing in syngas conversion to methanol demonstrated outstanding catalytic properties of Zn-containing magnetic oxides, whose activities are dependent on the Zn loading. Repeat experiments carried out with the best catalyst after magnetic separation showed remarkable catalyst stability even after five consecutive catalytic runs.

Mathematical model of zinc absorption: effects of dietary calcium, protein and iron on zinc absorption

PubMed Central

Miller, Leland V.; Krebs, Nancy F.; Hambidge, K. Michael

2013-01-01

A previously described mathematical model of Zn absorption as a function of total daily dietary Zn and phytate was fitted to data from studies in which dietary Ca, Fe and protein were also measured. An analysis of regression residuals indicated statistically significant positive relationships between the residuals and Ca, Fe and protein, suggesting that the presence of any of these dietary components enhances Zn absorption. Based on the hypotheses that (1) Ca and Fe both promote Zn absorption by binding with phytate and thereby making it unavailable for binding Zn and (2) protein enhances the availability of Zn for transporter binding, the model was modified to incorporate these effects. The new model of Zn absorption as a function of dietary Zn, phytate, Ca, Fe and protein was then fitted to the data. The proportion of variation in absorbed Zn explained by the new model was 0·88, an increase from 0·82 with the original model. A reduced version of the model without Fe produced an equally good fit to the data and an improved value for the model selection criterion, demonstrating that when dietary Ca and protein are controlled for, there is no evidence that dietary Fe influences Zn absorption. Regression residuals and testing with additional data supported the validity of the new model. It was concluded that dietary Ca and protein modestly enhanced Zn absorption and Fe had no statistically discernable effect. Furthermore, the model provides a meaningful foundation for efforts to model nutrient interactions in mineral absorption. PMID:22617116

Mathematical model of zinc absorption: effects of dietary calcium, protein and iron on zinc absorption.

PubMed

Miller, Leland V; Krebs, Nancy F; Hambidge, K Michael

2013-02-28

A previously described mathematical model of Zn absorption as a function of total daily dietary Zn and phytate was fitted to data from studies in which dietary Ca, Fe and protein were also measured. An analysis of regression residuals indicated statistically significant positive relationships between the residuals and Ca, Fe and protein, suggesting that the presence of any of these dietary components enhances Zn absorption. Based on the hypotheses that (1) Ca and Fe both promote Zn absorption by binding with phytate and thereby making it unavailable for binding Zn and (2) protein enhances the availability of Zn for transporter binding, the model was modified to incorporate these effects. The new model of Zn absorption as a function of dietary Zn, phytate, Ca, Fe and protein was then fitted to the data. The proportion of variation in absorbed Zn explained by the new model was 0·88, an increase from 0·82 with the original model. A reduced version of the model without Fe produced an equally good fit to the data and an improved value for the model selection criterion, demonstrating that when dietary Ca and protein are controlled for, there is no evidence that dietary Fe influences Zn absorption. Regression residuals and testing with additional data supported the validity of the new model. It was concluded that dietary Ca and protein modestly enhanced Zn absorption and Fe had no statistically discernable effect. Furthermore, the model provides a meaningful foundation for efforts to model nutrient interactions in mineral absorption.

Structural and Magnetic Properties of Transition-Metal-Doped Zn 1-x Fe x O.

PubMed

Abdel-Baset, T A; Fang, Yue-Wen; Anis, B; Duan, Chun-Gang; Abdel-Hafiez, Mahmoud

2016-12-01

The ability to produce high-quality single-phase diluted magnetic semiconductors (DMS) is the driving factor to study DMS for spintronics applications. Fe-doped ZnO was synthesized by using a low-temperature co-precipitation technique producing Zn 1-x Fe x O nanoparticles (x= 0, 0.02, 0.04, 0.06, 0.08, and 0.1). Structural, Raman, density functional calculations, and magnetic studies have been carried out in studying the electronic structure and magnetic properties of Fe-doped ZnO. The results show that Fe atoms are substituted by Zn ions successfully. Due to the small ionic radius of Fe ions compared to that of a Zn ions, the crystal size decreases with an increasing dopant concentration. First-principle calculations indicate that the charge state of iron is Fe (2+) and Fe (3+) with a zinc vacancy or an interstitial oxygen anion, respectively. The calculations predict that the exchange interaction between transition metal ions can switch from the antiferromagnetic coupling into its quasi-degenerate ferromagnetic coupling by external perturbations. This is further supported and explains the observed ferromagnetic bahaviour at magnetic measurements. Magnetic measurements reveal that decreasing particle size increases the ferromagnetism volume fraction. Furthermore, introducing Fe into ZnO induces a strong magnetic moment without any distortion in the geometrical symmetry; it also reveals the ferromagnetic coupling.

Theranostic multimodular potential of zinc-doped ferrite-saturated metal-binding protein-loaded novel nanocapsules in cancers

PubMed Central

Kamalapuram, Sishir K; Kanwar, Rupinder K; Roy, Kislay; Chaudhary, Rajneesh; Sehgal, Rakesh; Kanwar, Jagat R

2016-01-01

The present study successfully developed orally deliverable multimodular zinc (Zn) iron oxide (Fe3O4)-saturated bovine lactoferrin (bLf)-loaded polymeric nanocapsules (NCs), and evaluated their theranostic potential (antitumor efficacy, magnetophotothermal efficacy and imaging capability) in an in vivo human xenograft CpG-island methylator phenotype (CIMP)-1+/CIMP2−/chromosome instability-positive colonic adenocarcinoma (Caco2) and claudin-low, triple-negative (ER−/PR−/HER2−; MDA-MB-231) breast cancer model. Mice fed orally on the Zn-Fe-bLf NC diet showed downregulation in tumor volume and complete regression in tumor volume after 45 days of feeding. In human xenograft colon cancer, vehicle-control NC diet-group (n=5) mice showed a tumor volume of 52.28±11.55 mm3, and Zn-Fe-bLf NC diet (n=5)-treated mice had a tumor-volume of 0.10±0.073 mm3. In the human xenograft breast cancer model, Zn-Fe-bLf NC diet (n=5)-treated mice showed a tumor volume of 0.051±0.062 mm3 within 40 days of feeding. Live mouse imaging conducted by near-infrared fluorescence imaging of Zn-Fe-bLf NCs showed tumor site-specific localization and regression of colon and breast tumor volume. Ex vivo fluorescence-imaging analysis of the vital organs of mice exhibited sparse localization patterns of Zn-Fe-bLf NCs and also confirmed tumor-specific selective localization patterns of Zn-Fe-bLf NCs. Dual imaging using magnetic resonance imaging and computerized tomography scans revealed an unprecedented theranostic ability of the Zn-Fe-bLf NCs. These observations warrant consideration of multimodular Zn-Fe-bLf NCs for real-time cancer imaging and simultaneous cancer-targeted therapy. PMID:27099495

Effect of metal cation ratio on chemical properties of ZnFe2O4/AC composite and adsorption of organic contaminant

NASA Astrophysics Data System (ADS)

Meilia, Demara; Misbah Khunur, Mochamad; Setianingsih, Tutik

2018-01-01

Porous woody char is biochar prepared through pyrolisis. The biochar can be used as adsorbent. In this research, ZnFe2O4/AC composite was synthesized through imregnation of the woody biochar with ZnFe2O4 to study effect of mol ratio of Fe(III) and Zn(II) toward their physicochemistry and adsorption of drug wastewater. Paracetamol was used as adsorbate model. This research was conducted in several steps, including activation of the woody biochar using KOH activator at temperatur 500 °C for 15 min to produce the activated carbon, fungsionalization of the carbon using H2SO4 oxidator (6M) at temperature of 80 °C for 3 h, impregnation of the oxidized activated carbon with Zn-Fe-LDH (Layered Double Hydroxide) at various mol ratio of Fe(III) and Zn(III), including 1:2, 1:3 and 1:4 using NaOH solution (5M) for coprecipitation, and calcination of Zn-Fe-LDH/AC at 950 °C for 5 min to produce ZnFe2O4/AC. FTIR diffraction characterization indicated existence of M-O (M = Zn(II), Fe(III)) and OH functional groups. FTIR spectra showed increasing of bands connected to -OH by increasing of the ratio till the ratio was achieved at 1:4, then decreased again. The ratio mol showed effect on the adsorption of paracetamol. Profile of adsorption value was fit with changing of functional groups. The highest adsorption was achieved at the ratio of 1:4. After calcination it gave the adsorption value of 17,66 mg/g.

Catalytic conversion of syngas to mixed alcohols over Zn-Mn promoted Cu-Fe based catalyst

DOE PAGES

Lu, Yongwu; Yu, Fei; Hu, Jin; ...

2012-04-12

Zn-Mn promoted Cu-Fe based catalyst was synthesized by the co-precipitation method. Mixed alcohols synthesis from syngas was studied in a half-inch tubular reactor system after the catalyst was reduced. Zn-Mn promoted Cu-Fe based catalyst was characterized by SEM-EDS, TEM, XRD, and XPS. The liquid phase products (alcohol phase and hydrocarbon phase) were analyzed by GC-MS and the gas phase products were analyzed by GC. The results showed that Zn-Mn promoted Cu-Fe based catalyst had high catalytic activity and high alcohol selectivity. The maximal CO conversion rate was 72%, and the yield of alcohol and hydrocarbons were also very high. Cumore » (111) was the active site for mixed alcohols synthesis, Fe 2C (101) was the active site for olefin and paraffin synthesis. The reaction mechanism of mixed alcohols synthesis from syngas over Zn-Mn promoted Cu-Fe based catalyst was proposed. Here, Zn-Mn promoted Cu-Fe based catalyst can be regarded as a potential candidate for catalytic conversion of biomass-derived syngas to mixed alcohols.« less

The effect of Fe2NiO4 and Fe4NiO4Zn magnetic nanoparticles on anaerobic digestion activity.

PubMed

Chen, Jian Lin; Steele, Terry W J; Stuckey, David C

2018-06-11

Two types of magnetic nanoparticles (MNPs), i.e. Ni ferrite nanoparticles (Fe 2 NiO 4 ) and Ni Zn ferrite nanoparticles (Fe 4 NiO 4 Zn) containing the trace metals Ni and Fe, were added to the anaerobic digestion of synthetic municipal wastewater at concentrations between 1 and 100 mg Ni L -1 in order to compare their effects on biogas (methane) production and sludge activity. Using the production of methane over time as a measure, the assays revealed that anaerobic digestion was stimulated by the addition of 100 mg Ni L -1 in Fe 2 NiO 4 NPs, while it was inhibited by the addition of 1-100 mg Ni L -1 in Fe 4 NiO 4 Zn NPs. Especially at 100 mg Ni L -1 , Fe 4 NiO 4 Zn NPs resulted in a total inhibition of anaerobic digestion. The metabolic activity of the anaerobic sludge was tested using the resazurin reduction assay, and the assay clearly revealed the negative effect of Fe 4 NiO 4 Zn NPs and the positive effect of Fe 2 NiO 4 NPs. Re-feeding fresh synthetic medium reactivated the NPs added to the anaerobic sludge, except for the experiment with 100 mg Ni L -1 addition of Fe 4 NiO 4 Zn NPs. The findings in this present study indicate a possible new strategy for NPs design to enhance anaerobic digestion. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Effect of Fe incorporation on the optical behavior of ZnO thin films prepared by sol-gel derived spin coating techniques

NASA Astrophysics Data System (ADS)

Rakkesh, R. Ajay; Malathi, R.; Balakumar, S.

2013-02-01

In this work, Fe doped Zinc Oxide (ZnO) thin films were fabricated on the glass substrate by sol-gel derived spin coating technique. X-ray Diffraction studies revealed that the obtained pure and Fe doped ZnO thin films were in the wurtzite and spinel phase respectively. The three well defined Raman lines at 432, 543 and 1091 cm-1 also confirmed the lattice structure of the ZnO thin film has wurtzite symmetry. While doping Fe atoms in the ZnO, there was a significant change in the phase from wurtzite to spinel structure; owing to Fe (III) ions being incorporated into the lattice through substitution of Zn (II) ions. Room temperature PL spectra showed that the role of defect mediated red emissions at 612 nm was due to radial recombination of a photogenerated hole with an electron that belongs to the Fe atoms, which were discussed in detail.

Mid-infrared Fe2+:ZnSe semiconductor saturable absorber mirror for passively Q-switched Er3+-doped ZBLAN fiber laser

NASA Astrophysics Data System (ADS)

Ning, Shougui; Feng, Guoying; Dai, Shenyu; Zhang, Hong; Zhang, Wei; Deng, Lijuan; Zhou, Shouhuan

2018-02-01

A mid-infrared (mid-IR) semiconductor saturable absorber mirror (SESAM) based on Fe2+:ZnSe for passively Q-switched Er3+-doped ZBLAN fiber laser has been demonstrated. Fe2+:ZnSe SESAM was fabricated by electron beam evaporation method. Fe2+ was innovatively doped into the reflective Bragg stack, in which ZnSe layer served as both doped matrix and high refractive layer during the fabricating process. By using the Fe2+:ZnSe SESAM, stable passively Q-switched pulses with the minimum pulse width of 0.43 μs under a repetition rate of 160.82 kHz were obtained. The recorded maximum average output power of 873 mW with a peak power of 12.59 W and pulse energy of 5.43 μJ were achieved. The results demonstrated a new method for fabricating Fe2+:ZnSe SESAM, which can be used in compact mid-IR Q-switched fiber laser.

Synthesis and Characterization of Photocatalytic TiO 2 -ZnFe 2 O 4 Nanoparticles

DOE PAGES

Srinivasan, Sesha S.; Wade, Jeremy; Stefanakos, Elias K.

2006-01-01

A new coprecipimore » tation/hydrolysis synthesis route is used to create a TiO 2 -ZnFe 2 O 4 nanocomposite that is directed towards extending the photoresponse of TiO 2 from UV to visible wavelengths ( > 400   nm ). The effect of TiO 2 's accelerated anatase-rutile phase transformation due to the presence of the coupled ZnFe 2 O 4 narrow-bandgap semiconductor is evaluated. The transformation's dependence on pH, calcinations temperature, particle size, and ZnFe 2 O 4 concentration has been analyzed using XRD, SEM, and UV-visible spectrometry. The requirements for retaining the highly photoactive anatase phase present in a ZnFe 2 O 4 nanocomposite are outlined. The visible-light-activated photocatalytic activity of the TiO 2 -ZnFe 2 O 4 nanocomposites has been compared to an Aldrich TiO 2 reference catalyst, using a solar-simulated photoreactor for the degradation of phenol.« less

Fabrication of magnetic Fe@ZnO0.6S0.4 nanocomposite for visible-light-driven photocatalytic inactivation of Escherichia coli

NASA Astrophysics Data System (ADS)

Peng, Ziling; Wu, Dan; Wang, Wei; Tan, Fatang; Ng, Tsz Wai; Chen, Jianguo; Qiao, Xueliang; Wong, Po Keung

2017-02-01

Bacterial inactivation by magnetic photocatalysts has now received growing interests due to the easy separation for recycle and reuse of photocatalysts. In this study, magnetic Fe@ZnO0.6S0.4 photocatalyst was prepared by a facile two-step precipitation method. Multiple techniques such as X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffused reflectance spectra (UV-vis DRS) and vibrating sample magnetometer (VSM) were employed to characterize the structure, morphology and physicochemical properties of the photocatalyst. The as-obtained Fe@ZnO0.6S0.4 possessing magnetic property was easily collected from the reaction system by a magnet. Under white light-emitting-diode (LED) lamp irradiation, Fe@ZnO0.6S0.4 nanocomposite could completely inactivate 7-log of Escherichia coli K-12 within 5 h. More importantly, almost no decrease of photocatalytic efficiency in bacterial inactivation was observed even after five consecutive cycles, demonstrating Fe@ZnO0.6S0.4 exhibited good stability for reuse. The low released rate of Fe2+/Fe3+ and Zn2+ from Fe@ZnO0.6S0.4 composite further indicated the photocatalyst showed low cytotoxicity to bacterium and high stability under LED lamp irradiation. Facile preparation, high photocatalytic efficiency, good stability and reusability, and magnetic recovery property endow Fe@ZnO0.6S0.4 nanocomposite to be a promising photocatalytic material for bacterial inactivation.

Fe-tannic acid complex dye as photo sensitizer for different morphological ZnO based DSSCs

NASA Astrophysics Data System (ADS)

Çakar, Soner; Özacar, Mahmut

2016-06-01

In this paper we have synthesized different morphological ZnO nanostructures via microwave hydrothermal methods at low temperature within a short time. We described different morphologies of ZnO at different Zn(NO3)2/KOH mole ratio. The ZnO nanostructures were characterized via X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and UV-vis spectrophotometry. All ZnO structures have hexagonal wurtzite type structures. The FESEM images showed various morphologies of ZnO such as plate, rod and nanoparticles. Dye sensitized solar cells have been assembled by these different morphological structures photo electrode and tannic acid or Fe-tannic acid complex dye as sensitizer. We have achieved at maximum efficiencies of photovoltaic cells prepared with ZnO plate in all dye systems. The conversion efficiencies of dye sensitized solar cells are 0.37% and 1.00% with tannic acid and Fe-tannic acid complex dye, respectively.

Influence of trace elements mixture on bacterial diversity and fermentation characteristics of liquid diet fermented with probiotics under air-tight condition.

PubMed

He, Yuyong; Chen, Zhiyu; Liu, Xiaolan; Wang, Chengwei; Lu, Wei

2014-01-01

Cu2+, Zn2+, Fe2+ and I- are often supplemented to the diet of suckling and early weaning piglets, but little information is available regarding the effects of different Cu2+, Zn2+, Fe2+ and I- mixtures on bacteria growth, diversity and fermentation characteristics of fermented liquid diet for piglets. Pyrosequencing was performed to investigate the effect of Cu2+, Zn2+, Fe2+ and I- mixtures on the diversity, growth and fermentation characteristics of bacteria in the liquid diet fermented with Bacillus subtilis and Enterococcus faecalis under air-tight condition. Results showed that the mixtures of Cu2+, Zn2+, Fe2+ and I- at different concentrations promoted Bacillus growth, increased bacterial diversity and lactic acid production and lowered pH to about 5. The importance of Cu2+, Zn2+, Fe2+ and I- is different for Bacillus growth with the order Zn2+> Fe2+>Cu2+> I- in a 21-d fermentation and Cu2+>I->Fe2+>Zn2+ in a 42-d fermentation. Cu2+, Zn2+, Fe2+ and I- is recommended at a level of 150, 60, 150 and 0.6 mg/kg respectively for the production of fermented liquid diet with Bacillus subtilis. The findings improve our understanding of the influence of trace elements on liquid diet fermentation with probiotics and support the proper use of trace elements in the production of fermented liquid diet for piglets.

Comparison of the solar photocatalytic activity of ZnO-Fe2O3 and ZnO-Fe(0) on 2,4-D degradation in a CPC reactor.

PubMed

Maya-Treviño, M L; Villanueva-Rodríguez, M; Guzmán-Mar, J L; Hinojosa-Reyes, L; Hernández-Ramírez, A

2015-03-01

In this work a comparative study of the catalytic activity of ZnO-Fe2O3 and ZnO-Fe(0) 0.5 wt% materials was carried out in the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) as a commercial formulation Hierbamina®, using a compound parabolic collector (CPC) reactor. The catalysts were synthesized by the sol-gel method and characterized by X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy. The textural properties of solids were determined from N2 adsorption isotherms using the Brunauer-Emmett-Teller (BET) method. The incorporation of Fe(0) onto ZnO was demonstrated by X-ray photoelectron spectroscopy analysis. The photocatalytic tests were performed at pH 7, using 10 mg L(-1) of herbicide and 0.5 g L(-1) of catalyst loading. The decay in herbicide concentration was followed by reversed-phase chromatography. A complete degradation of 2,4-D was achieved using ZnO-Fe(0) while 47% of herbicide removal was attained with ZnO-Fe2O3 mixed oxide for an accumulated energy QUV ≈ 2 kJ L(-1). The removal percentage of total organic carbon (TOC) during the solar photocatalytic process was superior using ZnO-Fe(0), achieving 45% compared to the 15% obtained with the mixed oxide catalyst.

Preparation, characterization and photocatalytic activity of visible-light-driven plasmonic Ag/AgBr/ZnFe{sub 2}O{sub 4} nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xiaojuan, E-mail: lixiaojuan@fzu.edu.cn; Tang, Duanlian; Tang, Fan

2014-08-15

Highlights: • A plasmonic Ag/AgBr/ZnFe{sub 2}O{sub 4} photocatalyst has been successfully synthesized. • Ag/AgBr/ZnFe{sub 2}O{sub 4} nanocomposites exhibit high visible light photocatalytic activity. • Ag/AgBr/ZnFe{sub 2}O{sub 4} photocatalyst is stable and magnetically separable. - Abstract: A visible-light-driven plasmonic Ag/AgBr/ZnFe{sub 2}O{sub 4} nanocomposite has been successfully synthesized via a deposition–precipitation and photoreduction through a novel one-pot process. X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy were employed to investigate the crystal structure, chemical composition, morphology, and optical properties of the as-prepared nanocomposites. The photocatalytic activities of the nanocomposites were evaluated by photodegradationmore » of Rhodamine B (RhB) and phenol under visible light. The results demonstrated that the obtained Ag/AgBr/ZnFe{sub 2}O{sub 4} nanocomposites exhibited higher photocatalytic activity as compared to pure ZnFe{sub 2}O{sub 4}. In addition, the sample photoreduced for 20 min and calcined at 500 °C achieved the highest photocatalytic activity. Furthermore, the Ag/AgBr/ZnFe{sub 2}O{sub 4} nanocomposite has high stability under visible light irradiation and could be conveniently separated by using an external magnetic field.« less

Structural and Electrochemical Characterization of Zn1-xFexO-Effect of Aliovalent Doping on the Li⁺ Storage Mechanism.

PubMed

Giuli, Gabriele; Eisenmann, Tobias; Bresser, Dominic; Trapananti, Angela; Asenbauer, Jakob; Mueller, Franziska; Passerini, Stefano

2017-12-29

In order to further improve the energy and power density of state-of-the-art lithium-ion batteries (LIBs), new cell chemistries and, therefore, new active materials with alternative storage mechanisms are needed. Herein, we report on the structural and electrochemical characterization of Fe-doped ZnO samples with varying dopant concentrations, potentially serving as anode for LIBs (Rechargeable lithium-ion batteries). The wurtzite structure of the Zn 1-x Fe x O samples (with x ranging from 0 to 0.12) has been refined via the Rietveld method. Cell parameters change only slightly with the Fe content, whereas the crystallinity is strongly affected, presumably due to the presence of defects induced by the Fe 3+ substitution for Zn 2+ . XANES (X-ray absorption near edge structure) data recorded ex situ for Zn 0.9 Fe 0.1 O electrodes at different states of charge indicated that Fe, dominantly trivalent in the pristine anode, partially reduces to Fe 2+ upon discharge. This finding was supported by a detailed galvanostatic and potentiodynamic investigation of Zn 1-x Fe x O-based electrodes, confirming such an initial reduction of Fe 3+ to Fe 2+ at potentials higher than 1.2 V (vs. Li⁺/Li) upon the initial lithiation, i.e., discharge. Both structural and electrochemical data strongly suggest the presence of cationic vacancies at the tetrahedral sites, induced by the presence of Fe 3+ (i.e., one cationic vacancy for every two Fe 3+ present in the sample), allowing for the initial Li⁺ insertion into the ZnO lattice prior to the subsequent conversion and alloying reaction.

Separation of copper, iron, and zinc from complex aqueous solutions for isotopic measurement

USGS Publications Warehouse

Borrok, D.M.; Wanty, R.B.; Ridley, W.I.; Wolf, R.; Lamothe, P.J.; Adams, M.

2007-01-01

The measurement of Cu, Fe, and Zn isotopes in natural samples may provide valuable information about biogeochemical processes in the environment. However, the widespread application of stable Cu, Fe, and Zn isotope chemistry to natural water systems remains limited by our ability to efficiently separate these trace elements from the greater concentrations of matrix elements. In this study, we present a new method for the isolation of Cu, Fe, and Zn from complex aqueous solutions using a single anion-exchange column with hydrochloric acid media. Using this method we are able to quantitatively separate Cu, Fe, and Zn from each other and from matrix elements in a single column elution. Elution of the elements of interest, as well as all other elements, through the anion-exchange column is a function of the speciation of each element in the various concentrations of HCl. We highlight the column chemistry by comparing our observations with published studies that have investigated the speciation of Cu, Fe, and Zn in chloride solutions. The functionality of the column procedure was tested by measuring Cu, Fe, and Zn isotopes in a variety of stream water samples impacted by acid mine drainage. The accuracy and precision of Zn isotopic measurements was tested by doping Zn-free stream water with the Zn isotopic standard. The reproducibility of the entire column separation process and the overall precision of the isotopic measurements were also evaluated. The isotopic results demonstrate that the Cu, Fe, and Zn column separates from the tested stream waters are of sufficient purity to be analyzed directly using a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS), and that the measurements are fully-reproducible, accurate, and precise. Although limited in scope, these isotopic measurements reveal significant variations in ??65Cu (- 1.41 to + 0.30???), ??56Fe (- 0.56 to + 0.34???), and ??66Zn (0.31 to 0.49???) among samples collected from different abandoned mines within a single watershed. Hence, Cu, Fe, and Zn isotopic measurements may be a powerful tool for fingerprinting specific metal sources and/or examining biogeochemical reactions within fresh water systems.

Effect of temperature on the electrical properties of Zn0.95M0.05O (M = Zn, Fe, Ni)

NASA Astrophysics Data System (ADS)

Sedky, A.; Mohamed, S. B.

2014-01-01

We report here the structural and electrical properties of Zn0.95M0.05O ceramic varistors, M = Zn, Ni and Fe. The samples were tested for phase purity and structural morphology by using X-Ray diffraction XRD and scanning electron microscope SEM techniques. The current-voltage characteristics J-E were obtained by dc electrical measurements in the temperature range of 300-500 K. Addition of doping did not influence the hexagonal wurtzite structure of ZnO ceramics. Furthermore, the lattice parameters ratio c/a for hexagonal distortion and the length of the bond parallel to the c axis, u were nearly unaffected. The average grain size was decreased from 1.57 μm for ZnO to 1.19 μm for Ni sample and to 1.22 μm for Fe sample. The breakdown field EB was decreased as the temperature increased, in the following order: Fe > Zn > Ni. The nonlinear region was clearly observed for all samples as the temperature increased up to 400 K and completely disappeared with further increase of temperature up to 500 K. The values of nonlinear coefficient, a were between 1.16 and 42 for all samples, in the following order: Fe > Zn > Ni. Moreover, the electrical conductivity s was gradually increased as the temperature increased up to 500 K, in the following order: Ni > Zn > Fe. On the other hand, the activation energies were 0.194 eV, 0.136 and 0.223 eV for all samples, in the following order: Fe, Zn and Ni. These results have been discussed in terms of valence states, magnetic moment and thermo-ionic emission, which were produced by the doping, and controlling the potential barrier of ZnO.

Synthesis and characterization of ZnS@Fe3O4 fluorescent-magnetic bifunctional nanospheres

NASA Astrophysics Data System (ADS)

Koc, Kenan; Karakus, Baris; Rajar, Kausar; Alveroglu, Esra

2017-10-01

Herein, we synthesized and characterized fluorescent and super paramagnetic ZnS@Fe3O4 nanospheres. First, (3-mercaptopropyl) trimethoxysilane (MPS) capped ZnS quantum dots (QDs) and SiO2 coated Fe3O4 nanoparticles were synthesized separately by using solution growth and co-precipitation techniques. After synthesis and characterization of these two nanoparticles, they were conglutinated together in a nano sized sphere. The QDs were attached to the surface of the Fe3O4 nanoparticles by Sisbnd Osbnd Si bonds and so Sisbnd Osbnd Si bonds created a SiO2 network around the nanoparticles during the formation of the ZnS@Fe3O4 nanospheres. The synthesized MPS capped ZnS fluorescent QDs, SiO2 coated magnetite super paramagnetic nanoparticles and ZnS@Fe3O4 fluorescent-magnetic bifunctional nanospheres were characterized by using UV-Vis Absorption Spectroscopy, Fluorescence Spectroscopy, X-ray analysis, Vibrating Sample Magnetometer analysis, Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy, Scanning Electron Microscope and Energy-dispersive X-ray spectroscopy. ZnS@Fe3O4 bifunctional nanospheres were shown to retain the magnetic properties of magnetite, while exhibiting the luminescent optical properties of ZnS nanoparticles. The combination of fluorescent and magnetic behaviors of nano composites make them useful for potential applications in the field of bio-medical and environmental.

Development of phosphate rock integrated with iron amendment for simultaneous immobilization of Zn and Cr(VI) in an electroplating contaminated soil.

PubMed

Zhao, Ling; Ding, Zhenliang; Sima, Jingke; Xu, Xiaoyun; Cao, Xinde

2017-09-01

This study aims to develop an amendment for simultaneous immobilization of Zn and Cr(VI) in an abandoned electroplating contaminated soil. Nature phosphate rock was first activated with oxalic acid (O-PR) and then combined with FeSO 4 or zero-valent iron (ZVI) for immobilization of Zn and Cr(VI) from aqueous solutions. Finally, the optimized approach showing the highest immobilization ability in solution was applied in an electroplating contaminated soil. The O-PR combined with FeSO 4 was more effective in simultaneously removing Zn and Cr(VI) than the O-PR integrated with ZVI within the tested solution pH range of 5.5-8.5. Both O-PR with FeSO 4 and with ZVI removed over 95% of Zn from the solution; however, only 42-46% of Cr(VI) was immobilized by O-PR with ZVI, while O-PR with FeSO 4 almost precipitated all Cr(VI). Moreover, there were 75-95% Zn and 95-100% Cr(VI) remaining in the exhausted O-PR with FeSO 4 solid after toxicity characteristic leaching test (TCLP) while the exhausted O-PR with ZVI solid only retained 44-83% Zn and 32-72% Cr(VI). Zinc was immobilized mainly via formation of insoluble Fe-Zn phosphate co-precipitates, while iron-induced reduction of Cr(VI) into stable Cr(OH) 3 or Cr x Fe (1-x) (OH) 3 was responsible for Cr(VI) immobilization. Application of the O-PR integrated with FeSO 4 in the electroplating contaminated soil rapidly reduced the TCLP extractable Zn and Cr(VI) to below the standard limits, with decrease by 50% and 94%, respectively. This study revealed that combination of oxalic acid activated phosphate rock with FeSO 4 could be an effective amendment for remediation of Zn and Cr(VI) contaminated soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biofortification with Iron and Zinc Improves Nutritional and Nutraceutical Properties of Common Wheat Flour and Bread.

PubMed

Ciccolini, Valentina; Pellegrino, Elisa; Coccina, Antonio; Fiaschi, Anna Ida; Cerretani, Daniela; Sgherri, Cristina; Quartacci, Mike Frank; Ercoli, Laura

2017-07-12

The effect of field foliar Fe and Zn biofortification on concentration and potential bioavailability of Fe and Zn and health-promoting compounds was studied in wholemeal flour of two common wheat varieties (old vs modern). Moreover, the effect of milling and bread making was studied. Biofortification increased the concentration of Zn (+78%) and its bioavailability (+48%) in the flour of the old variety, whereas it was ineffective in increasing Fe concentration in both varieties. However, the old variety showed higher concentration (+41%) and bioavailability (+26%) of Fe than the modern one. As regard milling, wholemeal flour had higher Fe, Zn concentration and health-promoting compounds compared to white flour. Bread making slightly change Fe and Zn concentration but greatly increased their bioavailability (77 and 70%, respectively). All these results are of great support for developing a production chain of enriched functional bread having a protective role against chronic cardio-vascular diseases.

Synthesis, characterization and hemolysis studies of Zn(1-x)CaxFe2O4 ferrites synthesized by sol-gel for hyperthermia treatment applications

NASA Astrophysics Data System (ADS)

Jasso-Terán, Rosario Argentina; Cortés-Hernández, Dora Alicia; Sánchez-Fuentes, Héctor Javier; Reyes-Rodríguez, Pamela Yajaira; de-León-Prado, Laura Elena; Escobedo-Bocardo, José Concepción; Almanza-Robles, José Manuel

2017-04-01

The synthesis of Zn(1-x)CaxFe2O4 nanoparticles, x=0, 0.25, 0.50, 0.75 and 1.0, was performed by sol-gel method followed by a heat treatment at 400 °C for 30 min. These ferrites showed nanometric sizes and nearly superparamagnetic behavior. The Zn0.50Ca0.50Fe2O4 and CaFe2O4 ferrites presented a size within the range of 12-14 nm and appropriate heating ability for hyperthermia applications. Hemolysis testing demonstrated that Zn0.50Ca0.50Fe2O4 ferrite was not cytotoxic when using 10 mg of ferrite/mL of solution. According to the results obtained, Zn0.50Ca0.50Fe2O4 is a potential material for cancer treatment by magnetic hyperthermia therapy.

Improvement of the magnetic moment of NiZn ferrites induced by substitution of Nd3+ ions for Fe3+ ions

NASA Astrophysics Data System (ADS)

Wu, Xuehang; Chen, Wen; Wu, Wenwei; Wu, Juan; Wang, Qing

2018-05-01

Four types of Ni-Zn based ferrites materials having the general formula Ni0.5Zn0.5NdxFe2-xO4 (0.0 ≤ x ≤ 0.12) have been successfully synthesized by calcining oxalates in air and the influence of Nd content on the structure and magnetic properties of Ni0.5Zn0.5NdxFe2-xO4 is studied. X-ray diffraction examination confirms that a high-crystallized Ni0.5Zn0.5NdxFe2-xO4 with cubic spinel structure is obtained when the precursor is calcined at 1000 °C in air for 2 h. The substitutions of Nd3+ ions for partial Fe3+ ions do not change the spinel crystalline structure of MFe2O4. The incorporation of Nd3+ ions in place of Fe3+ ions in Ni-Zn ferrites increases the average crystallite size. Specific saturation magnetization decreases with increase in Nd content. This is because Nd3+ ions with smaller magnetic moment preferentially fill the octahedral sites. In addition, antiferromagnetic FeNdO3 increases with increase in Nd content. In this study, Ni0.5Zn0.5Nd0.08Fe1.92O4, calcined at 1000 °C, exhibits the highest magnetic moment (4.2954 μB) and the lowest coercivity (28.82 Oe).

Microstructural characteristics and aging response of Zn-containing Al-Mg-Si-Cu alloy

NASA Astrophysics Data System (ADS)

Cai, Yuan-hua; Wang, Cong; Zhang, Ji-shan

2013-07-01

Al-Mg-Si-Cu alloys with and without Zn addition were fabricated by conventional ingot metallurgy method. The microstructures and properties were investigated using optical microscopy (OM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), tensile test, hardness test, and electrical conductivity measurement. It is found that the as-cast Al-Mg-Si-Cu-Zn alloy is composed of coarse dendritic grains, long needle-like β/δ-AlFeSi white intermetallics, and Chinese script-like α-AlFeSi compounds. During high temperature homogenization treatment, only harmful needle-like β-AlFeSi phase undergoes fragmentation and spheroidizing at its tips, and the destructive needle-like δ-phase does not show any morphological and size changes. Phase transitions from β-AlFeSi to α-AlFeSi and from δ-AlFeSi to β-AlFeSi are also not found. Zn addition improves the aging hardening response during the former aging stage and postpones the peak-aged hardness to a long aging time. In T4 condition, Zn addition does not obviously increase the yield strength and decrease the elongation, but it markedly improves paint-bake hardening response during paint-bake cycle. The addition of 0.5wt% Zn can lead to an increment of 99 MPa in yield strength compared with the value of 69 MPa for the alloy without Zn after paint-bake cycle.

[Effects of straw returning combined with medium and microelements application on soil organic carbon sequestration in cropland.

PubMed

Jiang, Zhen Hui; Shi, Jiang Lan; Jia, Zhou; Ding, Ting Ting; Tian, Xiao Hong

2016-04-22

A 52-day incubation experiment was conducted to investigate the effects of maize straw decomposition with combined medium element (S) and microelements (Fe and Zn) application on arable soil organic carbon sequestration. During the straw decomposition, the soil microbial biomass carbon (MBC) content and CO 2 -C mineralization rate increased with the addition of S, Fe and Zn, respectively. Also, the cumulative CO 2 -C efflux after 52-day laboratory incubation significantly increased in the treatments with S, or Fe, or Zn addition, while there was no significant reduction of soil organic carbon content in the treatments. In addition, Fe or Zn application increased the inert C pools and their proportion, and apparent balance of soil organic carbon, indicating a promoting effect of Fe or Zn addition on soil organic carbon sequestration. In contrast, S addition decreased the proportion of inert C pools and apparent balance of soil organic carbon, indicating an adverse effect of S addition on soil organic carbon sequestration. The results suggested that when nitrogen and phosphorus fertilizers were applied, inclusion of S, or Fe, or Zn in straw incorporation could promote soil organic carbon mineralization process, while organic carbon sequestration was favored by Fe or Zn addition, but not by S addition.

NH3 molecule adsorption on spinel-type ZnFe2O4 surface: A DFT and experimental comparison study

NASA Astrophysics Data System (ADS)

Zou, Cong-yang; Ji, Wenchao; Shen, Zhemin; Tang, Qingli; Fan, Maohong

2018-06-01

Ammonia (NH3) is a caustic environment pollutant which contributes to haze formation and water pollution. Zinc ferrite (ZnFe2O4) exhibits good catalytic activity in NH3 removal. The density functional theory (DFT) was applied to explore the interaction mechanism of NH3 molecule adsorption on spinel-type ZnFe2O4 (1 1 0) surface with GGA-PW91 method in atomic and electronic level. The results indicated that NH3 molecule preferred to adsorb on surface Zn atom with the formation of H3Nsbnd Zn coordinate bond over ZnFe2O4 (1 1 0) surface. The H3Nsbnd Zn state was exothermic process with adsorption energy of -203.125 kJ/mol. About 0.157e were transferred from NH3 molecule to the surface which resulted in strong interaction. Higher activation degree occurred in H3Nsbnd Zn configuration with two Nsbnd H bonds elongated and NH3 structure became more flat on the surface. The PDOS change of NH3 molecule was consistent with the result of adsorption energy. It was concluded that s orbital of NH3 (N) and s, p orbitals of Zn atom overlapped at -0.619 Ha. The p orbital of NH3 (N) has interaction with d orbital of Zn atom suggesting the hybridization between them. Based on NH3 removal experimental and XPS spectra results, NH3sbnd ZnFe2O4 interaction was mainly depended on the coordination between Zn atom and NH3 molecule. The DFT calculations have deepened our understanding on NH3sbnd ZnFe2O4 interaction system.

Effect of Fe doping concentration on photocatalytic activity of ZnO nanosheets under natural sunlight

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khokhra, Richa; Kumar, Rajesh, E-mail: rajesh.kumar@juit.ac.in

2015-05-15

A facile room temperature, aqueous solution-based chemical method has been adopted for large-scale synthesis of Fe doped ZnO nanosheets. The XRD and SEM results reveal the as-synthesized products well crystalline and accumulated by large amount of interweave nanosheets, respectively. Energy dispersive spectroscopy data confirmed Fe doping of the ZnO nanosheets with a varying Fe concentration. The photoluminescence spectrum reveals a continuous suppression of defect related emissions intensity by increasing the concentration of the Fe ion. A photocatalytic activity using these samples under sunlight irradiation in the mineralization of methylene blue dye was investigated. The photocatalytic activity of Fe doped ZnOmore » nanosheets depends upon the presence of surface oxygen vacancies.« less

Crystal Structure and Magnetic Properties of New Cubic Quaternary Compounds RT2Sn2Zn18 (R = La, Ce, Pr, and Nd, and T = Co and Fe)

NASA Astrophysics Data System (ADS)

Isikawa, Yosikazu; Mizushima, Toshio; Ejiri, Jun-ichi; Kitayama, Shiori; Kumagai, Keigou; Kuwai, Tomohiko; Bordet, Pierre; Lejay, Pascal

2015-07-01

The new cubic quaternary intermetallic compounds RT2Sn2Zn18 (R = La, Ce, Pr, and Nd, and T = Co and Fe) were synthesized by the mixture-metal flux method using Zn and Sn. The crystal structure was investigated by powder X-ray diffraction and with a four-circle X-ray diffractometer using single crystals. The space group of the compounds is Fdbar{3}m (No. 227). The rare-earth atom is at the cubic site which is the center of a cage composed of Zn and Sn atoms. The crystal structure is the same as the CeCr2Al20-type crystal structure except the atoms at the 16c site, i.e., the Zn atoms at the 16c site are completely replaced by Sn atoms, indicating that the compounds are crystallographically new ordered quaternary compounds. The lattice parameter a and the physical properties of the magnetic susceptibility χ, the magnetization M, and the specific heat C of these cubic caged compounds were investigated. LaCo2Sn2Zn18 and LaFe2Sn2Zn18 are enhanced Pauli paramagnets that originate from the Co and Fe itinerant 3d electrons. CeCo2Sn2Zn18 and CeFe2Sn2Zn18 are also enhanced Pauli paramagnets that originate from both the 3d electrons and Ce 4f electrons. PrCo2Sn2Zn18 and PrFe2Sn2Zn18 are nonmagnetic materials with huge values of C divided by temperature, which indicates that the ground state of Pr ions is a non-Kramers' doublet. NdCo2Sn2Zn18 and NdFe2Sn2Zn18 are magnetic materials with the Néel temperatures of 1.0 and 3.8 K, respectively. All eight compounds have large magnetic moments of Co/Fe in the paramagnetic temperature region, and thus their magnetic moments are inferred to be magnetically frustrating owing to the pyrochlore lattice in the low-temperature region.

Ab initio understanding of magnetic properties in Zn2+ substitution of Fe3O4 ultra-thin film with dilute Zn substitution

NASA Astrophysics Data System (ADS)

Huang, Zhaocong; Chen, Qian; Jiang, Sheng; Dong, Shuai; Zhai, Ya

2018-05-01

The mechanism of the magnetic properties on the Zn2+ substituted Fe3O4 film have been investigated based on first principle calculations. It is found that the surface effect plays an important role in the occupation of Zn ion, and in turn changes the magnetic moment. It may also destroy the half metallic behavior of Fe3O4 film even if the Zn2+ concentration only is one Zn2+ per unit cell (4%), which is different from that in bulk material.

Enhanced magnetic fluid hyperthermia by micellar magnetic nanoclusters composed of Mn(x)Zn(1-x)Fe(2)O(4) nanoparticles for induced tumor cell apoptosis.

PubMed

Qu, Yang; Li, Jianbo; Ren, Jie; Leng, Junzhao; Lin, Chao; Shi, Donglu

2014-10-08

Monodispersed MnxZn1-xFe2O4 magnetic nanoparticles of 8 nm are synthesized and encapsulated in amphiphilic block copolymer for development of the hydrophilic magnetic nanoclusters (MNCs). These MNCs exhibit superparamagnetic characteristics, high specific absorption rate (SAR), large saturation magnetization (Ms), excellent stability, and good biocompatibility. MnFe2O4 and Mn0.6Zn0.4Fe2O4 are selected as optimum compositions for the MNCs (MnFe2O4/MNC and Mn0.6Zn0.4Fe2O4/MNC) and employed for magnetic fluid hyperthermia (MFH) in vitro. To ensure biosafety of MFH, the parameters of alternating magnetic field (AMF) and exposure time are optimized with low frequency, f, and strength of applied magnetic field, Happlied. Under optimized conditions, MFH of MnFe2O4/MNC and Mn0.6Zn0.4Fe2O4/MNC result in cancer cell death rate up to 90% within 15 min. The pathway of cancer cell death is identified as apoptosis, which occurs in mild hyperthermia near 43 °C. Both MnFe2O4/MNC and Mn0.6Zn0.4Fe2O4/MNC show similar efficiencies on drug-sensitive and drug-resistant cancer cells. On the basis of these findings, those MnxZn1-xFe2O4 nanoclusters can serve as a promising candidate for effective targeting, diagnosis, and therapy of cancers. The multimodal cancer treatment is also possible as amphiphilic block copolymer can encapsulate, in a similar fashion, different nanoparticles, hydrophobic drugs, and other functional molecules.

Photocatalytic degradation of organic dyes by Er3+: YAlO3/Co- and Fe-doped ZnO coated composites under solar irradiation

NASA Astrophysics Data System (ADS)

Chen, Yang; Lu, Chunxiao; Tang, Liang; Song, Yahui; Wei, Shengnan; Rong, Yang; Zhang, Zhaohong; Wang, Jun

2016-12-01

In this work, the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites were prepared by the sol-gel method. Then, they were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). Photo-degradation of azo fuchsine (AF) as a model dye under solar light irradiation was studied to evaluate the photocatalytic activity of the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites. It was found that the photocatalytic activity of Co- and Fe-doped ZnO composites can be obviously enhanced by upconversion luminescence agent (Er3+: YAlO3). Besides, the photocatalytic activity of Er3+: YAlO3/Fe-doped ZnO is better than that of Er3+: YAlO3/Co-doped ZnO. The influence of experiment conditions, such as the concentration of Er3+: YAlO3, heat-treatment temperature and time on the photocatalytic activity of the Er3+: YAlO3/Co- and Fe-doped ZnO coated composites was studied. In addition, the effects of solar light irradiation time, dye initial concentration, Er3+: YAlO3/Co- and Fe-doped ZnO amount on the photocatalytic degradation of azo fuchsine in aqueous solution were investigated in detail. Simultaneously, some other organic dyes, such as Methyl Orange (MO), Rhodamine B (RM-B), Acid Red B (AR-B), Congo Red (CR), and Methyl Blue (MB) were also studied. The possible excitation principle of Er3+: YAlO3/Co- and Fe-doped ZnO coated composites under solar light irradiation and the photocatalytic degradation mechanism of organic dyes were discussed.

Kinetic control on Zn isotope signatures recorded in marine diatoms

NASA Astrophysics Data System (ADS)

Köbberich, Michael; Vance, Derek

2017-08-01

Marine diatoms dominate the oceanic cycle of the essential micronutrient zinc (Zn). The stable isotopes of zinc and other metals are increasingly used to understand trace metal micronutrient cycling in the oceans. One clear feature of the early isotope data is the heavy Zn isotope signature of the average oceanic dissolved pool relative to the inputs, potentially driven by uptake of light isotopes into phytoplankton cells and export to sediments. However, despite the fact that diatoms strip Zn from surface waters across the Antarctic polar front in the Southern Ocean, the local upper ocean is not isotopically heavy. Here we use culturing experiments to quantify the extent of Zn isotope fractionation by diatoms and to elucidate the mechanisms driving it. We have cultured two different open-ocean diatom species (T. oceanica and Chaetoceros sp.) in a series of experiments at constant medium Zn concentration but at bioavailable medium Fe ranging from limiting to replete. We find that T. oceanica can maintain high growth rates and Zn uptake rates over the full range of bioavailable iron (Fe) investigated, and that the Zn taken up has a δ66Zn that is unfractionated relative to that of the bioavailable free Zn in the medium. The studied representative of the genus Chaetoceros, on the other hand, shows more significantly reduced Zn uptake rates at low Fe and records more variable biomass δ66Zn signatures, of up to 0.85‰ heavier than the medium. We interpret the preferential uptake of heavy isotopes at extremely low Zn uptake rates as potentially due to either of the following two mechanisms. First, the release of extracellular polymeric substances (EPS), at low Fe levels, may preferentially scavenge heavy Zn isotopes. Second, the Zn uptake rate may be slow enough to establish pseudo-equilibrium conditions at the transporter site, with heavy Zn isotopes forming more stable surface complexes. Thus we find that, in our experiments, Fe-limitation exerts a key control that not only limits diatom growth, but also affects the Zn uptake physiology of diatoms. Uptake of heavy isotopes occurs under Fe-limiting conditions that drive extremely low Zn uptake rates. On the other hand, more rapid Zn uptake rates result in biomass that is indistinguishable from the external bioavailable free Zn pool. These experimental results can, in principle, explain the range of Zn isotopic compositions found in the real surface ocean, given the geographically variable interplay between Fe-limitation, Zn uptake rates, and the degree of organic complexation of oceanic Zn.

Effects of complexing agents on electrochemical deposition of FeS x O y in ZnO/FeS x O y heterostructures

NASA Astrophysics Data System (ADS)

Supee, A.; Ichimura, M.

2017-12-01

Heterostructures which consist of ZnO and FeS x O y were deposited via electrochemical deposition (ECD) for application to solar cells. Galvanostatic ECD was used in FeS x O y deposition with a solution containing 100 mM Na2S2O3 and 30 mM FeSO4. To alter the film properties, L(+)-tartaric acid (C4H6O6) and lactic acid [CH3CH(OH)COOH] were introduced as the complexing agents into the FeS x O y deposition solution. Larger film thickness and smaller oxygen content were obtained for the films deposited with the complexing agents. ZnO was deposited on FeS x O y by two-step pulse ECD from a solution containing Zn(NO3)2. For the ZnO/FeS x O y heterostructures fabricated with/without complexing agents, rectifying properties were confirmed in the current density-voltage ( J- V) characteristics. However, photovoltaic properties were not improved with addition of both complexing agents.

Spinel, YbFe2O4, and Yb2Fe3O7 types of structure for compounds in the In2O3 and Sc2O3-A2O3-BO systems (A: Fe, Ga, or Al; B: Mg, Mn, Fe, Ni, Cu, or Zn) at temperatures over 1000C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimizuka, N.; Mohri, T.

In the Sc2O3-Ga2O3-CuO, Sc2O3-Ga2O3-ZnO, and Sc2O3-Al2O3-CuO systems, ScGaCuO4, ScGaZnO4, and ScAlCuO4 with the YbFe2O4-type structure and Sc2Ga2CuO7 with the Yb2Fe3O7-type structure were obtained. In the In2O3-A2O3-BO systems (A: Fe, Ga, or Al; B: Mg, Mn, Fe, Ni, or Zn), InGaFeO4, InGaNiO4, and InFeT MgO4 with the spinel structure, InGaZnO4, InGaMgO4, and InAl-CuO4 with the YbFe2O4-type structure, and In2Ga2MnO7 and In2Ga2ZnO7 with the Yb2Fe3O7-type structure were obtained. InGaMnO4 and InFe2O4 had both the YbFe2O4-type and spinel-type structures. The revised classification for the crystal structures of AB2O4 compounds is presented, based upon the coordination numbers of constituent A and B cations. 5more » references, 2 tables.« less

Effect of Co and Pr doping on the properties of solar-reflective ZnFe2O4 dark pigment

NASA Astrophysics Data System (ADS)

Suwan, M.; Sangwong, N.; Supothina, S.

2017-03-01

High NIR-reflective Co-doped ZnFe2O4 black pigments were synthesized by a simple solid-state reaction of ZnO and Fe2O3 in the presence of 3 to 30 wt.% Co3O4 at 1000 and 1100 °C. A series of black pigments with low L* values in a range of 25.5-26.5 and NIR reflectance of 39.5-48.7% were obtained at 1000 °C while the pigments with comparable L* values and slightly lower NIR reflectance were obtained at 1100 °C. A change of the pigment property could be attributed to substitution of Co2+ for Zn2+ as revealed by XRD analysis as well as reflectance spectra. Calcination of ZnO and Fe2O3 in the presence of 3 to 30 wt.% Pr6O11 at 1100 °C resulted in dark brown composite pigments consisting of ZnFe2O4, PrFe2O3 and unreacted Fe2O3 with L* value around 40 ±1 and NIR reflectance in a range of 48-50%.

Fahlore and Sphalerite from the Darasun Gold Deposit in the Eastern Transbaikal Region, Russia: I. Mineral Assemblages and Intergrowths, Chemical Composition, and Its Evolution

NASA Astrophysics Data System (ADS)

Lyubimtseva, N. G.; Bortnikov, N. S.; Borisovsky, S. E.; Prokofiev, V. Yu.; Vikent'eva, O. V.

2018-03-01

The mineral assemblages, mode of occurrence, and chemical compositions of coexisting fahlore and sphalerite from the Darasun gold deposit have been described. Three generations of fahlore and three generations of sphalerite have been recognized. The FeS content in sphalerite coexisting with fahlore ranges from 0.8 to 9.4 mol %. The complete solid solution series Fe-tetrahedrite-Zn-tetrahedrite-Fe-tennantite-Zn-tennantite reflected in Sb/(Sb + As) and Fe/(Fe + Zn) ratios ranging from 0 to 0.97 and from 0.07 to 1.00, respectively, with a predominant negative relationship between these ratios has been identified for the first time at the deposit. Stepped, oscillatory, and combined stepped-oscillatory growth zonings within fahlore grains and heterogeneous aggregates of fahlore have been found. Fahlore is enriched in As with respect to Sb, and Zn-tetrahedrite is followed by Fe- and Zn-tennantite from early to late generation; Zn-tetrahedrite is followed by Fe-tennantite in zoned grains and overgrown rims; sphalerite crystallized at decreased temperature and sulfur fugacity. The evolution of the chemical composition of fahlores was caused by the evolving temperature, fluid salinity, and conditions of metal migration.

Periodic table of 3d-metal dimers and their ions.

PubMed

Gutsev, G L; Mochena, M D; Jena, P; Bauschlicher, C W; Partridge, H

2004-10-08

The ground states of the mixed 3d-metal dimers TiV, TiCr, TiMn, TiFe, TiCo, TiNi, TiCu, TiZn, VCr, VMn, VFe, VCo, VNi, VCu, VZn, CrMn, CrFe, CrCo, CrNi, CrCu, CrZn, MnFe, MnCo, MnNi, MnCu, MnZn, FeCo, FeNi, FeCu, FeZn, CoNi, CoCu, CoZn, NiCu, NiZn, and CuZn along with their singly negatively and positively charged ions are assigned based on the results of computations using density functional theory with generalized gradient approximation for the exchange-correlation functional. Except for TiCo and CrMn, our assignment agrees with experiment. Computed spectroscopic constants (r(e),omega(e),D(o)) are in fair agreement with experiment. The ground-state spin multiplicities of all the ions are found to differ from the spin multiplicities of the corresponding neutral parents by +/-1. Except for TiV, MnFe, and MnCu, the number of unpaired electrons, N, in a neutral ground-state dimer is either N(1)+N(2) or mid R:N(1)-N(2)mid R:, where N(1) and N(2) are the numbers of unpaired 3d electrons in the 3d(n)4s(1) occupation of the constituent atoms. Combining the present and previous results obtained at the same level of theory for homonuclear 3d-metal and ScX (X=Ti-Zn) dimers allows one to construct "periodic" tables of all 3d-metal dimers along with their singly charged ions.

Enhanced photocatalytic activity and characterization of magnetic Ag/BiOI/ZnFe2O4 composites for Hg0 removal under fluorescent light irradiation

NASA Astrophysics Data System (ADS)

Li, Chengwei; Zhang, Anchao; Zhang, Lixiang; Song, Jun; Su, Sheng; Sun, Zhijun; Xiang, Jun

2018-03-01

A series of magnetic Ag/BiOI/ZnFe2O4 hybrids synthesized via hydrothermal process, subsequent deposition-precipitation and photoreduction method were employed to remove elemental mercury (Hg0) under fluorescent light irradiation. The effects of Ag content, fluorescent light irradiation, reaction temperature, pH value, flue gas composition, anions and photocatalyst dosage on Hg0 removal were investigated in detail. The as-synthesized photocatalysts were characterized using N2 adsorption-desorption, XRD, SEM, TEM, HRTEM, XPS, VSM, DRS, ESR, PL and photocurrent response. The results showed that the ternary Ag/BiOI/ZnFe2O4 hybrids possessed enhanced visible-light-responsive photocatalytic performances for Hg0 removal. Ag/BiOI/ZnFe2O4 photocatalyst could be easily recovered from the reaction solution by an extra magnet and was stable in the process of Hg0 removal. Lower content of Ag was highly dispersed on the surface of BiOI/ZnFe2O4, while higher content of Ag would result in some aggregations and/or the blockages of micropore. In comparison to BiOI/ZnFe2O4, Ag deposited BiOI/ZnFe2O4 material showed lower recombination rate of electron-hole pairs. The superior Hg0 oxidation removal could correspond to good match of BiOI and ZnFe2O4, excellent fluidity and surface plasmon resonance effect of Ag0 nanoparticles, which led to higher separation efficiency of photogenerated electrons and holes, thereby enhancing the hybrids' photocatalytic activity.

Effect of 120 MeV 28Si9+ ion irradiation on structural and magnetic properties of NiFe2O4 and Ni0.5Zn0.5Fe2O4

NASA Astrophysics Data System (ADS)

Sharma, R.; Raghuvanshi, S.; Satalkar, M.; Kane, S. N.; Tatarchuk, T. R.; Mazaleyrat, F.

2018-05-01

NiFe2O4, Ni0.5Zn0.5Fe2O4 samples were synthesized using sol-gel auto combustion method, and irradiated by using 120 MeV 28Si9+ ion with ion fluence of 1×1012 ions/cm2. Characterization of pristine, irradiated samples were done using X-Ray Diffraction (XRD), Field Emission Scanning Microscopy (FE-SEM), Energy Dispersive X-ray Analysis (EDAX) and Vibrating Sample Magnetometer (VSM). XRD validates the single phase nature of pristine, irradiated Ni- Zn nano ferrite except for Ni ferrite (pristine, irradiated) where secondary phases of α-Fe2O3 and Ni is observed. FE- SEM images of pristine Ni, Ni-Zn ferrite show inhomogeneous nano-range particle size distribution. Presence of diamagnetic ion (Zn2+) in NiFe2O4 increases oxygen positional parameter (u 4¯3m ), experimental, theoretical saturation magnetization (Msexp., Msth.), while decreases the grain size (Ds) and coercivity (Hc). With irradiation Msexp., Msth. increases but not much change are observed in Hc. New antistructure modeling for the pristine, irradiated Ni and Ni-Zn ferrite samples was used for describing the surface active centers.

Performance of Zn-Fe-Mn/MCM-48 sorbents for high temperature H2S removal and analysis of regeneration process

NASA Astrophysics Data System (ADS)

Huang, Z. B.; Liu, B. S.; Wang, F.; Amin, R.

2015-10-01

MCM-48 was synthesized using a rapid and facile process at room temperature. A series of 50%Zn-Fe-Mn/MCM-48 sorbents were prepared and their performance of hot coal gas desulfurization was investigated. High breakthrough sulfur capacity (13.2 g-S/100 g sorbent) and utilization (66.1%) of 50%1Zn2Fe2Mn/MCM-48 sorbent at 550 °C was achieved. The characterization results of XRD, BET, TPR and FT-IR revealed that MCM-48 had excellent thermal stability at less than 700 °C, ZnMn2O4 and (Mn, Zn)Fe2O4 were mainly active particles in fresh sorbents which were highly dispersed on support. The MCM-48 mesoporous structure remained intact after eight successive desulfurization/regeneration cycles. The regeneration process of 50%1Zn2Fe2Mn/MCM-48 sorbent was analyzed, it indicated that the breakthrough sulfur capacity decline of sorbent was due to the migration of Zn onto the sorbent surface and Zn accumulated on the surface and vaporized to the exterior from the surface. In the TPO test, the oxidation of Zn was different for 50%Zn/MCM-48 at 700 °C. It revealed that the temperature of regeneration for ZnO sorbent should be higher than 700 °C.

Magnetic properties of RFe2Zn20 and RCo2Zn20 (R=Y,Nd,Sm,Gd-Lu)

NASA Astrophysics Data System (ADS)

Jia, Shuang; Ni, Ni; Bud'Ko, S. L.; Canfield, P. C.

2009-09-01

Magnetization, resistivity, and specific heat measurements were performed on solution-grown single crystals of RFe2Zn20 and RCo2Zn20 (R=Y,Nd,Sm,Gd-Lu) . Whereas LuCo2Zn20 and YCo2Zn20 manifest unremarkable metallic behavior, LuFe2Zn20 and YFe2Zn20 display behaviors such as characteristic of nearly ferromagnetic Fermi liquids. When the well-defined 4f local moments (Gd3+-Tm3+) are embedded into this strongly polarizable host, they manifest enhanced ferromagnetic ordering and the values of TC for RFe2Zn20 (R=Gd-Tm) scale with the de Gennes factor. In addition, data on the RFe2Zn20 compounds indicate a small crystal electric field (CEF) effect compared with the interaction energy scale. On the other hand, the local moment bearing members of RCo2Zn20 (R=Nd,Sm,Gd-Tm) manifest weak magnetic interactions and the magnetic properties for R=Dy-Tm members are strongly influenced by the CEF effect on the R ions. The magnetic anisotropy and specific heat data for the Co series were used to determine the CEF coefficient of R ion with its cubic point symmetry. These CEF coefficients, determined for the Co series, are consistent with the magnetic anisotropy and specific heat data for the Fe series, which indicates similar CEF effects for the Fe and Co series. Such analysis, combined with specific heat and resistivity data, indicates that for R=Tb-Ho , the CEF splitting scale is smaller than their TC values, whereas for ErFe2Zn20 and TmFe2Zn20 the 4f electrons lose part of their full Hund’s rule ground state degeneracy above TC . YbFe2Zn20 and YbCo2Zn20 manifest typical but distinct heavy fermion behaviors associated with different Kondo temperatures.

Investigation on structural and electrical properties of Fe doped ZnO nanoparticles synthesized by solution combustion method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ram, Mast, E-mail: mastram1999@yahoo.com; Bala, Kanchan; Sharma, Hakikat

In the present study, nanoparticles of Fe doped zinc oxide (ZnO) [Zn{sub 1-x}Fe{sub x}O where x=0.0, 0.01, 0.02, 0.03 and 0.05] were prepared by cost effective solution combustion method. The powder X-ray diffractometry confirms the formation of single phase wurtzite structure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to investigate the micrsostructure of Fe-doped ZnO nanoparticles. The DC electrical conductivity was found to increase with temperature and measurement was carried out in the temperature range of 300-473K. DC electrical conductivity increases with temperature and decreases with Fe doping concentration.

Preparation of Superparamagnetic Zn0.5Mn0.5Fe2O4 Particle by Coprecipitation-Sonochemical Method for Radar Absorbing Material

NASA Astrophysics Data System (ADS)

Taufiq, A.; Bahtiar, S.; Sunaryono; Hidayat, N.; Hidayat, A.; Mufti, N.; Diantoro, M.; Fuad, A.; Munasir; Rahmawati, R.; Adi, W. A.; Pratapa, S.; Darminto

2017-05-01

One of many applications of spinel ferrite nanoparticles is related to their performance as radar absorbing materials. In this work, we report developing synthesis method through combined coprecipitation-sonochemical routes in preparing Zn0.5Mn0.5Fe2O4 nanoparticle from iron sand in Indonesia as a vital raw material. The structure, size, morphology, and elements of the Zn0.5Mn0.5Fe2O4 nanoparticle were investigated via X-Ray diffractometry and Transmission/Scanning Electron Microscopy (TEM/SEM) combining Energy Dispersive Spectroscopy (EDS). The magnetic properties of the Zn0.5Mn0.5Fe2O4 nanoparticle were characterized by using Vibrating Sample Magnetometer (VSM). Furthermore, the reflection loss character of the Zn0.5Mn0.5Fe2O4 nanoparticle was determined via Vector Network Analyzer (VNA). From the qualitative and quantitative analysis of the XRD data, it can be identified that the Zn0.5Mn0.5Fe2O4 particle formed a spinel cubic structure in a single phase with the lattice parameter of approximately 8.401 Å. It is known from the TEM image that the Zn0.5Mn0.5Fe2O4 particle had a size of about 9.7 nm and tended to agglomerate. Furthermore, the data analysis of the M(H) curve presented that the Zn0.5Mn0.5Fe2O4 nanoparticle has a superparamagnetic behavior with the saturation magnetization of approximately 43 emu/g. Finally, the data analysis of the reflection loss as a function of frequency showed that the Zn0.5Mn0.5Fe2O4 nanoparticle performs as a radar absorbing material with the absorption performance of approximately -11.0 dB at the frequency of 10.8 GHz

Influence of Gas Atmosphere Dew Point on the Selective Oxidation and the Reactive Wetting During Hot Dip Galvanizing of CMnSi TRIP Steel

NASA Astrophysics Data System (ADS)

Cho, Lawrence; Lee, Seok Jae; Kim, Myung Soo; Kim, Young Ha; De Cooman, Bruno C.

2013-01-01

The selective oxidation and reactive wetting of intercritically annealed Si-bearing CMnSi transformation-induced plasticity steels were investigated by high-resolution transmission electron microscopy. In a N2 + 10 pct H2 gas atmosphere with a dew point (DP) ranging from 213 K to 278 K (-60 °C to 5 °C), a continuous layer of selective oxides was formed on the surface. Annealing in a higher DP gas atmosphere resulted in a thinner layer of external oxidation and a greater depth of internal oxidation. The hot dipping was carried out in a Zn bath containing 0.22 mass pct Al, and the bath temperature was 733 K (460 °C). Coarse and discontinuous Fe2Al5- x Zn x grains and Fe-Zn intermetallics (ζ and δ) were observed at the steel/coating interface after the hot dip galvanizing (HDG) of panels were annealed in a low DP atmosphere 213 K (-60 °C). The Fe-Zn intermetallics were formed both in areas where the Fe2Al5- x Zn x inhibition layer had not been formed and on top of non-stoichiometric Fe-Al-Zn crystals. Poor wetting was observed on panels annealed in a low DP atmosphere because of the formation of thick film-type oxides on the surface. After annealing in higher DP gas atmospheres, i.e., 263 K and 278 K (-10 °C and 5 °C), a continuous and fine-grained Fe2Al5- x Zn x layer was formed. No Fe-Zn intermetallics were formed. The small grain size of the inhibition layer was attributed to the nucleation of the Fe2Al5- x Zn x grains on small ferrite sub-surface grains and the presence of granular surface oxides. A high DP atmosphere can therefore significantly contribute to the decrease of Zn-coating defects on CMnSi TRIP steels processed in HDG lines.

The structural, magnetic and optical properties of TMn@(ZnO)42 (TM = Fe, Co and Ni) hetero-nanostructure.

PubMed

Hu, Yaowen; Ji, Chuting; Wang, Xiaoxu; Huo, Jinrong; Liu, Qing; Song, Yipu

2017-11-28

The magnetic transition-metal (TM) @ oxide nanoparticles have been of great interest due to their wide range of applications, from medical sensors in magnetic resonance imaging to photo-catalysis. Although several studies on small clusters of TM@oxide have been reported, the understanding of the physical electronic properties of TM n @(ZnO) 42 is far from sufficient. In this work, the electronic, magnetic and optical properties of TM n @(ZnO) 42 (TM = Fe, Co and Ni) hetero-nanostructure are investigated using the density functional theory (DFT). It has been found that the core-shell nanostructure Fe 13 @(ZnO) 42 , Co 15 @(ZnO) 42 and Ni 15 @(ZnO) 42 are the most stable structures. Moreover, it is also predicted that the variation of the magnetic moment and magnetism of Fe, Co and Ni in TM n @ZnO 42 hetero-nanostructure mainly stems from effective hybridization between core TM-3d orbitals and shell O-2p orbitals, and a magnetic moment inversion for Fe 15 @(ZnO) 42 is investigated. Finally, optical properties studied by calculations show a red shift phenomenon in the absorption spectrum compared with the case of (ZnO) 48 .

The cycling of iron, zinc and cadmium in the North East Pacific Ocean - Insights from stable isotopes

NASA Astrophysics Data System (ADS)

Conway, Tim M.; John, Seth G.

2015-09-01

Dissolved stable isotope ratios of the transition metals provide useful information, both for understanding the cycling of these bioactive trace elements through the oceans, and tracing their marine sources and sinks. Here, we present seawater dissolved Fe, Zn and Cd concentration and stable isotope ratio (δ56Fe, δ66Zn, and δ114Cd) profiles from two stations in the Pacific Ocean, the SAFe Station (30°N 140°W) in the subtropical North East Pacific from the GEOTRACES IC2 cruise, and the marginal San Pedro Basin (33.8°N 118.4°W) within the South California Bight. These data represent, to our knowledge, the first full-water column profiles for δ66Zn and δ56Fe from the open-ocean North Pacific, and the first observations of dissolved δ66Zn and δ114Cd in a low-oxygen marginal basin. At the SAFe station, δ56Fe is isotopically lighter throughout the water column (-0.6 to +0.1‰, relative to IRRM-014) compared to the North Atlantic, suggesting significant differences in Fe sources or Fe cycling between these two ocean basins. A broad minimum in δ56Fe associated with the North Pacific oxygen minimum zone (OMZ; <75 μmol kg-1 dissolved oxygen; ∼550-2000 m depth) is consistent with reductive sediments along the California margin being an important source of dissolved Fe to the North Pacific. Other processes which may influence δ56Fe at SAFe include biological cycling in the upper ocean, and input of Fe from hydrothermal vents and oxic sediments below the OMZ. Zn and Cd concentration profiles at both stations broadly match the distribution of the macronutrients silicate and phosphate, respectively. At SAFe, δ114Cd increases towards the surface, reflecting the biological preference for assimilation of lighter Cd isotopes, while negative Cd∗ (-0.12) associated with low oxygen waters supports the recently proposed hypothesis of water-column CdS precipitation. In contrast to δ114Cd, δ66Zn at SAFe decreases towards the surface ocean, perhaps due to scavenging of isotopically heavy Zn, while at intermediate depths δ66Zn provides further evidence of a mid-depth dissolved δ66Zn maximum. We suggest this may be a global feature of Zn biogeochemistry related to either regeneration of heavy adsorbed Zn, or to ZnS formation and removal within the water column. Data from San Pedro shows that anoxic sediments can be a source of isotopically light Zn to the water column (δ66Zn of ∼-0.3‰ relative to JMC Lyon), though evidence of this signal is not observed being transported to SAFe. Within North Pacific Intermediate Water at SAFe (NPIW; ∼500 m) elevated Cd∗ and Zn∗ and a focused minimum in δ56Fe suggest possible transport of Fe, Zn, and Cd over thousands of km from subpolar waters, meaning that NPIW may have a strong influence on the subsurface distribution of trace metals throughout the North Pacific.

Synthesis of zinc ferrite/silver iodide composite with enhanced photocatalytic antibacterial and pollutant degradation ability.

PubMed

Xu, Yuanguo; Liu, Qingqing; Xie, Meng; Huang, Shuquan; He, Minqiang; Huang, Liying; Xu, Hui; Li, Huaming

2018-05-22

ZnFe 2 O 4 /AgI composites were first prepared successfully with a hydrothermal method, and ZnFe 2 O 4 nanoparticles were uniformly decorated on the surface of AgI particles. The photocatalytic activities of the obtained ZnFe 2 O 4 /AgI composites were investigated by the degradation of organic pollutants and the inactivation of bacteria under visible light irradiation. The results showed that the introduction of ZnFe 2 O 4 greatly enhanced the light harvesting ability and improved the separation efficiency of the photogenerated charge carriers, which contributed to the enhanced generation of reactive species and thus promoted the photocatalytic performance. The 5% ZnFe 2 O 4 /AgI composite exhibited the optimal photocatalytic disinfection of E. coli (100% removal efficiency in 80 min) as well as the photocatalytic degradation of rhodamine B (RhB) (98.5% removal rate in 40 min). Furthermore, four consecutive cycles also demonstrated the stable photocatalytic activity of the as-prepared ZnFe 2 O 4 /AgI composites. In addition, H 2 O 2 was identified as the predominant active species in the photocatalytic inactivation of bacteria. This study indicated that ZnFe 2 O 4 /AgI composites are a promising candidate for the treatment of wastewater. Copyright © 2018 Elsevier Inc. All rights reserved.

Magneto-optical properties of α-Fe2O3@ZnO nanocomposites prepared by the high energy ball-milling technique

NASA Astrophysics Data System (ADS)

Chaudhury, Chandana Roy; Roychowdhury, Anirban; Das, Anusree; Das, Dipankar

2016-05-01

Magnetic-fluorescent nanocomposites (NCs) with 10 wt% of α-Fe2O3 in ZnO have been prepared by the high energy ball-milling. The crystallite sizes of α-Fe2O3 and ZnO in the NCs are found to vary from 65 nm to 20 nm and 47 nm to 15 nm respectively as milling time is increased from 2 to 30 h. XRD analysis confirms presence of α-Fe2O3 and ZnO in pure form in all the NCs. UV-vis study of the NCs shows a continuous blue-shift of the absorption peak and a steady increase of band gap of ZnO with increasing milling duration that are assigned to decreasing particle size of ZnO in the NCs. Photoluminescence (PL) spectra of the NCs reveal three weak emission bands in the visible region at 421, 445 and 485 nm along with the strong near band edge emission at 391 nm. These weak emission bands are attributed to different defect - related energy levels e.g. Zn-vacancy, Zn interstitial and oxygen vacancy. Dc and ac magnetization measurements show presence of weakly interacting superparamagnetic (SPM) α-Fe2O3 particles in the NCs. 57Fe-Mössbauer study confirms presence of SPM hematite in the sample milled for 30 h. Positron annihilation lifetime measurements indicate presence of cation vacancies in ZnO nanostructures confirming results of PL studies.

Synthesis, characterization, and magnetic properties of ZnO-ZnFe2O4 nanoparticles with high photocatalytic activity

NASA Astrophysics Data System (ADS)

Falak, P.; Hassanzadeh-Tabrizi, S. A.; Saffar-Teluri, A.

2017-11-01

In the present research, a magnetic ZnO-ZnFe2O4 binary nanocomposite was synthesized by a one-step microemulsion method. The characteristics of the synthesized powders were characterized using various analytical instruments including X-ray diffraction, scanning electron microscope, transmission electron microscope, thermogravimetric and differential thermal analysis, vibrating sample magnetometer, and ultraviolet-visible spectroscopy. The results of transmission electron microscope proved that the synthesized nanoparticles have irregular morphologies and the average particle size is about 20 nm. The photocatalytic investigation of ZnO-ZnFe2O4 nanoparticles was carried out using methylene blue solution under UV light. The synthesized nanoparticles showed enhanced photocatalytic performance in comparison with the ZnO nanoparticles more than 40%. The magnetization saturation value of ZnO-ZnFe2O4 nanoparticles was about 5.8 emu/g, which was high enough to be magnetically removed by applying a magnetic field. The results showed that the magnetization and coercivity of the samples reduced by increasing calcination temperature.

Dielectric properties and carbothermic reduction of zinc oxide and zinc ferrite by microwave heating

PubMed Central

Fabritius, Timo; Heikkinen, Eetu-Pekka; Chen, Guo

2017-01-01

This paper aims to study the dielectric properties and carbothermic reduction of zinc oxide (zincite, ZnO) and zinc ferrite (franklinite, ZnFe2O4) by microwave heating. To achieve this aim, the dielectric properties were measured with an open-ended coaxial method to understand the behaviour of the samples under microwave irradiation. The effects of microwave power, duration time and sample mass on the heating rate, and the effects of the stoichiometric amount of graphite on the reduction of ZnO and decomposition of ZnFe2O4 were investigated. The results show that ZnFe2O4 has significantly higher dielectric properties compared to ZnO. Generally, for both samples, the dielectric values at room temperature were quite low, indicating that both ZnO and ZnFe2O4 are poor microwave absorbers. It was found that the temperatures have a more significant effect on the imaginary permittivities than on the real permittivities. The heating rate showed that the sample temperature increased with increase in microwave power and sample mass. Using 700 W of microwave power and two times the stoichiometric amount of graphite, almost complete reduction of ZnO was achieved in 12 min, while ZnFe2O4 completely decomposed to zincite and wustite in 3 min. PMID:28989772

Formation of zinc sulfide species during roasting of ZnO with pyrite and its contribution on flotation.

PubMed

Zheng, Yong-Xing; Lv, Jin-Fang; Wang, Hua; Wen, Shu-Ming; Pang, Jie

2018-05-18

In this paper, formation of zinc sulfide species during roasting of ZnO with FeS 2 was investigated and its contribution on flotation was illustrated. The evolution process, phase and crystal growth were investigated by thermogravimetry (TG), X-Ray diffraction (XRD) along with thermodynamic calculation and scanning electron microscopy-Energy-dispersive X-ray spectroscopy (SEM-EDS), respectively, to interpret the formation mechanism of ZnS species. It was found that ZnS was initially generated at about 450 °C and then the reaction prevailed at about 600 °C. The generated Fe x S would dissolve into ZnS and then form (Zn, Fe)S compound in form of Fe 2 Zn 3 S 5 when temperature increased to about 750 °C. This obviously accelerated ZnS phase formation and growth. In addition, it was known that increasing of ZnO dosage had few effects on the decomposition behavior of FeS 2 . Then, flotation tests of different zinc oxide materials before and after treatment were performed to further confirm that the flotation performances of the treated materials could be obviously improved. Finally, a scheme diagram was proposed to regular its application to mineral processing. It was systematically illustrated that different types of ZnS species needed to be synthetized when sulfidization roasting-flotation process was carried out to treat zinc oxide materials.

Mobility and fractionation of Fe, Pb and Zn in river sediments from a silver and base-metals mining area: Taxco, México.

PubMed

Espinosa, E; Armienta, M A

2007-08-01

The impact of mining wastes on both the concentration and environmental mobility of Zn, Pb and Fe was studied in a shallow river. The studied tributary of the Taxco river is located south of the historical Ag, Zn, Cu and Pb mining area of Taxco, about 150 km south of México City. Methodology included total concentration determinations and sequential extraction analyses of the operational defined fractions of sediments. Results indicated that Fe, Pb and Zn concentrations are up to 5, 100 and 390 times respectively, greater than regional background concentrations. Higher contents of Pb and Zn were observed in the rainy season versus the dry season, whereas Fe was lower in the rainy season. Zinc and lead increased downflow in the dry season, and did not show any trend during the rainy season. Speciation showed that Zn was mainly linked to the carbonatic fraction (25-39%), to the hydrous Fe/Mn oxides fraction (15-25%) and to the organic matter and sulfide fraction (14-48%); lead was mainly associated to the hydrous Fe/Mn oxides (49-59%) and residual (22-39%) fractions; finally, iron was contained mainly in the residual (65-78%) and the hydrous Fe/Mn oxides fraction (15%). Mobility decreased according to the relation: Zn > Pb > Fe. Sediments were classified as strongly polluted in zinc, strongly to very strongly polluted in Pb, and moderately to strongly polluted in iron. However, a low proportion of metals in the exchangeable fractions, indicates low bioavailability. Limestone presence played a very important role on Zn and Pb fractionation and environmental mobility. Results show the importance of including geological background in river pollution studies.

Meta-QTL analysis of seed iron and zinc concentration and content in common bean (Phaseolus vulgaris L.).

PubMed

Izquierdo, Paulo; Astudillo, Carolina; Blair, Matthew W; Iqbal, Asif M; Raatz, Bodo; Cichy, Karen A

2018-05-11

Twelve meta-QTL for seed Fe and Zn concentration and/or content were identified from 87 QTL originating from seven population grown in sixteen field trials. These meta-QTL include 2 specific to iron, 2 specific to zinc and 8 that co-localize for iron and zinc concentrations and/or content. Common bean (Phaseolus vulgaris L.) is the most important legume for human consumption worldwide and it is an important source of microelements, especially iron and zinc. Bean biofortification breeding programs develop new varieties with high levels of Fe and Zn targeted for countries with human micronutrient deficiencies. Biofortification efforts thus far have relied on phenotypic selection of raw seed mineral concentrations in advanced generations. While numerous quantitative trait loci (QTL) studies have been conducted to identify genomic regions associated with increased Fe and Zn concentration in seeds, these results have yet to be employed for marker-assisted breeding. The objective of this study was to conduct a meta-analysis from seven QTL studies in Andean and Middle American intra- and inter-gene pool populations to identify the regions in the genome that control the Fe and Zn levels in seeds. Two meta-QTL specific to Fe and two meta-QTL specific to Zn were identified. Additionally, eight Meta QTL that co-localized for Fe and Zn concentration and/or content were identified across seven chromosomes. The Fe and Zn shared meta-QTL could be useful candidates for marker-assisted breeding to simultaneously increase seed Fe and Zn. The physical positions for 12 individual meta-QTL were identified and within five of the meta-QTL, candidate genes were identified from six gene families that have been associated with transport of iron and zinc in plants.

Discrimination of Venezuelan spirituous beverages by a trace element-radial basis neural network approach.

PubMed

Hernández-Caraballo, Edwin A; Avila de Hernández, Rita M; Rivas-Echeverría, Francklin; Capote-Luna, Tarcisio

2008-01-15

Radial basis neural networks (RBNNs) were developed and evaluated for discrimination of specimens of 'aguardiente de Cocuy', a spirituous beverage produced in the northwestern region of Venezuela. The beverage is distilled from the must of Agave cocui Trelease in an artisanship fashion with little quality control. Forty specimens, with known concentrations of copper, iron, and zinc, were used in this study. The specimens were previously collected in various locations around Sucre Municipality (Falcón State) and Urdaneta Municipality (Lara State). The normalized concentrations of these elements served as indirect descriptors of origin (input data). They were presented to the neural networks through 1-3 input nodes in seven different combinations. In addition, two categories (two collection sites) and four categories (two collection sites+two manufacturing conditions) were designated as output data, in order to assess the impact of such selection on the discrimination performance. The overall performance of the four-category RBNNs was as follows (the input data is indicated in parentheses): (Cu-Fe)>(Cu-Zn)>(Cu)>(Zn)>(Fe-Zn)>(Cu-Fe-Zn)>(Fe). In this case, the highest percentage of correct hits was 82.5%. For the two-category RBNNs, the performance decreased as indicated below: (Cu)>(Cu-Fe)>(Cu-Zn)>(Fe-Zn)>(Zn) approximately (Cu-Fe-Zn)>(Fe). The reduction in the number of categories led to an increase in the discrimination performance of all the RBNNs, the best of which was 90.0%. The possibility of discriminating specimens of 'aguardiente de Cocuy' with such an accuracy, based on a single-element determination, is particularly attractive as it would result in a reduction of analysis' costs and laboratory's response time.

Facile synthesis of ZnFe2O4 photocatalysts for decolourization of organic dyes under solar irradiation

PubMed Central

Behera, Arjun; Kandi, Debasmita; Majhi, Sanjit Manohar

2018-01-01

ZnFe2O4 was fabricated by a simple solution-combustion method. The structural, optical and electronic properties are investigated by XRD, TEM, FESEM, UV–vis DRS, PL, FTIR and photocurrent measurements. The photocatalytic activity of the prepared material is studied with regard to the degradation of rhodamine B (Rh B) and Congo red under solar irradiation. The kinetic study showed that the material exhibits zeroth and first order reaction kinetics for the degradation of Rh B and Congo red, respectively. The photocatalytic behaviour of ZnFe2O4 was systematically studied as a function of the activation temperature. ZnFe2O4 prepared at 500 °C showed the highest activity in degrading Rh B and Congo red. The highest activity of ZnFe2O4-500 °C correlates well with the lowest PL intensity, highest photocurrent and lowest particle size. PMID:29515956

Facile synthesis of p-type Zn-doped α-Fe2O3 films for solar water splitting

NASA Astrophysics Data System (ADS)

Kuo, Chun-Lin; Hsu, Yu-Kuei; Lin, Yan-Gu

2014-10-01

A facile and simple fabrication of Zn-doped α-Fe2O3 thin films as a photocathode for solar hydrogen generation was proposed in this report. Transparent Zn-doped α-Fe2O3 films were prepared by a deposition-annealing (DA) process using nontoxic iron(III) chloride as the Fe precursor and zinc chloride as a acceptor dopant, followed by annealing at 550 °C in air. In terms of the structural examination of as-grown samples, X-ray diffraction analysis demonstrated an increase in the lattice parameters of Zn incorporated in Fe2O3 by substituting Fe in the host lattice. No second phase was determined, indicating no phase separation in the ternary materials. Energy dispersive spectroscopy results demonstrated that Zn, Fe, and O elements existed in the deposits. Furthermore, impedance measurements show that the Zn-dopant serves as an hole acceptor and increases the acceptor concentration by increasing concentration of zinc precursor. Significantly, the photoelectrochemical measurements exhibited remarkable cathodic current, corresponding to the reduction reaction of hydrogen. Finally, the optimum photocurrent can be achieved by controlled variation of the Fe and Zni precursor concentration, annealing conditions, and the number of DA cycles. According to our investigation, the understandings of morphology effect on PEC activity give the blueprint for materials design in the application of solar hydrogen.

Mixed Metal Oxides of the Type CoxZn1-xFe2O4 as Photocatalysts for Malachite Green Degradation Under UV Light Irradiation.

PubMed

Tzvetkov, Martin; Milanova, Maria; Cherkezova-Zheleva, Zara; Spassova, Ivanka; Valcheva, Evgenia; Zaharieva, Joana; Ivan, Mitov

2017-06-01

A combination of thermal and mechanical (high energy ball milling) treatment was applied in an attempt to obtain polycrystalline mixed metal binary and ternary oxides of the type CoxZn1-xFe2O4 (x = 0; 0.25; 0.5; 0.75; 1). The synthetic procedure used successfully produced single-phased, homogeneous ZnFe2O4, CoFe2O4, and Co0.75Zn0.25Fe2O4, as well as mixed oxides, whose composition depended both on the duration of the high energy ball milling and the ratio Zn(II)/Co(II). The formation of spinel-like structures was proved by XRD, Mössbauer spectroscopy and Raman spectroscopy. For the characterization of the samples low-temperature N2 adsorption, UV/Vis spectroscopy and transmission electron microscopy were applied. The energy band gap of the samples was calculated, suggesting they are promising photocatalysts. The decomposition of the Malachite Green in model water solutions under UV-light irradiation was successfully achieved in the presence of the samples as photocatalysts. The highest rate constant was obtained for the sample synthesized at longer milling time in combination with higher Zn(II)/Co(II) ratio. The photocatalytic activity of the ternary mixed oxides was compared with the pure hematite, α-Fe2O3, and the binary ZnFe2O4 and CoFe2O4 ferrites with spinel structure that were treated in the same way. A synergetic effect of α-Fe2O3 and the spinel-like structure on the photocatalytic properties of ternary mixed metal oxides was detected.

Synthesis of ZnFe2O4/SiO2 composites derived from a diatomite template.

PubMed

Liu, Zhaoting; Fan, Tongxiang; Zhou, Han; Zhang, Di; Gong, Xiaolu; Guo, Qixin; Ogawa, Hiroshi

2007-03-01

A novel porous ZnFe2O4/SiO2 composite product has been generated with a template-directed assembly method from porous diatomite under different synthesis conditions, such as precursor concentrations (metallic nitrates), calcination temperature and diatomite type. The phase composition and morphology of all the materials were examined by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results indicated that an inherited hierarchical porous structure from the diatomite template can be obtained, and the synthesis conditions were found to have clear effects on the formation of the ZnFe2O4/SiO2 composite. The ideal composite of ZnFe2O4/SiO2 can be obtained through optimization of diatomite template type, precursor solution and calcination temperature. Furthermore, the adsorption abilities of two types of diatomites were analyzed in detail using FTIR spectra and nitrogen adsorption measurements etc, which proved that A-diatomite (Shengzhou-diatomite) is better than B-diatomite (Changbai-diatomite) on the aspect of adsorbing Zn and Fe ions, and of forming the ZnFe2O4.

Phase Equilibria Studies in the System ZnO-``FeO''-Al2O3-CaO-SiO2 Relevant to Imperial Smelting Furnace Slags: Part I

NASA Astrophysics Data System (ADS)

Zhao, Baojun; Hayes, Peter C.; Jak, Evgueni

2010-04-01

The phase equilibria and liquidus temperatures in the system ZnO-“FeO”-Al2O3-CaO-SiO2 in equilibrium with metallic iron have been determined experimentally in the temperature range of 1423 K to 1553 K. The experimental conditions were focused on the composition range relevant to Imperial Smelting Furnace slags. The results are presented in the form of a pseudo-ternary section ZnO-“FeO”-(CaO + SiO2 + Al2O3) in which CaO/SiO2 = 0.93 and (CaO + SiO2)/Al2O3 = 7.0. It was found that wustite and spinel are the major primary phases and that zincite and melilite are also present in the composition range investigated. Wustite (Fe2+,Zn)O and spinel (Fe2+,Zn)O (A1,Fe3+)2O3 solid solutions are formed in this system, and the ZnO concentration in the spinel phase is found to be much greater than in the liquid phase.

Doping induced modifications in the electronic structure and magnetism of ZnO films: Valence band and conduction band studies

NASA Astrophysics Data System (ADS)

Katba, Savan; Jethva, Sadaf; Udeshi, Malay; Trivedi, Priyanka; Vagadia, Megha; Shukla, D. K.; Choudhary, R. J.; Phase, D. M.; Kuberkar, D. G.

2017-11-01

The electronic structure of Pulsed Laser Deposited (PLD) ZnO, Zn0.95Fe0.05O (ZFO), Zn0.98Al0.02O (ZAO) and Zn0.93Fe0.05Al0.02O (ZFAO) films were investigated by Photoelectron spectroscopy and X-ray absorption spectroscopy. X-ray diffraction and ϕ-scan measurements show epitaxial c-directional growth of the films. Temperature dependent magnetization and M-H loop measurements show the presence of room temperature magnetic ordering in all the films. Fittings of Fe 2p XPS and Fe L3,2 -edge XAS of ZFO and ZFAO films show the presence of Fe, in both, Fe+2 and Fe+3 states in tetrahedral symmetry. Valence band spectra in resonance mode show resonance photon energy at 56 eV showing the presence of Fe2+ state (∼2 eV) near the Fermi level. A significant effect of Fe and Al doping on the spectral shape of O K-edge XAS was observed. Results of the Spectroscopic studies reveal that, ferromagnetism in the films is due to the contribution of oxygen deficiency which increases the number of charge carriers that take part in the exchange interaction. Al co-doping with Fe (in ZFAO) results in the enhancement of saturation magnetization by increase in the carrier-mediated ferromagnetic exchange interaction.

Fixed distance photoinduced electron transfer between Fe and Zn porphyrins encapsulated within the Zn HKUST-1 metal organic framework.

PubMed

Larsen, Randy W; Wojtas, Lukasz

2015-02-21

An attractive strategy for the development of photocatalytic metal organic framework (MOF) materials is to co-encapsulate a photoactive electron donor with a catalytic electron acceptor within the MOF. Here we report the co-encapsulation of both Zn(ii) tetrakis(tetra 4-sulphonatophenyl)porphyrin (Zn4SP) and Fe(iii) tetrakis(tetra 4-sulphonatophenyl)porphyrin (Fe4SP) into an HKUST-1 (Zn) MOF and demonstrate photoinduced electron transfer (ET) between the co-encapsulated guest. Photo-excitation of the Zn4SP results in fixed-distance inter-molecular ET between the encapsulated (3)Zn4SP and the Fe(iii)4SP as evident by the reduction in the encapsulated (3)Zn4SP lifetime from 890 μs (kobs = 1.1 × 10(3) s(-1)) to 83 μs (kobs = 1.2 × 10(4) s(-1)) in the presence of Fe4SP giving a kET ∼ 1.1 × 10(4) s(-1). The data are consistent with ET taking place between encapsulated porphyrins that are two cages apart in distance with a reorganizational energy of ∼1.65 eV, β = 1.25 and ΔG° = -0.97 eV (within a semi-classical Marcus theory framework).

Electrochemical corrosion behavior, microstructure and magnetic properties of sintered Nd-Fe-B permanent magnet doped by CuZn5 powders

NASA Astrophysics Data System (ADS)

Liu, W. Q.; Wang, Z.; Sun, C.; Yue, M.; Liu, Y. Q.; Zhang, D. T.; Zhang, J. X.

2014-05-01

Nd-Fe-B permanent magnets with a small amount of CuZn5 powders doping were prepared by conventional sintered method. The effects of CuZn5 contents on magnetic properties and microstructure, electrochemical corrosion resistance of sintered Nd-Fe-B magnets were systematically studied. The results show that the magnetic properties of magnets do not have a significant variation by CuZn5 powders doping; the coercivity of magnets rises gradually, while the remanence of the magnets decreases a little with increasing of the CuZn5 amount. The CuZn5 doped magnets have more positive corrosion potential, Ecorr, and much lower corrosion current density, icorr, than the magnets without CuZn5 doping, indicating CuZn5 doping could improve the corrosion resistance. Both Zn and Cu enrich mainly into the Nd-rich phase, fully improve the wettability between the Nd-rich phase and the Nd2Fe14B phase, and repair the defects of the main phase, so the coercivity of magnets doped with CuZn5 powders rises. Such microstructure modification effectively restrains the aggressive inter-granular corrosion. As a result, the CuZn5 doped magnet possesses excellent corrosion resistance in NaCl electrolyte.

Low temperature magnetization and anomalous high temperature dielectric behaviour of (1-x) YMnO3/xZnFe2O4 composites

NASA Astrophysics Data System (ADS)

Kumar, Virendra; Gaur, Anurag

2018-04-01

We synthesized YMnO3 and ZnFe2O4 composites, (1-x)YMnO3/x(ZnFe2O4) with x = 0, 0.05, 0.10, and 0.15 by high temperature sintering. X-ray diffraction (XRD) patterns indicate the successful formation of composites. Weak ferromagnetism is manifested below Néel temperature (TN) for pristine YMnO3, according to (M-H) study performed at 10 K. For (1-x)YMnO3/xZnFe2O4 (x = 0.05, 0.10, 0.15) a thin coercivity is observed in all compositions, due to short range magnetic ordering at low temperature after the insertion of ZnFe2O4. For pristine YMnO3 explicit divarication between FC-ZFC curves is observed, with crimps observed in both FC and ZFC curves at 75 K, which is the TN of YMnO3. For 1-x(YMnO3)/x ZnFe2O4 composites (x = 0.05, 0.10, 0.15) crimps are perceived only in ZFC curves at slightly varying values of 39.8, 42.32 and 45.63 K respectively. Anomalous peaks are observed in high temperature dielectric curves above 400 K for 1-x(YMnO3)/xZnFe2O4 (x = 0, 0.05, 0.10, 0.15) composites due to Maxwell-Wagner relaxation effect.

Uniformly Dispersed ZnFe2O4 Nanoparticles on Nitrogen-Modified Graphene for High-Performance Supercapacitor as Electrode.

PubMed

Li, Lei; Bi, Huiting; Gai, Shili; He, Fei; Gao, Peng; Dai, Yunlu; Zhang, Xitian; Yang, Dan; Zhang, Milin; Yang, Piaoping

2017-02-21

A facile strategy has been adopted for the preparation of ZnFe 2 O 4 /NRG composite by anchoring ultrasmall ZnFe 2 O 4 nanoparticles on nitrogen-doped reduced graphene (denoted as NRG) for high-performance supercapacitor electrode. Remarkably, the growth of ZnFe 2 O 4 nanocrystals, the reduction of graphitic oxide and the doping of nitrogen to graphene have been simultaneously achieved in one process. It is found that the NRG employed as substrate can not only control the formation of nano-sized ZnFe 2 O 4 , but also guarantee the high dispersion without any agglomeration. Benefiting from this novel combination and construction, the hybrid material has large surface area which can provide high exposure of active sites for easy access of electrolyte and fast electron transport. When served as supercapacitor electrode, the ZnFe 2 O 4 /NRG composite exhibits a favorable specific capacitance of 244 F/g at 0.5 A/g within the potential range from -1 to 0 V, desirable rate stability (retain 131.5 F/g at 10 A/g) and an admirable cycling durability of 83.8% at a scan rate of 100 mV/s after 5000 cycles. When employed as symmetric supercapacitor, the device demonstrates favorable performance. These satisfactory properties of the ZnFe 2 O 4 /NRG composite can make it be of great promise in the supercapacitor application.

Cation distribution in NiZn-ferrite films determined using x-ray absorption fine structure

NASA Astrophysics Data System (ADS)

Harris, V. G.; Koon, N. C.; Williams, C. M.; Zhang, Q.; Abe, M.

1996-04-01

We have applied extended x-ray absorption fine structure (EXAFS) spectroscopy to study the cation distribution in a series of spin-sprayed NiZn-ferrite films, Ni0.15ZnyFe2.85-yO4 (y=0.16, 0.23, 0.40, 0.60). The Ni, Zn, and Fe EXAFS were collected from each sample and analyzed to Fourier transforms. Samples of Ni-ferrite, Zn-ferrite, and magnetite were similarly studied as empirical standards. These standards, together with EXAFS data generated from the theoretical EXAFS FEFF codes, allowed the correlation of features in the Fourier transforms with specific lattice sites in the spinel unit cell. We find that the Ni ions reside mostly on the octahedral (B) sites whereas the Zn ions are predominantly on the tetrahedral (A) sites. The Fe ions reside on both A and B sites in a ratio determined by the ratio of Zn/Fe. The addition of Zn displaces a larger fraction of Fe cations onto the B sites serving to increase the net magnetization. The fraction of A site Ni ions is measured to increase peaking at ≊25% for y=0.6. At higher Zn concentrations (y≥0.5) the lattice experiences local distortions around the Zn sites causing a decrease in the superexchange resulting in a decrease in the net magnetization.

Mössbauer spectroscopy of ZnxMg1-x Fe2O4 (0 ≤ x ≤ 0.74) nanostructures crystallized from borate glasses

NASA Astrophysics Data System (ADS)

El Shabrawy, S.; Miglierini, M.; Schaaf, P.; Tzankov, D.; Georgieva, M.; Harizanova, R.; Rüssel, C.

2018-03-01

Glasses in the system 51.7 B2O3/9.3 K2O/1 P2O5/10.4 Fe2O3/(27.6 - y) MgO/y ZnO (with y = 0, 1, 2.5, 5, 7.5, 10, 13.8, and 20) were prepared by the conventional melt quenching method. The glass samples were thermally treated at 560 °C for 3 h in ambient conditions. Using 57Fe Mössbauer spectroscopy, the effect of the substitution of MgO by ZnO in the glass network and the effect on the precipitated crystallized phase was studied. The results showed that the ratio of Zn2+:Mg2+ in the precipitated crystals increases with the ZnO concentration in the glass. The isomer shift values indicated that iron occurs as Fe3+, which is distributed at the tetrahedral (A) and the octahedral [B] sites. Introducing ZnO leads to a relative increase of the Fe3+ concentration at the B sites at the expense of that occupying the A sites. This indicates the precipitation of ZnxMg1-x Fe2O4 nanoparticles, where Zn2+ ions favorably occupy the A sites. The average hyperfine field of the samples showed a strong dependence on the Zn concentration. At the highest Zn concentration of 13.8 and 20 mol%, the samples are paramagnetic, while for the smaller ones, the samples are superparamagnetic.

Metals in sediments and fish from Sea Lots and Point Lisas harbors, Trinidad and Tobago

USGS Publications Warehouse

Mohammed, Azad; May, Thomas; Echols, Kathy; Walther, Mike; Manoo, Anton; Maraj, Dexter; Agard, John; Orazio, Carl

2012-01-01

Concentrations of heavy metals were determined in nearshore marine sediments and fish tissue from Sea Lots area on the west coast, at Caroni Lagoon National Park, and in the Point Lisas harbor, Trinidad. The most dominant metals found in sediments were Al, Fe and Zn with mean concentrations highest at Sea Lots (Al-39420 μg/g; Fe-45640 μg/g; Zn-245 μg/g), when compared to sediments from Point Lisas (Al-11936 μg/g; Fe-30171 μg/g; Zn-69 μg/g) and Caroni (Al-0400 μg/g; Fe-19000 μg/g; Zn-32 μg/g), High concentration of Cu, Al, Fe and Zn were also detected in fish tissue from Point Lisas and Caroni. Metal concentrations in fish tissue showed significant correlation with sediment metals concentration, which suggests that tissue levels are influenced by sediment concentration. Of the metals, only Zn, Hg and Cu had a bioaccumulation factor (BAF) greater than one, which suggests a high bioaccumulation potential for these metals.

Magnetic properties of M0.3Fe2.7O4 (M = Fe, Zn and Mn) ferrites nanoparticles

NASA Astrophysics Data System (ADS)

Modaresi, Nahid; Afzalzadeh, Reza; Aslibeiki, Bagher; Kameli, Parviz

2018-06-01

In the present article a comparative study on the structural and magnetic properties of nano-sized M0.3Fe0.7Fe2O4 (M = Fe, Zn and Mn) ferrites have been reported. The X-ray diffraction (XRD) patterns show that the crystallite size depends on the cation distribution. The Rietveld refinement of XRD patterns using MAUD software determines the distribution of cations and unit cell dimensions. The magnetic measurements show that the maximum and minimum value of saturation magnetization is obtained for Zn and Mn doped samples, respectively. The peak temperature of AC magnetic susceptibility of Zn and Fe doped samples below 300 K shows the superparamagnetic behavior in these samples at room temperature. the AC susceptibility results confirm the presence of strong interactions between the nanoparticles which leads to a superspin glass state in the samples at low temperatures.

Enhanced Al and Zn removal from coal-mine drainage during rapid oxidation and precipitation of Fe oxides at near-neutral pH

USGS Publications Warehouse

Burrows, Jill E.; Cravotta, Charles A.; Peters, Stephen C.

2017-01-01

Net-alkaline, anoxic coal-mine drainage containing ∼20 mg/L FeII and ∼0.05 mg/L Al and Zn was subjected to parallel batch experiments: control, aeration (Aer 1 12.6 mL/s; Aer 2 16.8 mL/s; Aer 3 25.0 mL/s), and hydrogen peroxide (H2O2) to test the hypothesis that aeration increases pH, FeII oxidation, hydrous FeIII oxide (HFO) formation, and trace-metal removal through adsorption and coprecipitation with HFO. During 5.5-hr field experiments, pH increased from 6.4 to 6.7, 7.1, 7.6, and 8.1 for the control, Aer 1, Aer 2, and Aer 3, respectively, but decreased to 6.3 for the H2O2 treatment. Aeration accelerated removal of dissolved CO2, Fe, Al, and Zn. In Aer 3, dissolved Al was completely removed within 1 h, but increased to ∼20% of the initial concentration after 2.5 h when pH exceeded 7.5. H2O2 promoted rapid removal of all dissolved Fe and Al, and 13% of dissolved Zn.Kinetic modeling with PHREEQC simulated effects of aeration on pH, CO2, Fe, Zn, and Al. Aeration enhanced Zn adsorption by increasing pH and HFO formation while decreasing aqueous CO2 available to form ZnCO30 and Zn(CO3)22− at high pH. Al concentrations were inconsistent with solubility control by Al minerals or Al-containing HFO, but could be simulated by adsorption on HFO at pH < 7.5 and desorption at higher pH where Al(OH)4− was predominant. Thus, aeration or chemical oxidation with pH adjustment to ∼7.5 could be effective for treating high-Fe and moderate-Zn concentrations, whereas chemical oxidation without pH adjustment may be effective for treating high-Fe and moderate-Al concentrations.

Acceptability of Iron- and Zinc-Biofortified Pearl Millet (ICTP-8203)-Based Complementary Foods among Children in an Urban Slum of Mumbai, India.

PubMed

Huey, Samantha Lee; Venkatramanan, Sudha; Udipi, Shobha A; Finkelstein, Julia Leigh; Ghugre, Padmini; Haas, Jere Douglas; Thakker, Varsha; Thorat, Aparna; Salvi, Ashwini; Kurpad, Anura V; Mehta, Saurabh

2017-01-01

Biofortification, a method for increasing micronutrient content of staple crops, is a promising strategy for combating major global health problems, such as iron and zinc deficiency. We examined the acceptability of recipes prepared using iron- and zinc-biofortified pearl millet (FeZnPM) (~80 ppm Fe, ~34 ppm Zn, varietal ICTP-8203), compared to conventional pearl millet (CPM) (~20 ppm Fe, ~19 ppm Zn) in preparation for an efficacy trial. Our objective was to examine the acceptability of FeZnPM compared to CPM among young children and mothers living in the urban slums of Mumbai. Standardized traditional feeding program recipes ( n  = 18) were prepared with either FeZnPM or CPM flour. The weight (g) of each food product was measured before and after consumption by children ( n  = 125) and the average grams consumed over a 3-day period were recorded. Mothers ( n  = 60) rated recipes using a 9-point hedonic scale. Mean intakes and hedonic scores of each food product were compared using t -tests across the two types of pearl millet. There were no statistically significant differences in consumption by children (FeZnPM: 25.27 ± 13.0 g; CPM: 21.72 ± 6.90 g) across the food products ( P  = 0.28). Overall mean hedonic scores for all recipes were between 7 to 9 points. CPM products were rated higher overall (8.22 ± 0.28) compared to FeZnPM products (7.95 ± 0.35) ( P  = 0.01). FeZnPM and CPM were similarly consumed and had high hedonic scores, demonstrating high acceptability in this population. These results support using these varieties of pearl millet in a proposed trial [http://Clinicaltrials.gov ID: NCT02233764; Clinical Trials Registry of India (CTRI), reference number REF/2014/10/007731, CTRI number CTRI/2015/11/006376] testing the efficacy of FeZnPM for improving iron status and growth.

Acceptability of Iron- and Zinc-Biofortified Pearl Millet (ICTP-8203)-Based Complementary Foods among Children in an Urban Slum of Mumbai, India

PubMed Central

Huey, Samantha Lee; Venkatramanan, Sudha; Udipi, Shobha A.; Finkelstein, Julia Leigh; Ghugre, Padmini; Haas, Jere Douglas; Thakker, Varsha; Thorat, Aparna; Salvi, Ashwini; Kurpad, Anura V.; Mehta, Saurabh

2017-01-01

Biofortification, a method for increasing micronutrient content of staple crops, is a promising strategy for combating major global health problems, such as iron and zinc deficiency. We examined the acceptability of recipes prepared using iron- and zinc-biofortified pearl millet (FeZnPM) (~80 ppm Fe, ~34 ppm Zn, varietal ICTP-8203), compared to conventional pearl millet (CPM) (~20 ppm Fe, ~19 ppm Zn) in preparation for an efficacy trial. Our objective was to examine the acceptability of FeZnPM compared to CPM among young children and mothers living in the urban slums of Mumbai. Standardized traditional feeding program recipes (n = 18) were prepared with either FeZnPM or CPM flour. The weight (g) of each food product was measured before and after consumption by children (n = 125) and the average grams consumed over a 3-day period were recorded. Mothers (n = 60) rated recipes using a 9-point hedonic scale. Mean intakes and hedonic scores of each food product were compared using t-tests across the two types of pearl millet. There were no statistically significant differences in consumption by children (FeZnPM: 25.27 ± 13.0 g; CPM: 21.72 ± 6.90 g) across the food products (P = 0.28). Overall mean hedonic scores for all recipes were between 7 to 9 points. CPM products were rated higher overall (8.22 ± 0.28) compared to FeZnPM products (7.95 ± 0.35) (P = 0.01). FeZnPM and CPM were similarly consumed and had high hedonic scores, demonstrating high acceptability in this population. These results support using these varieties of pearl millet in a proposed trial [http://Clinicaltrials.gov ID: NCT02233764; Clinical Trials Registry of India (CTRI), reference number REF/2014/10/007731, CTRI number CTRI/2015/11/006376] testing the efficacy of FeZnPM for improving iron status and growth. PMID:28971097

Abnormal variation of band gap in Zn doped Bi{sub 0.9}La{sub 0.1}FeO{sub 3} nanoparticles: Role of Fe-O-Fe bond angle and Fe-O bond anisotropy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Xunling; Liu, Weifang, E-mail: wfliu@tju.edu.cn, E-mail: shouyu.wang@yahoo.com; Wu, Ping

2015-07-27

Bi{sub 0.9}La{sub 0.1}FeO{sub 3} (BLFO) and Bi{sub 0.9}La{sub 0.1}Fe{sub 0.99}Zn{sub 0.01}O{sub 3} (BLFZO) nanoparticles were prepared via a sol-gel method. The oxygen vacancies and holes increase with Zn doping analyzed through X-ray photoelectron spectroscopy, which could contribute to the increase of leakage current density. However, with the increase of the defects (oxygen vacancies and holes), the band gap of BLFZO also is increased. To explain the abnormal phenomenon, the bandwidth of occupied and unoccupied bands was analyzed based on the structural symmetry driven by the Fe-O-Fe bond angle and Fe-O bond anisotropy.

Multifunctional Fe3O4/ZnO nanocomposites with magnetic and optical properties.

PubMed

Zou, Peng; Hong, Xia; Chu, Xueying; Li, Yajun; Liu, Yichun

2010-03-01

Multifunctional Fe3O4/ZnO nanocomposites were successfully synthesized through two-step solution-based methods. Fe3O4 nanoparticles were used as seeds for the deposit and growth of ZnO nanocrystals. Transmission electron microscopy (TEM) images, X-ray diffraction (XRD) patterns, and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) were employed to observe the morphology, size, structure, and crystalline phase of the nanocomposites and confirm their chemical composition. The results of magnetization curves, resonant Raman scattering, and photoluminescence spectra revealed that the nanocomposites simultaneously possessed the super-paramagnetism of Fe3O4 and the multiphonon resonant Raman scattering and photoluminescence (PL) properties of ZnO. Compared with that of pure Fe3O4, the saturation magnetization of the Fe3O4 component within the nanocomposites was enhanced. The Raman spectroscopic fingerprint of ZnO component was preserved, and the fluorescent background was efficiently reduced. The interfacial effect was found to play an important role in modulating or improving the properties of the nanocomposites.

Bioavailability of Fe and Zn in selected legumes, cereals, meat and milk products consumed in Fiji.

PubMed

Singh, Poonam; Prasad, Surendra; Aalbersberg, William

2016-09-15

The present study reports contents and the bioavailability of Fe and Zn from 25 selected raw and cooked food samples. The results showed highest variation of Fe content in raw food samples ranging from 2.19 ± 0.04 to 0.93 ± 0.03 mg/100g in legumes. The raw black eye bean, cheese and fish showed high Zn content up to 8.85 ± 0.01, 12.93 ± 0.26 and 172.03 ± 5.09 mg/100g, respectively. Pulses and cereals showed high level of ionizable Fe. Zn bioavailability was quite low in cereals as compared to pulses; 4.02% in yellow split to 17.40% in Bengal gram. Zn bioavailability of 17.40% is in cheese. Fe bioavailability is high in cooked rice 160.60%, white bread 428.30% and milk powder 241.67% showing that Fe bioavailability increased after cooking whereas the lowest in fish 0.84%. The multivariate and cluster analysis categorized studied foods into two main groups. Copyright © 2016 Elsevier Ltd. All rights reserved.

Factors affecting the partitioning of Cu, Zn and Pb in boulder coatings and stream sediments in the vicinity of a polymetallic sulfide deposit

USGS Publications Warehouse

Filipek, L.H.; Chao, T.T.; Carpenter, R.H.

1981-01-01

A sequential extraction scheme is utilized to determine the geochemical partitioning of Cu, Zn and Pb among hydrous Mn- and Fe-oxides, organics and residual crystalline silicates and oxides in the minus-80-mesh ( Fe-oxides > Mn-oxides; Zn, Mn-oxides {reversed tilde equals} organics > Fe-oxides; Pb, Fe-oxides > organics > Mn-oxides. In the sediments, organics are the most efficient scavengers of all three ore metals. These results emphasize the importance of organics as sinks for the ore metals, even in environments with high concentrations of Mn- and Fe-oxides. Of the ore metals, Zn appears to be the most mobile, and is partitioned most strongly into the coatings. However, anomaly contrast for hydromorphic Zn, normalized to the MnFe-oxide or organic content, is similar in sediments and coatings. Cu shows the highest anomaly on the boulder coatings, probably due to precipitation of a secondary Cu mineral. In contrast, detrital Pb in the pan concentrates shows a better anomaly than any hydromorphic Pb component. ?? 1981.

Dual nature of 3 d electrons in YbT 2 Zn 20 (T = Co; Fe) evidenced by electron spin resonance

DOE PAGES

Ivanshin, V. A.; Litvinova, T. O.; Gimranova, K.; ...

2015-03-18

The electron spin resonance experiments were carried out in the single crystals YbFe 2Zn 20. The observed spin dynamics is compared with that in YbCo 2Zn 20 and Yb 2Co 12P 7 as well as with the data of inelastic neutron scattering and electronic band structure calculations. Our results provide direct evidence that 3d electrons are itinerant in YbFe 2Zn 20 and localized in YbCo 2Zn 20. Possible connection between spin paramagnetism of dense heavy fermion systems, quantum criticality effects, and ESR spectra is discussed.

Mechanism of γ-irradiation induced phase transformations in nanocrystalline Mn{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jagadeesha Angadi, V.; Anupama, A.V.; Choudhary, Harish K.

The structural, infrared absorption and magnetic property transformations in nanocrystalline Mn{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} samples irradiated with different doses (0, 15, 25 and 50 kGy) of γ-irradiation were investigated in this work and a mechanism of phase transformation/decomposition is provided based on the metastable nature of the Mn-atoms in the spinel lattice. The nano-powder sample was prepared by solution combustion route and the pellets of the sample were exposed to γ-radiation. Up to a dose of 25 kGy of γ-radiation, the sample retained the single phase cubic spinel (Fd-3m) structure, but the disorder in the sample increased. On irradiatingmore » the sample with 50 kGy γ-radiation, the spinel phase decomposed into new stable phases such as α-Fe{sub 2}O{sub 3} and ZnFe{sub 2}O{sub 4} phases along with amorphous MnO phase, leading to a change in the surface morphology of the sample. Along with the structural transformations the magnetic properties deteriorated due to breakage of the ferrimagnetic order with higher doses of γ-irradiation. Our results are important for the understanding of the stability, durability and performance of the Mn-Zn ferrite based devices used in space applications. - Graphical abstract: The nanocrystalline Mn{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} ceramic sample transforms to crystalline α-Fe{sub 2}O{sub 3} and ZnFe{sub 2}O{sub 4} phases (and amorphous MnO phase) at a γ-irradiation dose of 50 kGy, as MnO goes out of the spinel lattice. The high energy γ-irradiation causes structural damage to the nanomaterials leading to change in morphology of the sample as seen in the SEM images. - Highlights: • Mn atoms are more unstable in the Mn-Zn ferrite spinel lattice than Zn-atoms. • Displacement of Mn atoms by γ-radiation from the lattice renders phase transformation. • In Mn{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4}, Mn-ferrite cell transforms to crystalline α-Fe{sub 2}O{sub 3} and amorphous MnO. • The stable ZnFe{sub 2}O{sub 4} phase retains its structure even after 50 KGy γ-irradiation. • The γ-irradiation degrades the magnetic properties of Mn{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} ceramics.« less

Spatial evolution of Zn-Fe-Pb isotopes of sphalerite within a single ore body: A case study from the Dongshengmiao ore deposit, Inner Mongolia, China

NASA Astrophysics Data System (ADS)

Gao, Zhaofu; Zhu, Xiangkun; Sun, Jian; Luo, Zhaohua; Bao, Chuang; Tang, Chao; Ma, Jianxiong

2018-01-01

Analyses of sphalerite minerals from the characteristic brecciated Zn-Pb ores of the main ore body in the giant Dongshengmiao deposit have revealed variations in δ66Zn from 0.17 to 0.40‰ and in δ56Fe from -1.78 to -0.35‰. Further, the investigated pyrrhotite samples have iron that is isotopically similar to that of associated sphalerite minerals. The most distinctive pattern revealed by the zinc and iron isotope data is the lateral trend of increasing δ66Zn and δ56Fe values from southwest to northeast within the main ore body. The lead isotopic homogeneity of ore sulfides from the main ore body suggests that there is only one significant source for metal, thus precluding the mixing of multiple metal sources as the key factor controlling spatial variations of zinc and iron isotopes. The most likely control on spatial variations is Rayleigh fractionation during hydrothermal fluid flow, with lighter Zn and Fe isotopes preferentially incorporated into the earliest sulfides to precipitate from fluids. Precipitations of sphalerite and pyrrhotite have played vital roles in the Zn and Fe isotopic variations, respectively, of the ore-forming system. Accordingly, the larger isotopic variability for Fe than Zn within the same hydrothermal system perhaps resulted from a larger proportion of precipitation for pyrrhotite than for sphalerite. The lateral trend pattern revealed by the zinc and iron isotope data is consistent with the occurrence of a cystic-shaped breccia zone, which is characterized by marked elevation in Cu. The results further confirm that Zn and Fe isotopes can be used as a vectoring tool for mineral prospecting.

Probing the Li Insertion Mechanism of ZnFe 2O 4 in Li-Ion Batteries: A Combined X-Ray Diffraction, Extended X-Ray Absorption Fine Structure, and Density Functional Theory Study [Probing the Li insertion mechanism of ZnFe 2O 4 in Li ion batteries: A combined XRD, EXAFS, and DFT study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yiman; Pelliccione, Christopher J.; Brady, Alexander B.

Here, we report an extensive study on fundamental properties that determine the functional electrochemistry of ZnFe 2O 4 spinel (theoretical capacity of 1000 mAh/g). For the first time, the reduction mechanism is followed through a combination of in situ X-ray diffraction data, synchrotron based powder diffraction, and ex-situ extended X-ray absorption fine structure allowing complete visualization of reduction products irrespective of their crystallinity. The first 0.5 electron equivalents (ee) do not significantly change the starting crystal structure. Subsequent lithiation results in migration of Zn 2+ ions from 8a tetrahedral sites into vacant 16c sites. Density functional theory shows that Limore » + ions insert into 16c site initially and then 8a site with further lithiation. Fe metal is formed over the next eight ee of reduction with no evidence of concurrent Zn 2+ reduction to Zn metal. Despite the expected formation of LiZn alloy from the electron count, we find no evidence for this phase under the tested conditions. Additionally, upon oxidation to 3 V, we observe an FeO phase with no evidence of Fe 2O 3. Electrochemistry data show higher electron equivalent transfer than can be accounted for solely based on ZnFe 2O 4 reduction indicating excess capacity ascribed to carbon reduction or surface electrolyte interphase formation.« less

Probing the Li Insertion Mechanism of ZnFe 2O 4 in Li-Ion Batteries: A Combined X-Ray Diffraction, Extended X-Ray Absorption Fine Structure, and Density Functional Theory Study [Probing the Li insertion mechanism of ZnFe 2O 4 in Li ion batteries: A combined XRD, EXAFS, and DFT study

DOE PAGES

Zhang, Yiman; Pelliccione, Christopher J.; Brady, Alexander B.; ...

2017-04-24

Here, we report an extensive study on fundamental properties that determine the functional electrochemistry of ZnFe 2O 4 spinel (theoretical capacity of 1000 mAh/g). For the first time, the reduction mechanism is followed through a combination of in situ X-ray diffraction data, synchrotron based powder diffraction, and ex-situ extended X-ray absorption fine structure allowing complete visualization of reduction products irrespective of their crystallinity. The first 0.5 electron equivalents (ee) do not significantly change the starting crystal structure. Subsequent lithiation results in migration of Zn 2+ ions from 8a tetrahedral sites into vacant 16c sites. Density functional theory shows that Limore » + ions insert into 16c site initially and then 8a site with further lithiation. Fe metal is formed over the next eight ee of reduction with no evidence of concurrent Zn 2+ reduction to Zn metal. Despite the expected formation of LiZn alloy from the electron count, we find no evidence for this phase under the tested conditions. Additionally, upon oxidation to 3 V, we observe an FeO phase with no evidence of Fe 2O 3. Electrochemistry data show higher electron equivalent transfer than can be accounted for solely based on ZnFe 2O 4 reduction indicating excess capacity ascribed to carbon reduction or surface electrolyte interphase formation.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coussy, Samuel; Grangeon, Sylvain; Bataillard, Philippe

The prediction of the long term trace element mobility in anthropogenic soils would be a way to anticipate land management and should help in reusing slightly contaminated materials. In the present study, iron (Fe) and zinc (Zn) status evolution was investigated in a 100-year old Technosol. The site of investigation is an old brownfield located in the Nord-Pas-de-Calais region (France) which has not been reshaped since the beginning of the last century. The whole soil profile was sampled as a function of depth, and trace elements mobility at each depth was determined by batch leaching test. A specific focus onmore » Fe and Zn status was carried out by bulk analyses, such as selective dissolution, X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). Fe and Zn status in the profile samples was also studied using laterally resolved techniques such as μ-particle induced X-ray emission (μ-PIXE) and μ-Rutherford backscattering spectroscopy (μ-RBS). The results indicate that (i) Fe is mainly under Fe(III) form, except a minor contribution of Fe(II) in the deeper samples, (ii) some Fe species inherited from the past have been weathered and secondary minerals are constituted of metal-bearing sulphates and Fe (hydr)oxides, (iii) ferrihydrite is formed during pedogenesis (iv) 20 to 30% more Fe (hydr)oxides are present in the surface than in depth and (v) Zn has tetrahedral coordination and is sorbed to phases of increasing crystallinity when depth increases. Zn-bearing phases identified in the present study are: complex Fe, Mn, Zn sulphides, sulphates, organic matter, and ferrihydrite. Soil formation on such material does not induce a dramatic increase of Zn solubility since efficient scavengers are concomitantly formed in the system. However, Technosols are highly heterogeneous and widely differ from one place to another. The behavior examined in this study is not generic and will depend on the type of Technosol and on the secondary minerals formed as well as on the nature and amount of organic matter.« less

Surfactant-free synthesis of octahedral ZnO/ZnFe2O4 heterostructure with ultrahigh and selective adsorption capacity of malachite green

NASA Astrophysics Data System (ADS)

Liu, Jue; Zeng, Min; Yu, Ronghai

2016-05-01

A new octahedral ZnO/ZnFe2O4 heterostructure has been fabricated through a facile surfactant-free solvothermal method followed by thermal treatment. It exhibits a record-high adsorption capacity (up to 4983.0 mg·g-1) of malachite green (MG), which is a potentially harmful dye in prevalence and should be removed from wastewater and other aqueous solutions before discharging into the environment. The octahedral ZnO/ZnFe2O4 heterostructure also demonstrates strong selective adsorption towards MG from two kinds of mixed solutions: MG/methyl orange (MO) and MG/rhodamine B (RhB) mixtures, indicating its promise in water treatment.

Surfactant-free synthesis of octahedral ZnO/ZnFe2O4 heterostructure with ultrahigh and selective adsorption capacity of malachite green

PubMed Central

Liu, Jue; Zeng, Min; Yu, Ronghai

2016-01-01

A new octahedral ZnO/ZnFe2O4 heterostructure has been fabricated through a facile surfactant-free solvothermal method followed by thermal treatment. It exhibits a record-high adsorption capacity (up to 4983.0 mg·g−1) of malachite green (MG), which is a potentially harmful dye in prevalence and should be removed from wastewater and other aqueous solutions before discharging into the environment. The octahedral ZnO/ZnFe2O4 heterostructure also demonstrates strong selective adsorption towards MG from two kinds of mixed solutions: MG/methyl orange (MO) and MG/rhodamine B (RhB) mixtures, indicating its promise in water treatment. PMID:27142194

Photocatalytic study and superparamagnetic nature of Zn-doped MgFe2O4 colloidal size nanocrystals prepared by solvothermal reflux method.

PubMed

Manohar, A; Krishnamoorthi, C

2017-08-01

Biocompatible Mg 1-x Zn x Fe 2 O 4 (x=0.2, 0.4, 0.5, 0.6 & 0.8) nanoparticles were synthesized by solvothermal reflux method. All compounds were crystallized in cubic spinel structure with slightly enhance of lattice parameter with biocompatible substituent Zn 2+ concentration. All compounds were shown spherical geometry with average particle diameter is around 12nm (colloidal size). The spinel structure formation was confirmed by X-ray diffraction,electron diffraction, infrared, Raman shift measurements. Infrared analysis shows oleic acid coating on the surface of nanoparticles and TGA analysis shows that oleic acid desorbs from nanoparticle by decomposition at around 400°C. UV-Vis-NIR spectra show all the compounds show energy band gap in the semiconductor range (≈ 1.9eV). All compounds show superparamagnetic characteristics at room temperature with enhanced saturated mass magnetization (M s ) with Zn 2+ concentration up to x=0.5 and then reduces with further enhance of x up to 0.8. The M s changes were ascribed to occupation of Zn 2+ at tetrahedral sites and proportional enhance of Fe 3+ at octahedral sites. The enhanced Fe 3+ concentration at octahedral sublattice leads to formation Fe 3+ -O 2- -Fe 3+ networks which favor antiferromagnetic interactions due to superexchange phenomenon. Photocatalytic activity of all compounds were studied through methylene blue (MB) degradation analysis. All compounds show ≈ 96% degradation of MB upon 70min irradiation of light on photoreactor vessel. In addition, photocatalytic activity (degradation efficiency) enhances with Zn 2+ concentration in MgFe 2 O 4 . The Zn 2+ substitution enhances both M s and photocatalytic activity biocompatible of MgFe 2 O 4 nanoparticles. Copyright © 2017. Published by Elsevier B.V.

Content and Bioaccumulation of Nine Mineral Elements in Ten Mushroom Species of the Genus Boletus

PubMed Central

Wang, Xue-Mei; Zhang, Ji; Li, Tao; Wang, Yuan-Zhong; Liu, Hong-Gao

2015-01-01

Concentrations and bioconcentration potential of nine elements (Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn) in ten species of wild edible Boletus and the corresponding underlying soils were analyzed. The analyses were performed using inductively coupled plasma atomic emission spectrophotometer. Boletus showed relative abundant contents of P, K, Fe, Mg, Ca, and Na and less of Zn, Cu, and Mn. Caps compared to stalks were enriched in P, K, Cu, Mg, and Zn, while stalks were enriched in Mn. The elements such as P and K were accumulated (BCF > 1), while Ca, Fe, Mg, Mn, and Na were excluded (BCF < 1) in the fruiting bodies. The correlation analysis indicated high correlations between Cu, Mn, Ca, and Fe in the mushrooms as compared to the corresponding soils. Significant correlations were also obtained between Cu-P (r = 0.775), Fe-P (r = 0.728), and Zn-P (r = 0.76) for caps and Cu-Mg (r = 0.721), Fe-Mg (r = 0.719), Zn-Mg (r = 0.824), and Zn-P (r = 0.818) for stalks. The results of this study imply that ability of fungi to accumulate elements from substrate could be influenced by mushroom species and underlying soil substrates. PMID:26146585

Content and Bioaccumulation of Nine Mineral Elements in Ten Mushroom Species of the Genus Boletus.

PubMed

Wang, Xue-Mei; Zhang, Ji; Li, Tao; Wang, Yuan-Zhong; Liu, Hong-Gao

2015-01-01

Concentrations and bioconcentration potential of nine elements (Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn) in ten species of wild edible Boletus and the corresponding underlying soils were analyzed. The analyses were performed using inductively coupled plasma atomic emission spectrophotometer. Boletus showed relative abundant contents of P, K, Fe, Mg, Ca, and Na and less of Zn, Cu, and Mn. Caps compared to stalks were enriched in P, K, Cu, Mg, and Zn, while stalks were enriched in Mn. The elements such as P and K were accumulated (BCF > 1), while Ca, Fe, Mg, Mn, and Na were excluded (BCF < 1) in the fruiting bodies. The correlation analysis indicated high correlations between Cu, Mn, Ca, and Fe in the mushrooms as compared to the corresponding soils. Significant correlations were also obtained between Cu-P (r = 0.775), Fe-P (r = 0.728), and Zn-P (r = 0.76) for caps and Cu-Mg (r = 0.721), Fe-Mg (r = 0.719), Zn-Mg (r = 0.824), and Zn-P (r = 0.818) for stalks. The results of this study imply that ability of fungi to accumulate elements from substrate could be influenced by mushroom species and underlying soil substrates.

Enhanced photocatalytic performances and magnetic recovery capacity of visible-light-driven Z-scheme ZnFe2O4/AgBr/Ag photocatalyst

NASA Astrophysics Data System (ADS)

He, Jie; Cheng, Yahui; Wang, Tianzhao; Feng, Deqiang; Zheng, Lingcheng; Shao, Dawei; Wang, Weichao; Wang, Weihua; Lu, Feng; Dong, Hong; Zheng, Rongkun; Liu, Hui

2018-05-01

High efficiency, high stability and easy recovery are three key factors for practical photocatalysts. Z-scheme heterostructure is one of the most promising photocatalytic systems to meet all above requirements. However, efficient Z-scheme photocatalysts which could absorb visible light are still few and difficult to implement at present. In this work, the composite photocatalysts ZnFe2O4/AgBr/Ag were prepared through a two-step method. A ∼92% photodegradation rate on methyl orange was observed within 30 min under visible light, which is much better than that of individual ZnFe2O4 or AgBr/Ag. The stability was also greatly improved compared with AgBr/Ag. The increased performance is resulted from the suitable band alignment of ZnFe2O4 and AgBr, and it is defined as Z-scheme mechanism which was demonstrated by detecting active species and electrochemical impedance spectroscopy. Besides, ZnFe2O4/AgBr/Ag is ferromagnetic and can be recycled by magnet. These results show that ZnFe2O4/AgBr/Ag is a potential magnetically recyclable photocatalyst which can be driven by visible light.

Inversion domain boundaries in ZnO with additions of Fe2O3 studied by high-resolution ADF imaging.

PubMed

Wolf, Frank; Freitag, Bert H; Mader, Werner

2007-01-01

Columns of metal atoms in the polytypoid compound Fe2O3(ZnO)15 could be resolved by high angle annular dark field imaging in a transmission electron microscopy (TEM)/STEM electron microscope--a result which could not be realized by high-resolution bright field imaging due to inherent strain from inversion domains and inversion domain boundaries (IDBs) in the crystals. The basal plane IDB was imaged in [11 00] yielding the spacing of the two adjacent ZnO domains, while imaging in [21 1 0] yields the position of single metal ions. The images allow the construction of the entire domain structure including the stacking sequence and positions of the oxygen ions. The IDB consists of a single layer of octahedrally co-ordinated Fe3+ ions, and the inverted ZnO domains are related by point symmetry at the iron position. The FeO6 octahedrons are compressed along the ZnO c-axis resulting in a FeO bond length of 0.208 nm which is in the range of FeO distances in iron containing oxides. The model of the basal plane boundary resembles that of the IDB in polytypoid ZnO-In2O3 compounds.

Effect of MgO on Liquidus Temperatures in the ZnO-"FeO"-Al2O3-CaO-SiO2-MgO System in Equilibrium with Metallic Iron

NASA Astrophysics Data System (ADS)

Zhao, Baojun; Hayes, Peter C.; Jak, Evgueni

2011-06-01

The phase equilibria in the ZnO-"FeO"-Al2O3-CaO-SiO2-MgO system have been determined experimentally in equilibrium with metallic iron. Synthetic slags were equilibrated at a high temperature, quenched, and then the compositions of the phases in equilibrium were measured using electron probe X-ray microanalysis. Pseudoternary sections of the form ZnO-"FeO"-(Al2O3 + CaO + SiO2) for CaO/SiO2 = 0.71, (CaO + SiO2)/Al2O3 = 5 and fixed MgO concentrations of 2, 4, and 6 wt pct have been constructed. Wustite (Fe2+,Mg,Zn)O and spinel (Fe2+,Mg,Zn)O·(Al,Fe3+)2O3 are the major primary phases in the temperature and composition ranges investigated. The liquidus temperatures are increased by 140 K in the wustite primary phase field and by 70 K in the spinel primary phase field with the addition of 6 wt pct MgO in the slag. The partitioning of MgO and ZnO between the solid and liquid phases has been discussed.

Triple-mixture of Zn, Mn, and Fe increases bioaccumulation and causes oxidative stress in freshwater neotropical fish.

PubMed

de Oliveira, Luciana Fernandes; Santos, Caroline; Risso, Wagner Ezequiel; Dos Reis Martinez, Claudia Bueno

2018-06-01

Metal bioaccumulation and oxidative stress biomarkers were determined in Prochilodus lineatus to understand the effects of short-term exposure to a triple-mixture of Zn, Mn, and Fe. Three independent tests were carried out, in which fish were exposed to 3 concentrations of Zn (0.18, 1.0, and 5.0 mg L -1 ), Mn (0.1, 0.5, and 5.0 mg L -1 ), and in the mix test to Fe (5.0 mg L -1 ) and a mixture of Zn (1.0 mg L -1 ) + Mn (0.5 mg L -1 ), with and without Fe. After exposure for 96 h, tissues were removed for metal bioaccumulation analysis and oxidative stress biomarkers were determined in liver, along with DNA damage in blood cells. Our results revealed that Zn and Mn were bioaccumulated in fish tissues after exposure to 5.0 mg L -1 , whereas Fe only bioaccumulated in muscle and gills after mixture exposure. Results indicated that 1 metal interfered with the other's bioaccumulation. In P. lineatus, 5 mg L -1 of both Mn and Fe were toxic, because damage was observed (lipid peroxidation [LPO] in liver and DNA damage in blood cells), whereas Zn induced liver responses (metallothionein [MT] and reduced glutathione [GSH] increases) to prevent damage. In terms of bioaccumulation and alterations of oxidative stress biomarkers, we showed that Zn, Mn, and Fe triple-mixture enhances individual metal toxicity in Neotropical fish P. lineatus. Environ Toxicol Chem 2018;37:1749-1756. © 2018 SETAC. © 2018 SETAC.

Graphene-palladium nanowires based electrochemical sensor using ZnFe2O4-graphene quantum dots as an effective peroxidase mimic.

PubMed

Liu, Weiyan; Yang, Hongmei; Ma, Chao; Ding, Ya-nan; Ge, Shenguang; Yu, Jinghua; Yan, Mei

2014-12-10

We proposed an electrochemical DNA sensor by using peroxidase-like magnetic ZnFe2O4-graphene quantum dots (ZnFe2O4/GQDs) nanohybrid as a mimic enzymatic label. Aminated graphene and Pd nanowires were successively modified on glassy carbon electrode, which improved the electronic transfer rate as well as increased the amount of immobilized capture ssDNA (S1). The nanohybrid ZnFe2O4/GQDs was prepared by assembling the GQDs on the surface of ZnFe2O4 through a photo-Fenton reaction, which was not only used as a mimic enzyme but also as a carrier to label complementary ssDNA (S3). By synergistically integrating highly catalytically activity of nano-sized GQDs and ZnFe2O4, the nanohybrid possessed highly-efficient peroxidase-like catalytic activity which could produce a large current toward the reduction of H2O2 for signal amplification. Thionine was used as an excellent electron mediator. Compared with traditional enzyme labels, the mimic enzyme ZnFe2O4/GQDs exhibited many advantages such as environment friendly and better stability. Under the optimal conditions, the approach provided a wide linear range from 10(-16) to 5×10(-9) M and low detection limit of 6.2×10(-17) M. The remarkable high catalytic capability could allow the nanohybrid to replace conventional peroxidase-based assay systems. The new, robust and convenient assay systems can be widely utilized for the identification of other target molecules. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of phase transformation on the microstructures and magnetostriction of Fe-Ga and Fe-Ga-Zn ferromagnetic shape memory alloys

NASA Astrophysics Data System (ADS)

Lin, Yin-Chih; Lin, Chien-Feng

2015-05-01

The phase transformation and magnetostriction of bulk Fe73Ga27 and Fe73Ga18Zn9 (at. %) ferromagnetic shape memory alloys (FSMs) were investigated by transmission electron microscopy (TEM), x-ray diffraction (XRD), and a magnetostrictive-meter setup. For the Fe73Ga27 FSM alloy solution treated at 1100 °C for 4 h and quenched in ice brine, the antiphase boundary segments of the D03 domain were observed in the A2 (disordered) matrix, and the Fe73Ga27 FSM alloy had an optimal magnetostriction (λ‖s = 71 × 10-6 and λ⊥s = -31 × 10-6). In Fe73Ga27 FSM alloy as-quenched, aged at 700 °C for 24 h, and furnace cooled, D03 nanoclusters underwent phase transformation to an intermediate tetragonal phase (i.e., L10-like martensite) via Bain distortion, and finally L12 (Fe3Ga) structures precipitated, as observed by TEM and XRD. The L10-like martensite and L12 phases in the aged Fe73Ga27 FSM alloy drastically decreased the magnetostriction from positive to negative (λ‖s = -20 × 10-6 and λ⊥s = -8 × 10-6). However, in Fe73Ga18Zn9 FSM alloy as-quenched and aged, the phase transformation of D03 to an intermediate tetragonal martensite phase and precipitation of L12 structures were not found. The results indicate that the aged Fe73Ga18Zn9 FSM alloy maintained stable magnetostriction (λ‖s = 36 × 10-6 and λ⊥s = -31 × 10-6). Adding Zn can improve the ferromagnetic shape memory effect of aged Fe73Ga18Zn9 alloy, which may be useful in application of the alloy in high temperature environments.

Influence of Fe doping on the structural, optical and acetone sensing properties of sprayed ZnO thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prajapati, C.S.; Kushwaha, Ajay; Sahay, P.P., E-mail: dr_ppsahay@rediffmail.com

2013-07-15

Graphical abstract: All the films are found to be polycrystalline ZnO possessing hexagonal wurtzite structure. The intensities of all the peaks are diminished strongly in the Fe-doped films, indicating their lower crystallinity as compared to the undoped ZnO film. The average crystallite size decreases from 35.21 nm (undoped sample) to 15.43 nm (1 at% Fe-doped sample). - Highlights: • Fe-doped ZnO films show smaller crystallinity with crystallite size: 15–26 nm. • Optical band gap in ZnO films decreases on Fe doping. • Fe-doped films exhibit the normal dispersion for the wavelength range 450–600 nm. • PL spectra of the Fe-dopedmore » films show quenching of the broad green-orange emission. • Acetone response of the Fe-doped films increases considerably at 300 °C. - Abstract: The ZnO thin films (undoped and Fe-doped) deposited by chemical spray pyrolysis technique have been analyzed by X-ray powder diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Results show that all the films possess hexagonal wurtzite structure of zinc oxide having crystallite sizes in the range 15–36 nm. On 1 at% Fe doping, the surface roughness of the film increases which favors the adsorption of atmospheric oxygen on the film surface and thereby increase in the gas response. Optical studies reveal that the band gap decreases due to creation of some defect energy states below the conduction band edge, arising out of the lattice disorder in the doped films. The refractive index of the films decreases on Fe doping and follows the Cauchy relation of normal dispersion. Among all the films examined, the 1 at% Fe-doped film exhibits the maximum response (∼72%) at 300 °C for 100 ppm concentration of acetone in air.« less

Auger electron diffraction study of the growth of Fe(001) films on ZnSe(001)

NASA Astrophysics Data System (ADS)

Jonker, B. T.; Prinz, G. A.

1991-03-01

The growth of Fe films on ZnSe(001) epilayers and bulk GaAs(001) substrates has been studied to determine the mode of film growth, the formation of the interface, and the structure of the overlayer at the 1-10 monolayer level. Auger electron diffraction (AED), x-ray photoelectron spectroscopy (XPS), and reflection high-energy electron diffraction data are obtained for incremental deposition of the Fe(001) overlayer. The coverage dependence of the AED forward scattering peaks reveals a predominantly layer-by-layer mode of film growth at 175 °C on ZnSe, while a more three-dimensional growth mode occurs on the oxide-desorbed GaAs(001) substrate. XPS studies of the semiconductor 3d levels indicate that the Fe/ZnSe interface is less reactive than the Fe/GaAs interface.

Mapping Quantitative Trait Loci Controlling High Iron and Zinc Content in Self and Open Pollinated Grains of Pearl Millet [Pennisetum glaucum (L.) R. Br.

PubMed Central

Kumar, Sushil; Hash, Charles T.; Thirunavukkarasu, Nepolean; Singh, Govind; Rajaram, Vengaldas; Rathore, Abhishek; Senapathy, Senthilvel; Mahendrakar, Mahesh D.; Yadav, Rattan S.; Srivastava, Rakesh K.

2016-01-01

Pearl millet is a multipurpose grain/fodder crop of the semi-arid tropics, feeding many of the world’s poorest and most undernourished people. Genetic variation among adapted pearl millet inbreds and hybrids suggests it will be possible to improve grain micronutrient concentrations by selective breeding. Using 305 loci, a linkage map was constructed to map QTLs for grain iron [Fe] and zinc [Zn] using replicated samples of 106 pearl millet RILs (F6) derived from ICMB 841-P3 × 863B-P2. The grains of the RIL population were evaluated for Fe and Zn content using atomic absorption spectrophotometer. Grain mineral concentrations ranged from 28.4 to 124.0 ppm for Fe and 28.7 to 119.8 ppm for Zn. Similarly, grain Fe and Zn in open pollinated seeds ranged between 22.4–77.4 and 21.9–73.7 ppm, respectively. Mapping with 305 (96 SSRs; 208 DArT) markers detected seven linkage groups covering 1749 cM (Haldane) with an average intermarker distance of 5.73 cM. On the basis of two environment phenotypic data, two co-localized QTLs for Fe and Zn content on linkage group (LG) 3 were identified by composite interval mapping (CIM). Fe QTL explained 19% phenotypic variation, whereas the Zn QTL explained 36% phenotypic variation. Likewise for open pollinated seeds, the QTL analysis led to the identification of two QTLs for grain Fe content on LG3 and 5, and two QTLs for grain Zn content on LG3 and 7. The total phenotypic variance for Fe and Zn QTLs in open pollinated seeds was 16 and 42%, respectively. Analysis of QTL × QTL and QTL × QTL × environment interactions indicated no major epistasis. PMID:27933068

The geochemical cycling of trace elements in a biogenic meromictic lake

NASA Astrophysics Data System (ADS)

Balistrieri, Laurie S.; Murray, James W.; Paul, Barbara

1994-10-01

The geochemical processes affecting the behavior and speciation of As, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, V, and Zn in Hall Lake, Washington, USA, are assessed by examining dissolved and acid soluble particulate profiles of the elements and utilizing results from thermodynamic calculations. The water column of this meromictic lake is highly stratified and contains distinctive oxic, suboxic, and anoxic layers. Changes in the redox state of the water column with depth affect the distribution of all the elements studied. Most noticeable are increases in dissolved Co, Cr, Fe, Mn, Ni, Pb, and Zn concentrations across the oxic-suboxic boundary, increases in dissolved As, Co, Cr, Fe, Mn, and V concentrations with depth in the anoxic layer, significant decreases in dissolved Cu, Ni, Pb, and Zn concentrations in the anoxic region below the sulfide maximum, and large increases in acid soluble particulate concentrations of As, Cr, Cu, Fe, Mo, Ni, Pb, V, and Zn in the anoxic zone below the sulfide maximum. Thermodynamic calculations for the anoxic region indicate that all redox sensitive elements exist in their reduced forms, the primary dissolved forms of Cu, Ni, Pb, and Zn are metal sulfide solution complexes, and solid sulfide phases of Cu, Fe, Mo, and Pb are supersaturated. Calculations using a vertical diffusion and reaction model indicate that the oxidation rate constant for Mn(II) in Hall Lake is estimated to be 0.006 d -1 and is at the lower end of the range of microbial oxidation rates observed in other natural systems. The main geochemical processes influencing the distribution and speciation of trace elements in Hall Lake appear to be transformations of dissolved elements between their oxidation states (As, Cr, Cu, Fe, Mn, V), cocycling of trace elements with Mn and Fe (As, Co, Cr, Cu, Mo, Ni, Pb, V, Zn), formation of soluble metal sulfide complexes (Co, Cu, Ni, Pb, Zn), sorption (As, Co, Cr, Ni, V), and precipitation (Cu, Fe, Mn, Mo, Pb, Zn).

The geochemical cycling of trace elements in a biogenic meromictic lake

USGS Publications Warehouse

Balistrieri, L.S.; Murray, J.W.; Paul, B.

1994-01-01

The geochemical processes affecting the behavior and speciation of As, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, V, and Zn in Hall Lake, Washington, USA, are assessed by examining dissolved and acid soluble particulate profiles of the elements and utilizing results from thermodynamic calculations. The water column of this meromictic lake is highly stratified and contains distinctive oxic, suboxic, and anoxic layers. Changes in the redox state of the water column with depth affect the distribution of all the elements studied. Most noticeable are increases in dissolved Co, Cr, Fe, Mn, Ni, Pb, and Zn concentrations across the oxic-suboxic boundary, increases in dissolved As, Co, Cr, Fe, Mn, and V concentrations with depth in the anoxic layer, significant decreases in dissolved Cu, Ni, Pb, and Zn concentrations in the anoxic region below the sulfide maximum, and large increases in acid soluble particulate concentrations of As, Cr, Cu, Fe, Mo, Ni, Pb, V, and Zn in the anoxic zone below the sulfide maximum. Thermodynamic calculations for the anoxic region indicate that all redox sensitive elements exist in their reduced forms, the primary dissolved forms of Cu, Ni, Pb, and Zn are metal sulfide solution complexes, and solid sulfide phases of Cu, Fe, Mo, and Pb are supersaturated. Calculations using a vertical diffusion and reaction model indicate that the oxidation rate constant for Mn(II) in Hall Lake is estimated to be 0.006 d-1 and is at the lower end of the range of microbial oxidation rates observed in other natural systems. The main geochemical processes influencing the distribution and speciation of trace elements in Hall Lake appear to be transformations of dissolved elements between their oxidation states (As, Cr, Cu, Fe, Mn, V), cocycling of trace elements with Mn and Fe (As, Co, Cr, Cu, Mo, Ni, Pb, V, Zn), formation of soluble metal sulfide complexes (Co, Cu, Ni, Pb, Zn), sorption (As, Co, Cr, Ni, V), and precipitation (Cu, Fe, Mn, Mo, Pb, Zn). ?? 1994.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Starcher, Autumn N.; Elzinga, Evert J.; Sparks, Donald L.

Previous research demonstrated the formation of single divalent metal (Co, Ni, and ZnAl) and mixed divalent metal (NiZnAl) layered double hydroxide (LDH) phases from reactions of the divalent metal with Al-bearing substrates and soils in both laboratory experiments and in the natural environment. Recently Fe(II)-Al-LDH phases have been found in laboratory batch reaction studies, and although they have yet to be found in the natural environment. Potential locations of Fe(II)-Al-LDH phases in nature include areas with suboxic and anoxic conditions. Because these areas can be environments of significant contaminant accumulation, it is important to understand the possible interactions and impactsmore » of contaminant elements on LDH phase formation. One such contaminant, Zn, can also form as an LDH and has been found to form as a mixed divalent layered hydroxide phase. To understand how Zn impacts the formation of Fe(II)-Al-LDH phase formation and kinetics, 3 mM or 0.8 mM Fe(II) and 0.8 mM Zn were batch reacted with either 10 g/L pyrophyllite or 7.5 g/L γ-Al2O3 for up to three months under anoxic conditions. Aqueous samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) and solid samples were analyzed with X-ray absorption spectroscopy (XAS). Shell-by-shell fits of Fe(II) and co-sorption samples with pyrophyllite show the formation of a mixed divalent metal (Fe(II)-Zn-Al) layered hydroxide phase, while Fe(II) and Zn co-sorption samples with γ-Al2O3 produce Fe(II)-Al-LDH phases and Zn in inner-sphere complexation with the γ-Al2O3. This study demonstrates the formation of a mixed divalent metal layered hydroxide and further iterates the importance of sorbent reactivity on LDH phase formation.« less

Unveiling the True Metallicity and Stellar Populations of Planetary Nebula Progenitor Stars

NASA Astrophysics Data System (ADS)

Dinerstein, Harriet L.; Geballe, T. R.; Sterling, N. C.

2011-01-01

We have measured the recently identified 3.625 micron [Zn IV] fine-structure line (Dinerstein & Geballe 2001, ApJ, 562, 515) in a dozen Galactic planetary nebulae (Dinerstein et al. 2007, BAAS, 211, 100.14). Because Zn is the least refractory of the Fe peak elements, the gas phase [Zn/H] abundance can be used as a proxy for the elemental [Fe/H] in the progenitor star, in contrast to Fe itself, which is heavily depleted into dust. We find that the observed Milky Way nebulae fall into two categories: objects which have roughly solar values of [Zn/H] and [O/Zn]; and nebulae with low Zn (clustering around [Zn/H] = -0.6) and elevated [O/H]. Most of the latter group have high radial velocities, |vrad| > 60 km/s. Our interpretation is that the objects with solar abundances and low velocities originate from thin disk stars, while the nebulae with low Zn are descendants of thick disk stars. A further implication is that the common assumption that O and other alpha species are reliable indicators of metallicity in planetary nebulae is not necessarily valid, and can lead to erroneous conclusions about the parent stellar population. This effect is particularly acute for O since [O/Fe] can be large, especially in metal-poor populations. In a planetary nebula formed by a star with this abundance pattern, a high value of [(O, alpha)/Fe] can offset a low [Fe/H], producing near-solar abundances for O and other alpha species. This can make it appear that the star belongs to a more metal-rich (in [Fe/H]) population than is actually the case. Obtaining Zn abundances for larger samples of planetary nebulae will be crucial to disentangling these abundance ratios and breaking the potential degeneracy of the O and alpha abundances. (This research was supported by NSF grant 0708245.)

Exploring the Cr{sup 2+} doping effect on structural, vibrational and dielectric properties of Mn-Zn ferrites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choudhary, Pankaj; Dar, M. A.; Varshney, Dinesh, E-mail: vdinesh33@rediffmail.com, E-mail: ty.ru123@gmail.com

2016-05-23

A series of Cr doped Mn-Zn ferrites with compositional formula Mn{sub 0.5}Zn{sub 0.5-x}Cr{sub x}Fe{sub 2}O{sub 4} (x = 0, 0.3, 0.5) were prepared by solid-state reaction route. X-ray diffraction (XRD) analysis reveals that the samples prepared are polycrystalline cubic spinel in structure (Fd3m) with some secondary phase of α–Fe{sub 2}O{sub 3}. Slight variation in the lattice parameter of Cr doped Mn{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} has been observed due to difference in ionic radii of cations. Small shift in Raman modes towards higher wave number has been observed. Further the line width decreases with the doping ions. A giant dielectricmore » constant ~10{sup 4} is observed for parent Mn{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} which is found to decrease with increase in Cr{sup 2+} doping. Low dielectric loss is observed for Mn{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} and improves with Cr{sup 2+} doping at Zn{sup 2+} site.« less

The assessment of soil availability and wheat grain status of zinc and iron in Serbia: Implications for human nutrition.

PubMed

Nikolic, Miroslav; Nikolic, Nina; Kostic, Ljiljana; Pavlovic, Jelena; Bosnic, Predrag; Stevic, Nenad; Savic, Jasna; Hristov, Nikola

2016-05-15

The deficiency of zinc (Zn) and iron (Fe) is a global issue causing not only considerable yield losses of food crops but also serious health problems. We have analysed Zn and Fe concentrations in the grains of two bread wheat cultivars along native gradient of micronutrient availability throughout Serbia. Although only 13% of the soil samples were Zn deficient and none was Fe deficient, the levels of these micronutrients in grain were rather low (median values of 21 mg kg(-1) for Zn and 36 mg kg(-1) for Fe), and even less adequate in white flour. Moreover, excessive P fertilization of calcareous soils in the major wheat growing areas strongly correlated with lower grain concentration of Zn. Our results imply that a latent Zn deficiency in wheat grain poses a high risk for grain quality relevant to human health in Serbia, where wheat bread is a staple food. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication and characterization of thin-film phosphor combinatorial libraries

NASA Astrophysics Data System (ADS)

Mordkovich, V. Z.; Jin, Zhengwu; Yamada, Y.; Fukumura, T.; Kawasaki, M.; Koinuma, H.

2002-05-01

The laser molecular beam epitaxy method was employed to fabricate thin-film combinatorial libraries of ZnO-based phosphors on different substrates. Fabrication of both pixel libraries, on the example of Fe-doped ZnO, and spread libraries, on the example of Eu-doped ZnO, has been demonstrated. Screening of the Fe-doped ZnO libraries led to the discovery of weak green cathodoluminescence with the maximum efficiency at the Fe content of 0.58 mol %. Screening of the Eu-doped ZnO libraries led to the discovery of unusual reddish-violet cathodoluminescence which is observed in a broad range of Eu concentration. No photoluminescence was registered in either system.

Theoretical study of the characteristics of a continuous wave iron-doped ZnSe laser

NASA Astrophysics Data System (ADS)

Pan, Qikun; Chen, Fei; Xie, Jijiang; Wang, Chunrui; He, Yang; Yu, Deyang; Zhang, Kuo

2018-03-01

A theoretical model describing the dynamic process of a continuous-wave Fe2+:ZnSe laser is presented. The influence of some of the operating parameters on the output characteristics of an Fe2+:ZnSe laser is studied in detail. The results indicate that the temperature rise of the Fe2+:ZnSe crystal is significant with the use of a high power pump laser, especially for a high doped concentration of crystal. The optimal crystal length increases with decreasing the doped concentration of crystal, so an Fe2+:ZnSe crystal with simultaneous doping during growth is an attractive choice, which usually has a low doped concentration and long length. The laser pumping threshold is almost stable at low temperatures, but increases exponentially with a working temperature in the range of 180 K to room temperature. The main reason for this phenomenon is the short upper level lifetime and serious thermal temperature rise when the working temperature is higher than 180 K. The calculated optimum output mirror transmittance is about 35% and the performance of a continuous-wave Fe2+:ZnSe laser is more efficient at a lower operating temperature.

Formation of the ZnFe2O4 phase in an electric arc furnace off-gas treatment system.

PubMed

Suetens, T; Guo, M; Van Acker, K; Blanpain, B

2015-04-28

To better understand the phenomena of ZnFe2O4 spinel formation in electric arc furnace dust, the dust was characterized with particle size analysis, X-ray fluorescence (XRF), electron backscatter diffraction (EBSD), and electron probe micro-analysis (EPMA). Different ZnFe2O4 formation reaction extents were observed for iron oxide particles with different particle sizes. ZnO particles were present as both individual particles and aggregated on the surface of larger particles. Also, the slag particles found in the off-gas were shown not to react with the zinc vapor. After confirming the presence of a ZnFe2O4 formation reaction, the thermodynamic feasibility of in-process separation - a new electric arc furnace dust treatment technology - was reevaluated. The large air intake and the presence of iron oxide particles in the off-gas were included into the thermodynamic calculations. The formation of the stable ZnFe2O4 spinel phase was shown to be thermodynamically favorable in current electric arc furnace off-gas ducts conditions even before reaching the post combustion chamber. Copyright © 2015 Elsevier B.V. All rights reserved.

Interactions of iron with manganese, zinc, chromium, and selenium as related to prophylaxis and treatment of iron deficiency.

PubMed

Bjørklund, Geir; Aaseth, Jan; Skalny, Anatoly V; Suliburska, Joanna; Skalnaya, Margarita G; Nikonorov, Alexandr A; Tinkov, Alexey A

2017-05-01

Iron (Fe) deficiency is considered as the most common nutritional deficiency. Iron deficiency is usually associated with low Fe intake, blood loss, diseases, poor absorption, gastrointestinal parasites, or increased physiological demands as in pregnancy. Nutritional Fe deficiency is usually treated with Fe tablets, sometimes with Fe-containing multimineral tablets. Trace element interactions may have a significant impact on Fe status. Existing data demonstrate a tight interaction between manganese (Mn) and Fe, especially in Fe-deficient state. The influence of Mn on Fe homeostasis may be mediated through its influence on Fe absorption, circulating transporters like transferrin, and regulatory proteins. The existing data demonstrate that the influence of zinc (Zn) on Fe status may be related to their competition for metal transporters. Moreover, Zn may be involved in regulation of hepcidin production. At the same time, human data on the interplay between Fe and Zn especially in terms of Fe-deficiency and supplementation are contradictory, demonstrating both positive and negative influence of Zn on Fe status. Numerous data also demonstrate the possibility of competition between Fe and chromium (Cr) for transferrin binding. At the same time, human data on the interaction between these metals are contradictory. Therefore, while managing hypoferremia and Fe-deficiency anemia, it is recommended to assess the level of other trace elements in parallel with indices of Fe homeostasis. It is supposed that simultaneous correction of trace element status in Fe deficiency may help to decrease possible antagonistic or increase synergistic interactions. Copyright © 2017 Elsevier GmbH. All rights reserved.

Fuel additives and heat treatment effects on nanocrystalline zinc ferrite phase composition

NASA Astrophysics Data System (ADS)

Hu, Ping; Pan, De-an; Wang, Xin-feng; Tian, Jian-jun; Wang, Jian; Zhang, Shen-gen; Volinsky, Alex A.

2011-03-01

Nanocrystalline ZnFe 2O 4 powder was prepared by the auto-combustion method using citric acid, acetic acid, carbamide and acrylic acid as fuel additives. Pure spinel zinc ferrite with the crystallite size of about 15 nm can be obtained by using acrylic acid as fuel additive. Samples prepared using other fuel additives contain ZnO impurities. In order to eliminate ZnO impurities, the sample prepared with citric acid as fuel additive was annealed at different temperatures up to 1000 °C in air and in argon. Annealed powders have pure ZnFe 2O 4 phase when annealing temperature is higher than 650 °C in air. Sample annealed at 650 °C in air is paramagnetic. However, annealed powders become a mixture of Fe 3O 4 and FeO after annealing at 1000 °C in argon atmosphere due to Zn volatility and the reduction reaction.

Efficiency of several leaching reagents on removal of Cu, Pb, Cd, and Zn from highly contaminated paddy soil.

PubMed

Gao, Ruili; Zhu, Pengfei; Guo, Guangguang; Hu, Hongqing; Zhu, Jun; Fu, Qingling

2016-11-01

The efficiency of five different single leaching reagents (tartaric acid (TA), citric acid (CA), CaCl 2 , FeCl 3 , EDTA) and two different composite leaching reagents (CA + FeCl 3 , CA + EDTA) on removing Cu, Pb, Zn, and Cd from contaminated paddy soil in Hunan Province (in China) was studied. The results indicated that the efficiencies of CA, FeCl 3 , and EDTA on extracting Cu, Pb, Cd, and Zn from soil were greater than that of TA and CaCl 2 , and their extraction efficiencies were EDTA ≥ FeCl 3 > CA. The efficiencies of CA + FeCl 3 on extracting Cu, Pb, Cd, and Zn were higher than that of single CA or FeCl 3 . The 25 mmol L -1 CA + 20 mmol L -1 FeCl 3 was a promising composite leaching reagent for paddy soil, and it could remove Cu (57.6 %), Pb (59.3 %), Cd (84.8 %), and Zn (28.0 %), respectively. With the same amount of leaching reagent, the efficiency of continuous leaching by several times was higher than that by once. In addition, the easily reducible and oxidizable fractions of heavy metals showed significant decrease during the process of leaching.

Digestibility and retention of zinc, copper, manganese, iron, calcium, and phosphorus in pigs fed diets containing inorganic or organic minerals.

PubMed

Liu, Y; Ma, Y L; Zhao, J M; Vazquez-Añón, M; Stein, H H

2014-08-01

The objective of this experiment was to measure the apparent total tract digestibility (ATTD) and the retention rate of Zn, Cu, Mn, and Fe in pigs fed either inorganic or organic sources of Zn, Cu, Mn, and Fe. The experimental design was a randomized complete block design with a 2 × 3 factorial arrangement of treatments. There were 2 types of diets (corn grits-based or corn-soybean meal [SBM]-based diets) and 3 micromineral treatments (basal micromineral premix [BMM], inorganic micromineral premix [IMM], and organic micromineral premix [OMM]). The BMM contained no added Zn, Cu, Mn, or Fe; the IMM microminerals were provided as sulfates of Zn, Cu, Mn, and Fe at 40, 50, 20, and 100 mg/kg, respectively. The OMM contained the same levels of the 4 microminerals as IMM, but Zn, Cu, Mn, and Fe in this premix were provided by Zn(2-hydroxy-4-methylthio butanoic acid [HMTBa])2, Cu(HMTBa)2, Mn(HMTBa)2, and FeGly, respectively. Forty-eight barrows (initial BW: 31.1 ± 4.2 kg) were housed individually and allowed ad libitum access to the corn grits diet with BMM for 2 wk. All pigs were then moved to metabolism cages and randomly assigned to 1 of the 6 treatment diets with 8 replicates per diet. Fecal and urine samples were collected for 5 d following a 5-d adaptation period. Compared with corn grits diets, pigs fed corn-SBM diets had greater (P < 0.05) absorption and retention of Zn, Cu, and Mn but less (P < 0.05) ATTD of Zn and Cu. Compared with BMM, supplementation of IMM or OMM increased (P < 0.05) absorption, retention, ATTD, and retention rate of Zn, Cu, Mn, and Fe. Compared with IMM, adding OMM to the corn-SBM diet improved (P < 0.05) the absorption and retention of Cu and Mn and the ATTD of Cu, but these differences were not observed in the corn grits diets (interaction, P < 0.05). In addition, adding OMM to the corn-SBM diet increased (P < 0.05) absorption and retention of Zn and Fe and ATTD of Zn, Mn, and Fe compared with adding IMM to the corn-SBM diet. Supplementation of OMM also increased (P < 0.05) the ATTD and retention rate of P in corn-SBM diets. Results indicate that Zn(HMTBa)2 has greater digestibility and Cu(HMTBa)2 and Mn(HMTBa)2 have greater digestibility and retention rates compared with their inorganic sulfates, if included in a corn-SBM diet. Supplementation of organic microminerals also improves the digestibility of P in a corn-SBM diet.

Electroplating sludge derived zinc-ferrite catalyst for the efficient photo-Fenton degradation of dye.

PubMed

Cao, Zhenbang; Zhang, Jia; Zhou, Jizhi; Ruan, Xiuxiu; Chen, Dan; Liu, Jianyong; Liu, Qiang; Qian, Guangren

2017-05-15

A zinc-dominant ferrite catalyst for efficient degradation of organic dye was prepared by the calcination of electroplating sludge (ES). Characterizations indicated that zinc ferrite (ZnFe 2 O 4 ) coexisted with Fe 2 O 3 structure was the predominant phase in the calcined electroplating sludge (CES). CES displayed a high decolorization ratio (88.3%) of methylene blue (MB) in the presence of H 2 O 2 combined with UV irradiation. The high efficiency could be ascribed to the photocatalytic process induced by ZnFe 2 O 4 and the photo-Fenton dye degradation by ferrous content, and a small amount of Al and Mg in the sludge might also contribute to the catalysis. Moreover, the degradation capability of dye by CES was supported by the synthetic ZnFe 2 O 4 with different Zn to Fe molar ratio (n(Zn): n(Fe)), as 84.81%-86.83% of dye was removed with n(Zn): n(Fe) ranged from 1:0.5 to 1:3. All synthetic ferrite samples in the simulation achieved adjacent equilibrium decolorization ratio, the flexible proportioning of divalent metal ions (M 2+ ) to trivalent metal ions (M 3+ ) applied in the synthesis indicated that the catalyst has a high availability. Therefore, an efficacious catalyst for the degradation of dye can potentially be derived from heavy metal-containing ES, it's a novel approach for the reutilization of ES. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sulfidation behavior of ZnFe2O4 roasted with pyrite: Sulfur inducing and sulfur-oxygen interface exchange mechanism

NASA Astrophysics Data System (ADS)

Min, Xiaobo; Zhou, Bosheng; Ke, Yong; Chai, Liyuan; Xue, Ke; Zhang, Chun; Zhao, Zongwen; Shen, Chen

2016-05-01

The sulfidation roasting behavior was analyzed in detail to reveal the reaction mechanism. Information about the sulfidation reaction, including phase transformation, ionic migration behavior and morphological change, were obtained by XRD, 57Fe Mossbauer spectroscopy, XPS and SEM analysis. The results showed that the sulfidation of zinc ferrite is a process of sulfur inducing and sulfur-oxygen interface exchange. This process can be divided into six stages: decomposition of FeS2, formation of the oxygen-deficient environment, migration of O2- induced by S2(g), formation of ZnFe2O4-δ, migration of Fe2+ accompanied by the precipitation of ZnO, and the sulfur-oxygen interface exchange reaction. The sulfidation products were zinc blende, wurtzite, magnetite and a fraction of zinc-bearing magnetite. These findings can provide theoretical support for controlling the process during which the recovery of Zn and Fe is achieved through the combined flotation-magnetic separation process.

The magnetic, electrical transport and thermal transport properties of Fe-based antipervoskite compounds ZnCxFe3

NASA Astrophysics Data System (ADS)

Lin, S.; Wang, B. S.; Lin, J. C.; Huang, Y. N.; Hu, X. B.; Lu, W. J.; Zhao, B. C.; Tong, P.; Song, W. H.; Sun, Y. P.

2011-10-01

The effects of carbon concentration on the crystal structure, magnetic, and electrical/thermal transport properties of ZnCxFe3 (1.0 ≤ x ≤ 1.5) have been investigated systematically. Both the Curie temperature and the saturated magnetization decrease firstly and then reach saturation with increasing x. The investigations of heat capacity and resistivity indicate that ZnC1.2Fe3 displays a strongly correlated Fermi liquid behavior considering its Kadowaki-Woods ratio (˜0.64 a0). Around the ferromagnetic-paramagnetic phase transition (˜358 K), a reversible room-temperature magnetocaloric effect is observed. The relative cooling power (RCP) is ˜164 J/kg (˜385 J/kg) with the magnetic field change ΔH = 20 kOe (45 kOe). Considering the considerable large RCP, inexpensive and innoxious raw materials, ZnC1.2Fe3 is suggested to be a promising candidate for room-temperature magnetic refrigeration. Furthermore, the studies of thermal transport properties indicate that ZnC1.2Fe3 can also be a potential thermoelectric material with the dimensionless figure of merit (ZT = α2T/ρk) reaching its maximum of 0.0112 around 170 K.

Mechanochemical destruction of DDTs with Fe-Zn bimetal in a high-energy planetary ball mill.

PubMed

Sui, Hong; Rong, Yuzhou; Song, Jing; Zhang, Dongge; Li, Haibo; Wu, Peng; Shen, Yangyang; Huang, Yujuan

2018-01-15

Mechanochemical destruction has been proposed as a promising, non-combustion technology for the disposal of toxic, halogenated, organic pollutants. In the study presented, additives including Fe, Zn, Fe-Zn bimetal, CaO and Fe 2 O 3 were tested for their effectiveness to remove DDTs by MC. The results showed that Fe-Zn bimetal was the most efficient additive, with 98% of DDTs removed after 4h. The Fe-Zn mass ratio was optimized to avoid possible spontaneous combustion of the ground sample during subsample collection. Inorganic water-soluble chloride in the ground sample increased by 91% after 4h of grinding, which indicated dechlorination during destruction of DDTs. In addition, relationships were established between the rate constant and the rotation speed or the charge ratio. Discrete Element Method (DEM) modeling was used to simulate the motion of the grinding ball and calculate both total impact energy and normal impact energy. The latter expressed a stronger, linear correlation with the rate constant. Therefore, normal impact energy is proposed to be the main driving force in the MC destruction of DDTs. Copyright © 2017 Elsevier B.V. All rights reserved.

Heavy Metals Induce Iron Deficiency Responses at Different Hierarchic and Regulatory Levels1[OPEN

PubMed Central

2017-01-01

In plants, the excess of several heavy metals mimics iron (Fe) deficiency-induced chlorosis, indicating a disturbance in Fe homeostasis. To examine the level at which heavy metals interfere with Fe deficiency responses, we carried out an in-depth characterization of Fe-related physiological, regulatory, and morphological responses in Arabidopsis (Arabidopsis thaliana) exposed to heavy metals. Enhanced zinc (Zn) uptake closely mimicked Fe deficiency by leading to low chlorophyll but high ferric-chelate reductase activity and coumarin release. These responses were not caused by Zn-inhibited Fe uptake via IRON-REGULATED TRANSPORTER (IRT1). Instead, Zn simulated the transcriptional response of typical Fe-regulated genes, indicating that Zn affects Fe homeostasis at the level of Fe sensing. Excess supplies of cobalt and nickel altered root traits in a different way from Fe deficiency, inducing only transient Fe deficiency responses, which were characterized by a lack of induction of the ethylene pathway. Cadmium showed a rather inconsistent influence on Fe deficiency responses at multiple levels. By contrast, manganese evoked weak Fe deficiency responses in wild-type plants but strongly exacerbated chlorosis in irt1 plants, indicating that manganese antagonized Fe mainly at the level of transport. These results show that the investigated heavy metals modulate Fe deficiency responses at different hierarchic and regulatory levels and that the interaction of metals with physiological and morphological Fe deficiency responses is uncoupled. Thus, this study not only emphasizes the importance of assessing heavy metal toxicities at multiple levels but also provides a new perspective on how Fe deficiency contributes to the toxic action of individual heavy metals. PMID:28500270

Heavy metals in water, sediments, plants and fish of Kali Nadi U. P. (India)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ajmal, M.; Uddin, R.; Khan, A.U.

1988-01-01

The distribution of heavy metals viz., Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn in the water, sediments, plants and fish samples collected from the Kali Nadi (India) have been determined. The studies have shown that there was considerable variation in the concentration of heavy metals from one sampling station to the other which may be due to the variation in the quality of industrial and sewage wastes being added to the river at different places. The orders of the concentration of heavy metals in water, sediments, plants (Eicchornia crassipes) and fish (Heteropnuestes fossilis) were Fe > Znmore » > Cu > Mn > Cr > Ni > Pb > Co > Cd; Fe > Zn > Mn > Ni > Cr > Co > Cu > Pb > Cd; Fe > Mn > Zn > Cu > Ni > Co > Pb > Cr > Cd and Fe > Zn > Mn > Ni > Pb >Co > Cr > Cu > Cd, respectively.« less

Magnetic moment in single crystalline BaFe2-xZnxAs2

NASA Astrophysics Data System (ADS)

Guo, Yanfeng; Wang, Xia; Li, Jun; Yamaura, Kazunari; Takayama-Muromachi, Eiji

2012-02-01

Nature of the magnetism for iron-based superconductors (FeSCs) has been actively studied since the discovery of this new family of compounds in 2008, largely owing to its significance for interpreting the paring mechanism. The approach through impurity substitution to shed light into this issue is always one of major ways. The substitution shows distinct responses to species of impurities, where partially replacement of Fe in parent FeSCs with a variety of d-metals like Co, Ni Ru, Rh, Pd, Ir, and Pt generally results in superconductivity, while recent progress in Zn doped FeSCs gives rather contrary result, where Zn severely degenerates the TC. Herein we show the magnetic and electrical studies on BaFe2-xZnxAs2 single crystals. Nonmagnetic Zn doping progressively suppresses the SDW without resulting in superconductivity, while it alternatively develops the spin-glass state, possibly suggestive of local magnetic moment around the Fe sites induced by Zn. The characterizations by X-ray diffraction, magnetic and electrical transport properties, specific heat capacity, and Hall coefficient have been done and the results will be discussed in detail.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phumying, Santi; Labuayai, Sarawuth; Swatsitang, Ekaphan

Graphical abstract: This figure shows the specific magnetization curves of the as-prepared MFe{sub 2}O{sub 4} (M = Ni, Co, Mn, Mg, Zn) powders obtained from room temperature VSM measurement. These curves are typical for a soft magnetic material and indicate hysteresis ferromagnetism in the field ranges of ±500 Oe, ±1000 Oe, and ±2000 Oe for the CoFe{sub 2}O{sub 4}, MgFe{sub 2}O{sub 4} and MnFe{sub 2}O{sub 4} respectively, whereas the samples of NiFe{sub 2}O{sub 4} and ZnFe{sub 2}O{sub 4} show a superparamagnetic behavior. Highlights: ► Nanocrystalline MFe{sub 2}O{sub 4} powders were synthesized by a novel hydrothermal method. ► Metal acetylacetonates andmore » aloe vera plant-extracted solution are used. ► This biosynthetic route is very simple and provides high-yield oxide nanomaterials. ► XRD and TEM results indicate that the prepared samples have only spinel structure. ► The maximum M{sub s} of 68.9 emu/g at 10 kOe were observed for the samples of MnFe{sub 2}O{sub 4}. - Abstract: Nanocrystalline spinel ferrite MFe{sub 2}O{sub 4} (M = Ni, Co, Mn, Mg, Zn) powders were synthesized by a novel hydrothermal method using Fe(acac){sub 3}, M(acac){sub 3} (M = Ni, Co, Mn, Mg, Zn) and aloe vera plant extracted solution. The X-ray diffraction and selected-area electron diffraction results indicate that the synthesized nanocrystalline have only spinel structure without the presence of other phase impurities. The crystal structure and morphology of the spinel ferrite powders, as revealed by TEM, show that the NiFe{sub 2}O{sub 4} and CoFe{sub 2}O{sub 4} samples contain nanoparticles, whereas the MnFe{sub 2}O{sub 4} and MgFe{sub 2}O{sub 4} samples consist of many nanoplatelets and nanoparticles. Interestingly, the ZnFe{sub 2}O{sub 4} sample contains plate-like structure of networked nanocrystalline particles. Room temperature magnetization results show a ferromagnetic behavior of the CoFe{sub 2}O{sub 4}, MnFe{sub 2}O{sub 4} and MgFe{sub 2}O{sub 4} samples, whereas the samples of NiFe{sub 2}O{sub 4} and ZnFe{sub 2}O{sub 4} exhibit a superparamagnetic behavior.« less

Mechanism of single metal exchange in the reactions of [M4(SPh)10]2- (M = Zn or Fe) with CoX2 (X = Cl or NO3) or FeCl2.

PubMed

Autissier, Valerie; Henderson, Richard A

2008-07-21

The kinetics of the reactions between [Zn4(SPh)10](2-) and an excess of MX2 (M = Co, X = NO3 or Cl; M = Fe, X = Cl), in which a Zn(II) is replaced by M(II), have been studied in MeCN at 25.0 degrees C. (1)H NMR spectroscopy shows that the ultimate product of the reactions is an equilibrium mixture of clusters of composition [Zn(n)M(4-n)(SPh)10](2-), and this is reflected in the multiphasic absorbance-time curves observed over protracted times (several minutes) using stopped-flow spectrophotometry to study the reactions. The kinetics of only the first phase have been determined, corresponding to the equilibrium formation of [Zn3M(SPh)10](2-). The effects of varying the concentrations of cluster, MX2, and ZnCl2 on the kinetics have been investigated. The rate law is consistent with the equilibrium nature of the metal exchange process and indicates a mechanism for the formation of [Zn3M(SPh)10](2-) involving two coupled equilibria. In the initial step binding of MX2 to a bridging thiolate in [Zn4(SPh)10](2-) results in breaking of a Zn-bridging thiolate bond. In the second step replacement of the cluster Zn involves transfer of the bridging thiolates from the Zn to M, with breaking of a Zn-bridged thiolate bond being rate-limiting. The kinetics for the reaction of ZnCl2 with [Zn3M(SPh)10](2-) (M = Fe or Co)} depends on the identity of M. This behavior indicates attack of ZnCl2 at a M-mu-SPh-Zn bridged thiolate. Similar studies on the analogous reactions between [Fe4(SPh)10](2-) and an excess of CoX2 (X = NO3 or Cl) in MeCN exhibit simpler kinetics but these are also consistent with the same mechanism.

Investigation of Cu-, Zn- and Fe-containing human brain proteins using isotopic-enriched tracers by LA-ICP-MS and MALDI-FT-ICR-MS

NASA Astrophysics Data System (ADS)

Becker, J. Susanne; Zoriy, Miroslav; Pickhardt, Carola; Przybylski, Michael; Becker, J. Sabine

2005-04-01

Identification of metal-containing proteins and determination of Cu, Fe, Zn concentration in very small protein volumes is of increasing importance in protein research. Proteins containing metal ions were analyzed directly and simultaneously in separated protein spots in two-dimensional gels (2D gels) by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) as an element mass spectrometric technique. In order to study the formation of proteins containing Cu, Zn and Fe in a human brain sample, isotopic-enriched tracers (54Fe, 65Cu and 67Zn) were doped to two-dimensional gels of separated Alzheimer-diseased brain proteins after two-dimensional (2D) gel electrophoresis. The protein spots were screened systematically by LA-ICP-MS with respect to these metal ion intensities. 54Fe/56Fe, 65Cu/63Cu and 67Zn/64Zn isotope ratios in metal-containing proteins were measured directly by LA-ICP-MS. The isotope ratio measurements obtained by LA-ICP-MS indicate certain protein spots with a natural isotope composition of Cu, Zn and/or Fe. These proteins already contained the metal investigated in the original proteins and are stable enough to survive the reducing conditions during gel electrophoresis. On the other hand, proteins with a changed isotope ratio of metals in comparison to the isotope ratio in nature demonstrate the accumulation of tracers within the protein complexes during the tracer experiments in 2D gels. The identification of singular protein spots from Alzheimer-diseased brain separated by 2D gel electrophoresis was attempted by biopolymer mass spectrometry using MALDI-FTICR-MS after excision from the 2D gel and tryptic digestion.

Green synthesis of novel zinc iron oxide (ZnFe2O4) nanocomposite via Moringa Oleifera natural extract for electrochemical applications

NASA Astrophysics Data System (ADS)

Matinise, N.; Kaviyarasu, K.; Mongwaketsi, N.; Khamlich, S.; Kotsedi, L.; Mayedwa, N.; Maaza, M.

2018-07-01

The main motivation of the research study involves development of reliable, accurate, inexpensive and environmental friendly method for the synthesis of zinc ferrite (ZnFe2O4) nanocomposites. It was thought of interest to synthesized zinc ferrite via green synthetic method using Moringa Oleifera extract. For the first time, we used green synthetic route via Moringa Oleifera extract acted as both chelating and reducing agents to synthesis spinel ZnFe2O4 nanocomposites. The physical and electrochemical properties were characterized using different techniques such as High Resolve Transmission Electron Microscope (HRTEM) Energy Dispersive X-ray Spectroscopy (EDS) X-ray diffraction (XRD) Fourier transform-infrared (FT-IR) Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The XRD pattern thus clearly illustrated that the ZnFe2O4 nanocmposites synthesized by the green method were good crystalline in nature. The time constant and exchange current of ZnFe2O4 nanocomposites from EIS analysis were calculated and found to be 5.2001 × 10-4 s/rad and 6.59432 × 10-4 A, respectively. Based on the electrochemical results, GCE/ZnFe2O4 electrode exhibited a good voltametric response, high electro-activity, and excellent electrochemical performance making it a highly suitable/promising electrode for electrochemical applications.

Whole-genome sequence of Cupriavidus sp. strain BIS7, a heavy-metal-resistant bacterium.

PubMed

Hong, Kar Wai; Thinagaran, Dinaiz al; Gan, Han Ming; Yin, Wai-Fong; Chan, Kok-Gan

2012-11-01

Cupriavidus sp. strain BIS7 is a Malaysian tropical soil bacterium that exhibits broad heavy-metal resistance [Co(II), Zn(II), Ni(II), Se(IV), Cu(II), chromate, Co(III), Fe(II), and Fe(III)]. It is particularly resistant to Fe(II), Fe(III), and Zn(II). Here we present the assembly and annotation of its genome.

Magnetically recyclable Ni0.5Zn0.5Fe2O4/Zn0.95Ni0.05O nano-photocatalyst: structural, optical, magnetic and photocatalytic properties.

PubMed

Qasim, Mohd; Asghar, Khushnuma; Singh, Braj Raj; Prathapani, Sateesh; Khan, Wasi; Naqvi, A H; Das, Dibakar

2015-02-25

A novel visible light active and magnetically separable nanophotocatalyst, Ni0.5Zn0.5Fe2O4/Zn0.95Ni0.05O (denoted as NZF@Z), with varying amount of Ni0.5Zn0.5Fe2O4, has been synthesized by egg albumen assisted sol gel technique. The structural, optical, magnetic, and photocatalytic properties have been studied by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), fourier transform infrared spectroscopy (FTIR), UV-visible (UV-Vis) spectroscopy, and vibrating sample magnetometry (VSM) techniques. Powder XRD, TEM, FTIR and energy dispersive spectroscopic (EDS) analyses confirm coexistence of Ni0.5Zn0.5Fe2O4 and Zn0.95Ni0.05O phases in the catalyst. Crystallite sizes of Ni0.5Zn0.5Fe2O4 and Zn0.95Ni0.05O in pure phases and nanocomposites, estimated from Debye-Scherrer equation, are found to be around 15-25 nm. The estimated particle sizes from TEM and FESEM data are ∼(22±6) nm. The calculated energy band gaps, obtained by Tauc relation from UV-Vis absorption spectra, of Zn0.95Ni0.05O, 15%NZF@Z, 40%NZF@Z and 60%NZF@Z are 2.95, 2.72, 2.64, and 2.54 eV respectively. Magnetic measurements (field (H) dependent magnetization (M)) show all samples to be super-paramagnetic in nature and saturation magnetizations (Ms) decrease with decreasing ferrite content in the nanocomposites. These novel nanocomposites show excellent photocatalytic activities on Rhodamin Dye. Copyright © 2014 Elsevier B.V. All rights reserved.

Controlled synthesis and microwave absorption properties of Ni0.6Zn0.4Fe2O4/PANI composite via an in-situ polymerization process

NASA Astrophysics Data System (ADS)

Wang, Min; Ji, Guangbin; Zhang, Baoshan; Tang, Dongming; Yang, Yi; Du, Youwei

2015-03-01

The binary composites of conducting polyaniline (PANI) and nickle zinc ferrite were synthesized by an in-situ polymerization process, and the electromagnetic absorption properties of the composites were also investigated. The FT-IR spectra present the peaks of PANI (1562, 1481, 1301, 1109, and 799 cm-1) and the bonds of NiZn ferrite (579 and 390 cm-1), indicating the existence of both NiZn ferrite particles and PANI in the composites. With the increasing ratio of nickle zinc ferrite, the composites distributes in irregular compared with pure PANI and Ni0.6Zn0.4Fe2O4. The TG curves of the pure PANI and PANI/Ni0.6Zn0.4Fe2O4 composites with different molar ratios clearly show the increase percentage of the ferrite in the composites. Furthermore, we found that the excellent electromagnetic absorption properties and wide absorption bandwidth can be achieved by adjusting proper molar ratios Ni0.6Zn0.4Fe2O4 to PANI. The maximum reflection loss of Ni0.6Zn0.4Fe2O4/PANI can reach to -41 dB at 12.8 GHz and the bandwidth exceeding -10 dB can reach to 5 GHz with the absorber thickness of 2.6 mm at the molar ratio of 1:2. This can be attributed to the enhancing magnetic loss and the better impedance matching. Therefore, Ni0.6Zn0.4Fe2O4/PANI ferrite composites can become a new kind of candidate in the field of the microwave absorbing.

Popcorn balls-like ZnFe2O4-ZrO2 microsphere for photocatalytic degradation of 2,4-dinitrophenol

NASA Astrophysics Data System (ADS)

Chen, Xi; Liu, Yutang; Xia, Xinnian; Wang, Longlu

2017-06-01

In this paper, novel popcorn balls-like ZnFe2O4-ZrO2 composite microspheres were successfully fabricated by a simple hydrothermal method. The morphology, structure and optical property of the microspheres were characterized. The microspheres were used as the photocatalysts to degrade 2,4-dinitrophenol, and exhibited superior photocatalytic performance. Under simulated solar visible light irradiation, the degradation rate of ZnFe2O4-ZrO2 photocatalyst (mass ratio of ZnFe2O4/ZrO2 = 2:1) was almost 7.4 and 2.4 times higher than those of pure ZnFe2O4 and ZrO2. The enhancement could attribute to stronger light absorption, lower carrier recombination and multi-porous structure of the microspheres. Moreover, the popcorn balls-like photocatalysts can be easily separated, because of the magnetism of the samples. After five times runs, the photocatalyst still showed 90% of its photocatalytic degradation efficiency. This work demonstrated a good prospect for removing organic pollutants in water.

Synthesis, characterization, and antibacterial activities of ZnLaFe2O4/NiTiO3 nanocomposite

NASA Astrophysics Data System (ADS)

Sobhani-Nasab, Ali; Zahraei, Zohreh; Akbari, Maryam; Maddahfar, Mahnaz; Hosseinpour-Mashkani, S. Mostafa

2017-07-01

In this research, for the first time, ZnLaFe2O4/NiTiO3 nanocomposites have been synthesized through a polyol assistant sol-gel method. To investigate the effect of different surfactants on the morphology and particle size of ZnLaFe2O4 nanostructure, cetrimonium bromide, sodium dodecyl sulfate, polyvinylpyrrolidone, polyvinyl alcohol, and oleic acid were used as surfactant agents. Based on the SEM results, it was found that morphology and particle size of the products could be affected by these surfactants. Furthermore, study on antibacterial effect of ZnLaFe2O4/NiTiO3 nanocomposites by colony forming unit (CFU) reduction assay showed that ZnLaFe2O4/NiTiO3 nanocomposites have antibacterial activity against Gram-negative Escherchia coli (ATCC 10536) and Gram-positive Staphylococcus aureus (ATCC 29737). Antibacterial results demonstrate that nanocomposite significantly reduced the growth rate of E. coli bacteria and S. aureus after 120 min. The structure and morphology of the resulting particles were characterized by XRD, FT-IR, EDX, and SEM analysis.

γ-irradiation induced zinc ferrites and their enhanced room-temperature ammonia gas sensing properties

NASA Astrophysics Data System (ADS)

Raut, S. D.; Awasarmol, V. V.; Ghule, B. G.; Shaikh, S. F.; Gore, S. K.; Sharma, R. P.; Pawar, P. P.; Mane, R. S.

2018-03-01

Zinc ferrite (ZnFe2O4) nanoparticles (NPs), synthesized using a facile and cost-effective sol-gel auto-combustion method, were irradiated with 2 and 5 kGy γ-doses using 60Co as a radioactive source. Effect of γ-irradiation on the structure, morphology, pore-size and pore-volume and room-temperature (300 K) gas sensor performance has been measured and reported. Both as-synthesized and γ-irradiated ZnFe2O4 NPs reveal remarkable gas sensor activity to ammonia in contrast to methanol, ethanol, acetone and toluene volatile organic gases. The responses of pristine, 2 and 5 kGy γ-irradiated ZnFe2O4 NPs are respectively 55%, 66% and 81% @100 ppm concentration of ammonia, signifying an importance of γ-irradiation for enhancing the sensitivity, selectivity and stability of ZnFe2O4 NPs as ammonia gas sensors. Thereby, due to increase in surface area and crystallinity on γ-doses, the γ-irradiation improves the room-temperature ammonia gas sensing performance of ZnFe2O4.

Hydrometallurgical Extraction of Zinc and Copper A 57Fe-Mössbauer and XRD Approach

NASA Astrophysics Data System (ADS)

Mulaba-Bafubiandi, A. F.; Waanders, F. B.

2005-02-01

The most commonly used route in the hydrometallurgical extraction of zinc and copper from a sulphide ore is the concentrate roast leach electro winning process. In the present investigation a zinc copper ore from the Maranda mine, located in the Murchison Greenstone Belt, South Africa, containing sphalerite (ZnS) and chalcopyrite (CuFeS2), was studied. The 57Fe-Mössbauer spectrum of the concentrate yielded pyrite, chalcopyrite and clinochlore, consistent with XRD data. Optimal roasting conditions were found to be 900°C for 3 h and the calcine produced contained according to X-ray diffractometry equal amounts of franklinite (ZnFe2O4) and zinc oxide (ZnO) and half the amount of willemite (Zn2SiO4). The Mössbauer spectrum showed predominantly franklinite (59%), hematite (6%) and other Zn- or Cu-depleted ferrites (35%). The latter could not be detected by XRD analyses as peak overlapping with other species occurred. Leaching was done with HCl, H2SO4 and HNO3, to determine which process would result in maximum recovery of Zn and Cu. More than 80% of both were recovered by using either one of the three techniques. From the residue of the leaching, the Fe-compounds were precipitated and <1% of the Zn and Cu was not recovered.

Sepiolite nanoplatform for the simultaneous assembly of magnetite and zinc oxide nanoparticles as photocatalyst for improving removal of organic pollutants.

PubMed

Akkari, M; Aranda, P; Mayoral, A; García-Hernández, M; Ben Haj Amara, A; Ruiz-Hitzky, E

2017-10-15

Novel ternary ZnO/Fe 3 O 4 -sepiolite nanostructured materials were developed in a two-step procedure based on the incorporation of ZnO nanoparticles on a substrate composed by magnetite nanoparticles previously assembled to the sepiolite fibrous silicate (Fe 3 O 4 -sepiolite). The structural and morphological characterization shows that both, ZnO and Fe 3 O 4 nanoparticles, were homogeneously dispersed on the surface of sepiolite. Therefore, the resulting material is characterized as a multifunctional nanoplatform simultaneously providing magnetic and photoactive properties. ZnO/Fe 3 O 4 -sepiolite materials exhibit superparamagnetic properties at room temperature, which is one of the sought properties in view to facilitate their recovery from the reaction medium after application as heterogeneous catalysts. ZnO/Fe 3 O 4 -sepiolite materials were tested as photocatalysts using methylene blue dye in water as model of a pollutant molecule, showing full decolorization after 2h of UV irradiation. Moreover, the photocatalytic activity of this nanoplataform may be maintained after reuse in several consecutive cycles of treatment. Remarkably, the ZnO/magnetite-sepiolite nanostructured material displays a similar activity as ZnO/sepiolite materials, but shows the additional advantage of easier recovery by means of a magnet which facilitates its reuse. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecular controls on Cu and Zn isotopic fractionation in Fe-Mn crusts

NASA Astrophysics Data System (ADS)

Little, S. H.; Sherman, D. M.; Vance, D.; Hein, J. R.

2014-06-01

The isotopic systems of the transition metals are increasingly being developed as oceanic tracers, due to their tendency to be fractionated by biological and/or redox-related processes. However, for many of these promising isotope systems the molecular level controls on their isotopic fractionations are only just beginning to be explored. Here we investigate the relative roles of abiotic and biotic fractionation processes in controlling modern seawater Cu and Zn isotopic compositions. Scavenging to Fe-Mn oxides represents the principal output for Cu and Zn to sediments deposited under normal marine (oxic) conditions. Using Fe-Mn crusts as an analogue for these dispersed phases, we investigate the phase association and crystal chemistry of Cu and Zn in such sediments. We present the results of an EXAFS study that demonstrate unequivocally that Cu and Zn are predominantly associated with the birnessite (δ-MnO2) phase in Fe-Mn crusts, as previously predicted from sequential leaching experiments (e.g., Koschinsky and Hein, 2003). The crystal chemistry of Cu and Zn in the crusts implies a reduction in coordination number in the sorbed phase relative to the free metal ion in seawater. Thus, theory would predict equilibrium fractionations that enrich the heavy isotope in the sorbed phase (e.g., Schauble, 2004). In natural samples, Fe-Mn crusts and nodules are indeed isotopically heavy in Zn isotopes (at ∼1‰) compared to deep seawater (at ∼0.5‰), consistent with the predicted direction of equilibrium isotopic fractionation based on our observations of the coordination environment of sorbed Zn. Further, ∼50% of inorganic Zn‧ is chloro-complexed (the other ∼50% is present as the free Zn2+ ion), and complexation by Cl- is also predicted to favour equilibrium partitioning of light Zn isotopes into the dissolved phase. The heavy Zn isotopic composition of Fe-Mn crusts and nodules relative to seawater can therefore be explained by an inorganic fractionation during uptake. However, Cu in Fe-Mn crusts is isotopically light (at ∼0.3 to 0.5‰) compared to the dissolved phase in seawater (at ∼0.9‰). We suggest that this is because dissolved Cu in the oceans is overwhelmingly complexed to strong organic ligands, which are better competitors for the heavy isotope.

Structure refinement of the δ1p phase in the Fe-Zn system by single-crystal X-ray diffraction combined with scanning transmission electron microscopy.

PubMed

Okamoto, Norihiko L; Tanaka, Katsushi; Yasuhara, Akira; Inui, Haruyuki

2014-04-01

The structure of the δ1p phase in the iron-zinc system has been refined by single-crystal synchrotron X-ray diffraction combined with scanning transmission electron microscopy. The large hexagonal unit cell of the δ1p phase with the space group of P63/mmc comprises more or less regular (normal) Zn12 icosahedra, disordered Zn12 icosahedra, Zn16 icosioctahedra and dangling Zn atoms that do not constitute any polyhedra. The unit cell contains 52 Fe and 504 Zn atoms so that the compound is expressed with the chemical formula of Fe13Zn126. All Fe atoms exclusively occupy the centre of normal and disordered icosahedra. Iron-centred normal icosahedra are linked to one another by face- and vertex-sharing forming two types of basal slabs, which are bridged with each other by face-sharing with icosioctahedra, whereas disordered icosahedra with positional disorder at their vertex sites are isolated from other polyhedra. The bonding features in the δ1p phase are discussed in comparison with those in the Γ and ζ phases in the iron-zinc system.

Distribution of Ca, Fe, Cu and Zn in primary colorectal cancer and secondary colorectal liver metastases

NASA Astrophysics Data System (ADS)

Al-Ebraheem, A.; Mersov, A.; Gurusamy, K.; Farquharson, M. J.

2010-07-01

A microbeam synchrotron X-ray fluorescence (μSRXRF) technique has been used to determine the localization and the relative concentrations of Zn, Cu, Fe and Ca in primary colorectal cancer and secondary colorectal liver metastases. 24 colon and 23 liver samples were examined, all of which were formalin fixed tissues arranged as microarrays of 1.0 mm diameter and 10 μm thickness. The distribution of these metals was compared with light transmission images of adjacent sections that were H and E stained to reveal the location of the cancer cells. Histological details were provided for each sample which enable concentrations of all elements in different tissue types to be compared. In the case of liver, significant differences have been found for all elements when comparing tumour, normal, necrotic, fibrotic, and blood vessel tissues (Kruskal Wallis Test, P<0.0001). The concentrations of all elements have also been found to be significantly different among tumour, necrotic, fibrotic, and mucin tissues in the colon samples (Kruskal Wallis Test, P<0.0001). The concentrations of all elements have been compared between primary colorectal samples and colorectal liver metastases. Concentration of Zn, Cu, Fe and Ca are higher in all types of liver tissues compared to those in the colon tissues. Comparing liver tumour and colon tumour samples, significant differences have been found for all elements (Mann Whitney, P<0.0001). For necrotic tissues, significant increase has been found for Zn, Ca, Cu and Fe (Mann Whitney, P<0.0001 for Fe and Zn, 0.014 for Ca, and 0.001 for Cu). The liver fibrotic levels of Zn, Ca, Cu and Fe were higher than the fibrotic colon areas (independent T test, P=0.007 for Zn and Mann Whitney test P<0.0001 for Cu, Fe and Ca). For the blood vessel tissue, the analysis revealed that the difference was only significant for Fe ( P=0.009) from independent T test.

Electronic and magnetic properties of Zn1-xFexSe alloys

NASA Astrophysics Data System (ADS)

Khatta, Swati; Tripathi, S. K.; Prakash, Satya

2017-12-01

The spin polarized density functional theory along with self consistent plane wave pseudopotential method is used to investigate electronic and magnetic properties of ternary Zn1-xFexSe alloys with x = 0.125, 0.25, 0.5 and 0.75. The exchange-correlation potential treated within generalized gradient approximation is used. The calculated spin-polarized band structures, partial and total density of states reveal that Zn0.875Fe0.125Se and Zn0.75Fe0.25Se exhibit half metallic ferromagnetic characteristics and Zn0.50Fe0.50Se is nearly half metallic in nature. The half metallic band gaps for x = 0.125 and 0.25 are 0.69 and 0.39 eV respectively, while the corresponding band gaps are 0.86 and 0.81 eV. The p-d hybridization reduces the magnetic moment of Fe atoms from its free space charge value of 4 μB and induces the small magnetic moments on Zn and Se sites. The results are compared with available experimental data.

Morphology dependent field emission characteristics of ZnS/silicon nanoporous pillar array

NASA Astrophysics Data System (ADS)

Wang, Ling Li; Zhao, Cheng Zhou; Kang, Li Ping; Liu, De Wei; Zhao, Hui Chun; Hao, Shan Peng; Zhang, Yuan Kai; Chen, Zhen Ping; Li, Xin Jian

2016-10-01

Through depositing zinc sulphide (ZnS) nanoparticals on silicon nanoporous pillar array (Si-NPA) and crater-shaped silicon nanoporous pillar array (c-Si-NPA) by chemical bath deposition (CBD) method, ZnS/Si-NPA and c-ZnS/Si-NPA were prepared and the field emission (FE) properties of them were investigated. The turn-on electric fields of were 3.8 V/mm for ZnS/Si-NPA and 5.0 V/mm for c-ZnS/Si-NPA, respectively. The lower turn-on electric fields of ZnS/Si-NPA than that of c-ZnS/Si-NPA were attributed to the different electric distribution of the field emitters causing by the different surface morphology of the two samples, which was further demonstrated via the simulated results by finite element modeling. The FN curves for the ZnS/Si-NPA showed two-slope behavior. All the results indicate that the morphology play an important role in the FE properties and designing an appropriate top morphology for the emitter is a very efficient way to improve the FE performance.

Colloid formation and metal transport through two mixing zones affected by acid mine drainage near Silverton, Colorado

USGS Publications Warehouse

Schemel, L.E.; Kimball, B.A.; Bencala, K.E.

2000-01-01

Stream discharges and concentrations of dissolved and colloidal metals (Al, Ca, Cu, Fe, Mg, Mn, Pb, and Zn), SO4, and dissolved silica were measured to identify chemical transformations and determine mass transports through two mixing zones in the Animas River that receive the inflows from Cement and Mineral Creeks. The creeks were the dominant sources of Al, Cu, Fe, and Pb, whereas the upstream Animas River supplied about half of the Zn. With the exception of Fe, which was present in dissolved and colloidal forms, the metals were dissolved in the acidic, high-SO4 waters of Cement Creek (pH 3.8). Mixing of Cement Creek with the Animas River increased pH to near-neutral values and transformed Al and some additional Fe into colloids which also contained Cu and Pb. Aluminium and Fe colloids had already formed in the mildly acidic conditions in Mineral Creek (pH 6.6) upstream of the confluence with the Animas River. Colloidal Fe continued to form downstream of both mixing zones. The Fe- and Al-rich colloids were important for transport of Cu, Pb, and Zn, which appeared to have sorbed to them. Partitioning of Zn between dissolved and colloidal phases was dependent on pH and colloid concentration. Mass balances showed conservative transports for Ca, Mg, Mn, SO4, and dissolved silica through the two mixing zones and small losses (< 10%) of colloidal Al, Fe and Zn from the water column.

Whole-Genome Sequence of Cupriavidus sp. Strain BIS7, a Heavy-Metal-Resistant Bacterium

PubMed Central

Hong, Kar Wai; Thinagaran, Dinaiz a/l; Gan, Han Ming; Yin, Wai-Fong

2012-01-01

Cupriavidus sp. strain BIS7 is a Malaysian tropical soil bacterium that exhibits broad heavy-metal resistance [Co(II), Zn(II), Ni(II), Se(IV), Cu(II), chromate, Co(III), Fe(II), and Fe(III)]. It is particularly resistant to Fe(II), Fe(III), and Zn(II). Here we present the assembly and annotation of its genome. PMID:23115161

Heavy Metals Induce Iron Deficiency Responses at Different Hierarchic and Regulatory Levels.

PubMed

Lešková, Alexandra; Giehl, Ricardo F H; Hartmann, Anja; Fargašová, Agáta; von Wirén, Nicolaus

2017-07-01

In plants, the excess of several heavy metals mimics iron (Fe) deficiency-induced chlorosis, indicating a disturbance in Fe homeostasis. To examine the level at which heavy metals interfere with Fe deficiency responses, we carried out an in-depth characterization of Fe-related physiological, regulatory, and morphological responses in Arabidopsis ( Arabidopsis thaliana ) exposed to heavy metals. Enhanced zinc (Zn) uptake closely mimicked Fe deficiency by leading to low chlorophyll but high ferric-chelate reductase activity and coumarin release. These responses were not caused by Zn-inhibited Fe uptake via IRON-REGULATED TRANSPORTER (IRT1). Instead, Zn simulated the transcriptional response of typical Fe-regulated genes, indicating that Zn affects Fe homeostasis at the level of Fe sensing. Excess supplies of cobalt and nickel altered root traits in a different way from Fe deficiency, inducing only transient Fe deficiency responses, which were characterized by a lack of induction of the ethylene pathway. Cadmium showed a rather inconsistent influence on Fe deficiency responses at multiple levels. By contrast, manganese evoked weak Fe deficiency responses in wild-type plants but strongly exacerbated chlorosis in irt1 plants, indicating that manganese antagonized Fe mainly at the level of transport. These results show that the investigated heavy metals modulate Fe deficiency responses at different hierarchic and regulatory levels and that the interaction of metals with physiological and morphological Fe deficiency responses is uncoupled. Thus, this study not only emphasizes the importance of assessing heavy metal toxicities at multiple levels but also provides a new perspective on how Fe deficiency contributes to the toxic action of individual heavy metals. © 2017 American Society of Plant Biologists. All Rights Reserved.

Magnetically addressable fluorescent Fe3O4/ZnO nanocomposites: Structural, optical and magnetization studies

NASA Astrophysics Data System (ADS)

Roychowdhury, A.; Pati, S. P.; Mishra, A. K.; Kumar, S.; Das, D.

2013-06-01

Fe3O4/ZnO nanocomposites (NCs) are prepared by a wet chemical route. X-ray diffraction, transmission electron microscopy and Fourier transform infrared spectroscopy studies confirm the coexistence of Fe3O4 and ZnO phases in the NCs. The UV-vis absorption spectra show a red shift of the absorption peak with increase in Fe3O4 content indicating a modification of the band structure of ZnO in the NCs. Photoluminescence emission spectra of the NCs display strong excitonic emission in the UV region along with weak emission bands in the visible range caused by electronic transitions involving defect-related energy levels in the band gap of ZnO. Positron annihilation lifetimes indicate that cation vacancies in the ZnO structure are the strong traps for positrons and the overall defect concentration in the NCs decreases with increase in Fe3O4 content. Dc magnetization measurements reveal an anomalous temperature dependence of the coercivity of the NCs that is argued to be due to the anomalous variation of magnetocrystalline anisotropy at lower temperature. The irreversibility observed in the temperature dependent ZFC-FC magnetization points to the presence of a spin-glass phase in the NCs.

Iron and zinc fortification of corn tortilla made either at the household or at industrial scale.

PubMed

Tovar, Luis Raul; Larios-Saldaña, Alfredo

2005-03-01

Fe and Zn deficiencies among the Mexican population are widespread, and one-third of children and women of childbearing age are anemic. Since diets that are Fe-deficient are most probably also Zn-deficient, a proprietary process was developed to fortify corn tortilla with these trace elements at the first stage of treatment with lime. Phytic acid (PA), Ca, Fe, and Zn content were determined, as well as the molar ratios of phytate/Fe, phytate/Zn, and Ca x phytate to Zn in traditional and fortified tortillas; the Student's t-test was used to detect differences between the treatments (p < 0.001). Contents of Fe and Zn in the fortified tortilla relative to the traditional tortilla were 1.9 and 3.4 times greater than the latter, whereas PA contents showed the opposite result, i.e. traditional tortillas had 1.65 times more PA than the fortified tortilla. Consequently the calculated molar ratios were statistically more favorable for fortified than for traditional tortillas (p < 0.001). The process developed allows making iron- and zinc-fortified tortillas by lime-treating or nixtamalizing corn either at the household, at small-scale tortilla shops, or at industrial scale by using lime fortified with both trace elements. The cost of this fortification is negligible.

Tuning the Kondo effect in Yb(Fe 1-xCo x) 2Zn 20

DOE PAGES

Kong, Tai; Taufour, Valentin; Bud'ko, Sergey L.; ...

2017-04-03

We study the evolution of the Kondo effect in heavy fermion compounds, Yb(Fe 1-xCo x) 2Zn 20 (0 ≲ x ≲ 1), by means of temperature-dependent electric resistivity and speci c heat. The ground state of YbFe 2Zn 20 can be well described by a Kondo model with degeneracy N = 8 and a T K ~30 K. In the presence of a very similar total CEF splitting with YbFe 2Zn 20, the ground state of YbCo 2Zn 20 is close to a Kondo state with degeneracy N = 2 and a much lower TK ~ 2 K. Upon Comore » substitution, the coherence temperature of YbFe 2Zn 20 is suppressed, accompanied by an emerging Schottky-like feature in speci c heat associated with the thermal depopulation of CEF levels upon cooling. For 0.4 ≲ x ≲ 0.9, the ground state remains roughly the same which can be qualitatively understood by Kondo effect in the presence of CEF splitting. There is no clear indication of Kondo coherence observable in resistivity within this substitution range down to 500 mK. The coherence re-appears at around x≳ 0.9 and the coherence temperature increases with higher Co concentration levels.« less

Mapping Grain Iron and Zinc Content Quantitative Trait Loci in an Iniadi-Derived Immortal Population of Pearl Millet

PubMed Central

Kumar, Sushil; Hash, Charles Tom; Nepolean, Thirunavukkarasu; Mahendrakar, Mahesh D.; Satyavathi, Chellapilla Tara; Singh, Govind; Rathore, Abhishek; Gupta, Rajeev; Srivastava, Rakesh K.

2018-01-01

Pearl millet is a climate-resilient nutritious crop requiring low inputs and is capable of giving economic returns in marginal agro-ecologies. In this study, we report large-effect iron (Fe) and zinc (Zn) content quantitative trait loci (QTLs) using diversity array technology (DArT) and simple sequence repeats (SSRs) markers to generate a genetic linkage map using 317 recombinant inbred line (RIL) population derived from the (ICMS 8511-S1-17-2-1-1-B-P03 × AIMP 92901-S1-183-2-2-B-08) cross. The base map [seven linkage groups (LGs)] of 196 loci was 964.2 cM in length (Haldane). AIMP 92901-S1-183-2-2-B-08 is an Iniadi line with high grain Fe and Zn, tracing its origin to the Togolese Republic, West Africa. The content of grain Fe in the RIL population ranged between 20 and 131 ppm (parts per million), and that of Zn from 18 to 110 ppm. QTL analysis revealed a large number of QTLs for high grain iron (Fe) and zinc (Zn) content. A total of 19 QTLs for Fe and Zn were detected, of which 11 were for Fe and eight were for Zn. The portion of the observed phenotypic variance explained by different QTLs for grain Fe and Zn content varied from 9.0 to 31.9% (cumulative 74%) and from 9.4 to 30.4% (cumulative 65%), respectively. Three large-effect QTLs for both minerals were co-mapped in this population, one on LG1 and two on LG7. The favorable QTL alleles of both mineral micronutrients were contributed by the male parent (AIMP 92901-deriv-08). Three putative epistasis interactions were observed for Fe content, while a single digenic interaction was found for Zn content. The reported QTLs may be useful in marker-assisted selection (MAS) programs, in genomic selection (GS) breeding pipelines for seed and restorer parents, and in population improvement programs for pearl millet. PMID:29751669

Mapping Grain Iron and Zinc Content Quantitative Trait Loci in an Iniadi-Derived Immortal Population of Pearl Millet.

PubMed

Kumar, Sushil; Hash, Charles Tom; Nepolean, Thirunavukkarasu; Mahendrakar, Mahesh D; Satyavathi, Chellapilla Tara; Singh, Govind; Rathore, Abhishek; Yadav, Rattan S; Gupta, Rajeev; Srivastava, Rakesh K

2018-05-11

Pearl millet is a climate-resilient nutritious crop requiring low inputs and is capable of giving economic returns in marginal agro-ecologies. In this study, we report large-effect iron (Fe) and zinc (Zn) content quantitative trait loci ( QTLs) using diversity array technology (DArT) and simple sequence repeats (SSRs) markers to generate a genetic linkage map using 317 recombinant inbred line (RIL) population derived from the (ICMS 8511-S1-17-2-1-1-B-P03 × AIMP 92901-S1-183-2-2-B-08) cross. The base map [seven linkage groups (LGs)] of 196 loci was 964.2 cM in length (Haldane). AIMP 92901-S1-183-2-2-B-08 is an Iniadi line with high grain Fe and Zn, tracing its origin to the Togolese Republic, West Africa. The content of grain Fe in the RIL population ranged between 20 and 131 ppm (parts per million), and that of Zn from 18 to 110 ppm. QTL analysis revealed a large number of QTLs for high grain iron (Fe) and zinc (Zn) content. A total of 19 QTLs for Fe and Zn were detected, of which 11 were for Fe and eight were for Zn. The portion of the observed phenotypic variance explained by different QTLs for grain Fe and Zn content varied from 9.0 to 31.9% (cumulative 74%) and from 9.4 to 30.4% (cumulative 65%), respectively. Three large-effect QTLs for both minerals were co-mapped in this population, one on LG1 and two on LG7. The favorable QTL alleles of both mineral micronutrients were contributed by the male parent (AIMP 92901-deriv-08). Three putative epistasis interactions were observed for Fe content, while a single digenic interaction was found for Zn content. The reported QTLs may be useful in marker-assisted selection (MAS) programs, in genomic selection (GS) breeding pipelines for seed and restorer parents, and in population improvement programs for pearl millet.

Hierarchical magnetic petal-like Fe3O4-ZnO@g-C3N4 for removal of sulfamethoxazole, suppression of photocorrosion, by-products identification and toxicity assessment.

PubMed

Mirzaei, Amir; Chen, Zhi; Haghighat, Fariborz; Yerushalmi, Laleh

2018-08-01

Herein, a petal-like photocatalyst, Fe 3 O 4 -ZnO@g-C 3 N 4 (FZG) with different g-C 3 N 4 to ZnO ratios was synthesized with hierarchical structure. The FZG1 photocatalyst, having the weight ratio of 1:1 for the initial urea and Fe 3 O 4 -ZnO (Fe-ZnO), presented the highest sulfamethoxazole (SMX) degradation rate of 0.0351 (min -1 ), which was 2.6 times higher than that of pristine ZnO. Besides the facile separation, the performance of photocatalyst was improved due to the function of iron oxide as an electron acceptor that reduced the electron/hole recombination rate. The coating of g-C 3 N 4 on the Fe-ZnO surface not only acted as a protective layer for ZnO against photocorrosion, but it also enhanced the photocatalytic activity of the catalyst for SMX degradation through the heterojunction mechanism. By using the FZG1 photocatalyst, 95% SMX removal was obtained after 90 min reaction, while 47% COD and 30% TOC removal were achieved after 60 min treatment under a low energy-consuming UV lamp (10 W). Moreover, a substantial reduction in the solution toxicity was shown after the treatment, as compared with the SMX solution before treatment. The LC-HR-MS/MS analysis results showed that the concentration of most detected by-products produced after 90 min reaction by FZG1 was considerably lower than those obtained using other synthesized photocatalysts. By performing radical scavenging experiments, OH ° radical was found to be the major reactive species. The FZG1 photocatalyst also displayed excellent reusability in five cycles and the leaching of zinc and iron ions was reduced by 54% and ∼100%, respectively, after coating Fe-ZnO with g-C 3 N 4 . Copyright © 2018 Elsevier Ltd. All rights reserved.

The role of reduced graphene oxide on the electrochemical activity of MFe2O4 (M = Fe, Co, Ni and Zn) nanohybrids

NASA Astrophysics Data System (ADS)

Suresh, Shravan; Prakash, Anand; Bahadur, D.

2018-02-01

In this work, a comparative study of electrochemical performance of reduced graphene oxide-ferrites (RGO-MFe2O4, M = Fe, Co, Ni, and Zn) nanohybrids synthesized by hydrothermal method was done. The structural morphology and investigation of other physical properties of nanohybrids confirm the cubic spinel phase of the MFe2O4, reduction of graphene oxide and the distribution of ferrite nanoparticles (NPs) on RGO nanosheets. The role of RGO on the electrochemical behavior of nanohybrids was understood by quantifying the charge storage capacitance and charging-discharging behavior in a 0.1 M Na2SO4 electrolyte. The specific capacitance values of pristine Fe3O4, CoFe2O4, NiFe2O4, and ZnFe2O4 are 128, 117, 15.2 and 9.1 F g-1 respectively whereas specific capacitance of RGO-Fe3O4, RGO-CoFe2O4, RGO-NiFe2O4 and RGO-ZnFe2O4 are 233, 200, 25 and 66.8 F g-1 respectively. Our investigation suggests that apart from specific surface area of nanohybrids other factors such as structural morphology determine interaction between nanohybrids and electrolyte ions which play critical role in elevating the performance of electrodes.

Changes in zinc speciation with mine tailings acidification in a semiarid weathering environment.

PubMed

Hayes, Sarah M; O'Day, Peggy A; Webb, Sam M; Maier, Raina M; Chorover, Jon

2011-09-01

High concentrations of residual metal contaminants in mine tailings can be transported easily by wind and water, particularly when tailings remain unvegetated for decades following mining cessation, as is the case in semiarid landscapes. Understanding the speciation and mobility of contaminant metal(loid)s, particularly in surficial tailings, is essential to controlling their phytotoxicities and to revegetating impacted sites. In prior work, we showed that surficial tailings samples from the Klondyke State Superfund Site (AZ, USA), ranging in pH from 5.4 to 2.6, represent a weathering series, with acidification resulting from sulfide mineral oxidation, long-term Fe hydrolysis, and a concurrent decrease in total (6000 to 450 mg kg(-1)) and plant-available (590 to 75 mg kg(-1)) Zn due to leaching losses and changes in Zn speciation. Here, we used bulk and microfocused Zn K-edge X-ray absorption spectroscopy (XAS) data and a six-step sequential extraction procedure to determine tailings solid phase Zn speciation. Bulk sample spectra were fit by linear combination using three references: Zn-rich phyllosilicate (Zn(0.8)talc), Zn sorbed to ferrihydrite (Zn(adsFeOx)), and zinc sulfate (ZnSO(4) · 7H(2)O). Analyses indicate that Zn sorbed in tetrahedral coordination to poorly crystalline Fe and Mn (oxyhydr)oxides decreases with acidification in the weathering sequence, whereas octahedral zinc in sulfate minerals and crystalline Fe oxides undergoes a relative accumulation. Microscale analyses identified hetaerolite (ZnMn(2)O(4)), hemimorphite (Zn(4)Si(2)O(7)(OH)(2) · H(2)O) and sphalerite (ZnS) as minor phases. Bulk and microfocused spectroscopy complement the chemical extraction results and highlight the importance of using a multimethod approach to interrogate complex tailings systems.

Growth of hybrid carbon nanostructures on iron-decorated ZnO nanorods

NASA Astrophysics Data System (ADS)

Mbuyisa, Puleng N.; Rigoni, Federica; Sangaletti, Luigi; Ponzoni, Stefano; Pagliara, Stefania; Goldoni, Andrea; Ndwandwe, Muzi; Cepek, Cinzia

2016-04-01

A novel carbon-based nanostructured material, which includes carbon nanotubes (CNTs), porous carbon, nanostructured ZnO and Fe nanoparticles, has been synthetized using catalytic chemical vapour deposition (CVD) of acetylene on vertically aligned ZnO nanorods (NRs). The deposition of Fe before the CVD process induces the presence of dense CNTs in addition to the variety of nanostructures already observed on the process done on the bare NRs, which range from amorphous graphitic carbon up to nanostructured dendritic carbon films, where the NRs are partially or completely etched. The combination of scanning electron microscopy and in situ photoemission spectroscopy indicate that Fe enhances the ZnO etching, and that the CNT synthesis is favoured by the reduced Fe mobility due to the strong interaction between Fe and the NRs, and to the presence of many defects, formed during the CVD process. Our results demonstrate that the resulting new hybrid shows a higher sensitivity to ammonia gas at ambient conditions (∼60 ppb) than the carbon nanostructures obtained without the aid of Fe, the bare ZnO NRs, or other one-dimensional carbon nanostructures, making this system of potential interest for environmental ammonia monitoring. Finally, in view of the possible application in nanoscale optoelectronics, the photoexcited carrier behaviour in these hybrid systems has been characterized by time-resolved reflectivity measurements.

Bioaccessible nutrients and bioactive components from fortified products prepared using finger millet (Eleusine coracana).

PubMed

Oghbaei, Morteza; Prakash, Jamuna

2012-08-30

Finger millet (Eleusine coracana), a staple food in semi-arid parts of the world, is a rich source of nutrients and bioactive components comparable to rice and wheat but with higher fibre content. Unprocessed and processed finger millet (whole flour (WFM), sieved flour (SFM), wafers and vermicelli with altered matrices (added Fe or Zn or reduced fibre)) were analysed for chemical composition, bioaccessible Fe, Zn and Ca, in vitro digestible starch (IVSD) and protein (IVPD) and bioactive components (polyphenols and flavonoids). WFM and SFM flours differed significantly in their composition. Sieving decreased the content of both nutrients and antinutrients in WFM but increased their digestibility/bioaccessibility. WFM products with Zn and Fe showed highest IVPD, whereas SFM products with Fe showed highest IVSD. Products with externally added Fe and Zn showed maximum bioaccessibility of Fe and Zn respectively. WFM had the highest levels of total polyphenols and flavonoids, 4.18 and 15.85 g kg⁻¹ respectively; however, bioaccessibility was highest in SFM vermicelli. The availability of nutrients and bioactive components was influenced by both processing methods and compositional alterations of the food matrix in finger millet products, and bioaccessibility of all constituents was higher in vermicelli (wet matrix) than in wafers (dry matrix). Copyright © 2012 Society of Chemical Industry.

Analysis of micromineral contents of school meals.

PubMed

Shin, Dongsoon

2014-08-01

Korean ordinary diets are referred to be good for human health in worldwide. However it is uncertain whether they provide microminerals enough for growth and health of teenagers. A main purpose of this study was to identify micromineral contents in school meals. The fifty cuisines were collected from elementary schools and middle schools in Gyeongnam area. The contents of Fe, Zn, Cu and Mn among microminerals were analyzed by using ICP-OES method. Data were expressed as mean, standard deviation and range value and linear regression analysis performed. Fe level of Pangibuseotpaprika-salad was the highest among side-dishes (average 346.6 µg) and Zn level of Sullung-tang was highest among soups (average 229.1 µg). Cu level of Buchu-kimchi was the highest among kimchies (average 217.5 µg) and Mn level of Gumeunkongyangnyum-gui was highest among side-dishes (average 198.4 µg). Generally cooked-rices as main dish had relative smaller amounts of microminerals than the other cuisines. The results showed that the ratio of Cu : Fe : Zn was approximately 12 : 4 : 1 and the relationship between Fe versus Zn or Fe versus Cu was significantly positive. Comparing to Korean Dietary Recommended Intakes (KDRI) level, school meals provided not sufficient amount (<25% DRI) of Fe, Zn or Mn, while they did excessive amount (>125% DRI) of Cu.

Mg1-xZnxFe2O4 nanoparticles: Interplay between cation distribution and magnetic properties

NASA Astrophysics Data System (ADS)

Raghuvanshi, S.; Mazaleyrat, F.; Kane, S. N.

2018-04-01

Correlation between cationic distribution, magnetic properties of Mg1-xZnxFe2O4 (0.0 ≤ x ≤ 1.0) ferrite is demonstrated, hardly shown in literature. X-ray diffraction (XRD) confirms the formation of cubic spinel nano ferrites with grain diameter between 40.8 to 55.4 nm. Energy dispersive spectroscopy (EDS) confirms close agreement of Mg/Fe, Zn/Fe molar ratio, presence of all elements (Mg, Zn, Fe, O), formation of estimated ferrite composition. Zn addition (for Mg) shows: i) linear increase of lattice parameter aexp, accounted for replacement of an ion with higher ionic radius (Zn > Mg); ii) presence of higher population of Fe3+ ions on B site, and unusual occurrence of Zn, Mg on A and B site leads to non-equilibrium cation distribution where we observe inverse to mixed structure, and is in contrast to reported literature where inverse to normal transition is reported; iii) effect on A-A, A-B, B-B exchange interactions, affecting coercivity Hc, Ms. A new empirical relation is also obtained showing linear relation between saturation magnetization Ms - inversion parameter δ, oxygen parameter u4 ¯ 3 m. Non-zero Y-K angle (αYK) values implies Y-K type magnetic ordering in the studied samples.

Enhanced magnetic properties in Mn0.6Zn0.4-xNixFe2O4 (x=0-0.4) nanoparticles

NASA Astrophysics Data System (ADS)

Mallesh, S.; Mandal, P.; Srinivas, V.

2018-04-01

Ni substituted MnZn ferrite fine particles were synthesized through sol-gel method. The structure, stability and magnetic properties have been investigated. Thermal stability of as-prepared (AP) particles is improved compared to that of Mn0.6Zn0.4Fe2O4 (MZF) ferrite particles. The as-prepared and samples annealed at 1200 °C exhibit pure spinel ferrite phase, while samples at intermediate temperatures (600 - 1000 °C) exhibit secondary phase of α-Fe2O3 along with ferrite phase. The Mn0.6Zn0.1Ni0.3Fe2O4 (Ni-MZF) sample shows significantly lower volume fraction of secondary phase compared to that of MZF. The observed magnetization of Ni-MZF is twice of that MZF samples. Present results suggest that a small amount (x=0.3) of Ni in place of nonmagnetic Zn in MZF significantly decreases the secondary phase fraction and improves the magnetic properties.

[Heavy metal concentration in Nanjing urban soils and their affecting factors].

PubMed

Lu, Ying; Gong, Zitong; Zhang, Ganlin; Zhang, Bo

2004-01-01

The concentration and source of heavy metals in Nanjing urban soils and their relationships with soil properties were studied. The results indicated that the soils in Nanjing urban were not obviously polluted by Fe, Ni, Co and V, but polluted by Mn, Cr, Cu, Zn, and Pb to a certain extent. The heavy metals were irregularly distributed in soil profiles. Fe, Ni, Co, and V were originated from soil materials, but Cu, Zn, Pb, and Cr were anthropogenic input. Probably, Mn had different origins in different soils. There were positive correlations among Fe, Cr, Ni, Co, and V concentration, and among Cu, Zn, Pb, and Cr concentration. The Fe, Co, V, and Ni concentration were positively correlated with soil clay content and CEC, and the Cu, Zn and Pb concentration were negatively correlated with clay content. There were positive correlations between Cu, Zn, Pb and Cr concentration and organic C content, and between Pb concentration and soil pH.

[The relevance of the trace elements zinc and iron in the milk fever disease of cattle].

PubMed

Heilig, M; Bäuml, D; Fürll, M

2014-01-01

The aim of this study was to analyse the concentrations of Zn and Fe as well as their relationships to metabolic parameters in milk fever cows. A total of 195 Simmental cows, downer cows and clinically healthy control animals were divided into five groups: a) control group (CG, n = 21), b) all cows with milk fever (MF) (n = 174), c) MF cows without additional diseases (n = 145), d) cows with MF and mastitis (n = 10) and e) cows with retained placenta or endometritis (n = 19). Selenium (Se), zinc (Zn), iron (Fe), calcium (Ca), inorganic phosphorus (Pi), tumour necrosis factor α (TNFα), haptoglobin (Hp), antioxidants (Trolox Equivalent Antioxidative Capacity: TEAC), non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), bilirubin, urea, creatinine, glucose, cholesterol, gamma-glutamyl transferase (GGT) and alkaline phosphatase (AP) were analysed in the blood serum. The concentrations of Zn, Fe, Ca, Pi and TEAC were lower in groups b) to e) whereas Hp was higher than in the CG (p ≤ 0.05). In group c), lower Ca and Pi concentrations were found when compared to groups d) and e) (p ≤ 0.05). In group e), Zn concentrations were significantly lower than in group c) (p ≤ 0.05). Zn was negatively correlated with K (CG) and positively correlated with TEAC, Cu, Mn and Fe (groups b and c) and with Mn (group e) (p ≤ 0.05). Fe was positively correlated with Ca (group c), Pi (group c), K (groups b and c) and Mg (groups b-d) as well as with Zn, Cu and Se (groups b and c) (p ≤ 0.05). In groups b) and c), TNFα was increased and negatively correlated with Fe (p ≤ 0.05). AP activity in groups b) and e) was lower than in the CG (p ≤ 0.05). These results and literature data support the hypothesis that Zn and Fe could be engaged in bone metabolism and be involved in the pathogenesis of MF. The concentrations of Hp and TEAC support this interpretation. Control of the Zn and Fe status of cows and Zn supplementation should be included in the prevention and advanced therapy of MF.

Molecular layers of ZnPc and FePc on Au(111) surface: Charge transfer and chemical interaction

NASA Astrophysics Data System (ADS)

Ahmadi, Sareh; Shariati, M. Nina; Yu, Shun; Göthelid, Mats

2012-08-01

We have studied zinc phthalocyanine (ZnPc) and iron phthalocyanine (FePc) thick films and monolayers on Au(111) using photoelectron spectroscopy and x-ray absorption spectroscopy. Both molecules are adsorbed flat on the surface at monolayer. ZnPc keeps this orientation in all investigated coverages, whereas FePc molecules stand up in the thick film. The stronger inter-molecular interaction of FePc molecules leads to change of orientation, as well as higher conductivity in FePc layer in comparison with ZnPc, which is reflected in thickness-dependent differences in core-level shifts. Work function changes indicate that both molecules donate charge to Au; through the π-system. However, the Fe3d derived lowest unoccupied molecular orbital receives charge from the substrate when forming an interface state at the Fermi level. Thus, the central atom plays an important role in mediating the charge, but the charge transfer as a whole is a balance between the two different charge transfer channels; π-system and the central atom.

[Catalytic stability in wet air oxidation of carboxylic acids over ZnFe0.25Al1.75 O4 catalyst].

PubMed

Xu, Ai-hua; Yang, Min; Du, Hong-zhang; Peng, Fu-yong; Sun, Cheng-lin

2007-07-01

Oxalic, formic and acetic acid are main intermediate products in catalytic wet air oxidation process (CWAO). The catalytic activity and stability in CWAO of the three short-chain organic acids over ZnFe0.25Al1.75O4 catalyst were studied. Oxalic acid is the only oxidizable intermediate and the largest amount of Fe leaching is 9.5 mg L(-1) at 160 degrees C during CWAO process. Formic and acetic acid have little influence on Fe leaching. Due to the strong reducible ability of oxalic acid, the amount of Fe leaching is larger in nitrogen atmosphere than that in oxygen atmosphere. Salicylic acid can be also degraded by ZnFe0.25Al1.75O4 catalyst with a high catalytic activity and stability.

Determination of Microelements in Human Milk and Infant Formula Without Digestion by ICP-OES.

PubMed

Đurović, Dijana; Milisavljević, Branka; Nedović-Vuković, Mirjana; Potkonjak, Branislav; Spasić, Snežana; Vrvić, Miroslav

2017-06-01

The concentrations of zinc (Zn), iron (Fe) and copper (Cu) in both human milk and infant formula were determined using a new sample preparation method, by inductively coupled plasma - optical emission spectometry (ICP-OES) and flame atomic absorption spectrometry (FAAS). Human milk samples were diluted in ultrapure water. The infant formula of powder samples (suitable for an infant 1-6 months of age) and standard reference material (SRM-1849) were analyzed in parallel. The results have shown that FAAS method was more sensitive for Fe determination in human milk while ICP-OES was more sensitive for both Zn and Cu detection. The limit of quantification for both Zn and Cu was 5 μg L-1 and 10 μg L-1 for Fe and the recovery for Zn, Fe and Cu was ranged from 90% to 94%, 97% to 103% and 90% to 102%, respectively. Mean concentrations of Zn, Fe, and Cu in human milk samples were 5.35, 0.47 and 0.83 mg L-1, respectively while these values in infant formula were ranged from 3.52-4.75 mg L-1, 3.37-4.56 mg L-1 and 0.28-0.41 mg L-1, respectively. Despite the sample complexity, the proposed method using dilution of milk samples with water was simple, rapid, effective and accurate. ICP-OES was a better method for Zn determination while FAAS was a better method for Fe determination. In the case of Cu both methods were comparable.

Route and Regulation of Zinc, Cadmium, and Iron Transport in Rice Plants (Oryza sativa L.) during Vegetative Growth and Grain Filling: Metal Transporters, Metal Speciation, Grain Cd Reduction and Zn and Fe Biofortification

PubMed Central

Yoneyama, Tadakatsu; Ishikawa, Satoru; Fujimaki, Shu

2015-01-01

Zinc (Zn) and iron (Fe) are essential but are sometimes deficient in humans, while cadmium (Cd) is toxic if it accumulates in the liver and kidneys at high levels. All three are contained in the grains of rice, a staple cereal. Zn and Fe concentrations in rice grains harvested under different levels of soil/hydroponic metals are known to change only within a small range, while Cd concentrations show greater changes. To clarify the mechanisms underlying such different metal contents, we synthesized information on the routes of metal transport and accumulation in rice plants by examining metal speciation, metal transporters, and the xylem-to-phloem transport system. At grain-filling, Zn and Cd ascending in xylem sap are transferred to the phloem by the xylem-to-phloem transport system operating at stem nodes. Grain Fe is largely derived from the leaves by remobilization. Zn and Fe concentrations in phloem-sap and grains are regulated within a small range, while Cd concentrations vary depending on xylem supply. Transgenic techniques to increase concentrations of the metal chelators (nicotianamine, 2′-deoxymugineic acid) are useful in increasing grain Zn and Fe concentrations. The elimination of OsNRAMP5 Cd-uptake transporter and the enhancement of root cell vacuolar Cd sequestration reduce uptake and root-to-shoot transport, respectively, resulting in a reduction of grain Cd accumulation. PMID:26287170

Zn0-CNTs-Fe3O4 catalytic in situ generation of H2O2 for heterogeneous Fenton degradation of 4-chlorophenol.

PubMed

Yang, Zhao; Gong, Xiao-Bo; Peng, Lin; Yang, Dan; Liu, Yong

2018-06-04

A novel Zn 0 -CNTs-Fe 3 O 4 composite was synthesized by the chemical co-precipitation combined with high sintering process at nitrogen atmosphere. The as-prepared composite was characterized by SEM, EDS, XRD, XPS, VSM and N 2 adsorption/desorption experiments. A novel heterogeneous Fenton-like system, composed of Zn 0 -CNTs-Fe 3 O 4 composite and dissolved oxygen (O 2 ) in solution, which can in situ generate H 2 O 2 and OH, was used for the degradation of 4-chlorophenol (4-CP). The influences of various operational parameters, including the initial pH, dosage of Zn 0 -CNTs-Fe 3 O 4 and initial concentration of 4-CP on the removal of 4-CP were investigated. The removal efficiencies of 4-CP and total organic carbon (TOC) were 99% and 57%, respectively, at the initial pH of 1.5, Zn 0 -CNTs-Fe 3 O 4 dosage of 2 g/L, 4-CP initial concentration of 50 mg/L and oxygen flow rate of 400 mL/min. Based on the results of the radical scavenger effect study, the hydroxyl radical was considered as the main reactive oxidants in Zn 0 -CNTs-Fe 3 O 4 /O 2 system and a possible degradation pathway of 4-CP was proposed. Copyright © 2018. Published by Elsevier Ltd.

Deriving Freshwater Quality Criteria for Iron, Lead, Nickel, and Zinc for Protection of Aquatic Life in Malaysia

PubMed Central

Shuhaimi-Othman, M.; Nadzifah, Y.; Nur-Amalina, R.; Umirah, N. S.

2012-01-01

Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (annelid), and Duttaphrynus melanostictus (tadpole) to determine 96 h LC50 values for Fe, Pb, Ni, and Zn. The final acute value (FAV) for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9 μg L−1, respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a criterion maximum concentration (CMC) and a criterion continuous concentration (CCC) for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4 μg L−1 and 9.0, 2.0, 19.9, and 36.7 μg L−1, respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC50 values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively. PMID:22919358

Route and Regulation of Zinc, Cadmium, and Iron Transport in Rice Plants (Oryza sativa L.) during Vegetative Growth and Grain Filling: Metal Transporters, Metal Speciation, Grain Cd Reduction and Zn and Fe Biofortification.

PubMed

Yoneyama, Tadakatsu; Ishikawa, Satoru; Fujimaki, Shu

2015-08-13

Zinc (Zn) and iron (Fe) are essential but are sometimes deficient in humans, while cadmium (Cd) is toxic if it accumulates in the liver and kidneys at high levels. All three are contained in the grains of rice, a staple cereal. Zn and Fe concentrations in rice grains harvested under different levels of soil/hydroponic metals are known to change only within a small range, while Cd concentrations show greater changes. To clarify the mechanisms underlying such different metal contents, we synthesized information on the routes of metal transport and accumulation in rice plants by examining metal speciation, metal transporters, and the xylem-to-phloem transport system. At grain-filling, Zn and Cd ascending in xylem sap are transferred to the phloem by the xylem-to-phloem transport system operating at stem nodes. Grain Fe is largely derived from the leaves by remobilization. Zn and Fe concentrations in phloem-sap and grains are regulated within a small range, while Cd concentrations vary depending on xylem supply. Transgenic techniques to increase concentrations of the metal chelators (nicotianamine, 2'-deoxymugineic acid) are useful in increasing grain Zn and Fe concentrations. The elimination of OsNRAMP5 Cd-uptake transporter and the enhancement of root cell vacuolar Cd sequestration reduce uptake and root-to-shoot transport, respectively, resulting in a reduction of grain Cd accumulation.

Controls on Fe(II)-Activated Trace Element Release from Goethite and Hematite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frierdich, Andrew J.; Catalano, Jeffrey G.

2012-03-26

Electron transfer and atom exchange (ETAE) between aqueous Fe(II) and Fe(III) oxides induces surface growth and dissolution that affects trace element fate and transport. We have recently demonstrated Ni(II) cycling through goethite and hematite (adsorbed Ni incorporates into the mineral structure and preincorporated Ni releases to solution) during Fe(II)-Fe(III) ETAE. However, the chemical parameters affecting net trace element release remain unknown. Here, we examine the chemical controls on Ni(II) and Zn(II) release from Ni- and Zn-substituted goethite and hematite during reaction with Fe(II). Release follows a rate law consistent with surface reaction limited mineral dissolution and suggests that release occursmore » near sites of Fe(III) reductive dissolution during Fe(II)-Fe(III) ETAE. Metal substituent type affects reactivity; Zn release is more pronounced from hematite than goethite, whereas the opposite trend occurs for Ni. Buildup of Ni or Zn in solution inhibits further release but this resumes upon fluid exchange, suggesting that sustained release is possible under flow conditions. Mineral and aqueous Fe(II) concentrations as well as pH strongly affect sorbed Fe(II) concentrations, which directly control the reaction rates and final metal concentrations. Our results demonstrate that structurally incorporated trace elements are mobilized from iron oxides into fluids without abiotic or microbial net iron reduction. Such release may affect micronutrient availability, contaminant transport, and the distribution of redox-inactive trace elements in natural and engineered systems.« less

Fe, Zn, and Cd stable isotopes from the eastern tropical South Pacific from GEOTRACES cruise GP16 - Methods and data

NASA Astrophysics Data System (ADS)

Helgoe, J. M.; Townsend, E.; John, S.

2014-12-01

A new method has been developed for the rapid analysis of metal concentrations and stable isotope ratios using a prepFAST automated sample processing robot. Although concentrations and isotopes are processed separately, similar methods are used for both. Initially all seawater is acidified to pH 2. Then Nobias resin with EDTA/IDA functional groups is added to either 10mL of sample for concentrations or ~1L samples for isotopes. Fe binds to the resin at low pH, and the pH is subsequently raised to allow Zn and Cd to bind. For concentration analyses, all subsequent chemistry is automated on the prepFAST including removal of seawater, rinsing of resin, and elution of resin into acid. For isotope samples these extraction techniques are performed manually, but the subsequent purification of Fe, Zn, and Cd by anion exchange chromatography is automated using the prepFAST. With these new methods, samples from the US GEOTRACES cruise GP16, in the eastern tropical South Pacific, are being analyzed. High concentrations of dissolved Fe are observed near the continental shelf and near submarine hydrothermal vents. Interestingly, isotope data show that dissolved Fe near the continental shelf generally has a δ56Fe close to 0 ‰. This δ56 Fe signature is suggestive of a non-reductive dissolution source for Fe, as Fe(II) released by reductive dissolution is typically closer to -2 ‰. Preliminary data show nutrient-type profiles for Zn and Cd, with Zn matching Si and Cd having a similar distribution to P. An increase in dissolved Zn near hydrothermal vents suggests a possible hydrothermal zinc source to the deep ocean. Continuing analysis of isotope data will reveal more about the source and biogeochemical cycling of these three chemically and biologically important trace metals throughout the eastern tropical Pacific Ocean.

Changes in zinc speciation with mine tailings acidification in a semi-arid weathering environment

PubMed Central

Hayes, Sarah M.; O’Day, Peggy A.; Webb, Sam M.; Maier, Raina M.; Chorover, Jon

2011-01-01

High concentrations of residual metal contaminants in mine tailings can be transported easily by wind and water, particularly when tailings remain unvegetated for decades following mining cessation, as is the case in semi-arid landscapes. Understanding the speciation and mobility of contaminant metal(loid)s, particularly in surficial tailings, is essential to controlling their phytotoxicities and to revegetating impacted sites. In prior work, we showed that surficial tailings samples from the Klondyke State Superfund Site (AZ, USA), ranging in pH from 5.4 to 2.6, represent a weathering series, with acidification resulting from sulfide mineral oxidation, long-term Fe hydrolysis, and a concurrent decrease in total (6,000 to 450 mg kg−1) and plant-available (590 to 75 mg kg−1) Zn due to leaching losses and changes in Zn speciation. Here, we used bulk and micro-focused Zn K-edge X-ray absorption spectroscopy (XAS) data and a six-step sequential extraction procedure to determine tailings solid phase Zn speciation. Bulk sample spectra were fit by linear combination using three references: Zn-rich phyllosilicate (Zn0.8talc), Zn sorbed to ferrihydrite (ZnadsFeOx), and zinc sulfate (ZnSO4·7H2O). Analyses indicate that Zn sorbed in tetrahedral coordination to poorly-crystalline Fe and Mn (oxyhydr)oxides decreases with acidification in the weathering sequence, whereas octahedral zinc in sulfate minerals and crystalline Fe oxides undergoes a relative accumulation. Micro-scale analyses identified hetaerolite (ZnMn2O4), hemimorphite (Zn4Si2O7(OH)2·H2O) and sphalerite (ZnS) as minor phases. Bulk and micro-focused spectroscopy complement the chemical extraction results and highlight the importance of using a multi-method approach to interrogate complex tailings systems. PMID:21761897

Structural and functional responses of periphyton and macroinvertebrate communities to ferric Fe, Cu, and Zn in stream mesocosms.

PubMed

Cadmus, Pete; Guasch, Helena; Herdrich, Adam T; Bonet, Berta; Urrea, Gemma; Clements, William H

2018-05-01

Two mesocosm experiments were conducted to examine effects of ferric iron (Fe) and mixtures of ferric Fe with aqueous metals (Cu, Zn) on stream benthic communities. Naturally colonized benthic communities were exposed to a gradient of ferric Fe (0, 0.4, 1.0, 2.5, 6.2, and 15.6 mg/L) that bracketed the current US Environmental Protection Agency water quality criterion value (1.0 mg/L). After 10 d of exposure to ferric Fe, total macroinvertebrate abundance, number of taxa, and abundance of all major macroinvertebrate groups (Ephemeroptera, Plecoptera, Trichoptera, and Diptera) were significantly reduced. Heptageniid mayflies and chironomids were especially sensitive to Fe oxide deposition and were significantly reduced at 0.4 and 1.0 mg/L total Fe, respectively. In a second mesocosm experiment, periphyton and macroinvertebrate communities were exposed to ferric Fe (0.60 mg/L) with or without aqueous Cu and Zn at 2 treatment levels: low (0.01 mg/L Cu + 0.1 mg/L Zn) and high (0.05 mg/L Cu + 0.5 mg/L Zn). In contrast to previous research, we observed no evidence of a protective effect of Fe on toxicity of metals. Growth rates and protein content of periphyton were significantly reduced by both ferric Fe and aqueous metals, whereas abundance of heptageniid mayflies (Cinygmula) and whole community metabolism were significantly reduced by ferric Fe alone. We hypothesize that Fe oxides inhibited algal growth and enhanced metal accumulation, leading to a reduction in the quantity and quality of food resources for grazers. Mesocosm experiments conducted using natural benthic communities provide a unique opportunity to quantify the relative importance of indirect physical effects and to develop a better understanding of the relationship between basal food resources and consumers in natural stream ecosystems. Environ Toxicol Chem 2018;37:1320-1329. © 2017 SETAC. © 2017 SETAC.

Metallic ions catalysis for improving bioleaching yield of Zn and Mn from spent Zn-Mn batteries at high pulp density of 10.

PubMed

Niu, Zhirui; Huang, Qifei; Wang, Jia; Yang, Yiran; Xin, Baoping; Chen, Shi

2015-11-15

Bioleaching of spent batteries was often conducted at pulp density of 1.0% or lower. In this work, metallic ions catalytic bioleaching was used for release Zn and Mn from spent ZMBs at 10% of pulp density. The results showed only Cu(2+) improved mobilization of Zn and Mn from the spent batteries among tested four metallic ions. When Cu(2+) content increased from 0 to 0.8 g/L, the maximum release efficiency elevated from 47.7% to 62.5% for Zn and from 30.9% to 62.4% for Mn, respectively. The Cu(2+) catalysis boosted bioleaching of resistant hetaerolite through forming a possible intermediate CuMn2O4 which was subject to be attacked by Fe(3+) based on a cycle of Fe(3+)/Fe(2+). However, poor growth of cells, formation of KFe3(SO4)2(OH)6 and its possible blockage between cells and energy matters destroyed the cycle of Fe(3+)/Fe(2+), stopping bioleaching of hetaerolite. The chemical reaction controlled model fitted best for describing Cu(2+) catalytic bioleaching of spent ZMBs. Copyright © 2015 Elsevier B.V. All rights reserved.

Correlation of Aflatoxin Contamination With Zinc Content of Chicken Feed †

PubMed Central

Jones, Frank T.; Hagler, Winston M.; Hamilton, Pat B.

1984-01-01

Feed samples from chicken houses in five commercial chicken operations were analyzed for Zn, Mn, Fe, Cu, Cd, and aflatoxin content. Mean aflatoxin content of these samples was 14 ppb (14 ng/g) as opposed to 1.2 ppb in samples taken when the feed was made. Aflatoxin content of the feed samples correlated (r = 0.325) significantly (P < 0.05) with Zn content but not with Mn, Fe, or Cu, all of which correlated significantly with Zn. Zn content of unamended feed (<20 ppm [20 μg/g]) is normally supplemented with a mineral premix containing Zn, Mn, Fe, and Cu to meet the nutrient requirements of chickens (40 ppm of Zn). The mean zinc concentration of the feed samples (117 ppm) was about threefold greater than the nutrient requirement and ranged from 58 to 162 ppm in individual samples. These field survey results parallel earlier reports of augmented production of aflatoxin in monocultures of aflatoxigenic fungi in corn and other ingredients supplemented with Zn. These results suggest that stricter control of Zn levels during manufacture could reduce aflatoxin contamination of feed consumed by chickens. PMID:16346486

Correlation of aflatoxin contamination with zinc content of chicken feed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, F.T.; Hagler, W.M. Jr.; Hamilton, P.B.

Feed samples from chicken houses in five commercial chicken operations were analyzed for Zn, Mn, Fe, Cu, Cd, and aflatoxin content. Mean aflatoxin content of these samples was 14 ppb (14 ng/g) as opposed to 1.2 ppb in samples taken when the feed was made. Aflatoxin content of the feed samples correlated significantly with Zn content but not with Mn, Fe, or Cu, all of which correlated significantly with Zn. Zn content of unamended feed (<20 ppm (20 ..mu..g/g) is normally supplemented with a mineral premix containing Zn, Mn, Fe, and Cu to meet the nutrient requirements of chickens (40more » ppm of Zn). The mean zinc concentration of the feed samples (117 ppm) was about threefold greater than the nutrient requirement and ranged from 58 to 162 ppm in individual samples. These field survey results parallel earlier reports of augmented production of aflatoxin in monocultures of aflatoxigenic fungi in corn and other ingredients supplemented with Zn. These results suggest that stricter control of Zn levels during manufacture could reduce aflatoxing contamination of feed consumed by chickens.« less

Seed priming with iron and zinc in bread wheat: effects in germination, mitosis and grain yield.

PubMed

Reis, Sara; Pavia, Ivo; Carvalho, Ana; Moutinho-Pereira, José; Correia, Carlos; Lima-Brito, José

2018-07-01

Currently, the biofortification of crops like wheat with micronutrients such as iron (Fe) and zinc (Zn) is extremely important due to the deficiencies of these micronutrients in the human diet and in soils. Agronomic biofortification with Fe and Zn can be done through different exogenous strategies such as soil application, foliar spraying, and seed priming. However, the excess of these micronutrients can be detrimental to the plants. Therefore, in the last decade, a high number of studies focused on the evaluation of their phytotoxic effects to define the best strategies for biofortification of bread wheat. In this study, we investigated the effects of seed priming with different dosages (1 mg L -1 to 8 mg L -1 ) of Fe and/or Zn in germination, mitosis and yield of bread wheat cv. 'Jordão' when compared with control. Overall, our results showed that: micronutrient dosages higher than 4 mg L -1 negatively affect the germination; Fe and/or Zn concentrations higher than 2 mg L -1 significantly decrease the mitotic index and increase the percentage of dividing cells with anomalies; treatments performed with 8 mg L -1 of Fe and/or 8 mg L -1 Zn caused negative effects in germination, mitosis and grain yield. Moreover, seed priming with 2 mg L -1 Fe + 2 mg L -1 Zn has been shown to be non-cytotoxic, ensuring a high rate of germination (80%) and normal dividing cells (90%) as well as improving tillering and grain yield. This work revealed that seed priming with Fe and Zn micronutrients constitutes a useful and alternative approach for the agronomic biofortification of bread wheat.

Effects of Long-Term Exposure to Zinc Oxide Nanoparticles on Development, Zinc Metabolism and Biodistribution of Minerals (Zn, Fe, Cu, Mn) in Mice

PubMed Central

Wang, Chao; Lu, Jianjun; Zhou, Le; Li, Jun; Xu, Jiaman; Li, Weijian; Zhang, Lili; Zhong, Xiang; Wang, Tian

2016-01-01

Zinc oxide nanoparticles (nano-ZnOs) are widely used and possess great potentials in agriculture and biomedicine. It is inevitable for human exposure to these nanoparticles. However, no study had been conducted to investigate the long term effects of nano-ZnOs. This study aimed at investigating effects of nano-ZnOs on development, zinc metabolism and biodistribution of minerals (Zn, Fe, Cu, and Mn) in mice from week 3 to 35. After the characteristics of nano-ZnOs were determined, they were added into the basal diet at 0, 50, 500 and 5000 mg/kg. Results indicated that added 50 and 500 mg/kg nano-ZnOs showed minimal toxicity. However, 5000 mg/kg nano-ZnOs significantly decreased body weight (from week 4 to 16) and increased the relative weights of the pancreas, brain and lung. Added 5000 mg/kg nano-ZnOs significantly increased the serum glutamic-pyruvic transaminase activity and zinc content, and significantly enhanced mRNA expression of zinc metabolism-related genes, including metallothionein 1(32.66 folds), metallothionein 2 (31.42 folds), ZIP8 (2.21folds), ZIP14 (2.45 folds), ZnT1 (4.76 folds), ZnT2 (6.19 folds) and ZnT4 (1.82 folds). The biodistribution determination showed that there was a significant accumulation of zinc in the liver, pancreas, kidney, and bones (tibia and fibula) after receiving 5000 mg/kg nano-ZnO diet, while no significant effects on Cu, Fe, and Mn levels, except for liver Fe content and pancreas Mn level. Our results demonstrated that long term exposure to 50 and 500 mg/kg nano-ZnO diets showed minimal toxicity. However, high dose of nano-ZnOs (5000 mg/kg) caused toxicity on development, and altered the zinc metabolism and biodistribution in mice. PMID:27732669

Effects of Long-Term Exposure to Zinc Oxide Nanoparticles on Development, Zinc Metabolism and Biodistribution of Minerals (Zn, Fe, Cu, Mn) in Mice.

PubMed

Wang, Chao; Lu, Jianjun; Zhou, Le; Li, Jun; Xu, Jiaman; Li, Weijian; Zhang, Lili; Zhong, Xiang; Wang, Tian

2016-01-01

Zinc oxide nanoparticles (nano-ZnOs) are widely used and possess great potentials in agriculture and biomedicine. It is inevitable for human exposure to these nanoparticles. However, no study had been conducted to investigate the long term effects of nano-ZnOs. This study aimed at investigating effects of nano-ZnOs on development, zinc metabolism and biodistribution of minerals (Zn, Fe, Cu, and Mn) in mice from week 3 to 35. After the characteristics of nano-ZnOs were determined, they were added into the basal diet at 0, 50, 500 and 5000 mg/kg. Results indicated that added 50 and 500 mg/kg nano-ZnOs showed minimal toxicity. However, 5000 mg/kg nano-ZnOs significantly decreased body weight (from week 4 to 16) and increased the relative weights of the pancreas, brain and lung. Added 5000 mg/kg nano-ZnOs significantly increased the serum glutamic-pyruvic transaminase activity and zinc content, and significantly enhanced mRNA expression of zinc metabolism-related genes, including metallothionein 1(32.66 folds), metallothionein 2 (31.42 folds), ZIP8 (2.21folds), ZIP14 (2.45 folds), ZnT1 (4.76 folds), ZnT2 (6.19 folds) and ZnT4 (1.82 folds). The biodistribution determination showed that there was a significant accumulation of zinc in the liver, pancreas, kidney, and bones (tibia and fibula) after receiving 5000 mg/kg nano-ZnO diet, while no significant effects on Cu, Fe, and Mn levels, except for liver Fe content and pancreas Mn level. Our results demonstrated that long term exposure to 50 and 500 mg/kg nano-ZnO diets showed minimal toxicity. However, high dose of nano-ZnOs (5000 mg/kg) caused toxicity on development, and altered the zinc metabolism and biodistribution in mice.

Effects of zinc toxicity on sugar beet (Beta vulgaris L.) plants grown in hydroponics.

PubMed

Sagardoy, R; Morales, F; López-Millán, A-F; Abadía, A; Abadía, J

2009-05-01

The effects of high Zn concentration were investigated in sugar beet (Beta vulgaris L.) plants grown in a controlled environment in hydroponics. High concentrations of Zn sulphate in the nutrient solution (50, 100 and 300 microm) decreased root and shoot fresh and dry mass, and increased root/shoot ratios, when compared to control conditions (1.2 microm Zn). Plants grown with excess Zn had inward-rolled leaf edges and a damaged and brownish root system, with short lateral roots. High Zn decreased N, Mg, K and Mn concentrations in all plant parts, whereas P and Ca concentrations increased, but only in shoots. Leaves of plants treated with 50 and 100 microm Zn developed symptoms of Fe deficiency, including decreases in Fe, chlorophyll and carotenoid concentrations, increases in carotenoid/chlorophyll and chlorophyll a/b ratios and de-epoxidation of violaxanthin cycle pigments. Plants grown with 300 microm Zn had decreased photosystem II efficiency and further growth decreases but did not have leaf Fe deficiency symptoms. Leaf Zn concentrations of plants grown with excess Zn were high but fairly constant (230-260 microg.g(-1) dry weight), whereas total Zn uptake per plant decreased markedly with high Zn supply. These data indicate that sugar beet could be a good model to investigate Zn homeostasis mechanisms in plants, but is not an efficient species for Zn phytoremediation.

Investigation of magnetic order in SmTr2Zn20 (Tr=Fe ,Co,Ru) and SmTr2Cd20 (Tr=Ni ,Pd)

NASA Astrophysics Data System (ADS)

Yazici, D.; White, B. D.; Ho, P.-C.; Kanchanavatee, N.; Huang, K.; Friedman, A. J.; Wong, A. S.; Burnett, V. W.; Dilley, N. R.; Maple, M. B.

2014-10-01

Single crystals of the "cage compounds" SmTr2Zn20 (Tr=Fe, Co, Ru) and SmTr2Cd20 (Tr=Ni, Pd) have been investigated by means of electrical resistivity, magnetization, and specific-heat measurements. The compounds SmFe2Zn20,SmRu2Zn20, and SmNi2Cd20 exhibit ferromagnetic order with Curie temperatures of TC=47.4, 7.6, and 7.5 K, respectively, whereas SmPd2Cd20 is an antiferromagnet with a Néel temperature of TN=3.4 K. No evidence for magnetic order is observed in SmCo2Zn20 down to 110 mK. The Sommerfeld coefficients γ are found to be 57 mJ /molK2 for SmFe2Zn20,79.5 mJ /molK2 for SmCo2Zn20,258 mJ /molK2 for SmRu2Zn20,165 mJ /molK2 for SmNi2Cd20, and 208 mJ /molK2 for SmPd2Cd20. Enhanced values of γ and a quadratic temperature dependence of the electrical resistivity at low temperature for SmRu2Zn20 and SmPd2Cd20 suggest an enhancement of the quasiparticle masses due to hybridization between localized 4f and conduction electron states.

Section 2: Phase transformation studies in mechanically alloyed Fe-Nz and Fe-Zn-Si intermetallics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jordan, A.; Uwakweh, O.N.C.; Maziasz, P.J.

1997-04-01

The initial stage of this study, which was completed in FY 1995, entailed an extensive analysis characterizing the structural evolution of the Fe-Zn intermetallic system. The primary interest in these Fe-Zn phases stems from the fact that they form an excellent coating for the corrosion protection of steel (i.e., automobile body panels). The Fe-Zn coating generally forms up to four intermetallic phases depending on the particular industrial application used, (i.e., galvanization, galvannealing, etc.). Since the different coating applications are non-equilibrium in nature, it becomes necessary to employ a non-equilibrium method for producing homogeneous alloys in the solid-state to reflect themore » structural changes occurring in a true coating. This was accomplished through the use of a high energy/non-equilibrium technique known as ball-milling which allowed the authors to monitor the evolution process of the alloys as they transformed from a metastable to stable equilibrium state. In FY 1996, this study was expanded to evaluate the presence of Si in the Fe-Zn system and its influence in the overall coating. The addition of silicon in steel gives rise to an increased coating. However, the mechanisms leading to the coating anomaly are still not fully understood. For this reason, mechanical alloying through ball-milling of pure elemental powders was used to study the structural changes occurring in the sandelin region (i.e., 0.12 wt % Si). Through the identification of invariant reactions (i.e., eutectic, etc.) the authors were able to explore the sandelin phenomenon and also determine the various fields or boundaries associated with the Fe-Zn-Si ternary system.« less

[Changes in serum lipids in rats treated with oral cooper].

PubMed

Alarcón-Corredor, O M; Carnevalí de Tatá, E; Reinosa-Füller, J; Contreras, Y; Ramírez de Fernández, M; Yánez-Domínguez, C

2000-09-01

Disturbances in lipid metabolism during copper deficiency in rats are well recognized. Copper deficiency is associated with the spontaneous retention of hepatic iron. Previous studies have reported that hypercholesterolemia and hypertriglyceridemia are associated with elevated hepatic iron concentrations in copper deficient rats. There was a direct relationship between the magnitude of blood lipids and the concentration of hepatic iron. Based on these data, it has been hypothesized that iron was responsible for the development of lipemia of copper deficiency. In this study was determined the effect of increasing doses of Cu(10, 20 and 50 ppm) in the diet, on the serum total lipids, total cholesterol, triglycerides (triacylglicerols), phospholipids, non-esterified fatty acids (NEFA) and liver iron and zinc concentrations in normal rats. The results were compared with normal rats that received a balanced diet containing 0.6 and 6 ppm of Cu, respectively. The results show that Cu-supplement diminished the cholesterol and triglyceride serum levels, increased the level of phospholipids, NEFA and concomitantly decreased the hepatic concentrations of Fe and Zn. There was a statistically significant (p < 0.05) simple correlation between triglycerides and liver Fe (r = 0.917; R2 = 64.03%), cholesterol and liver Zn (r = 0.872; R2 = 76.07%), cholesterol and liver Fe (r = 0.995; R2 = 99.10%), liver Fe and liver Cu (r = -0.612), liver Fe and liver Zn (r = 0.837), liver Cu and liver Zn (r = -0.612), and serum triglycerides and liver Zn (r = 0.967). The mechanism(s) by which Fe and Zn determine these changes is not known; none of the enzymes that act in cholesterol and triglyceride metabolism and biosynthesis require Fe and/or Zn. The increase of NEFA is due to changes in the process of lipolysis and re-esterification of the fatty acids in blood. However, additional studies are needed for the precise mechanisms of this interrelationships to be clarified.

Synthesis of Fe-based core@ZnO shell nanopowders by laser pyrolysis for biomedical applications

NASA Astrophysics Data System (ADS)

Gavrila-Florescu, Lavinia; Dumitrache, Florian; Balas, Mihaela; Fleaca, Claudiu Teodor; Scarisoreanu, Monica; Morjan, Iuliana P.; Dutu, Elena; Ilie, Alina; Banici, Ana-Maria; Locovei, Claudiu; Prodan, Gabriel

2017-12-01

Nano-sized Fe-based (metallic, carbidic and/or oxidic) core@ZnO shell particles have been successfully synthesized in one step by the laser-induced pyrolysis method in an oxygen-deficient environment. The specific precursors were separately introduced through a three concentric nozzles injector: Fe(CO)5 vapors carried by C2H4 sensitizer (central flow), Zn(C2H5)2 vapors carried and diluted with Ar (middle annular coflow) and Ar containing low amount of O2 (external flow). Keeping constant the ethylene-carried Fe(CO)5 and O2 flows, while diminishing the Zn(C2H5)2 flow, we observed an increase of the Fe/Zn ratio in the resulted nanopowders. Also, using the same metal precursor flows, a nonlinear correlation between O2 external flow and nanocomposite atomic oxygen content is evidenced, indicating a possible interference of supplementary oxidation after air exposure. However, the lowest oxygen content along with metallic zinc was found in the sample synthesized in the most oxygen-deficient environment. Transmission electron microscopy (TEM), high-resolution electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDS), X-ray photoelectron spectroscopy (XPS) and magnetic analyses were performed for a comprehensive characterization. The aqueous Fe-based@ZnO nanoparticles (NPs) suspensions were prepared using L-Dopa ( l-3,4-dihydroxy-phenylalanine) as stabilizing agent in physiologic media. Also, a biocompatibility in vitro study was performed for PBS (phosphate buffered saline)-dispersed L-Dopa-stabilized Fe-based@ZnO nanoparticles with the best core-shell structural features on both human normal lung fibroblasts and tumoral colorectal cells. Our results proved the ability of these newly synthesized nanostructures to target cancer cells in order to induce cytotoxicity and to exhibit biocompatibility on normal cells for maintaining the proper function of healthy tissue.

Structural, magnetic, optical, dielectric, electrical and modulus spectroscopic characteristics of ZnFe2O4 spinel ferrite nanoparticles synthesized via honey-mediated sol-gel combustion method

NASA Astrophysics Data System (ADS)

Yadav, Raghvendra Singh; Kuřitka, Ivo; Vilcakova, Jarmila; Urbánek, Pavel; Machovsky, Michal; Masař, Milan; Holek, Martin

2017-11-01

This paper reports a honey-mediated green synthesis of ZnFe2O4 spinel ferrite nanoparticles and the effect of further annealing on structural, magnetic, optical, dielectric and electrical properties. X-ray diffraction study confirmed the well formation of ZnFe2O4 spinel ferrite crystal structure. Raman and Fourier transform infrared spectroscopy confirmed the formation of spinel ferrite crystal structure. The scanning electron microscopy study revealed the formation of spherical morphology at lower annealing temperature with achieved particle size 30-60 nm, whereas, octahedral like morphology at higher annealing temperature with particle size 50-400 nm. Magnetization measurements were carried out using a vibrating sample magnetometer at room temperature. The estimated magnetic parameter such as saturation magnetization (Ms), remanence (Mr) and coercivity (Hc) showed variation in value with nano-crystallite size. The highest saturation magnetization (Ms) was 12.81 emu/g for as-synthesized ZnFe2O4 spinel ferrite nanoparticles, whereas, highest coercivity (Hc) was 25.77 Oe for ZnFe2O4 nanoparticles annealed at high temperature 1000 °C. UV-Visible reflectance spectroscopy showed the band gap variation from 1.90 eV to 2.14 eV with the increase of annealing temperature. The dielectric constant and dielectric loss were decreased with frequency showing the normal behavior of spinel ferrites. The variation in conductivity is explained in terms of the variation in microstructure and variation in the mobility of charge carriers associated with the cation redistribution induced by annealing or grain size. The modulus and impedance spectroscopy study revealed the influence of bulk grain and the grain boundary on the electrical resistance and capacitance of ZnFe2O4 nanoparticles. The results presented in this work are helpful for green synthesis of well-controlled size, morphology and physical properties of ZnFe2O4 nanoparticles.

Different magnetic origins of (Mn, Fe)-codoped ZnO powders and thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, Jiuping; Jiang, Fengxian; Quan, Zhiyong

2012-11-15

Graphical abstract: The effects of the sample forms, fabricated methods, and process conditions on the structural and magnetic properties of (Mn, Fe)-codoped ZnO powders and films were systematically studied. The origins of ferromagnetism in the vacuum-annealed powder and PLD-deposited film are different. The former originates from the impurities of magnetic clusters, whereas the latter comes from the almost homogenous phase. Highlights: ► The magnetic natures of Zn{sub 0.98}Mn{sub 0.01}Fe{sub 0.01}O powders and thin films come from different origins. ► The ferromagnetism of the powder is mainly from the contribution of magnetic clusters. ► Whereas the ferromagnetic behavior of the filmmore » comes from the almost homogenous phase. -- Abstract: The structural and magnetic properties of (Mn, Fe)-codoped ZnO powders as well as thin films were investigated. The X-ray diffraction and magnetic measurements indicated that the higher sintering temperature facilitates more Mn and Fe incorporation into ZnO. Magnetic measurements indicated that the powder sintered in air at 800 °C showed paramagnetic, but it exhibited obvious room temperature ferromagnetism after vacuum annealing at 600 °C. The results revealed that magnetic clusters were the major contributors to the observed ferromagnetism in vacuum-annealed Zn{sub 0.98}Mn{sub 0.01}Fe{sub 0.01}O powder. Interestingly, the room temperature ferromagnetism was also observed in the Zn{sub 0.98}Mn{sub 0.01}Fe{sub 0.01}O film deposited via pulsed laser deposition from the air-sintered paramagnetic target, but the secondary phases in the film were not detected from X-ray diffraction, transmission electron microscopy, and zero-field cooling and field cooling. Apparently, the magnetic natures of powders and films come from different origins.« less

Enhanced Photocatalytic Activity of Two-Pot-Synthesized BiFeO3-ZnFe2O4 Heterojunction Nanocomposite

NASA Astrophysics Data System (ADS)

Ghasemi, A.; Hasheminiasari, M.; Masoudpanah, S. M.; Safizade, B.

2018-04-01

BiFeO3-ZnFe2O4 heterojunction nanocomposites have been produced by a chemical synthesis method using one- and two-pot approaches. X-ray diffraction patterns of as-calcined samples indicated formation of pure zinc ferrite (ZnFe2O4) and bismuth ferrite (BiFeO3) phases, each retaining its crystal structure. Diffuse reflectance spectrometry was applied to calculate the optical bandgap of the photocatalysts, revealing values in the range from 2.03 eV to 2.17 eV, respectively. The maximum photodegradation of methylene blue of about 97% was achieved using two-pot-synthesized photocatalyst after 120 min of visible-light irradiation due to the higher probability of charge separation of photogenerated electron-hole pairs in the heterojunction structure. Photoluminescence spectra showed lower emission intensity of two-pot-synthesized photocatalyst, due to its lower recombination rate originating from greater charge separation.

Iron from nanocompounds containing iron and zinc is highly bioavailable in rats without tissue accumulation

NASA Astrophysics Data System (ADS)

Hilty, Florentine M.; Arnold, Myrtha; Hilbe, Monika; Teleki, Alexandra; Knijnenburg, Jesper T. N.; Ehrensperger, Felix; Hurrell, Richard F.; Pratsinis, Sotiris E.; Langhans, Wolfgang; Zimmermann, Michael B.

2010-05-01

Effective iron fortification of foods is difficult, because water-soluble compounds that are well absorbed, such as ferrous sulphate (FeSO4), often cause unacceptable changes in the colour or taste of foods. Poorly water-soluble compounds, on the other hand, cause fewer sensory changes, but are not well absorbed. Here, we show that poorly water-soluble nanosized Fe and Fe/Zn compounds (specific surface area ~190 m2 g-1) made by scalable flame aerosol technology have in vivo iron bioavailability in rats comparable to FeSO4 and cause less colour change in reactive food matrices than conventional iron fortificants. The addition of Zn to FePO4 and Mg to Fe/Zn oxide increases Fe absorption from the compounds, and doping with Mg also improves their colour. After feeding rats with nanostructured iron-containing compounds, no stainable Fe was detected in their gut wall, gut-associated lymphatics or other tissues, suggesting no adverse effects. Nanosizing of poorly water-soluble Fe compounds sharply increases their absorption and nutritional value.

Iron from nanocompounds containing iron and zinc is highly bioavailable in rats without tissue accumulation.

PubMed

Hilty, Florentine M; Arnold, Myrtha; Hilbe, Monika; Teleki, Alexandra; Knijnenburg, Jesper T N; Ehrensperger, Felix; Hurrell, Richard F; Pratsinis, Sotiris E; Langhans, Wolfgang; Zimmermann, Michael B

2010-05-01

Effective iron fortification of foods is difficult, because water-soluble compounds that are well absorbed, such as ferrous sulphate (FeSO(4)), often cause unacceptable changes in the colour or taste of foods. Poorly water-soluble compounds, on the other hand, cause fewer sensory changes, but are not well absorbed. Here, we show that poorly water-soluble nanosized Fe and Fe/Zn compounds (specific surface area approximately 190 m(2) g(-1)) made by scalable flame aerosol technology have in vivo iron bioavailability in rats comparable to FeSO(4) and cause less colour change in reactive food matrices than conventional iron fortificants. The addition of Zn to FePO(4) and Mg to Fe/Zn oxide increases Fe absorption from the compounds, and doping with Mg also improves their colour. After feeding rats with nanostructured iron-containing compounds, no stainable Fe was detected in their gut wall, gut-associated lymphatics or other tissues, suggesting no adverse effects. Nanosizing of poorly water-soluble Fe compounds sharply increases their absorption and nutritional value.

Benthic macroalgae as biological indicators of heavy metal pollution in the marine environments: a biomonitoring approach for pollution assessment.

PubMed

Chakraborty, Sukalyan; Bhattacharya, Tanushree; Singh, Gurmeet; Maity, Jyoti Prakash

2014-02-01

Metal pollution in the marine coastline environment is an important topical issue in the context of ecological disturbance and climate change. Heavy metal contaminations (Cd, Cr, Cu, Mn, Ni, Pb and Zn) in seawater and surficial sediments, as well as macroalgal diversity, were determined in six different locations along the coast of the Gulf of Kutch in India. The marine coastline environment was found to be enriched with Cd and Zn in comparison to other metals. Significant (p ≤ 0.05) inter-elemental positive-correlations were observed between Fe-Mn, Fe-Cu, Fe-Cr, Fe-Zn, Cr-Cu, Cu-Mn, and Cd-Zn, as well as negative-correlations between Cd-Pb, Ni-Pb, and Zn-Pb. Though genus specific macroalgal responses to heavy metal accumulation were significant, species specific response was insignificant (p ≤ 0.05). The relative abundance of metals in macroalgae followed the order of Fe>Zn>Mn>Cu>Cd>Cr>Ni>Pb. The high uptake of metals in green algae (Ulva lactuca and Enteromorpha intestinalis) and brown algae (Padina gymnospora and Dictyota bartayresiana) suggested that these algae may be used as potential biomonitors for heavy metal pollution. Three pollution indicators, Contamination Factor (CF), Enrichment Factor (EF) and Geochemical Index (Igeo) were calculated to determine the degree of metal pollution in the marine coastline and the contribution of anthropogenic influence. © 2013 Published by Elsevier Inc.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pawar, C. S., E-mail: charudutta-p@yahoo.com; Gujar, M. P.; Mathe, V. L.

Nano crystalline Nickel Zinc ferrite (Ni{sub 0.25}Zn{sub 0.75}Fe{sub 2}O{sub 4}) thin films were synthesized by Sol Gel method for gas response. The phase and microstructure of the obtained Ni{sub 0.25}Zn{sub 0.75}Fe{sub 2}O{sub 4} thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The nanostructured Ni{sub 0.25}Zn{sub 0.75}Fe{sub 2}O{sub 4} thin film shows single spinel phase. Magnetic study was obtained with the help of VSM. The effects of working temperature on the gas response were studied. The results reveal that the Ni{sub 0.25}Zn{sub 0.75}Fe{sub 2}O{sub 4} thin film gas sensor shows good selectivity to chlorine gas at roommore » temperature. The sensor shows highest sensitivity (∼50%) at room temperature, indicating its application in detecting chlorine gas at room temperature in the future.« less

Efficient Auger Charge-Transfer Processes in ZnO

NASA Astrophysics Data System (ADS)

Stehr, J. E.; Chen, S. L.; Svensson, B. G.; Buyanova, I. A.; Chen, W. M.

2018-05-01

Photoluminescence and magneto-optical measurements are performed on a line peaking at 3.354 eV (labeled as NBX) in electron-irradiated ZnO. Even though the energy position of the NBX line is close to that for bound excitons in ZnO, it has distinctively different magneto-optical properties. Photoelectron paramagnetic resonance measurements reveal a connection and a charge-transfer process involving NBX and Fe and Al centers. The experimental results are explained within a model which assumes that the NBX is a neutral donor bound exciton at a defect center located near a Fe impurity and an Auger-type charge-transfer process occurs between NBX and Fe3 + . While the NBX dissociates, its hole is captured by an excited state of Fe3 + and the released energy is transferred to the NBX electron, which is excited to the conduction band and subsequently trapped by a substitutional AlZn shallow donor.

The effects of copper, manganese and zinc on plant growth and elemental accumulation in the manganese-hyperaccumulator Phytolacca americana.

PubMed

Zhao, Huijun; Wu, Liangqi; Chai, Tuanyao; Zhang, Yuxiu; Tan, Jinjuan; Ma, Shengwen

2012-09-01

Synchrotron radiation X-ray fluorescence (SRXRF) and inductively coupled plasma mass spectrometry were used to estimate major, minor and trace elements in Cu-, Zn- and Mn-treated Phytolacca americana. The effects of the addition of Cu, Zn and Mn on morphological parameters, such as root length, shoot height, and fresh and dry weights of shoots and roots, were also examined. In addition, the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidases (GPX) and catalase (CAT) and the expression of Fe-SOD, Cu/Zn-SOD, metallothionein-2 and glutathione S-transferase (GST) exposed to the highest amounts of Cu, Zn or Mn were detected. Our results confirmed the following: (1) Zn supplementation leads to chlorosis, disturbed elemental homeostasis and decreased concentrations of micro- and macroelements such as Fe, Mg, Mn, Ca and K. Cu competed with Fe, Mn and Zn uptake in plants supplemented with 25 μM Cu. However, no antagonistic interactions took place between Cu, Zn, Mn and Fe uptake in plants supplemented with 100 μM Cu. Mn supplementation at various concentrations had no negative effects on elemental deficits. Mn was co-located with high concentrations of Fe and Zn in mature leaves and the concentrations of macro elements were unchanged. (2) P. americana supplemented with increased concentrations of Zn and Cu exhibited lower biomass production and reduced plant growth. (3) When plants were supplemented with the highest Zn and Cu concentrations, symptoms of toxicity corresponded to decreased SOD or CAT activities and increased APX and GPX activities. However, Mn tolerance corresponded to increased SOD and CAT activities and decreased POD and APX activities. Our study revealed that heavy metals partially exert toxicity by disturbing the nutrient balance and modifying enzyme activities that induce damage in plants. However, P. americana has evolved hyper accumulating mechanisms to maintain elemental balance and redox homeostasis under excess Mn. Copyright © 2012 Elsevier GmbH. All rights reserved.

Assessment of trace metals contamination in the coastal sediments of the Egyptian Mediterranean coast

NASA Astrophysics Data System (ADS)

El Baz, Sherif M.; Khalil, Mohamed M.

2018-07-01

Trace metals contamination has been recently increased in the Egyptian Mediterranean coast owing to the nearby anthropological activities. This investigation aimed to detect the concentrations of six different trace metals (Fe, Mn, Cu, Cd, Pb and Zn) in surface sediments from the central part of the Egyptian Mediterranean coast, and to assess their state of contamination from different indices and risk factor calculations. Mean concentrations of Cu, Pb and Zn were lower and the mean concentration of Cd was higher compared to the background values. The assessment of pollution was mainly based on the contamination indices. Based on the contamination factor, Pb was the most enriched element followed by Cd, Mn, Zn and Cu. Most of the sites show low contamination with respect to Pb, Mn, Cd, Fe, Zn and Cu. The pollution load index also suggests that all the coastal sediments are unpolluted. According to the geoaccumulation index, the sediments were classified into unpolluted with Mn, Cd, Fe and Pb, and unpolluted to moderately polluted with Pb. Risk evaluation revealed that Cd had the greatest ecological risk, followed by Pb, Cu, Mn, while Zn had the lowest risk. With the aid of statistical methods, the origin of metals is classified into two clusters (A and B). Group A consists of Fe, Mn and Cu, whereas group B contains Zn, Pb and Cd. In the first cluster Fe and Mn are joined to each other at a positive and significant similarity (0.68). Fe is recognized as an indicator of lithogenous origin, therefore, its higher similarity with Mn may be indicative of the similar origin for Manganese. In the second cluster Pb and Zn are joined to each other at a positive and significant similarity (0.80). Pb is recognized as an indicator of anthropogenic origin, therefore, its higher similarity with Zn may be indicative of the similar origin for Zinc.

Synthesis, Characterization, and Study of In Vitro Cytotoxicity of ZnO-Fe3O4 Magnetic Composite Nanoparticles in Human Breast Cancer Cell Line (MDA-MB-231) and Mouse Fibroblast (NIH 3T3).

PubMed

Bisht, Gunjan; Rayamajhi, Sagar; Kc, Biplab; Paudel, Siddhi Nath; Karna, Deepak; Shrestha, Bhupal G

2016-12-01

Novel magnetic composite nanoparticles (MCPs) were successfully synthesized by ex situ conjugation of synthesized ZnO nanoparticles (ZnO NPs) and Fe 3 O 4 NPs using trisodium citrate as linker with an aim to retain key properties of both NPs viz. inherent selectivity towards cancerous cell and superparamagnetic nature, respectively, on a single system. Successful characterization of synthesized nanoparticles was done by XRD, TEM, FTIR, and VSM analyses. VSM analysis showed similar magnetic profile of thus obtained MCPs as that of naked Fe 3 O 4 NPs with reduction in saturation magnetization to 16.63 emu/g. Also, cell viability inferred from MTT assay showed that MCPs have no significant toxicity towards noncancerous NIH 3T3 cells but impart significant toxicity at similar concentration to breast cancer cell MDA-MB-231. The EC50 value of MCPs on MDA-MB-231 is less than that of naked ZnO NPs on MDA-MB-231, but its toxicity on NIH 3T3 was significantly reduced compared to ZnO NPs. Our hypothesis for this prominent difference in cytotoxicity imparted by MCPs is the synergy of selective cytotoxicity of ZnO nanoparticles via reactive oxygen species (ROS) and exhausting scavenging activity of cancerous cells, which further enhance the cytotoxicity of Fe 3 O 4 NPs on cancer cells. This dramatic difference in cytotoxicity shown by the conjugation of magnetic Fe 3 O 4 NPs with ZnO NPs should be further studied that might hold great promise for the development of selective and site-specific nanoparticles. Schematic representation of the conjugation, characterization and cytotoxicity analysis of Fe 3 O 4 -ZnO magnetic composite particles (MCPs).

Tracing fluid transfer across subduction zones using iron and zinc stable isotopes

NASA Astrophysics Data System (ADS)

Williams, H. M.; Debret, B.; Pons, M. L.; Bouilhol, P.

2016-12-01

In subduction zones, serpentinite devolatilization within the downgoing slab and the fluids released play a fundamental role in volatile transfer as well as the redox evolution of the sub-arc mantle. Constraining subduction-related serpentinite devolatilisation is essential in order to better understand of the nature and composition of slab-derived fluids and fluid/rock interactions. Fe and Zn stable isotopes can trace fluid composition and speciation as isotope partitioning is driven by changes in oxidation state, coordination, and bonding environment. In the case of serpentinite devolatilisation, Fe isotope fractionation should reflect changes in Fe redox state and the formation of Fe-Cl- and SO42- complexes (Hill et al., GCA 2010); Zn isotope fractionation should be sensitive to complexation with CO32-, HS- and SO42- anions (Fujii et al., GCA 2011). We targeted samples from Western Alps ophiolite complexes, interpreted as remnants of serpentinized oceanic lithosphere metamorphosed and devolatilized during subduction (Hattori and Guillot, G3 2007; Debret et al., Chem. Geol. 2013). A striking negative correlation is present between bulk serpentinite Fe isotope composition and Fe3+/Fetot, with the highest grade samples displaying the heaviest Fe isotope compositions and lowest Fe3+/Fetot (Debret et al., Geology, 2016). The same samples also display a corresponding variation in Zn isotopes, with the highest grade samples displaying isotopically light compositions (Pons et al., in revision). The negative correlation between Fe and Zn isotopes and decrease in Fe3+/Fetot can explained by serpentinite sulfide breakdown and the release of fluids enriched in isotopically light Fe and heavy Zn sulphate complexes. The migration of these SOX-bearing fluids from the slab to the slab-mantle interface or mantle wedge has important implications for the redox evolution of the sub-arc mantle and the transport of metals from the subducting slab.

Roles of Zinc and Iron on Bone Health in a Rat Model of Osteoporosis

NASA Astrophysics Data System (ADS)

Yan, Danhua

Bone is one of the most vital organs in animals, serving as both structural and protective functions. Remodeling of bone is an important indicator of bone health, and disorders in bone remodeling may lead to bone diseases such as osteoporosis. Osteoporosis increases risk of bone fracture and even death, and much more preferable to be happened in postmenopausal women due to great changes in hormones. Micronutrients, such as Zinc (Zn) and Iron (Fe), would as well influence bone health in different manners. That Zn would promote bone health is widely accepted, for the reasons Zn increases osteoblast cell proliferation and differentiation, inhibits osteoclast cell activities, and forms alkaline phosphatase that does help to maintain bone metabolism. Diseases caused by Fe overload is usually related to osteoporosis. Ferric ion could facilitate osteoclast differentiation, inhibit osteoblast and alkaline phosphatase activities, and interfere with hydroxyapatite crystal growth and depositions. However, changes of concentrations and distributions for Zn and Fe in osteoporotic bones are seldom studied. In this thesis, ovariectomized rat femur bones are used as a model of postmenopausal osteoporosis. Rats from different ages and health conditions are categorized as 6 AM (6-month age matched control), 6 OVX (6-month ovariectomized control), 12 AM (12-month age matched control), 12 OVX (12-month ovariectomized control). The trace elements Zn and Fe is studied through Synchrotron Radiation X-Ray Fluorescence (SRXRF). Elemental maps are used to observe changes in distribution, and further quantitative analysis is used to discover changes in concentration among different animal groups. Both the decrease of Zn and the increase of Fe are significant from healthy to osteoporotic bones (p<0.05). In the meanwhile, accumulation of Zn (p<0.05) and Fe (p>0.1) is also observed over age in healthy groups. Both elements show changes in distribution, that healthy animals present a more even distribution while in OVX groups the tendency of aggregation is observed. These results agree with most of the predictions and add evidence for effects of Zn and Fe on bone health. Hypothesis is further made to rationalize the changing trend observed and explain mechanisms behind.

The influence of inorganic nitrogen fertilizer forms on micronutrient retranslocation and accumulation in grains of winter wheat.

PubMed

Barunawati, Nunun; Giehl, Ricardo F Hettwer; Bauer, Bernhard; von Wirén, Nicolaus

2013-01-01

The fortification of cereal grains with metal micronutrients is a major target to combat human malnutrition of Fe and Zn. Based on recent studies showing that N fertilization can promote Fe and Zn accumulation in cereal grains, we investigated here the influence of nitrate- or ammonium-based N fertilization on the accumulation of Fe, Zn, and Cu as well as metal chelator pools in flag leaves and grains of winter wheat. Fertilization with either N form increased the concentrations of N and of the metal chelator nicotianamine (NA) in green leaves, while 2'-deoxymugineic acid (DMA) remained unaffected. Despite the differential response to N fertilization of NA and DMA levels in flag leaves, N fertilization remained without any significant effect on the net export of these metals during flag leaf senescence, which accounted for approximately one third of the total Fe, Zn, or Cu content in leaves. The significant increase in the accumulation of Fe, Zn, and Cu found in the grains of primarily ammonium-fertilized plants was unrelated to the extent of metal retranslocation from flag leaves. These results indicate that an increased N nutritional status of flag leaves promotes the accumulation of Fe, Zn, and Cu in flag leaves, which is accompanied by an increased pool of NA but not of DMA. With regard to the far higher concentrations of DMA relative to NA in leaves and leaf exudates, DMA may be more relevant for the mobilization and retranslocation of these metals in high-yielding wheat production.

Examining Two Sets of Introgression Lines in Rice (Oryza sativa L.) Reveals Favorable Alleles that Improve Grain Zn and Fe Concentrations

PubMed Central

Hu, Xia; Cheng, Li-Rui; Xu, Jian-Long; Shi, Yu-Min; Li, Zhi-Kang

2015-01-01

In the modern world, the grain mineral concentration (GMC) in rice (Oryza sativa L.) not only includes important micronutrient elements such as iron (Fe) and zinc (Zn), but it also includes toxic heavy metal elements, especially cadmium (Cd) and lead (Pb). To date, the genetic mechanisms underlying the regulation of GMC, especially the genetic background and G × E effects of GMC, remain largely unknown. In this study, we adopted two sets of backcross introgression lines (BILs) derived from IR75862 (a Zn-dense rice variety) as the donor parent and two elite indica varieties, Ce258 and Zhongguangxiang1, as recurrent parents to detect QTL affecting GMC traits including Fe, Zn, Cd and Pb concentrations in two environments. We detected a total of 22 loci responsible for GMC traits, which are distributed on all 12 rice chromosomes except 5, 9 and 10. Six genetic overlap (GO) regions affecting multiple elements were found, in which most donor alleles had synergistic effects on GMC. Some toxic heavy metal-independent loci (such as qFe1, qFe2 and qZn12) and some regions that have opposite genetic effects on micronutrient (Fe and Zn) and heavy metal element (Pb) concentrations (such as GO-IV) may be useful for marker-assisted biofortification breeding in rice. We discuss three important points affecting biofortification breeding efforts in rice, including correlations between different GMC traits, the genetic background effect and the G × E effect. PMID:26161553

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

NASA Astrophysics Data System (ADS)

Huang, Shih-Yi; Jiang, Shiuh-Jen; Sahayam, A. C.

2014-11-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min- 1 methane (CH4) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g- 1 for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g- 1 (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions.

Self-assembled organic-inorganic magnetic hybrid adsorbent ferrite based on cyclodextrin nanoparticles.

PubMed

Denadai, Angelo M L; De Sousa, Frederico B; Passos, Joel J; Guatimosim, Fernando C; Barbosa, Kirla D; Burgos, Ana E; de Oliveira, Fernando Castro; da Silva, Jeann C; Neves, Bernardo R A; Mohallem, Nelcy D S; Sinisterra, Rubén D

2012-01-01

Organic-inorganic magnetic hybrid materials (MHMs) combine a nonmagnetic and a magnetic component by means of electrostatic interactions or covalent bonds, and notable features can be achieved. Herein, we describe an application of a self-assembled material based on ferrite associated with β-cyclodextrin (Fe-Ni/Zn/βCD) at the nanoscale level. This MHM and pure ferrite (Fe-Ni/Zn) were used as an adsorbent system for Cr(3+) and Cr(2)O(7) (2-) ions in aqueous solutions. Prior to the adsorption studies, both ferrites were characterized in order to determine the particle size distribution, morphology and available binding sites on the surface of the materials. Microscopy analysis demonstrated that both ferrites present two different size domains, at the micro- and nanoscale level, with the latter being able to self-assemble into larger particles. Fe-Ni/Zn/βCD presented smaller particles and a more homogeneous particle size distribution. Higher porosity for this MHM compared to Fe-Ni/Zn was observed by Brunauer-Emmett-Teller isotherms and positron-annihilation-lifetime spectroscopy. Based on the pKa values, potentiometric titrations demonstrated the presence of βCD in the inorganic matrix, indicating that the lamellar structures verified by transmission electronic microscopy can be associated with βCD assembled structures. Colloidal stability was inferred as a function of time at different pH values, indicating the sedimentation rate as a function of pH. Zeta potential measurements identified an amphoteric behavior for the Fe-Ni/Zn/βCD, suggesting its better capability to remove ions (cations and anions) from aqueous solutions compared to that of Fe-Ni/Zn.

Natural Variation at the FRD3 MATE Transporter Locus Reveals Cross-Talk between Fe Homeostasis and Zn Tolerance in Arabidopsis thaliana

PubMed Central

Pineau, Christophe; Loubet, Stéphanie; Lefoulon, Cécile; Chalies, Claude; Fizames, Cécile; Lacombe, Benoit; Ferrand, Marina; Loudet, Olivier; Berthomieu, Pierre; Richard, Odile

2012-01-01

Zinc (Zn) is essential for the optimal growth of plants but is toxic if present in excess, so Zn homeostasis needs to be finely tuned. Understanding Zn homeostasis mechanisms in plants will help in the development of innovative approaches for the phytoremediation of Zn-contaminated sites. In this study, Zn tolerance quantitative trait loci (QTL) were identified by analyzing differences in the Bay-0 and Shahdara accessions of Arabidopsis thaliana. Fine-scale mapping showed that a variant of the Fe homeostasis-related FERRIC REDUCTASE DEFECTIVE3 (FRD3) gene, which encodes a multidrug and toxin efflux (MATE) transporter, is responsible for reduced Zn tolerance in A. thaliana. Allelic variation in FRD3 revealed which amino acids are necessary for FRD3 function. In addition, the results of allele-specific expression assays in F1 individuals provide evidence for the existence of at least one putative metal-responsive cis-regulatory element. Our results suggest that FRD3 works as a multimer and is involved in loading Zn into xylem. Cross-homeostasis between Fe and Zn therefore appears to be important for Zn tolerance in A. thaliana with FRD3 acting as an essential regulator. PMID:23236296

Effects of microstructure and CaO addition on the magnetic and mechanical properties of NiCuZn ferrites

NASA Astrophysics Data System (ADS)

Wang, Sea-Fue; Hsu, Yung-Fu; Liu, Yi-Xin; Hsieh, Chung-Kai

2015-11-01

In this study, the effects of grain size and the addition of CaCO3 on the magnetic and mechanical properties of Ni0.5Cu0.3Zn0.2Fe2O4 ceramics were investigated. The bending strength of the ferrites increased from 66 to 84 MPa as the grain size of the sintered ceramics decreased from 10.25 μm to 7.53 μm, while the change in hardness was insignificant. The addition of various amounts of CaCO3 densified the Ni0.5Cu0.3Zn0.2Fe2O4 ceramics at 1075 °C. In the pure Ni0.5Cu0.3Zn0.2Fe2O4 ceramic, second phase CuO was segregated at the grain boundaries. With the CaCO3 content ≥1.5 wt%, a small amount of discrete plate-like second phase Fe2CaO4 was observed, together with the disappearance of the second phase CuO. The grain size of the Ni0.5Cu0.3Zn0.2Fe2O4 ceramic dropped from 7.80 μm to 4.68 μm, and the grain size distribution widened as the CaCO3 content increased from 0 to 5 wt%. Initially rising to 807 after CaCO3 addition up to 2.0 wt%, due to a reduced grain size, the Vickers hardness began to drop as the CaCO3 content increased. The bending strength grew linearly with the CaCO3 content and reached twice the value for the Ni0.5Cu0.3Zn0.2Fe2O4 ceramic with an addition of 5.0 wt% CaCO3. The initial permeability of the Ni0.5Cu0.3Zn0.2Fe2O4 ceramic decreased substantially from 402 to 103 as the addition of CaCO3 in ferrite increased from 0 to 5 wt%, and the quality factor of the Ni0.5Cu0.3Zn0.2Fe2O4 ceramic was maximized at 95 for 1.0 wt% CaCO3 addition.

High performance top-gated ferroelectric field effect transistors based on two-dimensional ZnO nanosheets

NASA Astrophysics Data System (ADS)

Tian, Hongzheng; Wang, Xudong; Zhu, Yuankun; Liao, Lei; Wang, Xianying; Wang, Jianlu; Hu, Weida

2017-01-01

High quality ultrathin two-dimensional zinc oxide (ZnO) nanosheets (NSs) are synthesized, and the ZnO NS ferroelectric field effect transistors (FeFETs) are demonstrated based on the P(VDF-TrFE) polymer film used as the top gate insulating layer. The ZnO NSs exhibit a maximum field effect mobility of 588.9 cm2/Vs and a large transconductance of 2.5 μS due to their high crystalline quality and ultrathin two-dimensional structure. The polarization property of the P(VDF-TrFE) film is studied, and a remnant polarization of >100 μC/cm2 is achieved with a P(VDF-TrFE) thickness of 300 nm. Because of the ultrahigh remnant polarization field generated in the P(VDF-TrFE) film, the FeFETs show a large memory window of 16.9 V and a high source-drain on/off current ratio of more than 107 at zero gate voltage and a source-drain bias of 0.1 V. Furthermore, a retention time of >3000 s of the polarization state is obtained, inspiring a promising candidate for applications in data storage with non-volatile features.

CoFe2O4-TiO2 and CoFe2O4-ZnO thin film nanostructures elaborated from colloidal chemistry and atomic layer deposition.

PubMed

Clavel, Guylhaine; Marichy, Catherine; Willinger, Marc-Georg; Ravaine, Serge; Zitoun, David; Pinna, Nicola

2010-12-07

CoFe(2)O(4)-TiO(2) and CoFe(2)O(4)-ZnO nanoparticles/film composites were prepared from directed assembly of colloidal CoFe(2)O(4) in a Langmuir-Blodgett monolayer and atomic layer deposition (ALD) of an oxide (TiO(2) or ZnO). The combination of these two methods permits the use of well-defined nanoparticles from colloidal chemistry, their assembly on a large scale, and the control over the interface between a ferrimagnetic material (CoFe(2)O(4)) and a semiconductor (TiO(2) or ZnO). Using this approach, architectures can be assembled with a precise control from the Angstrom scale (ALD) to the micrometer scale (Langmuir-Blodgett film). The resulting heterostructures present well-calibrated thicknesses. Electron microscopy and magnetic measurement studies give evidence that the size of the nanoparticles and their intrinsic magnetic properties are not altered by the various steps involved in the synthesis process. Therefore, the approach is suitable to obtain a layered composite with a quasi-monodisperse layer of ferrimagnetic nanoparticles embedded in an ultrathin film of semiconducting material.

Rietveld refinement and electrical properties of Ni-Zn spinel ferrites

NASA Astrophysics Data System (ADS)

Hooda, Ashima; Sanghi, Sujata; Agarwal, Ashish; Khasa, Satish; Hooda, Bhawana

2017-05-01

NiFe2O4, ZnFe2O4, Ni0.5Zn0.5Fe2O4 spinel samples have been synthesized by conventional solid state reaction technique. Powder X-ray diffraction and Rietveld refinement revealed that the samples were single Spinel phase with space group fd3m. The average crystalline size (D), lattice constant (a), X-ray density (ρx), measured density (ρm) and Porosity (P) of prepared samples were determined from XRD data. The dc electrical resistivity (p) was measured as a function of temperature. The variations of ρ were explained on the basis of Verwey and de Bohr mechanism. The value of DC resistivity found to increase with increase Zn concentration.

Evaluating the influence of National Research Council levels of copper, iron, manganese, and zinc using organic (Bioplex) minerals on resulting tissue mineral concentrations, metallothionein, and liver antioxidant enzymes in grower-finisher swine diets.

PubMed

Gowanlock, D W; Mahan, D C; Jolliff, J S; Hill, G M

2015-03-01

Graded levels of a trace mineral premix containing an organic (Bioplex) source of Cu, Fe, Mn, and Zn was evaluated with additional treatments containing organic Zn or Fe. Grower-finisher pigs were fed from 25 to 115 kg BW. The number of pigs in the experiment, the breeding/genetics of the pigs, the management, and the average age of the pigs were previously reported. The experiment was conducted as a randomized complete block design in 7 replicates. Treatments were 1) basal diet without supplemental Cu, Fe, Mn, and Zn; 2) basal diet + 2.5 mg/kg Cu, 50 mg/kg Fe, 1.5 mg/kg Mn, and 40 mg/kg Zn (50% NRC); 3) basal diet + 5 mg/kg Cu, 100 mg/kg Fe, 3 mg/kg Mn, and 80 mg/kg Zn (100% NRC); 4) basal diet + 25 mg Zn/kg; 5) basal diet + 50 mg Zn/kg; and 6) basal diet + 50 mg Fe/kg. Selenium and I were added to all diets at 0.3 and 0.14 mg/kg, respectively. Diets were composed of corn-soybean meal, dicalcium phosphate, and limestone with phytase added to enhance mineral availability. Three pigs per pen were bled at 55, 80, and 115 kg BW and plasma was analyzed for microminerals. When the average replicate BW was 115 kg, 3 pigs per pen of an equal gender ratio were killed. The liver, kidney, and heart were removed and analyzed for microminerals. Liver, duodenum, and jejunal metallothionein and the antioxidant enzymes in the liver containing these microminerals were determined. The results demonstrated that plasma minerals were unaffected at the 3 BW intervals. Liver and duodenum metallothionein protein were greater ( < 0.05) as dietary micromineral levels increased but jejunum metallothionein did not change as microminerals increased. The activity of Cu/Zn superoxide dismutase (SOD) was not affected as the levels of the micromineral increased, whereas the activity of Mn SOD increased slightly ( < 0.05) to the 50% NRC treatment level. Liver Zn (relative and total) increased ( < 0.05) as dietary micromineral levels increased and also when Zn was added singly to the diet. Liver, kidney, and heart Cu and Mn concentrations were similar at the various micromineral levels. The activities of liver enzymes containing graded levels of Zn were not affected by dietary microminerals at 115 kg BW. These results indicate that the supplemental levels of Cu, Fe, and Mn were not necessary for grower-finisher pigs and that these innate microminerals in a corn-soybean meal diet were adequate, whereas a need for supplemental Zn was demonstrated.

Source analysis of radiocesium in river waters using road dust tracers.

PubMed

Murakami, Michio; Saha, Mahua; Iwasaki, Yuichi; Yamashita, Rei; Koibuchi, Yukio; Tsukada, Hirofumi; Takada, Hideshige; Sueki, Keisuke; Yasutaka, Tetsuo

2017-11-01

Following the Fukushima Dai-ichi Nuclear Power Station accident, regional road dust, heavily contaminated with radiocesium, now represents a potential source of radiocesium pollution in river water. To promote effective countermeasures for reducing the risk from radiocesium pollution, it is important to understand its sources. This study evaluated the utility of metals, including Al, Fe, and Zn as road dust tracers, and applied them to analyze sources of 137 Cs in rivers around Fukushima during wet weather. Concentrations of Zn in road dust were higher than agricultural and forest soils, whereas concentrations of Fe and Al were the opposite. Concentrations of Zn were weakly but significantly correlated with benzothiazole, a molecular marker of tires, indicating Zn represents an effective tracer of road dust. Al, Fe, and Zn were frequently detected in suspended solids in river water during wet weather. Distribution coefficients of these metals and 137 Cs exceeded 10 4 , suggesting sorptive behavior in water. Although concentrations of Al, Fe, Zn, and 137 Cs were higher in fine fractions of road dust and soils than in coarse fractions, use of ratios of 137 Cs to Al, Fe, or Zn showed smaller differences among size fractions. The results demonstrate that combinations of these metals and 137 Cs are useful for analyzing sources of radiocesium in water. These ratios in river water during wet weather were found to be comparable with or lower than during dry weather and were closer to soils than road dust, suggesting a limited contribution from road dust to radiocesium pollution in river water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Formation of interfacial compounds and the effects on stripping behaviors of a cold-sprayed Zn-Al coating on interstitial-free steel

NASA Astrophysics Data System (ADS)

Liang, Y. L.; Wang, Z. B.; Zhang, J. B.; Lu, K.

2015-06-01

By means of cold spray, a Zn-Al coating was successfully deposited on an interstitial-free (IF) steel sheet. The formation of interfacial compounds between the coating and the IF steel was studied during diffusion annealing at 400 °C. And its correlations with the stripping behaviors of the coating were investigated by using a three-point bending method. The results showed that Fe-Zn and Fe-Al-Zn compounds begin to form at the coating/substrate interface after an annealing duration of 60 min, and the stripping resistance increases slightly before that duration and then decreases significantly by further increasing annealing duration. The enhanced stripping resistance at the earlier stage might be due to the modifications of microstructure and deformation compatibility of the sprayed coating, while the decreased stripping resistance at the later stage is related to the high stress concentration at the interface of the formed brittle Fe-Al-Zn phase and the Zn-Al coating.

Induction of Nickel Accumulation in Response to Zinc Deficiency in Arabidopsis thaliana

PubMed Central

Nishida, Sho; Kato, Aki; Tsuzuki, Chisato; Yoshida, Junko; Mizuno, Takafumi

2015-01-01

Excessive accumulation of nickel (Ni) can be toxic to plants. In Arabidopsis thaliana, the Fe2+ transporter, iron (Fe)-regulated transporter1 (IRT1), mediates Fe uptake and also implicates in Ni2+ uptake at roots; however, the underlying mechanism of Ni2+ uptake and accumulation remains unelucidated. In the present study, we found that zinc (Zn) deficient conditions resulted in increased accumulation of Ni in plants, particularly in roots, in A. thaliana. In order to elucidate the underlying mechanisms of Ni uptake correlating zinc condition, we traced 63Ni isotope in response to Zn and found that (i) Zn deficiency induces short-term Ni2+ absorption and (ii) Zn2+ inhibits Ni2+ uptake, suggesting competitive uptake between Ni and Zn. Furthermore, the Zrt/Irt-like protein 3 (ZIP3)-defective mutant with an elevated Zn-deficient response exhibited higher Ni accumulation than the wild type, further supporting that the response to Zn deficiency induces Ni accumulation. Previously, expression profile study demonstrated that IRT1 expression is not inducible by Zn deficiency. In the present study, we found increased Ni accumulation in IRT1-null mutant under Zn deficiency in agar culture. These suggest that Zn deficiency induces Ni accumulation in an IRT1-independen manner. The present study revealed that Ni accumulation is inducible in response to Zn deficiency, which may be attributable to a Zn uptake transporter induced by Zn deficiency. PMID:25923075

Magnetic Properties of NdFe10Mo2-N Bonded Magnet

NASA Astrophysics Data System (ADS)

Zhang, Hong-Wei; Hu, Bo-Ping; Han, Zhong-Fan; Jin, Han-Min; Fu, Quan

1997-06-01

The dependence of remanence and coercivity on the magnetizing field is studied for isotropic and anisotropic epoxy resin bonded magnets. It was found that the coercivity of the NdFe10Mo2-N bonded magnet is mainly controlled by nucleation of reversed magnetic domains. Variation of iHc with Zn content and heat treatment conditions is studied. The value of 0 iHc obtained in the best Zn-bonded condition is about 0.15 T higher than before bonding. The variation of the amount of α-Fe with processing conditions is demonstrated for anisotropic Zn-bonded magnets.

Synthesis, characterization and magnetic properties of MWCNTs decorated with Zn-substituted MnFe2O4 nanoparticles using waste batteries extract

NASA Astrophysics Data System (ADS)

Gabal, M. A.; Al-Harthy, E. A.; Al Angari, Y. M.; Abdel Salam, M.; Asiri, A. M.

2016-06-01

Mn1-xZnxFe2O4 (x=0.2-0.8) nano-crystals, synthesized from recycling of Zn-C batteries, were successfully self-assembled alongside multi-walled carbon nanotubes (MWCNTs) via an environmentally friend sucrose auto-combustion method. The effect of Zn-content on structural and magnetic properties were investigated and discussed. XRD revealed the formation of single-phase ferrites. DTA-TG experiment showed that the auto-combustion reaction finished at about 350 °C. TEM exhibited that the MWCNTs are well decorated with ferrite particles. Hysteresis loop measurements revealed ferromagnetic behavior, with saturation magnetization decrease by the addition of MWCNTs or increasing Zn-Content. The kinetics of methylene blue dye (MB) removal using MWCNTs/Mn0.8Zn0.2Fe2O nano-composite was investigated and discussed.

Highly selective removal of Zn(II) ion from hot-dip galvanizing pickling waste with amino-functionalized Fe3O4@SiO2 magnetic nano-adsorbent.

PubMed

Bao, Shuangyou; Tang, Lihong; Li, Kai; Ning, Ping; Peng, Jinhui; Guo, Huibin; Zhu, Tingting; Liu, Ye

2016-01-15

Amino-functionalized Fe3O4@SiO2 magnetic nano-adsorbent was used as a novel sorbent to highly selective removal of Zn(II) ion from hot-dip galvanizing pickling waste in the presence of Fe(II). These hot-dip galvanizing pickling waste mainly contain ZnCl2 and FeCl2 in aqueous HCl media. The properties of this magnetic adsorbent were examined by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), infrared spectrometer (FT-IR) and BET surface area measurements. Various factors influencing the adsorption of Zn(II) ion such as initial concentration of metal ions, the amount of adsorbent, pH value of the solutions, the concentration of coexisting iron ion were investigated by batch experiments. The results indicated that the adsorption equilibrium data obeyed the Freundlich model with maximum adsorption capacities for Zn(II) to 169.5mg/g. The maximum adsorption occurred at pH 5±0.1 and Fe(II) interferences had no obvious influence. This work provides a potential and unique technique for zinc ion removal from hot-dip galvanizing pickling waste. Copyright © 2015 Elsevier Inc. All rights reserved.

Bioelements in hair of children with selected neurological disorders.

PubMed

Józefczuk, Jan; Kasprzycka, Wiktoria; Czarnecki, Rafał; Graczyk, Alfreda; Józefczuk, Paweł; Krzysztof, Magda; Lampart, Urszula; Mrozowska-Ząbek, Ewa; Surdy, Weronika; Kwiatkowska-Graczyk, Róża

2017-01-01

We have analyzed concentrations of magnesium (Mg), calcium (Ca), copper (Cu), zinc (Zn) and iron (Fe) in hair of a group of 82 children with mental retardation, in which 9 patients suffered from epilepsy, 18 from the Down's syndrome and 55 from cerebral palsy. Girls comprised little over 50% of the patients. In the group of boys with epilepsy, we found Mg, Ca, Cu and Fe deficiency, and normal level of Zn. In the group of girls with epilepsy, apart from low Fe concentration, a high level of Ca, Mg, Zn, and Cu was noted. For girls with the Down's syndrome, a high or normal level of Ca, Mg, Zn and Cu was found, whereas the Fe concentration varied and presented itself in a non-characteristic way. Both groups of children with cerebral palsy, i.e. boys and girls, displayed low Fe concentration in their hair; low Cu level was found in older patients as well. In this group of patients, we also noted high concentrations of Ca, Mg and Zn in girls and normal in boys. A high concentration of Ca in girls with cerebral palsy requires separate analysis. The obtained results could be useful as guidance in the direction and determination of the amount of possible patient nutritional supplementation.

Removal of dibutyl phthalate from aqueous environments using a nanophotocatalytic Fe, Ag-ZnO/VIS-LED system: modeling and optimization.

PubMed

Akbari-Adergani, B; Saghi, M H; Eslami, A; Mohseni-Bandpei, A; Rabbani, M

2018-06-01

An (Fe, Ag) co-doped ZnO nanostructure was synthesized by a simple chemical co-precipitation method and used for the degradation of dibutyl phthalate (DBP) in aqueous solution under visible light-emitting diode (LED) irradiation. (Fe, Ag) co-doped ZnO nanorods were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, UV-VIS diffuse reflectance spectroscopy, elemental mapping, Field emission scanning electron microscopy, transmission electron microscope and Brunauer-Emmett-Teller surface area analysis. A Central Composite Design was used to optimize the reaction parameters for the removal of DBP by the (Fe, Ag) co-doped ZnO nanorods. The four main reaction parameters optimized in this study were the following: pH, time of radiation, concentration of the nanorods and initial DBP concentration. The interaction between the four parameters was studied and modeled using the Design Expert 10 software. A maximum reduction of 95% of DBP was achieved at a pH of 3, a photocatalyst concentration of 150 mg L -1 and a DBP initial DBP concentration of 15 mg L -1 . The results showed that the (Fe, Ag) co-doped ZnO nanorods under low power LED irradiation can be used as an effective photocatalyst for the removal of DBP from aqueous solutions.

Disturbances to metal partitioning during toxicity testing of iron(II)-rich estuarine pore waters and whole sediments.

PubMed

Simpson, Stuart L; Batley, Graeme E

2003-02-01

Metal partitioning is altered when suboxic estuarine sediments containing Fe(II)-rich pore waters are disturbed during collection, preparation, and toxicity testing. Experiments with model Fe(II)-rich pore waters demonstrated the rates at which adsorptive losses of Cd, Cu, Ni, Mn, Pb, and Zn occur upon exposure to air. Experiments with Zn-contaminated estuarine sediments demonstrated large and often unpredictable changes to metal partitioning during sediment storage, removal of organisms, and homogenization before testing. Small modifications to conditions, such as aeration of overlying waters, caused large changes to the metal partitioning. Disturbances caused by sediment collection required many weeks for reestablishment of equilibrium. Bioturbation by benthic organisms led to oxidation of pore-water Fe(II) and lower Zn fluxes because of the formation of Fe hydroxide precipitates that adsorb pore-water Zn. For five weeks after the addition of organisms to sediments, Zn fluxes increased slowly as the organisms established themselves in the sediments, indicating that the establishment of equilibrium was not rapid. The results are discussed in terms of the dynamic nature of suboxic, Fe(II)-rich estuarine sediments, how organisms perturb their environment, and the importance of understanding chemistry in toxicity testing with whole sediments or pore water. Recommendations are provided for the handling of sediments for toxicity testing.

Hypothesis testing for the validation of the kinetic spectrophotometric methods for the determination of lansoprazole in bulk and drug formulations via Fe(III) and Zn(II) chelates.

PubMed

Rahman, Nafisur; Kashif, Mohammad

2010-03-01

Point and interval hypothesis tests performed to validate two simple and economical, kinetic spectrophotometric methods for the assay of lansoprazole are described. The methods are based on the formation of chelate complex of the drug with Fe(III) and Zn(II). The reaction is followed spectrophotometrically by measuring the rate of change of absorbance of coloured chelates of the drug with Fe(III) and Zn(II) at 445 and 510 nm, respectively. The stoichiometric ratio of lansoprazole to Fe(III) and Zn(II) complexes were found to be 1:1 and 2:1, respectively. The initial-rate and fixed-time methods are adopted for determination of drug concentrations. The calibration graphs are linear in the range 50-200 µg ml⁻¹ (initial-rate method), 20-180 µg ml⁻¹ (fixed-time method) for lansoprazole-Fe(III) complex and 120-300 (initial-rate method), and 90-210 µg ml⁻¹ (fixed-time method) for lansoprazole-Zn(II) complex. The inter-day and intra-day precision data showed good accuracy and precision of the proposed procedure for analysis of lansoprazole. The point and interval hypothesis tests indicate that the proposed procedures are not biased. Copyright © 2010 John Wiley & Sons, Ltd.

Exposure of Mn and FeSODs, but not Cu/ZnSOD, to NO leads to nitrosonium and nitroxyl ions generation which cause enzyme modification and inactivation: an in vitro study.

PubMed

Niketíc, V; Stojanović, S; Nikolić, A; Spasić, M; Michelson, A M

1999-11-01

The effect of NO treatment in vitro on structural and functional alterations of Cu/Zn, Mn, and Fe type of SODs was studied. Significant difference in response to NO of Cu/ZnSOD compared to the Mn and Fe types was demonstrated. Cu/ZnSOD was shown to be stable with respect to NO: even on prolonged exposure, NO produced negligible effect on its structure and activity. In contrast, both Mn and Fe types were found to be NO-sensitive: exposure to NO led to their fast and extensive inactivation, which was accompanied by extensive structural alterations, including (in some of the samples tested) the cleavage of enzyme polypeptide chains, presumably at His residues of the enzyme metal binding sites. The generation of nitrosonium (NO+) and nitroxyl (NO-) ions in NO treated Mn and FeSODs, which produce enzyme modifications and inactivation, was demonstrated. The physiological and biomedical significance of described findings is briefly discussed.

A novel method for vanadium slag comprehensive utilization to synthesize Zn-Mn ferrite and Fe-V-Cr alloy.

PubMed

Liu, Shi-Yuan; Li, Shu-Jin; Wu, Shun; Wang, Li-Jun; Chou, Kuo-Chih

2018-07-15

Vanadium slag is a by-product from steelmaking process of vanadium-titanium magnetite, which mainly contains FeO, MnO, V 2 O 3 , and Cr 2 O 3 , The elements Fe and Mn are major components of Mn-Zn ferrite. The elements V and Cr are major components of V-Cr alloy. In view of the potential application in these study, a Mn 0.8 Zn 0.2 Fe 2 O 4 of high saturation magnetization (Ms = 68.6 emu/g) and low coercivity (Hc = 3.3 Oe) was successfully synthesized from the leaching solutions of vanadium slag by adding appropriate chemical reagents, ZnCl 2 and MnCl 2 ·4H 2 O, via roasting at 1300 °C for 1 h. The minor components (CaO and SiO 2 ) in the leaching solution of vanadium slag segregated to the grain boundaries resulting in increasing the resistivity of ferrite. The value of DC resistivity of Mn 0.8 Zn 0.2 Fe 2 O 4 at 25 °C reached 1230.7Ω m. The residue containing Fe, V and Cr was chlorinated by AlCl 3 and the Fe 3+ , V 3+ , and Cr 3+ ions were released into the NaCl-KCl eutectic. The current-time curve for the electrolysis of molten salt was investigated. Alloy (Fe, V, and Cr) of granular shape was obtained. The residue can be used to produce the mulite. This process provided a new approach to utilize slag from steelmaking. Copyright © 2018 Elsevier B.V. All rights reserved.

Localization and distribution of Zn and Fe in grains of biofortified bread wheat lines through micro- and triaxial-X-ray fluorescence spectrometry

NASA Astrophysics Data System (ADS)

Cardoso, P.; Mateus, T. C.; Velu, G.; Singh, R. P.; Santos, J. P.; Carvalho, M. L.; Lourenço, V. M.; Lidon, F.; Reboredo, F.; Guerra, M.

2018-03-01

X-ray fluorescence analysis has been performed in wheat grains from a field trial where some biofortified and non-biofortified wheat varieties were subjected to Zn biofortification through soil fertilizer application. A set of ten biofortified and non-biofortified wheat varieties developed at the International Maize and Wheat Improvement Center, Mexico, were used for this study. Two analytical methods were employed to investigate the contents and localization of the trace metals Zn and Fe within the grains, one with polarized monochromatic X-rays for lower limits of detection, and another featuring polycapillary lenses for micrometric beam size (μ-EDXRF). Elemental maps were obtained with μ-EDXRF allowing for the study of Zn and Fe localization in plants grown in normal and Zn-enriched soil. It is acknowledged that the biofortification procedures result in around 30% average increase in overall Zn concentration when compared to other high Zn genotypes grown in normal soil. A genotypic ranking was performed taking into account the influence of the measurement methods and field conditions and the obtained results show that two of the top three varieties regarding zinc contents also rank among the top three in terms of Fe concentration. Elemental mapping analysis seems to favor the use of integral flour for the manufacture of bread and pasta products, as the bran retains most of the minerals.

Fe2 PO5 -Encapsulated Reverse Energetic ZnO/Fe2 O3 Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water.

PubMed

Qin, Dong-Dong; He, Cai-Hua; Li, Yang; Trammel, Antonio C; Gu, Jing; Chen, Jing; Yan, Yong; Shan, Duo-Liang; Wang, Qiu-Hong; Quan, Jing-Jing; Tao, Chun-Lan; Lu, Xiao-Quan

2017-07-10

Zinc oxide is regarded as a promising candidate for application in photoelectrochemical water oxidation due to its higher electron mobility. However, its instability under alkaline conditions limits its application in a practical setting. Herein, we demonstrate an easily achieved wet-chemical route to chemically stabilize ZnO nanowires (NWs) by protecting them with a thin layer Fe 2 O 3 shell. This shell, in which the thickness can be tuned by varying reaction times, forms an intact interface with ZnO NWs, thus protecting ZnO from corrosion in a basic solution. The reverse energetic heterojunction nanowires are subsequently activated by introducing an amorphous iron phosphate, which substantially suppressed surface recombination as a passivation layer and improved photoelectrochemical performance as a potential catalyst. Compared with pure ZnO NWs (0.4 mA cm -2 ), a maximal photocurrent of 1.0 mA cm -2 is achieved with ZnO/Fe 2 O 3 core-shell NWs and 2.3 mA cm -2 was achieved for the PH 3 -treated NWs at 1.23 V versus RHE. The PH 3 low-temperature treatment creates a dual function, passivation and catalyst layer (Fe 2 PO 5 ), examined by X-ray photoelectron spectroscopy, TEM, photoelectrochemical characterization, and impedance measurements. Such a nano-composition design offers great promise to improve the overall performance of the photoanode material. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of Oral Administration of CrCl3 on the Contents of Ca, Mg, Mn, Fe, Cu, and Zn in the Liver, Kidney, and Heart of Chicken.

PubMed

Liu, Yanhan; Zhao, Xiaona; Zhang, Xiao; Zhao, Xuejun; Liu, Yongxia; Liu, Jianzhu

2016-06-01

This study aimed to investigate the effects of oral administration of trivalent chromium on the contents of Ca, Mg, Mn, Fe, Cu, and Zn in the heart, liver, and kidney. Different levels of 1/8, 1/4, and 1/2 LD50 (LD50 = 5000 mg/kg body mass) CrCl3 milligrams per kilogram body mass daily were added into the water to establish the chronic poisoning model. Ca, Mg, Mn, Fe, Cu, and Zn were detected with the flame atomic absorption spectrometry in the organs exposed 14, 28, and 42 days to CrCl3, respectively. Results showed that Cr was accumulated in the heart, liver, and kidney significantly (P < 0.05) with extended time and dose. The contents of Ca and Fe increased, whereas those of Mg, Mn, Cu, and Zn decreased in the heart, liver, and kidney of each treated group, which had a dose- and time-dependent relationship, but the contents of Mg and Zn in the heart took on a fluctuated change. These particular observations were different from those in the control group. In conclusion, the oral administration of CrCl3 could change the contents of Ca, Mg, Mn, Fe, Cu, and Zn in the heart, liver, and kidney, which may cause disorders in the absorption and metabolism of the metal elements of chickens.

Sustainable synthesis of metals-doped ZnO nanoparticles from zinc-bearing dust for photodegradation of phenol.

PubMed

Wu, Zhao-Jin; Huang, Wei; Cui, Ke-Ke; Gao, Zhi-Fang; Wang, Ping

2014-08-15

A novel strategy of waste-cleaning-waste is proposed in the present work. A metals-doped ZnO (M-ZnO, M = Fe, Mg, Ca and Al) nanomaterial has been prepared from a metallurgical zinc-containing solid waste "fabric filter dust" by combining sulfolysis and co-precipitation processes, and is found to be a favorable photocatalyst for photodegradation of organic substances in wastewater under visible light irradiation. All the zinc and dopants (Fe, Mg, Ca and Al) for preparing M-ZnO are recovered from the fabric filter dust, without any addition of chemical as elemental source. The dust-derived M-ZnO samples deliver single phase indexed as the hexagonal ZnO crystal, with controllable dopants species. The photocatalytic activity of the dust-derived M-ZnO samples is characterized by photodegradation of phenol aqueous solution under visible light irradiation, giving more prominent photocatalytic behaviors than undoped ZnO. Such enhancements may be attributed to incorporation of the dust-derived metal elements (Fe, Mg, Ca and Al) into ZnO structure, which lead to the modification of band gap and refinement of grain size. The results show a feasibility to utilize the industrial waste as a resource of photodegradating organic substances in wastewater treatments. Copyright © 2014 Elsevier B.V. All rights reserved.

Enrichment of Zinc in Galactic Chemodynamical Evolution Models

NASA Astrophysics Data System (ADS)

Hirai, Yutaka; Saitoh, Takayuki R.; Ishimaru, Yuhri; Wanajo, Shinya

2018-03-01

The heaviest iron-peak element Zinc (Zn) has been used as an important tracer of cosmic chemical evolution. Spectroscopic observations of the metal-poor stars in Local Group galaxies show an increasing trend of [Zn/Fe] ratios toward lower metallicity. However, the enrichment of Zn in galaxies is not well understood due to poor knowledge of astrophysical sites of Zn, as well as metal mixing in galaxies. Here we show possible explanations for the observed trend by taking into account electron-capture supernovae (ECSNe) as one of the sources of Zn in our chemodynamical simulations of dwarf galaxies. We find that the ejecta from ECSNe contribute to stars with [Zn/Fe] ≳ 0.5. We also find that scatters of [Zn/Fe] in higher metallicities originate from the ejecta of type Ia supernovae. On the other hand, it appears difficult to explain the observed trends if we do not consider ECSNe as a source of Zn. These results come from an inhomogeneous spatial metallicity distribution due to the inefficiency of the metal mixing. We find that the optimal value of the scaling factor for the metal diffusion coefficient is ∼0.01 in the shear-based metal mixing model in smoothed particle hydrodynamics simulations. These results suggest that ECSNe could be one of the contributors of the enrichment of Zn in galaxies.

Effect of Zn doping on structural and dielectric properties of tetragonal Ni{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} (0.0 ≤ x ≤ 0.5)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lone, S. A.; Dar, M. A.; Kumar, A.

2015-06-24

A series of Ni-Zn ferrite with compositional formula Ni{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} (0.0 ≤ x ≤ 0.5) were prepared by solid-state reaction route. The influence of the Zn content on the structural and dielectric properties of NiFe{sub 2}O{sub 4} was investigated using X-ray powder diffraction (XRD), Raman spectroscopy and dielectric measurements. XRD analysis reveals that the samples are polycrystalline single-phase cubic spinel in structure excluding the presence of any secondary phase corresponding to any structure. Slight variation in the lattice parameter of Zn doped NiFe{sub 2}O{sub 4} has been observed due to difference in ionic radii of cations. Ramanmore » analysis reveals the doublet like nature of A{sub 1g} mode for all synthesized samples. Small shift in Raman modes and increment in the line width has been observed with the doping ions. Furthermore, room temperature dielectric properties of all the prepared samples have been reported. It is observed that for each sample the dielectric constant decreases with an increase of frequency and becomes constant at higher frequencies.« less

Rietveld-refinement and optical study of the Fe doped ZnO thin film by RF magnetron sputtering

NASA Astrophysics Data System (ADS)

Kumar, Arun; Dhiman, Pooja; Singh, M.

2017-05-01

Fe Doped ZnO Dilute Magnetic Semiconductor thin film prepared by RF magnetron sputtering on glass substrate and Influence of 3% Fe-doping on structural and Optical properties has been studied. The Rietveld-refinement analysis shows that Fe doping has a significant effect on crystalline structure, grain size and strain in the thin film. Two dimensional and three-dimensional atom probe tomography of the thin film shows that Fe ions are randomly distributed which is supported by Xray Diffraction (XRD). Fe-doping is found to effectively modify the band gap energy up to 3.5 eV.

Self-assembled organic–inorganic magnetic hybrid adsorbent ferrite based on cyclodextrin nanoparticles

PubMed Central

Denadai, Ângelo M L; De Sousa, Frederico B; Passos, Joel J; Guatimosim, Fernando C; Barbosa, Kirla D; Burgos, Ana E; de Oliveira, Fernando Castro; da Silva, Jeann C; Neves, Bernardo R A; Mohallem, Nelcy D S

2012-01-01

Summary Organic–inorganic magnetic hybrid materials (MHMs) combine a nonmagnetic and a magnetic component by means of electrostatic interactions or covalent bonds, and notable features can be achieved. Herein, we describe an application of a self-assembled material based on ferrite associated with β-cyclodextrin (Fe-Ni/Zn/βCD) at the nanoscale level. This MHM and pure ferrite (Fe-Ni/Zn) were used as an adsorbent system for Cr3+ and Cr2O7 2− ions in aqueous solutions. Prior to the adsorption studies, both ferrites were characterized in order to determine the particle size distribution, morphology and available binding sites on the surface of the materials. Microscopy analysis demonstrated that both ferrites present two different size domains, at the micro- and nanoscale level, with the latter being able to self-assemble into larger particles. Fe-Ni/Zn/βCD presented smaller particles and a more homogeneous particle size distribution. Higher porosity for this MHM compared to Fe-Ni/Zn was observed by Brunauer–Emmett–Teller isotherms and positron-annihilation-lifetime spectroscopy. Based on the pKa values, potentiometric titrations demonstrated the presence of βCD in the inorganic matrix, indicating that the lamellar structures verified by transmission electronic microscopy can be associated with βCD assembled structures. Colloidal stability was inferred as a function of time at different pH values, indicating the sedimentation rate as a function of pH. Zeta potential measurements identified an amphoteric behavior for the Fe-Ni/Zn/βCD, suggesting its better capability to remove ions (cations and anions) from aqueous solutions compared to that of Fe-Ni/Zn. PMID:23209524

Efficacy of heat generation in CTAB coated Mn doped ZnFe2O4 nanoparticles for magnetic hyperthermia

NASA Astrophysics Data System (ADS)

Raland, R. D.; Borah, J. P.

2017-01-01

Manganese doped Zinc ferrite (Mn-ZnFe2O4, where Mn  =  0%, 3%, 5% and 7%) nanoparticles were synthesized by a simple co-precipitation method. CTAB (cetyltrimethylammonium bromide) was used as a surfactant to inhibitgrowth and agglomeration. In this work, we have discussed on the influence of CTAB and Mn doping in tailoring the structural and magnetic properties of Mn-ZnFe2O4 nanoparticles for the effective application of magnetic hyperthermia. X-ray diffraction (XRD) pattern confirmed the formation of cubic spinel structure of Mn-ZnFe2O4 nanoparticles. Lattice parameter and x-ray densities were obtained from the Rietveld refinement of the XRD pattern. The presence of CTAB as a stabilizing layer adsorbed on the surface of the nanoparticles were confirmed by transmission electron microscope (TEM) and Raman vibrational spectrum. The saturation magnetization showsan increasing trend with Mn addition owing to cationic re-distribution and an increase super-exchange interaction between the two sub-lattices. Superparamagnetic behaviorof Mn-ZnFe2O4 nanoparticles were confirmed by temperature-dependent zero-field-cooling (ZFC) and field-cooling (FC) magnetization curves. The efficiency of induction heating measured by its specific absorption rate (SAR) and intrinsic loss power (ILP) value varies as a function of saturation magnetization. It has been hypothesized that the maximum generation of heat arises from Neel relaxation mechanism. The optimum generation of heat of Mn-ZnFe2O4 nanoparticle is determined by the higher frequency (f  =  337 kHz) range and maximum concentration of Mn doping.

The effects of different heat treatment annealing on structural properties of LaFe11.5Si1.5 compound

NASA Astrophysics Data System (ADS)

Norizan, Yang Nurhidayah Asnida; Din, Muhammad Faiz Md; Zamri, Wan Fathul Hakim W.; Hashim, Fakroul Ridzuan; Jusoh, Mohd Taufik; Rahman, Mohd Rashid Abdul

2018-02-01

The cubic NaZn13-type LaFe13-xSix based compounds have been studied systematically and has become one of the most interesting systems for exploring large MCE. Its magnetic properties are strongly doping dependent and provides many of advantage compare to other as magnetic materials for magnetic refrigerator application. In other to produce high quality of cubic NaZn13-type structure, the structural properties of LaFe11.5Si1.5 compounds annealed at different temperature have been investigated. The LaFe11.5Si1.5 compounds was prepared by arc melting and annealed at two different heat treatment which are 1323 K for 14 days and 1523 K for 4 hour. The powder X-ray diffraction (XRD) shows that a short time and high temperature annealing process has benefits for the formation of the NaZn13-type phase compared to a long time and low temperature annealing process. This is shown by the weight fraction of cubic NaZn13- type structure increases from 80% for low temperature annealing to 83% for high temperature annealing. At the same time, high temperature annealing increase the main structure and decrease the impurity (α-Fe and LaFeSi). Furthermore, it can be clearly seen in the Rietveld refinement results that the lattice parameter is increase at the high temperature annealing because of more cubic NaZn13 is formed at higher temperature.

Geology, S-Pb isotopes, and 40Ar/39Ar geochronology of the Zhaxikang Sb-Pb-Zn-Ag deposit in Southern Tibet: implications for multiple mineralization events at Zhaxikang

NASA Astrophysics Data System (ADS)

Sun, Xiang; Zheng, Youye; Pirajno, Franco; McCuaig, T. Campbell; Yu, Miao; Xia, Shenlan; Song, Qingjie; Chang, Huifang

2018-03-01

Several Au, Sb, Sb-Au, Pb-Zn, and Sb-Pb-Zn-Ag deposits are present throughout the North Himalaya in southern Tibet, China. The largest Sb-Pb-Zn-Ag deposit is Zhaxikang (18 Mt at 0.6 wt% Sb, 2.0 wt% Pb, 3.5 wt% Zn, and 78 g/t Ag). Zhaxikang veins are hosted within N-S trending faults, which crosscut the Early-Middle Jurassic Ridang Formation consisting of shale interbedded with sandstone and limestone deposited on a passive continental margin. Ore paragenesis indicates that Zhaxikang mineralization occurred in two main phases composed of six total stages. The initial phase was characterized by assemblages of fine-grained Mn-Fe carbonate + arsenopyrite + pyrite + sphalerite (stage 1), followed by relatively coarse-grained Mn-Fe carbonate + Fe-rich sphalerite + galena + pyrite (stage 2). The second phase was marked by assemblages of quartz + pyrite + Fe-poor sphalerite and Ag-rich galena + tetrahedrite + sericite (stage 3), quartz + Sb-Pb sulfosalt minerals mainly composed of boulangerite and jamesonite (stage 4), quartz + stibnite ± cinnabar (stage 5), and quartz ± calcite (stage 6). Sulfides of stage 2 have δ34SV-CDT of 8.4-12.0‰, 206Pb/204Pb ratios of 19.648 to 19.659, 207Pb/204Pb ratios of 15.788 to 15.812, and 208Pb/204Pb ratios of 40.035 to 40.153. Sulfides of stage 3 have similar δ34SV-CDT of 6.1-11.2‰ and relatively more radiogenic lead isotopes (206Pb/204Pb = 19.683-19.792). Stage 4 Sb-Pb sulfosalt minerals have δ34SV-CDT of 5.0-7.2‰ and even more radiogenic lead (206Pb/204Pb = 19.811-19.981). By contrast, stibnite of stage 5 has δ34SV-CDT of 4.5-7.8‰ and less radiogenic lead (206Pb/204Pb = 18.880-18.974). Taken together with the geological observations that the Pb-Zn-bearing Mn-Fe carbonate veins were crosscut by various types of quartz veins, sphalerite and galena of stage 2 underwent dissolution and remobilization, and that Sb-Pb(-Fe) sulfosalts formed at the expense of Pb from stage 2 galena and of Fe from stage 2 sphalerite, we argue that the early Pb-Zn veins were overprinted by later Sb-rich fluids. Stage 2 fluids were likely acidic and oxidized and leached lead from high-grade metamorphic rocks of the Greater Himalayan crystalline complex (GHC) and sulfur from reduced rocks, such as slate of the Ridang Formation, along N-S trending faults, leading to precipitation of Pb-Zn sulfides and Mn-Fe carbonate and formation of solution collapse breccias. Later Sb-rich fluids leached Pb from the GHC and the pre-existing sulfides and deposited Fe-poor sphalerite, Ag-rich galena, tetrahedrite, Sb-Pb sulfosalts, and stibnite in quartz veins that cut pre-existing Pb-Zn-bearing Mn-Fe carbonate veins. The Sb-rich fluids also likely leached Pb from Early Cretaceous gabbro and formed stibnite at shallow levels where early Pb-Zn-bearing Mn-Fe carbonate veins are absent. A sericite 40Ar-39Ar plateau age of 17.9 ± 0.5 Ma from stage 3 veins represents the timing of the onset of stage 3 mineralization.

X-ray diffraction study of the caged magnetic compound DyFe 2 Zn 20 at low temperatures

NASA Astrophysics Data System (ADS)

Ohashi, M.; Ohashi, K.; Sawabu, M.; Miyagawa, M.; Maeta, K.; Isikawa, Y.

2018-05-01

We have carried out high-angle X-ray powder diffraction measurements of the caged magnetic compound DyFe2Zn20 at low temperature between 14 and 300 K. Even though a strong magnetic anisotropy exists in the magnetization and magnetic susceptibility due to strong exchange interaction between Fe and Dy, almost all X-ray powder diffraction peaks correspond to Bragg reflections of the cubic structural models not only at room temperature paramagnetic state but also at low temperature magnetic ordering state. The Debye temperature is obtained to be 227 K from the results of the volumetric thermal expansion coefficient, which is approximately coincident with that of CeRu2Zn20 (245 K) and that of pure Zn metal (235 K).

Dissolved trace elements in a nitrogen-polluted river near to the Liaodong Bay in Northeast China.

PubMed

Bu, Hongmei; Song, Xianfang; Guo, Fen

2017-01-15

Dissolved trace element concentrations (Ba, Fe, Mn, Si, Sr, and Zn) were investigated in the Haicheng River near to the Liaodong Bay in Northeast China during 2010. Dissolved Ba, Fe, Mn, and Sr showed significant spatial variation, whereas dissolved Fe, Mn, and Zn displayed seasonal variations. Conditions such as water temperature, pH, and dissolved oxygen were found to have an important impact on redox reactions involving dissolved Ba, Fe, and Zn. Dissolved Fe and Mn concentrations were regulated by adsorption or desorption of Fe/Mn oxyhydroxides and the effects of organic carbon complexation on dissolved Ba and Sr were found to be significant. The sources of dissolved trace elements were found to be mainly from domestic sewage, industrial waste, agricultural surface runoff, and natural origin, with estimated seasonal and annual river fluxes established as important inputs of dissolved trace elements from the Haicheng River into the Liaodong Bay or Bohai Sea. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Solution Concentration on Magnetic Ni0.5Zn0.5Fe₂O₄ Nanoparticles and Their Adsorption Behavior of Neutral Red.

PubMed

Li, Shasha; Liu, Qifeng; Lu, Rongzhu; Wu, Xiaoyang; Chen, Jian

2018-07-01

Magnetic Ni0.5Zn0.5Fe2O4 nanoparticles were prepared via the methanol combustion process, the morphology, chemical composition, microstructure and magnetic properties of them were investigated by SEM, EDX, TEM, XRD, VSM, and BET. The experimental data revealed that the solution concentration was a key factor to the Ni0.5Zn0.5Fe2O4 nanoparticles, with the solution concentration of ferric nitrate decreasing from 3.37 to 1.12 mol/L, the saturation magnetization decreased from 69.3 Am2/kg to 37.2 Am2/kg, and the average crystalline size of Ni0.5Zn0.5Fe2O4 nanoparticles decreased from 32 to 25 nm. While, with the solution concentration of ferric nitrate decreasing from 1.12 to 0.56 mol/L, the saturation magnetization increased from 37.2 Am2/kg to 104.6 Am2/kg, and the average crystalline size increased from 25 to 44 nm. The adsorption behavior of neutral red (NR) onto magnetic Ni0.5Zn0.5Fe2O4 nanoparticles was investigated by UV spectroscopy at room temperature; the adsorption kinetics data related to the adsorption of NR from aqueous solutions were in good agreement with the pseudo-second-order kinetic model in a range of initial concentration of 50-300 mg/L. By comparison of the Langmuir and Freundlich models for adsorption isotherm of NR, the Langmuir model (correlation coefficient R2 = 0.9918) could be used to evaluate the adsorption isotherm of NR onto magnetic Ni0.5Zn0.5Fe2O4 nanoparticles at room temperature, which suggested that the adsorption of NR onto magnetic Ni0.5Zn0.5Fe2O4 nanoparticles was monolayer, and the adsorption energy was constant.

Investigation of site preference of Zn doped Ba{sub 3}Co{sub 2−x}Zn{sub x}Fe{sub 24}O{sub 41} by Mössbauer spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Jung Tae; Kim, Chul Sung, E-mail: cskim@kookmin.ac.kr

2014-05-07

The polycrystalline Ba{sub 3}Co{sub 2−x}Zn{sub x}Fe{sub 24}O{sub 41} (x = 0.0, 0.5, 1.0) samples were prepared by using solid-state-reaction method. The crystal structures and magnetic properties of samples were investigated with x-ray diffractometer, vibrating sample magnetometer, and Mössbauer spectroscopy. The crystal structure of Ba{sub 3}Co{sub 2−x}Zn{sub x}Fe{sub 24}O{sub 41} (x = 0.0, 0.5, 1.0) samples was determined to be a hexagonal structure with P6{sub 3}/mmc space group at 295 K, and the saturation magnetization (M{sub s}) of Ba{sub 3}Co{sub 2−x}Zn{sub x}Fe{sub 24}O{sub 41} (x = 0.0, 0.5, 1.0) samples were found to be M{sub s} = 50.9, 53.1, 55.0 emu/g, respectively. From the temperature dependence of magnetizationmore » curves under 100 Oe between 4.2 and 740 K, we were able to observe the spin transition, and both spin transition temperature (T{sub s}) and Curie temperature (T{sub C}) decrease with increasing Zn concentration. Mössbauer spectra of all samples were obtained and analyzed at various temperatures ranging from 4.2 to 295 K. With ten-sextets for Fe sites corresponding to the Z-type hexagonal crystallographic sites, all spectra below T{sub C} were fitted by least-square method. In addition, from the site occupation numbers of Fe, calculated from the relative areas fitted to the Mössbauer spectra, we find that Zn ions preferentially occupy the tetrahedral sublattices of down sites.« less

Different Phosphorus Supplies Altered the Accumulations and Quantitative Distributions of Phytic Acid, Zinc, and Iron in Rice (Oryza sativa L.) Grains.

PubMed

Su, Da; Zhou, Lujian; Zhao, Qian; Pan, Gang; Cheng, Fangmin

2018-02-21

Development of rice cultivars with low phytic acid (lpa) is considered as a primary strategy for biofortification of zinc (Zn) and iron (Fe). Here, two rice genotypes (XS110 and its lpa mutant) were used to investigate the effect of P supplies on accumulations and distributions of PA, Zn, and Fe in rice grains by using hydroponics and detached panicle culture system. Results showed that higher P level increased grain PA concentration on dry matter basis (g/kg), but it markedly decreased PA accumulation on per grain basis (mg/grain). Meanwhile, more P supply reduced the amounts and bioavailabilities of Zn and Fe both in milled grains and in brown grains. Comparatively, lpa mutant was more susceptive to exogenous P supply than its wild type. Hence, the appropriate P fertilizer application should be highlighted in order to increase grain microelement (Zn and Fe) contents and improve nutritional quality in rice grains.

Synthesis and gas sensing properties of α-Fe(2)O(3)@ZnO core-shell nanospindles.

PubMed

Zhang, Jun; Liu, Xianghong; Wang, Liwei; Yang, Taili; Guo, Xianzhi; Wu, Shihua; Wang, Shurong; Zhang, Shoumin

2011-05-06

α-Fe(2)O(3)@ZnO core-shell nanospindles were synthesized via a two-step hydrothermal approach, and characterized by means of SEM/TEM/XRD/XPS. The ZnO shell coated on the nanospindles has a thickness of 10-15 nm. Considering that both α-Fe(2)O(3) and ZnO are good sensing materials, we have investigated the gas sensing performances of the core-shell nanocomposite using ethanol as the main probe gas. It is interesting to find that the gas sensor properties of the core-shell nanospindles are significantly enhanced compared with pristine α-Fe(2)O(3). The enhanced sensor properties are attributed to the unique core-shell nanostructure. The detailed sensing mechanism is discussed with respect to the energy band structure and the electron depletion theory. The core-shell nanostructure reported in this work provides a new path to fabricate highly sensitive materials for gas sensing applications.

Room-temperature H2S Gas Sensor Based on Au-doped ZnFe2O4 Yolk-shell Microspheres.

PubMed

Yan, Yin; Nizamidin, Patima; Turdi, Gulmira; Kari, Nuerguli; Yimit, Abliz

2017-01-01

Room-temperature type H 2 S sensing devices that use Au-doped ZnFe 2 O 4 yolk-shell microspheres as the active material have been fabricated using a solvothermal method as well as subsequent annealing and a chemical etching process. The samples are characterized using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS). The results demonstrate that the doping of Au does not change the spinel structure of the products, which were yolk-shell microspheres, while the particle size varied with the Au doping concentration. Also, the as-fabricated sensor device exhibited excellent selectivity toward H 2 S gas at the room temperature; the gas-sensing property of 2 wt% Au-doped ZnFe 2 O 4 microspheres was the best. The Au-doped ZnFe 2 O 4 yolk-shell microspheres can be promising as a sensing material for H 2 S gas detecting at room temperature.

Fe1-xZnxS ternary solid solution as an efficient Fenton-like catalyst for ultrafast degradation of phenol.

PubMed

Gao, Jing; Liu, Yutang; Xia, Xinnian; Wang, Longlu; Dong, Wanyue

2018-07-05

Heterogeneous Fenton-like system has been proved to be an promising alternative to Fenton system due to its easy separation. However, it's a challenge to design heterogeneous Fenton-like catalysts with high activity and great durability. Here, ternary solid solution Fe 1-x Zn x S were prepared via hydrothermal synthesis as heterogeneous Fenton-like catalysts. The Fe 0.7 Zn 0.3 S sample exhibited state of the art activity for yielding OH by H 2 O 2 decomposition, and the ultrafast degradation of phenol was achieved in 4 min at initial acidic condition under room temperature. The phenol degradation rate constant of Fe 0.7 Zn 0.3 S was 99 and 70 times of ZnS and FeS, respectively. Further, we show that the unique structural configuration of iron atoms, the formation of FeS 2 -pyrite with (200) plane, are responsible for the excellent activity. The intermediate products were identified by LC-MS and a possible pathway was accordingly proposed to elucidate the mechanism of phenol degradation by OH. Overall, this work provides an idea for the rational design of the relevant heterogeneous Fenton-like catalysts. Copyright © 2018 Elsevier B.V. All rights reserved.

Study of 57Fe Mössbauer effect in RFe 2Zn 20 ( R = Lu, Yb, Gd)

DOE PAGES

Bud’ko, Sergey L.; Kong, Tai; Ma, Xiaoming; ...

2015-08-04

In this document we report measurements of 57Fe Mössbauer spectra for RFe 2Zn 20 ( R = Lu, Yb, Gd) from ~ 4.5 K to room temperature. The obtained isomer shift values are very similar for all three compounds, their temperature dependence was analyzed within the Debye model and resulted in an estimate of the Debye temperatures of 450-500 K. The values of quadrupole splitting at room temperature change with the cubic lattice constant a in a linear fashion. For GdFe 2Zn 20, ferromagnetic order is seen as an appearance of a sextet in the spectra. The 57Fe site hyperfinemore » field for T → 0 was evaluated to be ~ 2.4 T.« less

Investigation of magnetic order in SmTr2Zn20 (Tr = Fe, Co, Ru) and SmTr2Cd20 (Tr = Ni, Pd)

NASA Astrophysics Data System (ADS)

Yazici, Duygu; White, B. D.; Ho, P.-C.; Kanchanavatee, N.; Huang, K.; Dilley, N. R.; Maple, M. B.

2015-03-01

Single crystals of the cage compounds Sm Tr 2Zn20 (Tr = Fe, Co, Ru) and Sm Tr 2Cd20 (Tr = Ni, Pd) have been investigated by means of electrical resistivity, magnetization, and specific heat measurements. The compounds SmFe2Zn20, SmRu2Zn20,andSmNi2Cd20 exhibit ferromagnetic order with Curie temperatures of TC = 47.4 K, 7.6 K, and 7.5 K, respectively, whereas SmPd2Cd20 is an antiferromagnet with a Néel temperature of TN = 3.4 K. No evidence for magnetic order is observed in SmCo2Zn20 down to 110 mK. The Sommerfeld coefficients γ are found to be 57 mJ/mol-K2 for SmFe2Zn20, 79.5 mJ/mol-K2 for SmCo2Zn20, 258 mJ/mol-K2 for SmRu2Zn20, 165 mJ/mol-K2 for SmNi2Cd20, and 208 mJ/mol-K2 for SmPd2Cd20. Enhanced values of Sommerfeld coefficients γ and a quadratic temperature dependence of the electrical resistivity at low temperature for SmRu2Zn20andSmPd2Cd20 suggest an enhancement of the quasiparticle masses due to hybridization between localized 4 f and conduction electron states. Research at UCSD was supported by the U.S. DOE under Grant No. DE-FG02-04-ER46105 and the U.S. NSF under Award Grant No. DMR 1206553. Research at California State University, Fresno was supported by the U.S. NSF under Grant No. DMR 1104544.

Effects of phase transformation on the microstructures and magnetostriction of Fe-Ga and Fe-Ga-Zn ferromagnetic shape memory alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Yin-Chih, E-mail: lin3312@cc.kuas.edu.tw; Lin, Chien-Feng

2015-05-07

The phase transformation and magnetostriction of bulk Fe{sub 73}Ga{sub 27} and Fe{sub 73}Ga{sub 18}Zn{sub 9} (at. %) ferromagnetic shape memory alloys (FSMs) were investigated by transmission electron microscopy (TEM), x-ray diffraction (XRD), and a magnetostrictive-meter setup. For the Fe{sub 73}Ga{sub 27} FSM alloy solution treated at 1100 °C for 4 h and quenched in ice brine, the antiphase boundary segments of the D0{sub 3} domain were observed in the A2 (disordered) matrix, and the Fe{sub 73}Ga{sub 27} FSM alloy had an optimal magnetostriction (λ{sub ‖}{sup s }= 71 × 10{sup −6} and λ{sub ⊥}{sup s }= −31 × 10{sup −6}). In Fe{sub 73}Ga{sub 27} FSM alloy as-quenched, aged at 700 °C formore » 24 h, and furnace cooled, D0{sub 3} nanoclusters underwent phase transformation to an intermediate tetragonal phase (i.e., L1{sub 0}-like martensite) via Bain distortion, and finally L1{sub 2} (Fe{sub 3}Ga) structures precipitated, as observed by TEM and XRD. The L1{sub 0}-like martensite and L1{sub 2} phases in the aged Fe{sub 73}Ga{sub 27} FSM alloy drastically decreased the magnetostriction from positive to negative (λ{sub ‖}{sup s }= −20 × 10{sup −6} and λ{sub ⊥}{sup s }= −8 × 10{sup −6}). However, in Fe{sub 73}Ga{sub 18}Zn{sub 9} FSM alloy as-quenched and aged, the phase transformation of D0{sub 3} to an intermediate tetragonal martensite phase and precipitation of L1{sub 2} structures were not found. The results indicate that the aged Fe{sub 73}Ga{sub 18}Zn{sub 9} FSM alloy maintained stable magnetostriction (λ{sub ‖}{sup s }= 36 × 10{sup −6} and λ{sub ⊥}{sup s }= −31 × 10{sup −6}). Adding Zn can improve the ferromagnetic shape memory effect of aged Fe{sub 73}Ga{sub 18}Zn{sub 9} alloy, which may be useful in application of the alloy in high temperature environments.« less

Profile of Some Trace Elements in the Liver of Camels, Sheep, and Goats in the Sudan

PubMed Central

Ibrahim, Ibrahim Abdullah; Shamat, Ali Mahmoud; Hussien, Mohammed Osman; El Hussein, Abdel Rahim Mohammed

2013-01-01

One hundred camels (Camelus dromedaries) and fifty sheep and goats being adult, male, and apparently healthy field animals were studied to provide data regarding the normal values of some hepatic trace elements. Liver samples were collected during postmortem examination, digested, and analyzed for Cu, Zn, Fe, Co, and Mn using atomic absorption spectrophotometry. The results showed that the differences in mean liver concentrations of Cu, Zn, Fe, and Co between camels, sheep, and goats were statistically significant (P < 0.05). Hepatic Cu, Fe, and Co concentrations were higher in camels than in sheep and goats. All liver samples were adequate for Fe and Co, whereas only camel liver was adequate for Cu. In camels, hepatic Zn concentration was inadequately lower than that in sheep and goats. No difference in Mn concentration was detected between camels, sheep, and goats. All liver samples were inadequate compared to free-ranging herbivores. In camels, significant correlation (r 2 = −0.207, P value = 0.04) was detected between Zn and Co, whereas in sheep significant correlation (r 2 = −0.444, P value = 0.026) was detected between Zn and Mn. No significant correlation between trace elements was detected in goats. PMID:26464909

Cross-links (XL) and Zn action in ferritin related to an H-specific site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yablonski, M.J.; Theil, E.C.

1991-03-15

Zn and subunit cross-links (F{sub 2}DNB) alter ferritin iron core formation in vivo and in vitro; the effect is observed in ferritins composed of two subunit types (H and L). Protein coats from sheep spleen ferritin (SSF) ({plus minus} XL), a model for a protein with H and L subunits (1:1), and horse spleen ferritin (HSF), a model for H deficient protein were reconstituted with Fe{sup 2+}, {plus minus} Zn, at pH 6.1 and 7.0 in order to investigate the effects of Zn and XLs on H and L subunits. Core formation was measured both as {Delta}A{sub 420} and themore » accessibility of Fe{sup 2+} to 1,10-phenanthroline. At pH 6.1, Zn decreased the {Delta}A{sub 420} in 1 min {ge} 87X (SSF) or 15X (HSF). XLs ({plus minus}Zn) decreased {Delta}A{sub 420} at 1 min similarly; at pH 7.0, Zn reduced {Delta}A{sub 420} at 1 min in SSF 3X with no effect on HSF. At both values of pH, Zn increased accessibility equally for SSF and HSF. The data indicate that : Zn has different effects on core formation measured as {Delta}A{sub 420} at 1 min or Fe{sup 2+} entry into ferritin; cross-links and Zn affects a common site involved in core formation; and Zn affects an H subunit-specific site which may involve histidine.« less

Heavy metal speciation in solid-phase materials from a bacterial sulfate reducing bioreactor using sequential extraction procedure combined with acid volatile sulfide analysis.

PubMed

Jong, Tony; Parry, David L

2004-04-01

Heavy metal mobility, bioavailability and toxicity depends largely on the chemical form of metals and ultimately determines potential for environmental pollution. For this reason, determining the chemical form of heavy metals and metalloids, immobilized in sludges by biological mediated sulfate reduction, is important to evaluate their mobility and bioavailability. A modified Tessier sequential extraction procedure (SEP), complemented with acid volatile sulfide (AVS) and simultaneous extracted metals (SEM) measurements, were applied to determine the partitioning of five heavy metals (defined as Fe, Ni, Zn and Cu, and the metalloid As) in anoxic solid-phase material (ASM) from an anaerobic, sulfate reducing bioreactor into six operationally defined fractions. These fractions were water soluble, exchangeable, bound to carbonates (acid soluble), bound to Fe-Mn oxides (reducible), bound to organic matter and sulfides (oxidizable) and residual. It was found that the distribution of Fe, Ni, Zn, Cu and As in ASM was strongly influenced by its association with the above solid fractions. The fraction corresponding to organic matter and sulfides appeared to be the most important scavenging phases of As, Fe, Ni, Zn and Cu in ASM (59.8-86.7%). This result was supported by AVS and SEM (Sigma Zn, Ni and Cu) measurements, which indicated that the heavy metals existed overwhelmingly as sulfides in the organic matter and sulfide fraction. A substantial amount of Fe and Ni at 16.4 and 20.1%, respectively, were also present in the carbonate fraction, while an appreciable portion of As (18.3%) and Zn (19.4%) was bound to Fe-Mn oxides. A significant amount of heavy metals was also associated with the residual fraction, ranging from 2.1% for Zn to 18.8% for As. Based on the average total extractable heavy metal (TEHM) values, the concentration of heavy metals in the ASM was in the order of Cu > Ni > Zn > Fe > As. If the mobility and bioavailability of heavy metals are assumed to be related to their solubility and chemical forms, and that they decrease with each successive extraction step, then the apparent mobility and bioavailability of these five heavy metals in ASM increase in the order of Cu < As < Ni < Fe < Zn. The SEM/AVS ratio was less than one in eight replicate ASM samples, indicating that the ASM was non-toxic with regards to having a low probability of bioavailable metals in the pore water.

Broiler litter as a micronutrient source for cotton: concentrations in plant parts.

PubMed

Tewolde, H; Sistani, K R; Rowe, D E

2005-01-01

Analytically, poultry litter contains nearly all essential micronutrients but the extent of phytoavailability of these nutrients and whether cotton (Gossypium hirsutum L.) and other crop plants can receive adequate amounts of these nutrients from litter is not fully known. The objective of this research was to determine whether cotton receives sufficient amounts of Fe, Cu, Mn, and Zn from litter and estimate the efficiency of cotton in extracting these metal nutrients from litter in the absence of any other source of the micronutrients. The greenhouse research used plastic pots filled with approximately 11 kg of a 2:1 (v/v) sand to vermiculite growing mix. Cotton (cv. Stoneville 474) was grown in the pots fertilized with broiler litter at rates of 30, 60, 90, or 120 g pot(-1) in a factorial combination with four supplemental nutrient solution (NS) treatments. The nutrient solutions consisted of full Hoagland's nutrient solution (NS-full); a solution of the macronutrients N, P, K, Ca, and Mg (NS-macro); a solution of the micronutrients Fe, Zn, Mn, Cu, B, and Mo (NS-micro); and water (NS-none). Based on tissue nutrient analysis, a one-time broiler litter application supplied adequate amounts of Fe, Cu, and Mn to bring the concentration of these nutrients in upper leaves within published sufficiency ranges. Zinc, with <17 mg kg(-1) concentration in the upper leaves, was the only micronutrient below the established sufficiency range regardless of the rate of applied litter. Cotton extracted Fe and Mn more efficiently than Cu or Zn, removing as much as 8.8% of Fe and 7.2% of Mn supplied by 30 g litter pot(-1). In contrast, the extraction efficiency was 1.7% for Cu and 1.9% for Zn. Roots accumulated 58% of the total absorbed Fe and 64% of Cu, and leaves accumulated 32% of the Fe and only 13% of the Cu supplied by litter. In contrast, only 16% of the total absorbed Mn and 23% of Zn accumulated in roots while leaves accumulated 64% of the total Mn and 37% of Zn. These results demonstrate that broiler litter is a valuable source of the metal nutrients supplying Fe, Cu, and Mn in full and Zn in part, but a very large fraction of the litter-supplied metal nutrients remained in the growing mix.

Coordination polymer-derived nano-sized zinc ferrite with excellent performance in nitro-explosive detection.

PubMed

Singha, Debal Kanti; Mahata, Partha

2017-08-29

Herein, a mixed metal coordination polymer, {(H 2 pip)[Zn 1/3 Fe 2/3 (pydc-2,5) 2 (H 2 O)]·2H 2 O} 1 {where H 2 pip = piperazinediium and pydc-2,5 = pyridine-2,5-dicarboxylate}, was successfully synthesized using a hydrothermal technique. To confirm the structure and phase purity of 1, single crystals of an isomorphous pure Fe compound, {(H 2 pip)[Fe(pydc-2,5) 2 (H 2 O)]·2H 2 O} 1a, were synthesized based on similar synthetic conditions. Single crystal X-ray data of 1a confirmed the one-dimensional anionic metal-organic coordination polymer hydrogen bonded with protonated piprazine (piperazinediium) and lattice water molecules. The phase purity of 1 and 1a were confirmed via powder X-ray diffraction. Compound 1 was systematically characterized using IR, TGA, SEM, and EDX elemental mapping analysis. Compound 1 was used as a single source precursor for the preparation of nano-sized ZnFe 2 O 4 via thermal decomposition. The as-obtained ZnFe 2 O 4 was fully characterized using PXRD, SEM, TEM, and EDX elemental mapping analysis. It was found that ZnFe 2 O 4 was formed in its pure form with particle size in the nano-dimension. The aqueous dispersion of nano-sized ZnFe 2 O 4 exhibits a strong emission at 402 nm upon excitation at 310 nm. This emissive property was employed for luminescence-based detection of nitroaromatic explosives in an aqueous medium through luminescence quenching for the first time. Importantly, selective detections have been observed for phenolic nitroaromatics based on differential luminescence quenching behaviour along with a detection limit of 57 ppb for 2,4,6-trinitrophenol (TNP) in water.

Determination of some heavy metals (Fe, Cu, Zn and Pb) in blood by total reflection X-ray fluorescence

NASA Astrophysics Data System (ADS)

Bounakhla, M.; Doukkali, A.; Lalaoui, K.; Aguenaou, H.; Mokhtar, N.; Attrassi, B.

2003-05-01

The main purpose of this study is the interaction between nutrition (micronutrients heavy metals: Fe, Zn, Cu) and toxic heavy metals such as Pb in blood of children living in Gharb region of Morocco. This region receives all pollution carried by the Sebou river coming mainly from industrial activities. A rapid and simple analytical procedure was used for the determination of Fe, Cu and Zn trace amounts in blood by total-reflection X-ray fluorescence technique. This method is an energy dispersive XRF technique in a special geometry of primary beam, sample and detector. The sample is deposited on a plane polished surface of a suitable reflector material. It is presented as a few drops (25 μl) from a solution of blood digested in a mixture of HNO3 and H2O2 using a microwaves accelerated reaction system. The accuracy of measurements has been investigated by using certified materials. The concentration of Cu was found to be normal in all samples (\\cong1 ppm) which ruled out any interaction between this element and the others. On the other hand, amounts of Fe and Zn are very variables, suggesting an interaction between Fe and Zn. However, amounts of Pb in blood are inferior to 50 ppb, suggesting that no interaction exist with this metal and micronutrients.

Magnetic solid-phase extraction using nanoporous three dimensional graphene hybrid materials for high-capacity enrichment and simultaneous detection of nine bisphenol analogs from water sample.

PubMed

Wang, Lingling; Zhang, Zhenzhen; Zhang, Jing; Zhang, Lei

2016-09-09

The synthesis of a magnetic nanoporous three dimensional graphene (3DG)/ZnFe2O4 composite has been achieved. Through formation of graphene hydrogel, ZnFe2O4 magnetic particles was successfully introduced into the nanoporous 3DG, resulting in a magnetic porous carbon material. The morphology, structure, and magnetic behavior of the as-prepared 3DG/ZnFe2O4 were characterized by using the techniques of SEM, XRD, BET, VSM, FTIR, Raman and TGA. The 3DG/ZnFe2O4 has a high specific surface area and super paramagnetism. Its performance was evaluated by the magnetic solid-phase extraction of nine bisphenol analogs (BPs) from water samples followed by HPLC analysis, and showed excellent adsorption capability for the nine target compounds. Under optimized condition, the lower method detection limits (0.05-0.18ngmL(-1)), the higher enrichment factors (800 fold) and good recoveries (95.1-103.8%) with relative standard deviation (RSD) values less than 6.2% were achieved. The results indicated that the developed method based on the use of 3DG/ZnFe2O4 as the magnetic adsorbent has the advantages of convenience and high efficiency, and can be successfully applied to detect the nine BPs in real water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Assessing bioavailability levels of metals in effluent-affected rivers: effect of Fe(III) and chelating agents on the distribution of metal speciation.

PubMed

Han, Shuping; Naito, Wataru; Masunaga, Shigeki

To assess the effects of Fe(III) and anthropogenic ligands on the bioavailability of Ni, Cu, Zn, and Pb, concentrations of bioavailable metals were measured by the DGT (diffusive gradients in thin films) method in some urban rivers, and were compared with concentrations calculated by a chemical equilibrium model (WHAM 7.0). Assuming that dissolved Fe(III) (<0.45 μm membrane filtered) was in equilibrium with colloidal iron oxide, the WHAM 7.0 model estimated that bioavailable concentrations of Ni, Cu, and Zn were slightly higher than the corresponding values estimated assuming that dissolved Fe(III) was absent. In contrast, lower levels of free Pb were predicted by the WHAM 7.0 model when dissolved Fe(III) was included. Estimates showed that most of the dissolved Pb was present as colloidal iron-Pb complex. Ethylene-diamine-tetra-acetic acid (EDTA) concentrations at sampling sites were predicted from the relationship between EDTA and the calculated bioavailable concentration of Zn. When both colloidal iron and predicted EDTA concentrations were included in the WHAM 7.0 calculations, dissolved metals showed a strong tendency to form EDTA complexes, in the order Ni > Cu > Zn > Pb. With the inclusion of EDTA, bioavailable concentrations of Ni, Cu, and Zn predicted by WHAM 7.0 were different from those predicted considering only humic substances and colloidal iron.

Assessment of dietary intake and mineral status in pregnant women.

PubMed

Kocyłowski, Rafał; Lewicka, Iwona; Grzesiak, Mariusz; Gaj, Zuzanna; Sobańska, Anna; Poznaniak, Joanna; von Kaisenberg, Constantin; Suliburska, Joanna

2018-06-01

To evaluate the dietary intake of pregnant women and their nutritional status of Ca, Mg, Fe, Zn, and Cu, as the nutritional status of pregnant women is an important factor for the proper progression of a pregnancy and the development and health of the foetus. The study was conducted on 108 pregnant women ages 18-42, at 6-32 weeks of gestation. We used a questionnaire and a 24-h recall nutrition interview. Hair samples were taken for testing and the level of each mineral was assessed using atomic absorption spectrometry. The results were analysed using the Dietetyk and Statistica 10 software. Low levels of Fe, Zn, Ca, Mg, vitamin D, and folic acid intake were seen in the pregnant women, with the use of dietary supplements significantly increasing their intake of Fe, Zn, and folic acid. The concentration of zinc and magnesium in the women's hair was shown to be affected by their age and, in the case of magnesium, by the week of pregnancy. It was observed that the diet of pregnant women is characterised by low levels of Fe, Zn, Ca, Mg, vitamin D, and folic acid. Dietary supplementation with vitamins and minerals significantly increases the daily Fe and folic acid intake in pregnant women. The concentration of Zn and Mg in hair depends on the age of pregnant women and Mg level in the hair of women decreases during pregnancy.

A general approach for MFe2O4 (M = Zn, Co, Ni) nanorods and their high performance as anode materials for lithium ion batteries

NASA Astrophysics Data System (ADS)

Wang, Nana; Xu, Huayun; Chen, Liang; Gu, Xin; Yang, Jian; Qian, Yitai

2014-02-01

MFe2O4 (M = Zn, Co, Ni) nanorods are synthesized by a template-engaged reaction, with β-FeOOH nanorods as precursors which are prepared by a hydrothermal method. The final products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). The electrochemical properties of the MFe2O4 (M = Zn, Co, Ni) nanorods are tested as the anode materials for lithium ion batteries. The reversible capacities of 800, 625 and 520 mAh g-1 are obtained for CoFe2O4, ZnFe2O4 and NiFe2O4, respectively, at the high current density of 1000 mA g-1 even after 300 cycles. The superior lithium-storage performances of MFe2O4 (M = Zn, Co, Ni) nanorods can be attributed to the one-dimensional (1D) nanostructure, which can shorten the diffusion paths of lithium ions and relax the strain generated during electrochemical cycling. These results indicate that this method is an effective, simple and general way to prepare good electrochemical properties of 1D spinel Fe-based binary transition metal oxides. In addition, the impact of different reaction temperatures on the electrochemical properties of MFe2O4 nanorods is also investigated.

Soluble Supercapacitors: Large and Reversible Charge Storage in Colloidal Iron-Doped ZnO Nanocrystals.

PubMed

Brozek, Carl K; Zhou, Dongming; Liu, Hongbin; Li, Xiaosong; Kittilstved, Kevin R; Gamelin, Daniel R

2018-05-09

Colloidal ZnO semiconductor nanocrystals have previously been shown to accumulate multiple delocalized conduction-band electrons under chemical, electrochemical, or photochemical reducing conditions, leading to emergent semimetallic characteristics such as quantum plasmon resonances and raising prospects for application in multielectron redox transformations. Here, we demonstrate a dramatic enhancement in the capacitance of colloidal ZnO nanocrystals through aliovalent Fe 3+ -doping. Very high areal and volumetric capacitances (33 μF cm -2 , 233 F cm -3 ) are achieved in Zn 0.99 Fe 0.01 O nanocrystals that rival those of the best supercapacitors used in commercial energy-storage devices. The redox properties of these nanocrystals are probed by potentiometric titration and optical spectroscopy. These data indicate an equilibrium between electron localization by Fe 3+ dopants and electron delocalization within the ZnO conduction band, allowing facile reversible charge storage and removal. As "soluble supercapacitors", colloidal iron-doped ZnO nanocrystals constitute a promising class of solution-processable electronic materials with large charge-storage capacity attractive for future energy-storage applications.

Bimetallic iron–iron and iron–zinc complexes of the redox-active ONO pincer ligand† †Electronic supplementary information (ESI) available: Complete experimental procedures and magnetic measurements and models. CCDC 1417565–1417567. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5sc03006d Click here for additional data file. Click here for additional data file.

PubMed Central

Wong, Janice L.; Higgins, Robert F.; Bhowmick, Indrani; Cao, David Xi; Szigethy, Géza; Ziller, Joseph W.

2016-01-01

A new bimetallic platform comprising a six-coordinate Fe(ONO)2 unit bound to an (ONO)M (M = Fe, Zn) has been discovered ((ONOcat)H3 = bis(3,5-di-tert-butyl-2-phenol)amine). Reaction of Fe(ONO)2 with either (ONOcat)Fe(py)3 or with (ONOq)FeCl2 under reducing conditions led to the formation of the bimetallic complex Fe2(ONO)3, which includes unique five- and six-coordinate iron centers. Similarly, the reaction of Fe(ONO)2 with the new synthon (ONOsq˙)Zn(py)2 led to the formation of the heterobimetallic complex FeZn(ONO)3, with a six-coordinate iron center and a five-coordinate zinc center. Both bimetallic complexes were characterized by single-crystal X-ray diffraction studies, solid-state magnetic measurements, and multiple spectroscopic techniques. The magnetic data for FeZn(ONO)3 are consistent with a ground state S = 3/2 spin system, generated from a high-spin iron(ii) center that is antiferromagnetically coupled to a single (ONOsq˙)2– radical ligand. In the case of Fe2(ONO)3, the magnetic data revealed a ground state S = 7/2 spin system arising from the interactions of one high-spin iron(ii) center, one high-spin iron(iii) center, and two (ONOsq˙)2– radical ligands. PMID:28808535

Quantitative bioimaging of trace elements in the human lens by LA-ICP-MS.

PubMed

Konz, Ioana; Fernández, Beatriz; Fernández, M Luisa; Pereiro, Rosario; González-Iglesias, Héctor; Coca-Prados, Miguel; Sanz-Medel, Alfredo

2014-04-01

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used for the quantitative imaging of Fe, Cu and Zn in cryostat sections of human eye lenses and for depth profiling analysis in bovine lenses. To ensure a tight temperature control throughout the experiments, a new Peltier-cooled laser ablation cell was employed. For quantification purposes, matrix-matched laboratory standards were prepared from a pool of human lenses from eye donors and spiked with standard solutions containing different concentrations of natural abundance Fe, Cu and Zn. A normalisation strategy was also carried out to correct matrix effects, lack of tissue homogeneity and/or instrumental drifts using a thin gold film deposited on the sample surface. Quantitative images of cryo-sections of human eye lenses analysed by LA-ICP-MS revealed a homogeneous distribution of Fe, Cu and Zn in the nuclear region and a slight increase in Fe concentration in the outer cell layer (i.e. lens epithelium) at the anterior pole. These results were assessed also by isotope dilution mass spectrometry, and Fe, Cu and Zn concentrations determined by ID-ICP-MS in digested samples of lenses and lens capsules.

Effect of Zn addition on structural, magnetic properties, antistructural modeling of Co1-xZnxFe2O4 nano ferrite

NASA Astrophysics Data System (ADS)

Raghuvanshi, S.; Kane, S. N.; Tatarchuk, T. R.; Mazaleyrat, F.

2018-05-01

Effect of Zn addition on cationic distribution, structural properties, magnetic properties, antistructural modeling of nanocrystalline Co1-xZnxFe2O4 (0.08 ≤ x ≤ 0.56) ferrite is reported. XRD confirms the formation of single phase cubic spinel nano ferrites with average grain diameter ranging between 41.2 - 54.9 nm. Coercivity (Hc), anisotropy constant (K1) decreases with Zn addition, but experimental, theoretical saturation magnetization (Ms, Ms(t)) increases upto x = 0.32, then decreases, attributed to the breaking of collinear ferrimagnetic phase. Variation of magnetic properties is correlated with cationic distribution. A new antistructural modeling for describing active surface centers is discussed to explain change in concentration of donor's active centers Zn'B, Co'B, acceptor's active centers Fe*A are explained.

The Role of Magmatic Volatile Input, Near-surface Seawater Entrainment and Sulfide Deposition in Regulating Metal Concentrations Within Manus Basin Hydrothermal Systems

NASA Astrophysics Data System (ADS)

Craddock, P. R.; Tivey, M. K.; Seewald, J. S.; Rouxel, O.; Bach, W.

2007-12-01

Analyses of Fe, Mn, Cu, Zn, Pb, Ag, Cd, Co and Sb in vent fluid samples from four hydrothermal systems in the Manus back-arc basin, Papua New Guinea, were carried out by ICP-MS. Vienna Woods is located on the well- defined, basalt-dominated Manus Spreading Center, while the other systems are hosted in felsic volcanics on the Pual Ridge (PACMANUS), within a caldera (DESMOS), and on volcanic cones (SuSu Knolls). Metal concentrations were coupled with other fluid data (pH, SO4, Ca, H2S) to discriminate effects of deep- seated water-rock reaction and magmatic volatile input from near surface seawater entrainment, mixing, and consequent mineral precipitation and metal remobilization. Both magmatic volatile input (e.g. SO2, HCl, HF) and sulfide precipitation can increase fluid acidity and thus affect the aqueous mobility of metals. At Vienna Woods, 280°C end-member (Mg = 0) fluids have high pH (>4.2) and low metal contents (Fe <160 uM, Cu <10 uM, Zn <40 uM) relative to most mid-ocean ridge (MOR) vent fluids. The high pH and lack of evidence for magmatic volatile input are consistent with fluid compositions regulated by subsurface seawater- basalt/andesite reactions. Despite low aqueous Zn concentrations, Zn-rich (wurtzite-lined) chimneys are common at Vienna Woods active vents, reflecting deposition from fluids characterized by low Fe and Cu and high pH. At PACMANUS, black smoker fluids (T >300°C, pH ~ 2.7) are enriched in sulfide-forming metals by an order of magnitude relative to Vienna Woods fluids. Enrichments at PACMANUS reflect efficient leaching of metals at low pH, with the lower pH likely a result of input of magmatic volatiles. In addition, some vents fluids show clear evidence for seawater entrainment, subsurface precipitation of Cu-Fe-sulfides and preferential remobilization of Zn-sulfides (lower T, non-zero Mg, lower Fe, Cu, H2S and pH (2.3-2.4), but higher Zn, Pb, Cd and Ag, compared to black smokers). The higher metal concentrations and lower pH of fluids from PACMANUS versus Vienna Woods are reflected in chimney deposit compositions with Zn-poor sulfide linings composed of Cu-Fe-sulfides and As-Sb-sulfosalts in high T and lower T vents, respectively. At DESMOS caldera, fluid data suggest extensive magmatic volatile input (e.g. pH <1.5, elevated F and SO4) but lesser reaction with the basement felsic rocks (low Li, Rb, Mn). Sampled "acid-sulfate" fluids are low temperature (T ~180°C) with Mg >46 mM, and very high concentrations of some metals for these Mg concentrations (Fe >5 mM, Zn >50 - 400 uM). At SuSu Knolls, vent fluid compositions similar to those at both PACMANUS and DESMOS are observed. Smoker fluids have high but variable metal concentrations of similar magnitude to PACMANUS. Acid-sulfate fluids from North Su have low pH (<2), non-zero Mg (>40 mM), and high Fe and Zn concentrations, similar to DESMOS fluids. At SuSu Knolls, fluid compositions reflect either high temperature water-rock reaction (smoker fluids) or magmatic volatile input (acid-sulfate fluids). As at PACMANUS, chimney deposits that correspond to venting fluids are Cu-Fe-As-Sb-rich and Zn-poor, likely reflecting deposition from low pH, high Cu and Fe fluids.

Experimental study of THz electro-optical sampling crystals ZnSe, ZnTe and GaP

NASA Astrophysics Data System (ADS)

Zhukova, M.; Makarov, E.; Putilin, S.; Tsypkin, A.; Chegnov, V.; Chegnova, O.; Bespalov, V.

2017-11-01

The application of optoelectronic techniques to the generation and detection of THz radiation is now well established. Wide gap semiconductor crystals of groups II-VI, III-V and III-VI are abundantly used. However, some limitations are occurred while using powerful laser systems. In this paper we introduce experimental results of two-photon absorption (2PA) in ZnSe, ZnTe and GaP studied with femtosecond pump-probe supercontinuum spectroscopy. Using of supercontinuum helps us to measure 2PA absorption dynamics and nonlinear index of refraction in wide frequency ranges. Besides influence of Fe concentration in ZnSe:Fe crystals on transmitted THz radiation is described.

Novel ZnO/MgO/Fe2O3 composite optomagnetic nanoparticles.

PubMed

Kamińska, I; Sikora, B; Fronc, K; Dziawa, P; Sobczak, K; Minikayev, R; Paszkowicz, W; Elbaum, D

2013-05-15

A facile sol-gel synthesis of novel ZnO/MgO/Fe2O3 nanoparticles (NPs) is reported and their performance is compared to that of ZnO/MgO. Powder x-ray diffraction (XRD) patterns reveal the crystal structure of the prepared samples. The average particle size of the sample was found to be 4.8 nm. The optical properties were determined by UV-vis absorption and fluorescence measurements. The NPs are stable in biologically relevant solutions (phosphate buffered saline (PBS), 20 mM, pH = 7.0) contrary to ZnO/MgO NPs which degrade in the presence of inorganic phosphate. Superparamagnetic properties were determined with a superconducting quantum interference device (SQUID). Biocompatible and stable in PBS ZnO/MgO/Fe2O3 core/shell composite nanocrystals show luminescent and magnetic properties confined to a single NP at room temperature (19-24 ° C), which may render the material to be potentially useful for biomedical applications.

Platinum-free catalysts for low temperature fuel cells

NASA Astrophysics Data System (ADS)

Lastovina, Tatiana; Pimonova, Julia; Budnyk, Andriy

2017-04-01

In this work, we have successfully prepared Zn/Co-N/C and Zn/Co-Fe/N/C composites, both derived from single zeolitic imidazolate framework (ZIF) precursor Zn/Co-ZIF containing equivalent quantities of Zn and Co metal sites. The composites were formed by pyrolysis of the precursor at 700 °C in inert gas atmosphere as such and after mixing it with Fe(II) salt and 1,10-phenontraline in ethanol. Catalytic tests for oxygen reduction reaction (ORR) in electrochemical cell demonstrated promising results allowing us to consider these composites as potential Pt-free catalysts for low temperature fuel cells.

Removal of phosphorus by the core-shell bio-ceramic/Zn-layered double hydroxides (LDHs) composites for municipal wastewater treatment in constructed rapid infiltration system.

PubMed

Zhang, Xiangling; Guo, Lu; Huang, Hualing; Jiang, Yinghe; Li, Meng; Leng, Yujie

2016-06-01

Constructed rapid infiltration systems (CRIS) are a reasonable option for treating wastewater, owing to their simplicity, low cost and low energy consumption. Layered double hydroxides (LDHs), novel materials with high surface area and anion exchange capacity, faced the problem of the application in CRIS due to the powdered form. To overcome this shortcoming, Zn-LDHs (FeZn-LDHs, CoZn-LDHs, AlZn-LDHs) were prepared by co-precipitation method and in-situ coated on the surface of the natural bio-ceramic to synthesize the core-shell bio-ceramic/Zn-LDHs composites. Characterization by Scanning Electron Microscope (SEM) and X-ray Fluorescence Spectrometer (XRFS) indicated that the Zn-LDHs were successful loaded on the natural bio-ceramic. Column tests experiments indicated that the bio-ceramic/Zn-LDHs efficiently enhanced the removal performance of phosphorus. The efficiently removal rates of bio-ceramic/FeZn-LDHs were 71.58% for total phosphorous (TP), 74.91% for total dissolved phosphorous (TDP), 82.31% for soluble reactive phosphorous (SRP) and 67.58% for particulate phosphorus (PP). Compared with the natural bio-ceramic, the average removal rates were enhanced by 32.20% (TP), 41.33% (TDP), 49.06% (SRP) and 10.50% (PP), respectively. Adsorption data of phosphate were better described by the Freundlich model for the bio-ceramic/Zn-LDHs and natural bio-ceramic, except for the bio-ceramic/CoZn-LDHs. The maximum adsorption capacity of bio-ceramic/AlZn-LDHs (769.23 mg/kg) was 1.77 times of the natural bio-ceramic (434.78 mg/kg). The effective desorption of phosphate could achieve by using a mixed solution of 5 M NaCl + 0.1 M NaOH, it outperformed the natural bio-ceramic of 18.95% for FeZn-LDHs, 7.59% for CoZn-LDHs and 12.66% for AlZn-LDHs. The kinetic data of the bio-ceramic/Zn-LDHs were better described by the pseudo-second-order equation. Compared the removal amount of phosphate by the natural bio-ceramic, the physical effects were improved little, but the chemical effects were enhanced for 112.49% for FeZn-LDHs, 111.89% for CoZn-LDHs and 122.67% for AlZn-LDHs. Therefore, the way of coating Zn-LDHs on the bio-ceramic efficiently improved the chemical effects in phosphate removal, supporting that it can use as potential substrates for the removal of phosphorus in CRIS. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multiple heavy metals extraction and recovery from hazardous electroplating sludge waste via ultrasonically enhanced two-stage acid leaching.

PubMed

Li, Chuncheng; Xie, Fengchun; Ma, Yang; Cai, Tingting; Li, Haiying; Huang, Zhiyuan; Yuan, Gaoqing

2010-06-15

An ultrasonically enhanced two-stage acid leaching process on extracting and recovering multiple heavy metals from actual electroplating sludge was studied in lab tests. It provided an effective technique for separation of valuable metals (Cu, Ni and Zn) from less valuable metals (Fe and Cr) in electroplating sludge. The efficiency of the process had been measured with the leaching efficiencies and recovery rates of the metals. Enhanced by ultrasonic power, the first-stage acid leaching demonstrated leaching rates of 96.72%, 97.77%, 98.00%, 53.03%, and 0.44% for Cu, Ni, Zn, Cr, and Fe respectively, effectively separated half of Cr and almost all of Fe from mixed metals. The subsequent second-stage leaching achieved leaching rates of 75.03%, 81.05%, 81.39%, 1.02%, and 0% for Cu, Ni, Zn, Cr, and Fe that further separated Cu, Ni, and Zn from mixed metals. With the stabilized two-stage ultrasonically enhanced leaching, the resulting over all recovery rates of Cu, Ni, Zn, Cr and Fe from electroplating sludge could be achieved at 97.42%, 98.46%, 98.63%, 98.32% and 100% respectively, with Cr and Fe in solids and the rest of the metals in an aqueous solution discharged from the leaching system. The process performance parameters studied were pH, ultrasonic power, and contact time. The results were also confirmed in an industrial pilot-scale test, and same high metal recoveries were performed. Copyright 2010 Elsevier B.V. All rights reserved.

Synthesis, structural and magnetic behavior studies of Zn-Al substituted cobalt ferrite nanoparticles

NASA Astrophysics Data System (ADS)

Zare, Samad; Ati, Ali A.; Dabagh, Shadab; Rosnan, R. M.; Othaman, Zulkafli

2015-06-01

A series of nano-sized Zn-Al substituted cobalt ferrite Co(1-x)Zn(x)Fe2-xAlxO4 with 0.0 ⩽ x ⩽ 1.0 have been synthesized by chemical co-precipitation technique. The XRD spectra revealed the single phase spinel structure of Co(1-x)Zn(x)Fe2-xAlxO4 with average size of nanoparticles are estimated to be 17-30 nm. These are small enough to achieve the suitable signal to noise ratio, which is important in the high-density recording media. The FTIR spectra show the characteristic of two strong absorption bands at 560-600 cm-1 corresponds to the intrinsic stretching vibrations of the metal at the tetrahedral site and lowest band is observed at 370-410 cm-1 corresponds to octahedral site. The crystalline structures of nanoparticles composite were characterized by Field Emission Scanning Electron Microscopy (FE-SEM). The magnetic properties such as saturation magnetization, remanence magnetization, and coercivity were calculated from the hysteresis loops. Saturation magnetization were found to increase up to x = 0.4 while remanence magnetization and coercivity continuously decrease with increasing Zn-Al concentration. The stability in coercivity while increase in saturation magnetization confirms that the Co0.6Zn0.4Fe1.6Al0.4O4 ferrite sample is suitable for applications in high-density recording media.

Chemical fractionation of heavy metals in urban soils of Guangzhou, China.

PubMed

Lu, Ying; Zhu, Feng; Chen, Jie; Gan, Haihua; Guo, Yanbiao

2007-11-01

Knowledge of the total concentration of heavy metals is not enough to fully assess the environmental impact of urban soils. For this reason, the determination of metal speciation is important to evaluate their environment and the mobilization capacity. Sequential extraction technique proposed by the former European Community Bureau of Reference (BCR) was used to speciate Cd, Cu, Fe, Mn, Ni, Pb, and Zn in urban soils from Guangzhou into four operationally defined fractions: HOAc extractable, reducible, oxidizable, and residual. The Cu, Fe, Ni, and Zn were predominantly located in the residual fraction, Pb in the reducible fraction, and Cd and Mn within the HOAc extractable fraction. The order of Cd in each fraction was generally HOAc extractable > reducible > residual > oxidizable; Cu and Fe were residual > reducible > oxidizable > HOAc extractable; Mn was HOAc extractable > residual > reducible > oxidizable; Ni and Zn were residual > reducible > HOAc extractable > oxidizable; and Pb was reducible > residual > oxidizable > HOAc extractable. Cadmium was identified as being the most mobile of the elements, followed by Mn, Zn, Ni, Cu, Pb and Fe. Iron-Mn oxides can play an important role in binding Cd, Cu, Ni, Pb, and Zn and in decreasing their proportion associated with the residual fraction in the soils. With total concentrations of Cd, Cu, Ni, Pb, Zn, and Mn increase, these metals more easily release and may produce more negative effects on the urban environment.

Oxygen and sulfur isotope systematics of sulfate produced during abiotic and bacterial oxidation of sphalerite and elemental sulfur

USGS Publications Warehouse

Balci, N.; Mayer, B.; Shanks, Wayne C.; Mandernack, K.W.

2012-01-01

Studies of metal sulfide oxidation in acid mine drainage (AMD) systems have primarily focused on pyrite oxidation, although acid soluble sulfides (e.g., ZnS) are predominantly responsible for the release of toxic metals. We conducted a series of biological and abiotic laboratory oxidation experiments with pure and Fe-bearing sphalerite (ZnS & Zn 0.88Fe 0.12S), respectively, in order to better understand the effects of sulfide mineralogy and associated biogeochemical controls of oxidation on the resultant ?? 34S and ?? 18O values of the sulfate produced. The minerals were incubated in the presence and absence of Acidithiobacillus ferrooxidans at an initial solution pH of 3 and with water of varying ?? 18O values to determine the relative contributions of H 2O-derived and O 2-derived oxygen in the newly formed sulfate. Experiments were conducted under aerobic and anaerobic conditions using O 2 and Fe(III) aq as the oxidants, respectively. Aerobic incubations with A. ferrooxidans, and S o as the sole energy source were also conducted. The ??34SSO4 values from both the biological and abiotic oxidation of ZnS and ZnS Fe by Fe(III) aq produced sulfur isotope fractionations (??34SSO4-ZnS) of up to -2.6???, suggesting the accumulation of sulfur intermediates during incomplete oxidation of the sulfide. No significant sulfur isotope fractionation was observed from any of the aerobic experiments. Negative sulfur isotope enrichment factors (??34SSO4-ZnS) in AMD systems could reflect anaerobic, rather than aerobic pathways of oxidation. During the biological and abiotic oxidation of ZnS and ZnS Fe by Fe(III) aq all of the sulfate oxygen was derived from water, with measured ?? 18OSO 4-H 2O values of 8.2??0.2??? and 7.5??0.1???, respectively. Also, during the aerobic oxidation of ZnS Fe and S o by A. ferrooxidans, all of the sulfate oxygen was derived from water with similar measured ?? 18OSO 4-H 2O values of 8.1??0.1??? and 8.3??0.3???, respectively. During biological oxidation of ZnS by O 2, an estimated 8% of sulfate-oxygen was derived from O 2, which is enriched in 18O relative to water, thus resulting in a larger apparent ?? 18OSO 4-H 2O value of 9.5???. Based on the data presented we hypothesize that the similar ?? 18OSO 4-H 2O values of ~8??? from all of the aerobic and anaerobic experiments result from a common rate-limiting step that involves oxygen isotopic exchange between a sulfite (SO3-) intermediate and H 2O. Our results indicate that the ??18OSO4 values cannot be used to distinguish biological and abiotic, nor aerobic versus anaerobic, pathways of sphalerite oxidation. However, the ?? 18OSO 4-H 2O values of ~8??? measured here are distinctly higher than ?? 18OSO 4-H 2O values of ~4??? previously reported for pyrite oxidation indicating the influence of sulfide mineralogy on measured ?? 18OSO 4 values. ?? 2011 Elsevier Ltd.

Superparamagnetic MFe2O 4 (M = Ni, Co, Zn, Mn) nanoparticles: synthesis, characterization, induction heating and cell viability studies for cancer hyperthermia applications.

PubMed

Sabale, Sandip; Jadhav, Vidhya; Khot, Vishwajeet; Zhu, Xiaoli; Xin, Meiling; Chen, Hongxia

2015-03-01

Superparamagnetic nanoferrites are prepared by simple and one step refluxing in polyol synthesis. The ferrite nanoparticles prepared by this method exhibit particle sizes below 10 nm and high degree of crystallinity. These ferrite nanoparticles are compared by means of their magnetic properties, induction heating and cell viability studies for its application in magnetic fluid hyperthermia. Out of all studied nanoparticles in present work, only ZnFe2O4 and CoFe2O4 MNPs are able to produce threshold hyperthermia temperature. This rise in temperature is discussed in detail in view of their magneto-structural properties. Therefore ZnFe2O4 and CoFe2O4 MNPs with improved stability, magnetic induction heating and cell viability are suitable candidates for magnetic hyperthermia.

Inert anode containing oxides of nickel, iron and zinc useful for the electrolytic production of metals

DOEpatents

Ray, Siba P.; Weirauch, Jr., Douglas A.; Liu, Xinghua

2002-01-01

An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe.sub.2 O.sub.3 and ZnO. The inert anode composition may comprise the following mole fractions of NiO, Fe.sub.2 O.sub.3 and ZnO: 0.2 to 0.99 NiO; 0.0001 to 0.8 Fe.sub.2 O.sub.3 ; and 0.0001 to 0.3 ZnO. The inert anode may optionally include other oxides and/or at least one metal phase, such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The Ni--Fe--Co--O ceramic material exhibits very low solubility in Hall cell baths used to produce aluminum.

Magnetic and dielectric properties in the UHF frequency band of half-dense Ni-Zn-Co ferrites ceramics with Fe-excess and Fe-deficiency

NASA Astrophysics Data System (ADS)

Mattei, Jean-Luc; Souriou, David; Chevalier, Alexis

2018-02-01

This work investigates electromagnetic properties of half-dense ceramics with compositions Ni0.5Zn0.3Co0.2FeyO4-δ where y = 1.98 (Iron deficient, noted ID) or y = 2.3 (Iron in excess, noted IE). IE and ID materials are obtained by chemical coprecipitation route. The obtained nano-sized powders are pressed and annealed at two temperatures (800 °C, 900 °C), so has to obtain half-massive ceramics. Ferrous and ferric ions coexist in the crystalline structures, but the former in a less extend for ID ferrite. The concomitant influences of Fe2+ and Fe3+ on the dielectric and magnetic losses (ε″/ε‧ and μ″/μ‧, respectively) are considered at frequency up to 6 GHz. The permeability dispersion changes from relaxation-like to resonance-like with the decrease in ferrous ions. In reason of the relaxing-like behavior of Fe2+, and because of a relatively high amount in Fe2+, IE sample shows lower total losses (magnetic and dielectric) than ID sample. These conclusions applied for TA = 900 °C. At frequencies above 700 MHz, the total loss values (IE and ID samples) are prohibitive for antenna downsizing whatever is the firing temperature value (800 °C and 900 °C). Whereas at frequencies below 700 MHz Ni0.5Zn0.3Co0.2Fe2.3O4+δ may leads to better antenna performances than Ni0.5Zn0.3Co0.2Fe1.98O4-δ.

Point Defect Distributions in ZnSe Crystals: Effects of Gravity Vector Orientation During Physical Vapor Transport Growth

NASA Technical Reports Server (NTRS)

Su, Ching-Hua; Feth, S.; Hirschfeld, D.; Smith, T. M.; Wang, Ling Jun; Volz, M. P.; Lehoczky, S. L.

1999-01-01

ZnSe crystals were grown by the physical vapor transport technique under horizontal and vertical (stabilized and destabilized) configurations. Secondary ion mass spectroscopy and photoluminescence measurements were performed on the grown ZnSe samples to map the distributions of [Si], [Fe], [Cu], [Al] and [Li or Na] impurities as well as Zn vacancy, [V (sub Zn)]. Annealings of ZnSe under controlled Zn pressures were studied to correlate the measured photoluminescence emission intensity to the equilibrium Zn partial pressure. In the horizontal grown crystals the segregations of [Si], [Fe], [Al] and [V (sub Zn)] were observed along the gravity vector direction whereas in the vertically stabilized grown crystal the segregation of these point defects was radially symmetrical. No apparent pattern was observed on the measured distributions in the vertically destabilized grown crystal. The observed segregations in the three growth configurations were interpreted based on the possible buoyancy-driven convection in the vapor phase.

Distribution and chemistry of suspended particles from an active hydrothermal vent site on the Mid-Atlantic Ridge at 26°N

NASA Astrophysics Data System (ADS)

Trocine, Robert P.; Trefry, John H.

1988-04-01

Suspended particles were collected from an area of active hydrothermal venting at the Trans-Atlantic Geotraverse (TAG) Hydrothermal Field on the Mid-Atlantic Ridge and analyzed for Fe, Mn, Cd, Zn, Cu, V, Ni, Cr, Pb, Mg, Ca, Al and Si. Rapid advection of vent-derived precipitates produced a lens with total suspended matter (TSM) loadings of 14-60 μg/l at 200-700 m above the seafloor; TSM concentrations > 60 μg/l were observed only at near-vent sites. The distribution of suspended particles correlated well with increased dissolved Mn concentrations and particulate Fe values near the vent source. Particulate Fe values decreased linearly relative to TSM concentrations as hydrothermal precipitates mixed with background suspended matter. Near-vent precipitates were characterized by up to 35% Fe, 2% Zn, 0.6% Cu and > 100 μg/g Cd. In comparison to Fe, particulate Cd, Zn and Cu values decreased dramatically away from the vent source. This trend supports differential settling and/or dissolution of Cd-, Zn- and Cu-bearing phases. Particulate Mn and Fe values were inversely related with only 50 μg Mn/g in the near-vent particles. At near-vent sites, > 99% of the total Mn was in solution; this fraction decreased to 75-80% at background TSM values. In contrast to Cd, Zn and Cu, particulate V levels show a continuous, linear decrease with particulate Fe values. This trend is explained by adsorption of V on Fe-oxides in the vent plume. Scavenging of Cr, Pb and Mg by hydrothermal precipitates is also suggested by the data. Nickel and Al values were low in near-vent particles at < 100 and < 3 μg/g, respectively. The complementary behavior of dissolved Mn and particulate trace metals provides a useful framework for studying broad aspects of hydrothermal plume processes.

Boric acid flux synthesis, structure and magnetic property of MB₁₂O₁₄(OH)₁₀ (M=Mn, Fe, Zn)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Dingfeng; Cong, Rihong; Gao, Wenliang, E-mail: gaowl@cqu.edu.cn

2013-05-01

Three new borates MB₁₂O₁₄(OH)₁₀ (M=Mn, Fe, Zn) have been synthesized by boric acid flux methods, which are isotypic to NiB₁₂O₁₄(OH)₁₀. Single-crystal XRD was performed to determine the crystal structures in detail. They all crystallize in the monoclinic space group P2₁/c. The size of MO{sub 6} (M=Mg, Mn, Fe, Co, Ni, Zn) octahedron shows a good agreement with the Shannon effective ionic radii of M²⁺. Magnetic measurements indicate MnB₁₂O₁₄(OH)₁₀ is antiferromagnetic without a long-range ordering down to 2 K. The values of its magnetic superexchange constants were evaluated by DFT calculations, which explain the observed magnetic behavior. The UV–vis diffuse reflectancemore » spectrum of ZnB₁₂O₁₄(OH)₁₀ suggests a band gap ~4.6 eV. DFT calculations indicate it has a direct band gap 4.9 eV. The optical band gap is contributed by charge transfers from the occupied O 2p to the unoccupied Zn 4s states. - Graphical abstract: Experimental and theoretical studies indicate MnB₁₂O₁₄(OH)₁₀ is antiferromagnetic without a long-range ordering. DFT calculations show ZnB₁₂O₁₄(OH)₁₀ has a direct band gap of 4.9 eV. Highlights: • MB₁₂O₁₄(OH)₁₀ (M=Mn, Fe, Zn) are synthesized by two-step boric acid flux method. • Single-crystal XRD was performed to determine the crystal structures in detail. • Size of MO₆ (M=Mg, Mn, Fe, Co, Ni, Zn) agrees with the effective ionic radii. • MnB₁₂O₁₄(OH)₁₀ is antiferromagnetic without a long-range ordering down to 2 K. • DFT calculations indicate ZnB₁₂O₁₄(OH)₁₀ has a direct band gap 4.9 eV.« less

Serum trace elements in obese women with or without diabetes

PubMed Central

Yerlikaya, F. Hümeyra; Toker, Aysun; Arıbaş, Alpay

2013-01-01

Background & objectives: Relationship of trace elements with obesity and diabetes is complex, alterations in their metabolism can be induced by the diseases and their complications. To study the role of the trace elements in diabetes and obesity, serum trace elements levels (Cr, Se, Fe, Zn, Cu and Mn) were measured in obese women with or without diabetes as well as healthy women. Further, correlation between serum trace elements levels and glucose, insulin, homeostasis model assessment (HOMA-IR), glycated haemoglobin (HbA1c), body mass index (BMI), waist circumferences, waist -to -hip ratio and high-sensitivity C-reactive protein(hsCRP) were also determined in these women. Methods: This study was performed with morbidly obese (BMI >40 kg/m2) women with diabetes (n=41), without diabetes (n=45) and 50 healthly non obese women. Anthropometric measurements were taken and levels of serum Zn, Cr, Fe Cu and Mn were determined. Biochemical parameters included serum glucose, insulin, lipids, haemoglobin, hsCRP and HbA1C. Results: The levels of Zn (P<0.001), Mn (P<0.05), Fe (P<0.05) were significantly lower and the level of Cu (P<0.001) and Cu / Zn ratio (P<0.05) were significantly higher in the diabetic obese women than those of the healthy women. Also, the levels of Zn and Fe were significantly lower and the levels of Cu were significantly higher in the non diabetic obese women than those of the healthy group. Serum Zn levels negatively and serum Cu levels positively correlated with anthropometric values in diabetic and non diabetic obese women. Further, serum Zn, Mn and Cr levels negatively correlated and serum Se levels positively correlated glycaemia control parameters in diabetic obese women. In addition, serum Zn levels negatively correlated with hsCRP in diabetic and nondiabetic obese females. Interpretation & conclusions: Our findings showed significant association between Zn and Fe deficiencies and obesity. Also, obese women with diabetes may be at a greater risk of developing imbalances and deficiencies of trace elements compared with obese women without diabetes. PMID:23563378

Zn(II) stimulation of Fe(II)-activated repression in the iron-dependent repressor from Mycobacterium tuberculosis.

PubMed

Stapleton, Brian; Walker, Lawrence R; Logan, Timothy M

2013-03-19

Thermodynamic measurements of Fe(II) binding and activation of repressor function in the iron-dependent repressor from Mycobacterium tuberculosis (IdeR) are reported. IdeR, a member of the diphtheria toxin repressor family of proteins, regulates iron homeostasis and contributes to the virulence response in M. tuberculosis. Although iron is the physiological ligand, this is the first detailed analysis of iron binding and activation in this protein. The results showed that IdeR binds 2 equiv of Fe(II) with dissociation constants that differ by a factor of 25. The high- and low-affinity iron binding sites were assigned to physical binding sites I and II, respectively, using metal binding site mutants. IdeR was also found to contain a high-affinity Zn(II) binding site that was assigned to physical metal binding site II through the use of binding site mutants and metal competition assays. Fe(II) binding was modestly weaker in the presence of Zn(II), but the coupled metal binding-DNA binding affinity was significantly stronger, requiring 30-fold less Fe(II) to activate DNA binding compared to Fe(II) alone. Together, these results suggest that IdeR is a mixed-metal repressor, where Zn(II) acts as a structural metal and Fe(II) acts to trigger the physiologically relevant promoter binding. This new model for IdeR activation provides a better understanding of IdeR and the biology of iron homeostasis in M. tuberculosis.

Effect of chromium doping on the structural and vibrational properties of Mn-Zn ferrites

NASA Astrophysics Data System (ADS)

Saleem, M.; Varshney, Dinesh

2018-05-01

The synthesis of Mn0.5Zn0.5-xCrxFe2O4 (x = 0.0, 0.1, 0.2 and 0.5) via sol-gel Auto-combustion technique is reported. The x-ray diffraction spectra analysis revealed the cubic spinel structure for all the prepared spinel ferrite samples with the space group Fd3m. The structural studies identify the decrease of lattice parameter however the crystallite size decreases on increasing the Cr concentration. The Raman spectrum reveals five active phonon modes at room temperature and shifting of modes toward the higher frequency side on moving from Mn-ZnFe2O4 to Mn-CrFe2O4.

Surface and local electronic structure modification of MgO film using Zn and Fe ion implantation

NASA Astrophysics Data System (ADS)

Singh, Jitendra Pal; Lim, Weon Cheol; Lee, Jihye; Song, Jonghan; Lee, Ik-Jae; Chae, Keun Hwa

2018-02-01

Present work is motivated to investigate the surface and local electronic structure modifications of MgO films implanted with Zn and Fe ions. MgO film was deposited using radio frequency sputtering method. Atomic force microscopy measurements exhibit morphological changes associated with implantation. Implantation of Fe and Zn ions leads to the reduction of co-ordination geometry of Mg2+ ions in host lattice. The effect is dominant at bulk of film rather than surface as the large concentration of implanted ions resides inside bulk. Moreover, the evidences of interaction among implanted ions and oxygen are not being observed using near edge fine structure measurements.

Bioaccessibility and size distribution of metals in road dust and roadside soils along a peri-urban transect.

PubMed

Padoan, Elio; Romè, Chiara; Ajmone-Marsan, Franco

2017-12-01

Road dust (RD), together with surface soils, is recognized as one of the main sinks of pollutants in urban environments. Over the last years, many studies have focused on total and bioaccessible concentrations while few have assessed the bioaccessibility of size-fractionated elements in RD. Therefore, the distribution and bioaccessibility of Fe, Mn, Cd, Cr, Cu, Ni, Pb, Sb and Zn in size fractions of RD and roadside soils (<2.5μm, 2.5-10μm and 10-200μm) have been studied using aqua regia extraction and the Simple Bioaccessibility Extraction Test. Concentrations of metals in soils are higher than legislative limits for Cu, Cr, Ni, Pb and Zn. Fine fractions appear enriched in Fe, Mn, Cu, Pb, Sb and Zn, and 2.5-10μm particles are the most enriched. In RD, Cu, Pb, Sb and Zn derive primarily from non-exhaust sources, while Zn is found in greater concentrations in the <2.5μm fraction, where it most likely has an industrial origin. Elemental distribution across soils is dependent on land use, with Zn, Ni, Cu and Pb being present in higher concentrations at traffic sites. In addition, Fe, Ni and Cr feature greater bioaccessibility in the two finer fractions, while anthropic metals (Cu, Pb, Sb and Zn) do not. In RD, only Zn has significantly higher bioaccessibility at traffic sites compared to background, and the finest particles are always the most bioaccessible; >90% of Pb, Zn and Cu is bioaccessible in the <2.5μm fraction, while for Mn, Ni, Sb, Fe and Cr, values vary from 76% to 5%. In the 2.5-10μm fraction, the values were 89% for Pb, 67% for Zn and 60% for Cu. These results make the evaluation of the bioaccessibility of size-fractionated particles appear to be a necessity for correct estimation of risk in urban areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Protein profile of Lupinus texensis phloem sap exudates: searching for Fe- and Zn-containing proteins.

PubMed

Lattanzio, Giuseppe; Andaluz, Sofía; Matros, Andrea; Calvete, Juan José; Kehr, Julia; Abadía, Anunciación; Abadía, Javier; López-Millán, Ana-Flor

2013-08-01

The aim of this study was to obtain a comprehensive overview of the phloem sap protein profile of Lupinus texensis, with a special focus on proteins binding Fe and Zn. L. texensis was chosen as model plant given the simplicity to obtain exudates from sieve elements. Protein profiling by 2DE revealed 249 spots, and 54 of them were unambiguously identified by MALDI-MS and ESI-MS/MS. The largest number of identified protein species belongs to protein modification/turnover and general metabolism (19-21%), followed by redox homeostasis (9%) and defense and cell structural components (7%). This protein profile is similar to that reported in other plant species, suggesting that the phloem sap proteome is quite conserved. Staining of 2DE gels for Fe-containing proteins and affinity chromatography experiments revealed the presence of two low molecular weight Fe-binding proteins in phloem sap: a metallothionein-like protein type 2B identified in the Fe-affinity chromatography, and a second protein identified with both Fe staining methods. This protein species had a molecular weight of 13.5 kDa, a pI of 5.6 and 51% homology to a phloem-specific protein from Medicago truncatula. Zinc affinity chromatography revealed four Zn-binding proteins in phloem sap, one belonging to the dehydrin family and three Zn finger proteins. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biofortified indica rice attains iron and zinc nutrition dietary targets in the field

PubMed Central

Trijatmiko, Kurniawan R.; Dueñas, Conrado; Tsakirpaloglou, Nikolaos; Torrizo, Lina; Arines, Felichi Mae; Adeva, Cheryl; Balindong, Jeanette; Oliva, Norman; Sapasap, Maria V.; Borrero, Jaime; Rey, Jessica; Francisco, Perigio; Nelson, Andy; Nakanishi, Hiromi; Lombi, Enzo; Tako, Elad; Glahn, Raymond P.; Stangoulis, James; Chadha-Mohanty, Prabhjit; Johnson, Alexander A. T.; Tohme, Joe; Barry, Gerard; Slamet-Loedin, Inez H.

2016-01-01

More than two billion people are micronutrient deficient. Polished grains of popular rice varieties have concentration of approximately 2 μg g−1 iron (Fe) and 16 μg g−1 zinc (Zn). The HarvestPlus breeding programs for biofortified rice target 13 μg g−1 Fe and 28 μg g−1 Zn to reach approximately 30% of the estimated average requirement (EAR). Reports on engineering Fe content in rice have shown an increase up to 18 μg g−1 in glasshouse settings; in contrast, under field conditions, 4 μg g−1 was the highest reported concentration. Here, we report on selected transgenic events, field evaluated in two countries, showing 15 μg g−1 Fe and 45.7 μg g−1 Zn in polished grain. Rigorous selection was applied to 1,689 IR64 transgenic events for insert cleanliness and, trait and agronomic performances. Event NASFer-274 containing rice nicotianamine synthase (OsNAS2) and soybean ferritin (SferH-1) genes showed a single locus insertion without a yield penalty or altered grain quality. Endosperm Fe and Zn enrichment was visualized by X-ray fluorescence imaging. The Caco-2 cell assay indicated that Fe is bioavailable. No harmful heavy metals were detected in the grain. The trait remained stable in different genotype backgrounds. PMID:26806528

Found: Rice that produces grains with improved nutritional value

USDA-ARS?s Scientific Manuscript database

Rice provides the major source of nutrition for a large proportion of the world’s population, and is a key ingredient in baby foods in the U.S. Mineral nutrients such as Ca, Fe, and Zn play critical roles in human health, with over 3 billion people suffering from Fe and Zn deficiencies. Unfortunat...

Toxicity of Metals to a Freshwater Ostracod: Stenocypris major

PubMed Central

Shuhaimi-Othman, Mohammad; Yakub, Nadzifah; Ramle, Nur-Amalina; Abas, Ahmad

2011-01-01

Adults of freshwater ostracod Stenocypris major (Crustacea, Candonidae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed, and median lethal times (LT50) and concentrations (LC50) were calculated. LT50 and LC50 increased with the decrease in mean exposure concentrations and times, respectively, for all metals. LC50s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 25.2, 13.1, 1189.8, 526.2, 19743.7, 278.9, 3101.9, and 510.2 μg/L, respectively. Metals bioconcentration in S. major increases with exposure to increasing concentrations, and Cd was the most toxic to S. major, followed by Cu, Fe, Mn, Pb, Zn, Al, and Ni (Cd>Cu>Fe>Mn>Pb>Zn>Al>Ni). Comparison of LC50 values for metals for this species with those for other freshwater crustacean reveals that S. major is equally or more sensitive to metals than most other tested crustacean. PMID:21559091

Geochemical studies of Fe, Mn, Co, As, Cr, Sb, Zn, Sc and V in surface sediments from Jiaozhou Bay

NASA Astrophysics Data System (ADS)

Wu, Run; Li, Pei-Quan; Miao, Lu-Tian; Zhang, Shu-Xin; Tian, Wei-Zhi

1994-12-01

The contents of nearly forty-elements in surface sediments in Jiaozhou Bay were determined using a Neutron Activation Analysis Technique (Grancini, et al., 1976; Li Peiquan et al., 1985, 1986; Li Xiuxia et al., 1986). This paper's detailed discussion on only nine elements (Fe, Mn, Co, Cr, Sc, As, Sb, Zn and V) includes their distributions, concentrations, correlationships, material sources, background, etc. Based on Zavaristski's classification method, Fe, Mn, Co, Cr and V belong to the second group; As and Sb to the eighth groups: Sc and Zn to the third and sixth groups. It was found that their notably good correlationship is mainly due to the similarity of their ionic structures and that their variation is controlled by the Fe content (except Mn). The source of sediments is mainly terristrial material, and the composition of sediment is similar to that of shale and shale+clay. The contents for a large number of elements are within the scope of the background level, but there still is pollution of Zn and Cr, at least in a few stations.

Optimization of operating parameters for gas-phase photocatalytic splitting of H2S by novel vermiculate packed tubular reactor.

PubMed

Preethi, V; Kanmani, S

2016-10-01

Hydrogen production by gas-phase photocatalytic splitting of Hydrogen Sulphide (H2S) was investigated on four semiconductor photocatalysts including CuGa1.6Fe0.4O2, ZnFe2O3, (CdS + ZnS)/Fe2O3 and Ce/TiO2. The CdS and ZnS coated core shell particles (CdS + ZnS)/Fe2O3 shows the highest rate of hydrogen (H2) production under optimized conditions. Packed bed tubular reactor was used to study the performance of prepared photocatalysts. Selection of the best packing material is a key for maximum removal efficiency. Cheap, lightweight and easily adsorbing vermiculate materials were used as a novel packing material and were found to be effective in splitting H2S. Effect of various operating parameters like flow rate, sulphide concentration, catalyst dosage, light irradiation were tested and optimized for maximum H2 conversion of 92% from industrial waste H2S. Copyright © 2016 Elsevier Ltd. All rights reserved.

The role of iron(II) dilution in the magnetic and photomagnetic properties of the series [Fe(x)Zn(1-x)(bpp)₂](NCSe)₂.

PubMed

Baldé, Chérif; Desplanches, Cédric; Le Gac, Fréderic; Guionneau, Philippe; Létard, Jean-François

2014-06-07

The effects of metal dilution on the spin-crossover behavior of iron(II) in the mixed crystal series [Fe(x)Zn(1-x)(bpp)2](NCSe)2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) have been studied using magnetic susceptibility, photomagnetism and diffuse reflectivity measurements. For each mixed-crystal system, the thermal spin transition temperature, T(1/2), and the relaxation temperature of the photo-induced high-spin state, T(LIESST), have been systematically determined. It appears that T(1/2) decreases with the metal dilution while T(LIESST) remains unchanged. Dilution also tends to decrease the hysteresis width and smooth the transition curves. These effects were discussed first qualitatively and then quantitatively on the basis of a kinetic study governing the photo-induced back conversion taking into account the relative sizes of Zn(II) and Fe(II) ions. Interestingly, single crystals were obtained for [Fe(0.6)Zn(0.4)(bpp)2](NCSe)2 allowing the X-ray diffraction crystal-structure determination.

Fe2O3/ZnO/ZnFe2O4 composites for the efficient photocatalytic degradation of organic dyes under visible light

NASA Astrophysics Data System (ADS)

Li, Xiaojuan; Jin, Bo; Huang, Jingwen; Zhang, Qingchun; Peng, Rufang; Chu, Shijin

2018-06-01

In this study, novel ternary Fe2O3/ZnO/ZnFe2O4 (ZFO) composites were successfully prepared through a simple hydrothermal reaction with subsequent thermal treatment. The as-prepared products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis, Barrett-Joyner-Halenda (BJH) measurement, and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic degradation of rhodamine B (Rh B) under visible light irradiation indicated that the ZFO composites calcined at 500 °C has the best photocatalytic activity (the photocatalytic degradation efficiency can reach up to 95.7% within 60 min) and can maintain a stable photocatalytic degradation efficiency for at least three cycles. In addition, the photocatalytic activity of ZFO composites toward dye decomposition follows the order cationic Rh B > anionic methyl orange. Finally, using different scavengers, superoxide and hydroxyl radicals were identified as the primary active species during the degradation reaction of Rh B.

Electrodeposition of quaternary alloys in the presence of magnetic field

PubMed Central

2010-01-01

Electrodeposition of Ni-Co-Fe-Zn alloys was done in a chloride ion solution with the presence and absence of a Permanent Parallel Magnetic Field (PPMF). The PPMF was applied parallel to the cathode surface. The deposition profile was monitored chronoamperometrically. It was found that the electrodeposition current was enhanced in the presence of PPMF (9 T) compared to without PPMF. The percentage of current enhancement (Γ%) was increased in the presence of PPMF, with results of Γ% = 11.9%, 16.7% and 18.5% at -1.1, -1.2 and -1.3 V respectively for a 2400 sec duration. In chronoamperometry, the Composition Reference Line (CRL) for Ni was around 57%, although the nobler metals (i.e. Ni, Co) showed anomalous behaviour in the presence of Zn and Fe. The anomalous behaviour of the Ni-Co-Fe-Zn electrodeposition was shown by the Energy Dispersive X-Ray (EDX) results. From Atomic Force Microscopy (AFM) measurements, it was found that the surface roughness of the Ni-Co-Fe-Zn alloy films decreased in the presence of a PPMF. PMID:20604934

Folic acid-functionalized magnetic ZnFe2O4 hollow microsphere core/mesoporous silica shell composite particles: synthesis and application in drug release.

PubMed

Yang, Dandan; Wei, Kaiwei; Liu, Qi; Yang, Yong; Guo, Xue; Rong, Hongren; Cheng, Mei-Ling; Wang, Guoxiu

2013-07-01

A drug delivery system was designed by deliberately combining the useful functions into one entity, which was composed of magnetic ZnFe2O4 hollow microsphere as the core, and mesoporous silica with folic acid molecules as the outer shell. Amine groups coated magnetic ZnFe2O4 hollow microsphere core/mesoporous silica shell (MZHM-MSS-NH2) composite particles were first synthesized by a one-pot direct co-condensation method. Subsequently a novel kind of folic acid-functionalized magnetic ZnFe2O4 hollow microsphere core/mesoporous silica shell (MZHM-MSS-NHFA) composite particles were synthesized by conjugating folic acid as targeted molecule to MZHM-MSS-NH2. Ibuprofen, a well-known antiphlogistic drug, was used as a model drug to assess the loading and releasing behavior of the composite microspheres. The results show that the MZHM-MSS-NHFA system has the higher capacity of drug storage and good sustained drug-release property. Copyright © 2013 Elsevier B.V. All rights reserved.

DETECTION OF PHOSPHORUS, SULPHUR, AND ZINC IN THE CARBON-ENHANCED METAL-POOR STAR BD+44 493

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roederer, Ian U.; Placco, Vinicius M.; Beers, Timothy C., E-mail: iur@umich.edu

2016-06-20

The carbon-enhanced metal-poor star BD+44°493 ([Fe/H] = −3.9) has been proposed as a candidate second-generation star enriched by metals from a single Pop III star. We report the first detections of P and S and the second detection of Zn in any extremely metal-poor carbon-enhanced star, using new spectra of BD+44°493 collected by the Cosmic Origins Spectrograph on the Hubble Space Telescope . We derive [P/Fe] = −0.34 ± 0.21, [S/Fe] = +0.07 ± 0.41, and [Zn/Fe] = −0.10 ± 0.24. We increase by 10-fold the number of Si i lines detected in BD+44°493, yielding [Si/Fe] = +0.15 ± 0.22.more » The [S/Fe] and [Zn/Fe] ratios exclude the hypothesis that the abundance pattern in BD+44°493 results from depletion of refractory elements onto dust grains. Comparison with zero-metallicity supernova (SN) models suggests that the stellar progenitor that enriched BD+44°493 was massive and ejected much less than 0.07 M {sub ⊙} of {sup 56}Ni, characteristic of a faint SN.« less

Antibacterial activity of trimetal (CuZnFe) oxide nanoparticles.

PubMed

Alzahrani, Khalid E; Niazy, Abdurahman A; Alswieleh, Abdullah M; Wahab, Rizwan; El-Toni, Ahmed M; Alghamdi, Hamdan S

2018-01-01

The increasing resistance of pathogenic bacteria to antibiotics is a challenging worldwide health problem that has led to the search for new and more efficient antibacterial agents. Nanotechnology has proven to be an effective tool for the fight against bacteria. In this paper, we present the synthesis and traits of trimetal (CuZnFe) oxide nanoparticles (NPs) using X-ray diffraction, high-resolution transmission electron microscopy, and energy dispersive x-ray spectroscopy. We evaluated the antibacterial activity of these NPs against gram-negative Escherichia coli and gram-positive Enterococcus faecalis and then compared it to that of their pure single-metal oxide components CuO and ZnO. Our study showed that the antibacterial activity of the trimetal oxide NPs was greater against E . coli than against E . faecalis . Overall, the antimicrobial effect of trimetal NPs is between those of pure ZnO and CuO nanoparticles, which may mean that their cytotoxicity is also between that of pure ZnO and CuO NPs, making them potential antibiotics. However, the cytotoxicity of trimetal NPs to mammalian cells needs to be verified. The combination of three metal oxide NPs (ZnO, CuO, and Fe 2 O 3 ) in one multimetal (CuZnFe) oxide NPs will enhance the therapeutic strategy against a wide range of microbial infections. Bacteria are unlikely to develop resistance against this new NP because bacteria must go through a series of mutations to become resistant to the trimetal oxide NP. Therefore, this NP can combat existing and emerging bacterial infections.

The impact of processing parameters on the properties of Zn-bonded Nd-Fe-B magnets

NASA Astrophysics Data System (ADS)

Kelhar, Luka; Zavašnik, Janez; McGuiness, Paul; Kobe, Spomenka

2016-12-01

We report on the effect of loading factor and pressure on the density and the magnetic properties of Zn-bonded Nd-Fe-B magnets produced by pulsed-electric-current sintering (PECS). The idea behind this study is to fabricate bonded magnets with a metallic binder in order for the bonded magnet to operate at temperatures higher than 180 °C: the current upper-limit for polymer-bonded magnets. These composites are made of hard-magnetic powder in the form of melt-spun ribbons bonded with the low-melting-point metal Zn. The binder additions were varied from 10 to 30 wt%, and pressures of 50 and 500 MPa were applied. The high-pressure mode with 20 wt% Zn resulted in a 24% increase of Jr, compared to the low-pressure mode. The magnetic measurements revealed a maximum remanence of 0.64 T for 10 wt% Zn, while the coercivity is largely unaffected by the processing conditions. The density of the composites was up to 7.0 g/cm3, corresponding to 94% of the theoretical density. Compared to commercial polymer-bonded magnets, the Zn-bonded counterparts exhibit a slightly lower Jr, but the coercivity is retained. We show that there is a minor diffusion of Zn into the Nd-Fe-B, forming a 1 μm thin transition layer, but it does not harm the magnetic properties. These metal-bonded Nd-Fe-B magnets are ideal for use in high-temperature automotive applications like under-the-hood sensors and other magnet-based devices that are close to the engine.

Synchrotron study of metal localization in Typha latifolia L. root sections

DOE PAGES

Qian, Yu; Jones, Keith W.; Feng, Huan; ...

2015-09-15

Understanding mechanisms that control plant root metal assimilation in soil is critical to the sustainable management of metal-contaminated land. With the assistance of the synchrotron X-ray fluorescence technique, this study investigated possible mechanisms that control the localization of Fe, Cu, Mn, Pb and Zn in the root tissues of Typha latifolia L. collected from a contaminated wetland. Metal localizations especially in the case of Fe and Pb in the dermal tissue and the vascular bundles were different. Cluster analysis was performed to divide the dermal tissue into iron-plaque-enriched dermal tissue and regular dermal tissue based on the spatial distribution ofmore » Pb and Fe. Factor analysis showed that Cu and Zn were closely correlated to each other in the dermal tissues. The association of Cu, Zn and Mn with Fe was strong in both regular dermal tissue and iron-plaque-enriched dermal tissue, while significant (p < 0.05) correlation of Fe with Pb was only observed in tissues enriched with iron plaque. In the vascular bundles, Zn, Mn and Cu showed strong association, suggesting that the localization of these three elements was controlled by a similar mechanism. Iron plaque in the peripheral dermal tissues acted as a barrier for Pb and a buffer for Zn, Cu and Mn. Furthermore, the Casparian strip regulated the transportation of metals from dermal tissues to the vascular bundles. The results suggested that the mechanisms controlling metal localization in root tissues varied with both tissue types and metals.« less

Quantifying Spatial Variability of Selected Soil Trace Elements and Their Scaling Relationships Using Multifractal Techniques

PubMed Central

Zhang, Fasheng; Yin, Guanghua; Wang, Zhenying; McLaughlin, Neil; Geng, Xiaoyuan; Liu, Zuoxin

2013-01-01

Multifractal techniques were utilized to quantify the spatial variability of selected soil trace elements and their scaling relationships in a 10.24-ha agricultural field in northeast China. 1024 soil samples were collected from the field and available Fe, Mn, Cu and Zn were measured in each sample. Descriptive results showed that Mn deficiencies were widespread throughout the field while Fe and Zn deficiencies tended to occur in patches. By estimating single multifractal spectra, we found that available Fe, Cu and Zn in the study soils exhibited high spatial variability and the existence of anomalies ([α(q)max−α(q)min]≥0.54), whereas available Mn had a relatively uniform distribution ([α(q)max−α(q)min]≈0.10). The joint multifractal spectra revealed that the strong positive relationships (r≥0.86, P<0.001) among available Fe, Cu and Zn were all valid across a wider range of scales and over the full range of data values, whereas available Mn was weakly related to available Fe and Zn (r≥0.18, P<0.01) but not related to available Cu (r = −0.03, P = 0.40). These results show that the variability and singularities of selected soil trace elements as well as their scaling relationships can be characterized by single and joint multifractal parameters. The findings presented in this study could be extended to predict selected soil trace elements at larger regional scales with the aid of geographic information systems. PMID:23874944

Characterization and application of the hetero-junction ZnFe2O4/TiO2 for Cr(VI) reduction under visible light

NASA Astrophysics Data System (ADS)

Rekhila, G.; Trari, M.; Bessekhouad, Y.

2017-06-01

The spinel ZnFe2O4 prepared by nitrate route is used as dispersed photons collector capable to sensitize TiO2 under visible light and to reduce Cr(VI) into trivalent state. The transport properties, optical and photo-electrochemical characterizations are correlated, to build the energetic diagram of the hetero-system ZnFe2O4/TiO2/CrO4 - solution. A gap of 1.97 eV is obtained for the spinel from the diffuse reflectance. The conduction band of ZnFe2O4 (-1.47 V SCE) favors the electrons injection into TiO2, permitting a physical separation of the charge carriers. The oxidation of oxalic acid by photoholes prevents the corrosion of the spinel. The best configuration ZnFe2O4 (75 %)/TiO2 (25 %) is used to catalyze the downhill reaction (2HCrO4 - + 3C2H4O4 + 1.5O2 + 8H+ → 2Cr3+ + 6CO2 + 11 H2O, Δ G° = -557 kcal mol-1). 60 % of Cr(VI) are reduced after 3 h of visible light illumination and the photoactivity follows a first-order kinetic with a half-life of 70 min. The water reduction competes with the HCrO4 - reduction which is the reason in the regression of the photoactivity; a hydrogen evolution rate of 24 µmol mg-1 h-1 is obtained.

Fe induced optical limiting properties of Zn1-xFexS nanospheres

NASA Astrophysics Data System (ADS)

Vineeshkumar, T. V.; Raj, D. Rithesh; Prasanth, S.; Unnikrishnan, N. V.; Mahadevan Pillai, V. P.; Sudarasanakumar, C.

2018-02-01

Zn1-xFexS (x = 0.00, 0.01, 0.03, 0.05) nanospheres were synthesized by polyethylene glycol assisted hydrothermal method. XRD studies revealed that samples of all concentrations exhibited cubic structure with crystallite grain size 7-9 nm. TEM and SEM show the formation of nanospheres by dense aggregation of smaller particles. Increasing Zn/Fe ratio tune the band gap from 3.4 to 3.2 eV and also quenches the green luminescence. FTIR spectra reveal the presence of capping agent, intensity variation and shifting of LO and TO phonon modes confirm the presence of Fe ions. Nonlinear optical properties were measured using open and closed aperture z-scan techniques, employing frequency doubled 532 nm pumping sources which indicated reverse saturable absorption (RSA) process. The nonlinear optical coefficients are obtained by two photon absorption (2PA). Composition dependent nonlinear optical coefficients ;β;, nonlinear refractive index, third order susceptibility and optical limiting threshold were estimated. The sample shows good nonlinear absorption and enhancement of optical limiting behavior with increasing Fe volume fraction. Contribution of RSA on optical nonlinearity of Zn1-xFexS nanospheres are also investigated using three different input energies. Zn1-xFexS with comparatively small limiting threshold value is a promising candidate for optical power limiting applications.

Alternating current magnetic susceptibility and heat dissipation by Mn{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} nanoparticles for hyperthermia treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kondo, T.; Mori, K.; Hachisu, M.

2015-05-07

Mn-Zn ferrite, Mn{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} nanoparticles encapsulated in amorphous SiO{sub 2} were prepared using our original wet chemical method. X-ray diffraction patterns confirmed that the diameters of these particles were within 7–30 nm. Magnetization measurements for various sample compositions revealed that the saturation magnetization (M{sub s}) of 7 nm particles was maximum for the x = 0.2 sample. AC magnetic susceptibility measurements were performed for Mn{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} (x = 0.2) samples with 13–30 nm particles. The peak of the imaginary part of the magnetic susceptibility χ″ shifted to higher temperatures as the particle size increased. An AC field was found to causemore » the increase in temperature, with the 18 nm particles exhibiting the highest temperature increase, as expected. In addition, in vitro experiments were carried out to study the hyperthermia effects of Mn{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x = 0.2, 18 nm) particles on human cancer cells.« less

Galvanizing and Galvannealing Behavior of CMnSiCr Dual-Phase Steels

NASA Astrophysics Data System (ADS)

Lin, Ko-Chun; Chu, Peng-Wei; Lin, Chao-Sung; Chen, Hon-Bor

2013-06-01

Alloying elements, such as Mn, Mo, Si, and Cr, are commonly used to enhance the strength of advanced high-strength steels. Those elements also play an important role in the hot-dip galvanizing (GI) and galvannealing (GA) process. In this study, two kinds of CMnSiCr dual-phase steels were galvanized and galvannealed using a hot-dip simulator to investigate the effect of the alloying elements on the microstructure of the GI and GA coatings. The results showed that the dual-phase steels had good galvanizability because no bare spots were observed and the Fe-Zn phases were readily formed at the interface. However, the alloying reaction during the GA process was significantly hindered. XPS analysis showed that external oxidation occurred under an extremely low dew point [213 K to 203 K (-60 °C to -70 °C)] atmosphere during the annealing prior to hot dipping. However, most of the oxides were reduced during the GI process. After the GI process, the Al was present as solid solutes in the Fe-Zn phase, suggesting that the Fe-Zn phase was formed from the transformation of the Fe-Al inhibition alloy. Meanwhile, the solubility of Si in the ζ phase was extremely low. With continued GA reaction, the ζ phase transformed into the δ phase, which contained approximately 1.0 at.pct Si. The Si also diffused into the Zn layer during the GA reaction. Hence, the ζ phase did not homogeneously nucleate at the steel substrate/Zn coating interface, but was found at the area away from the interface. Therefore, the Fe-Zn phases on the CMnSiCr dual-phase steels were relatively non-uniform compared to those on interstitial-free steel.

Effect of Zn doping on structural, magnetic and dielectric properties of LaFeO{sub 3} synthesized through sol–gel auto-combustion process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhat, Irshad; Husain, Shahid, E-mail: s.husain@lycos.com; Khan, Wasi

2013-11-15

Graphical abstract: - Highlights: • We have synthesized the samples of LaFe{sub 1−x}Zn{sub x}O{sub 3} (0 ≤ x ≤ 0.3) using sol–gel auto-combustion process. • The doping of Zn{sup 2+} hugely enhances the dielectric constant (ε′) and it shows a colossal value. • The parent compound LaFeO{sub 3} does not show any relaxation peak, but the substitution of Zn at Fe{sup 3+} site brings the relaxation in the system. • The system shows a peak behavior thereby giving the Debye like dipolar relaxation response. - Abstract: We have studied the structural and dielectric properties of nano-crystalline LaFe{sub 1−x}Zn{sub x}O{sub 3}more » (0 ≤ x ≤ 0.3) pervoskite samples synthesized through sol–gel auto-combustion technique. X-ray diffraction and FTIR spectroscopy are used to confirm the single phase characteristics. Microstructural features are investigated using scanning electron microscope and compositional analysis is performed through energy dispersive spectroscopy. The average grain sizes, calculated from the Scherrer formula, lie in the range below 30 nm. The hysteresis (M-H) curves display a weak magnetic order and a shift in the hysteresis loops. Dielectric response has been discussed, in the framework of “universal dielectric response” model. The value of dielectric constant (ε′) increases drastically on Zn doping. The dielectric loss factor (ε″) shows Debye like dipolar relaxation behavior. The observed peaks in loss factor (ε″) are attributed to the fact that a strong correlation between the conduction mechanism and the dielectric behavior exists in ferrites.« less

Efficient metal adsorption and microbial reduction from Rawal Lake wastewater using metal nanoparticle coated cotton.

PubMed

Ali, Attarad; Gul, Ayesha; Mannan, Abdul; Zia, Muhammad

2018-05-17

This study was designed to investigate removal of toxic metals and reduction of bacterial count from Rawal Lake wastewater with novel nanocomposite sorbents. Iron, zinc and silver oxide nanoparticles (NPs) were attached on cotton. The nanocomposites (iron NPs on cotton (FeCt), zinc NPs on cotton (ZnCt) and silver NPs on cotton (AgCt)) were characterized by FTIR, XRD and SEM, which showed successful adsorption of 10-30 nm size nanoparticles. Batch experiments were performed to determine the adsorption capacity of nanocomposite for metal removal. All the three adsorbents demonstrated 100% adsorption efficiency for Ag + , Co 2+ , Fe 3+ , Zn 2+ and Cu 2+ whereas less adsorption for Cd 2+ and Cr 3+ . The maximum adsorbance (qe) was exhibited by Co 2+ on ZnCt, FeCt and AgCt as 125.0, 111.1 and 100.0 mg g -1 , respectively. The efficiency of adsorbents for metal ions sorption was found as AgCt > ZnCt > FeCt while the order of adsorption for metals was observed as Fe 3+  > Co 2+  > Zn 2+  > Cu 2+  > Ag +  > Cr 3+  > Cd 2 + . The adsorption mechanism mostly follow Langmuir isotherm and pseudo-second order kinetic model. The maximum microbial reduction was exhibited by AgCt followed by ZnCt and FeCt. The microbes were further processed for staining and biochemical characteristics to evaluate resistance and sensitive microbes. The study concludes that the NPs doped on cotton can be effectively used for adsorption of heavy metals and reduction of microbial count from natural wastewater making it valuable for human consumption. In addition, the nanoparticles impregnated cotton can be efficiently used in water filtration plants. Copyright © 2018. Published by Elsevier B.V.

Fractionation of Cu and Zn isotopes during adsorption onto amorphous Fe(III) oxyhydroxide: Experimental mixing of acid rock drainage and ambient river water

USGS Publications Warehouse

Balistrieri, L.S.; Borrok, D.M.; Wanty, R.B.; Ridley, W.I.

2008-01-01

Fractionation of Cu and Zn isotopes during adsorption onto amorphous ferric oxyhydroxide is examined in experimental mixtures of metal-rich acid rock drainage and relatively pure river water and during batch adsorption experiments using synthetic ferrihydrite. A diverse set of Cu- and Zn-bearing solutions was examined, including natural waters, complex synthetic acid rock drainage, and simple NaNO3 electrolyte. Metal adsorption data are combined with isotopic measurements of dissolved Cu (65Cu/63Cu) and Zn (66Zn/64Zn) in each of the experiments. Fractionation of Cu and Zn isotopes occurs during adsorption of the metal onto amorphous ferric oxyhydroxide. The adsorption data are modeled successfully using the diffuse double layer model in PHREEQC. The isotopic data are best described by a closed system, equilibrium exchange model. The fractionation factors (??soln-solid) are 0.99927 ?? 0.00008 for Cu and 0.99948 ?? 0.00004 for Zn or, alternately, the separation factors (??soln-solid) are -0.73 ?? 0.08??? for Cu and -0.52 ?? 0.04??? for Zn. These factors indicate that the heavier isotope preferentially adsorbs onto the oxyhydroxide surface, which is consistent with shorter metal-oxygen bonds and lower coordination number for the metal at the surface relative to the aqueous ion. Fractionation of Cu isotopes also is greater than that for Zn isotopes. Limited isotopic data for adsorption of Cu, Fe(II), and Zn onto amorphous ferric oxyhydroxide suggest that isotopic fractionation is related to the intrinsic equilibrium constants that define aqueous metal interactions with oxyhydroxide surface sites. Greater isotopic fractionation occurs with stronger metal binding by the oxyhydroxide with Cu > Zn > Fe(II).

Iron sand - ZnO based materials of natural origin for dye decolorization under sunlight irradiation

NASA Astrophysics Data System (ADS)

Salprima Yudha, S.; Angasa, Eka; Fitriani, Dyah; Falahudin, Aswin

2017-03-01

A mixed iron sand - ZnO materials was prepared by heating a mixture of natural iron sand and ZnO at 900 °C for 5 hours. XRD study of the sample revealed that, in the mixed iron sand - ZnO present some minor peaks that similar with XRD pattern of γ-Fe2O3 and/or Fe3O4. Observation of the sample using SEM, showed a compact morpholgy and almost homogenenous in particles size. In purpose to evaluate the ability of this materials for textile dying wastewater treatment, a study on rhodamine B decolorization was carried out as a reperesentative.

Investigations on structural, vibrational and dielectric properties of nanosized Cu doped Mg-Zn ferrites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yadav, Anand; Department of Physics, MEDICAPS Institute of Science and Technology, Pithampur 453331; Rajpoot, Rambabu

2016-05-23

Transition metal Cu{sup 2+} doped Mg-Zn ferrite [Mg{sub 0.5}Zn{sub 0.5-x}Cu{sub x}Fe{sub 2}O{sub 4} (0.0 ≤ x ≤ 0.5)] were prepared by sol gel auto combustion (SGAC) method to probe the structural, vibrational and electrical properties. X-ray diffraction (XRD) pattern reveals a single-phase cubic spinel structure without the presence of any secondary phase corresponding to other structure. The average particle size of the parent Mg{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} is found to be ~29.8 nm and is found to increase with Cu{sup 2+} doping. Progressive reduction in lattice parameter of Mg{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} has been observed due to difference inmore » ionic radii of cations with improved Cu doping. Spinel cubic structure is further confirmed by Raman spectroscopy. Small shift in Raman modes towards higher wave number has been observed in doped Mg-Zn ferrites. The permittivity and dielectric loss decreases at lower doping and increases at higher order doping of Cu{sup 2+}.« less

Magnetic properties of Gd T2Zn20 (T =Fe , Co) investigated by x-ray diffraction and spectroscopy

NASA Astrophysics Data System (ADS)

Mardegan, J. R. L.; Francoual, S.; Fabbris, G.; Veiga, L. S. I.; Strempfer, J.; Haskel, D.; Ribeiro, R. A.; Avila, M. A.; Giles, C.

2016-01-01

We investigate the magnetic and electronic properties of the Gd T2Zn20 (T =Fe and Co) compounds using x-ray resonant magnetic scattering (XRMS), x-ray absorption near-edge structure (XANES), and x-ray magnetic circular dichroism (XMCD). The XRMS measurements reveal that GdCo2Zn20 has a commensurate antiferromagnetic spin structure with a magnetic propagation vector τ ⃗=(1/2 ,1/2 ,1/2 ) below the Néel temperature (TN˜ 5.7 K). Only the Gd ions carry a magnetic moment forming an antiferromagnetic structure with magnetic representation Γ6. For the ferromagnetic GdFe2Zn20 compound, an extensive investigation was performed at low temperature and under magnetic field using XANES and XMCD. A strong XMCD signal of about 12.5 % and 9.7 % is observed below the Curie temperature (TC˜85 K ) at the Gd L2 and L3 edges, respectively. In addition, a small magnetic signal of about 0.06 % of the jump is recorded at the Zn K edge, suggesting that the Zn 4 p states are spin polarized by the Gd 5 d extended orbitals.

Controllable synthesis, magnetic properties, and enhanced photocatalytic activity of spindlelike mesoporous α-Fe(2)O(3)/ZnO core-shell heterostructures.

PubMed

Wu, Wei; Zhang, Shaofeng; Xiao, Xiangheng; Zhou, Juan; Ren, Feng; Sun, Lingling; Jiang, Changzhong

2012-07-25

Mesoporous spindlelike iron oxide/ZnO core-shell heterostructures are successfully fabricated by a low-cost, surfactant-free, and environmentally friendly seed-mediate strategy with the help of postannealing treatment. The material composition and stoichiometry, as well as these magnetic and optical properties, have been examined and verified by means of high-resolution transmission electron microscopy and X-ray diffraction, the thickness of ZnO layer can be simply tailored by the concentration of zinc precursor. Considering that both α-Fe2O3 and ZnO are good photocatalytic materials, we have investigated the photodegradation performances of the core-shell heterostructures using organic dyes Rhodamin B (RhB). It is interesting to find that the as-obtained iron oxides/ZnO core-shell heterostructures exhibited enhanced visible light or UV photocatalytic abilities, remarkably superior to the as-used α-Fe2O3 seeds and commercial TiO2 products (P25), mainly owing to the synergistic effect between the narrow and wide bandgap semiconductors and effective electron-hole separation at the interfaces of iron oxides/ZnO.

Magnetic properties of GdT 2Zn 20 (T = Fe, Co) investigated by x-ray diffraction and spectroscopy

DOE PAGES

J. R. L. Mardegan; Fabbris, G.; Francoual, S.; ...

2016-01-26

In this study, we investigate the magnetic and electronic properties of the GdT 2Zn 20 (T=Fe and Co) compounds using x-ray resonant magnetic scattering (XRMS), x-ray absorption near-edge structure (XANES), and x-ray magnetic circular dichroism (XMCD). The XRMS measurements reveal that GdCo 2Zn 20 has a commensurate antiferromagnetic spin structure with a magnetic propagation vector →/ τ = (12,12,12) below the Néel temperature (T N ~ 5.7 K). Only the Gd ions carry a magnetic moment forming an antiferromagnetic structure with magnetic representation Γ 6. For the ferromagnetic GdFe 2Zn 20 compound, an extensive investigation was performed at low temperaturemore » and under magnetic field using XANES and XMCD. A strong XMCD signal of about 12.5% and 9.7% is observed below the Curie temperature (T C ~ 85K) at the Gd L 2 and L 3 edges, respectively. In addition, a small magnetic signal of about 0.06% of the jump is recorded at the Zn K edge, suggesting that the Zn 4p states are spin polarized by the Gd 5d extended orbitals.« less

Molecular mapping of the grain iron and zinc concentration, protein content and thousand kernel weight in wheat (Triticum aestivum L.)

PubMed Central

Krishnappa, Gopalareddy; Chaudhary, Swati; Ahlawat, Arvind Kumar; Singh, Santosh Kumar; Shukla, Ram Bihari; Jaiswal, Jai Prakash; Singh, Gyanendra Pratap; Solanki, Ishwar Singh

2017-01-01

Genomic regions responsible for accumulation of grain iron concentration (Fe), grain zinc concentration (Zn), grain protein content (PC) and thousand kernel weight (TKW) were investigated in 286 recombinant inbred lines (RILs) derived from a cross between an old Indian wheat variety WH542 and a synthetic derivative (Triticum dicoccon PI94624/Aegilops squarrosa [409]//BCN). RILs were grown in six environments and evaluated for Fe, Zn, PC, and TKW. The population showed the continuous distribution for all the four traits, that for pooled Fe and PC was near normal, whereas, for pooled Zn, RILs exhibited positively skewed distribution. A genetic map spanning 2155.3cM was constructed using microsatellite markers covering the 21 chromosomes and used for QTL analysis. 16 quantitative trait loci (QTL) were identified in this study. Four QTLs (QGFe.iari-2A, QGFe.iari-5A, QGFe.iari-7A and QGFe.iari-7B) for Fe, five QTLs (QGZn.iari-2A, QGZn.iari-4A, QGZn.iari-5A, QGZn.iari-7A and QGZn.iari-7B) for Zn, two QTLs (QGpc.iari-2A and QGpc.iari-3A) for PC, and five QTLs (QTkw.iari-1A, QTkw.iari-2A, QTkw.iari-2B, QTkw.iari-5B and QTkw.iari-7A) for TKW were identified. The QTLs together explained 20.0%, 32.0%, 24.1% and 32.3% phenotypic variation, respectively, for Fe, Zn, PC and TKW. QGpc.iari-2A was consistently expressed in all the six environments, whereas, QGFe.iari-7B and QGZn.iari-2A were identified in two environments each apart from pooled mean. QTkw.iari-2A and QTkw.iari-7A, respectively, were identified in four and three environments apart from pooled mean. A common region in the interval of Xgwm359-Xwmc407 on chromosome 2A was associated with Fe, Zn, and PC. One more QTL for TKW was identified on chromosome 2A but in a different chromosomal region (Xgwm382-Xgwm359). Two more regions on 5A (Xgwm126-Xgwm595) and 7A (Xbarc49-Xwmc525) were found to be associated with both Fe and Zn. A QTL for TKW was identified (Xwmc525-Xbarc222) in a different chromosomal region on the same chromosome (7A). This reflects at least a partly common genetic basis for the four traits. It is concluded that fine mapping of the regions of the three chromosomes of A genome involved in determining the accumulation of Fe, Zn, PC, and TKW in this mapping population may be rewarding. PMID:28384292

Nano/microstructure and optical properties of ZnO particles precipitated from zinc acetylacetonate

NASA Astrophysics Data System (ADS)

Petrović, Željka; Ristić, Mira; Musić, Svetozar; Fabián, Martin

2015-06-01

The influence of experimental conditions on the nano/microstructure and optical properties of ZnO particles produced by rapid hydrolysis of zinc acetylacetonate, followed by aging of the precipitation system at 160 °C, was investigated. Samples were characterized by XRD, FE scanning electron microscopy (FE-SEM), FT-IR, UV/Vis/NIR and photoluminescence (PL) spectroscopies. XRD patterns of all samples were assigned to the hexagonal ZnO phase (wurtzite-type), as well as the corresponding FT-IR spectra. FE-SEM inspection showed a high dependence of the ZnO nano/microstructure on the chemical composition of the reaction mixture and autoclaving time after the rapid hydrolysis of zinc acetylacetonate. Microstructural differences were noticed between C2H5OH/H2O and H2O media, as well as under the influence of NH4OH addition. Measurements of nanocrystallite sizes showed no significant preferential orientation in the (1 0 0) and (0 0 2) directions relative to the (1 0 1) and (1 1 0) directions. Somewhat smaller crystallite sizes were noticed for ZnO samples synthesized by adding the NH4OH solution. Dissolution/recrystallization of ZnO particles played an important role in the formation of different ZnO nano/microstructures. The band gap values for prepared ZnO samples were calculated on the basis of recorded UV/Vis spectra. PL spectra were recorded for ZnO samples in powder form and their suspensions in pure ethanol. Noticed differences are discussed.

ZnO supported CoFe2O4 nanophotocatalysts for the mineralization of Direct Blue 71 in aqueous environments.

PubMed

Sathishkumar, Panneerselvam; Pugazhenthiran, Nalenthiran; Mangalaraja, Ramalinga Viswanathan; Asiri, Abdullah M; Anandan, Sambandam

2013-05-15

In this study, an attempt was made to render both the magnetic and photocatalytic properties in a semiconductor material to enhance the efficiency of degradation and recycling possibility of magnetic nanophotocatalysts. CoFe2O4 and CoFe2O4 loaded ZnO nanoparticles were prepared by a simple co-precipitation method and characterized using various analytical tools and in addition to check its visible light assisted photocatalytic activity. CoFe2O4/ZnO nanocatalyst coupled with acceptor, peroxomonosulphate (PMS) showed 1.69-fold enhancement in Direct Blue 71 (triazo dye; DB71) mineralization within 5h. The accomplished enrichment in decolorization was due to the production of more number of non-selective and active free radicals at the catalyst surface. Copyright © 2013 Elsevier B.V. All rights reserved.

Renierite, Cu10ZnGe2Fe4S16-Cu11GeAsFe4S16: a coupled solid solution series.

USGS Publications Warehouse

Bernstein, L.R.

1986-01-01

The composition of renierite is found to be Cu10(Zn1-xCux)Ge2-xAsxFe4S16 (0 = or < x = or < 1), with continuous solid solution between the zincian and arsenian end-members, Cu10ZnGe2Fe4S16 and Cu11GeAsFe4S16, through the coupled substitution Zn(II) + Ge(IV) = Cu(I) + As(V). This is the first reported example of extensive coupled solid solution in a sulphide mineral. Arsenian renierite, not previously characterized, is similar to zincian renierite in polished section, with a slightly redder colour and lower anisotropy. It is reddish orange with relief very similar to that of bornite, though it is harder (VHN25 = 286) and does not tarnish in air. It is slightly bireflective, with colours varying from orange-yellow to reddish orange in nearly crossed polarizers. The strongest powder XRD lines are: 3.042(100), 1.861(29), 1.869(16), 1.594(11) and 1.017(10) A; D(calc.) 4.50 g/cm3. Specimens have been found at the Ruby Creek copper deposit, Alaska, where zincian renierite also occurs, and at the Inexco no. 1 mine, Jamestown, Colorado.-J.A.Z.

Removal of metals from landfill leachate by sorption to activated carbon, bone meal and iron fines.

PubMed

Modin, Hanna; Persson, Kenneth M; Andersson, Anna; van Praagh, Martijn

2011-05-30

Sorption filters based on granular activated carbon, bone meal and iron fines were tested for their efficiency of removing metals from landfill leachate. Removal of Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sr and Zn were studied in a laboratory scale setup. Activated carbon removed more than 90% of Co, Cr, Cu, Fe, Mn and Ni. Ca, Pb, Sr and Zn were removed but less efficiently. Bone meal removed over 80% of Cr, Fe, Hg, Mn and Sr and 20-80% of Al, Ca, Cu, Mo, Ni, Pb and Zn. Iron fines removed most metals (As, Ca, Co, Cr, Cu, Fe, Mg, Mn, Pb, Sr and Zn) to some extent but less efficiently. All materials released unwanted substances (metals, TOC or nutrients), highlighting the need to study the uptake and release of a large number of compounds, not only the target metals. To remove a wide range of metals using these materials two or more filter materials may need to be combined. Sorption mechanisms for all materials include ion exchange, sorption and precipitation. For iron fines oxidation of Fe(0) seems to be important for metal immobilisation. Copyright © 2011 Elsevier B.V. All rights reserved.

Dye-Sensitized Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) Nanofibers for Efficient Photocatalytic Hydrogen Evolution.

PubMed

Gonce, Mehmet Kerem; Aslan, Emre; Ozel, Faruk; Hatay Patir, Imren

2016-03-21

The photocatalytic hydrogen evolution activities of low-cost and noble-metal-free Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofiber catalysts have been investigated using triethanolamine as an electron donor and eosin Y as a photosensitizer under visible-light irradiation. The rates of hydrogen evolution by Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofibers have been compared with each other and with that of the noble metal Pt. The hydrogen evolution rates for the nanofibers change in the order Cu2 NiSnS4 >Cu2 FeSnS4 >Cu2 CoSnS4 >Cu2 ZnSnS4 >Cu2 MnSnS4 (2028, 1870, 1926, 1420, and 389 μmol g(-1) h(-1) , respectively). The differences between the hydrogen evolution rates of the nanofibers could be attributed to their energy levels. Moreover, Cu2 NiSnS4, Cu2 FeSnS4 , and Cu2 CoSnS4 nanofibers show higher and more stable photocatalytic hydrogen production rates than that of the noble metal Pt under long-term irradiation with visible light. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Room-temperature photomagnetism in the spinel ferrite (Mn,Zn,Fe)3O4 as seen via soft x-ray magnetic circular dichroism

NASA Astrophysics Data System (ADS)

Bettinger, J. S.; Piamonteze, C.; Chopdekar, R. V.; Liberati, M.; Arenholz, E.; Suzuki, Y.

2009-10-01

We have used x-ray magnetic circular dichroism (XMCD) in conjunction with multiplet simulations to directly probe the origin of photomagnetism in nanocrystalline (Mn,Zn,Fe)3O4 . A photomagnetic effect at room temperature has been observed in these films with HeNe illumination. We have verified an intervalence charge transfer among octahedral Fe cations to account for the increase in magnetization observed at and above room temperature in small magnetic fields. Using XMCD, we demonstrate that the dichroism of Fe in octahedral sites increases by 18% at room temperature, while the dichroism of Fe in tetrahedral sites does not change.

Effects of SnO2, WO3, and ZrO2 addition on the magnetic and mechanical properties of NiCuZn ferrites

NASA Astrophysics Data System (ADS)

Wang, Sea-Fue; Yang, Hsiao-Ching; Hsu, Yung-Fu; Hsieh, Chung-Kai

2015-01-01

In this study, the effects of SnO2, WO3 and ZrO2 addition at levels up to 5 wt% on the magnetic and mechanical properties of Ni0.5Cu0.3Zn0.2Fe2O4 ceramics were investigated. Only Ni0.5Cu0.3Zn0.2Fe2O4 ceramic with a SnO2 addition of ≥3.5 wt% required a densification temperature of 1150 °C, while the others reached maximum densification at 1075 °C. All samples revealed a pure spinel phase and a uniform microstructure, except for the Ni0.5Cu0.3Zn0.2Fe2O4 ceramic with the WO3 addition, which showed an exaggerated grain growth accompanied with a small amount of needle-shaped Cu0.85Zn0.15WO4 second phase. The fracture mode in the pure Ni0.5Cu0.3Zn0.2Fe2O4 ceramic revealed a transgranular phase, as the CuO second phase increased the grain boundary strength; the Ni0.5Cu0.3Zn0.2Fe2O4 ceramics sintered with 5 wt% additives showed an intergranular phase. The Vickers hardness and the bending strength of the Ni0.5Cu0.3Zn0.2Fe2O4 ceramic were 733.6 and 62.0 MPa, respectively. The Vickers hardness of the ferrite with added SnO2 or ZrO2 showed only a slight improvement, while an apparent change (832.7) was observed with the addition of 5.0 wt% WO3. The bending strength of the ferrite was optimized at 75.7 MPa with 2.0 wt% SnO2 and at 90.5 MPa with 3.5 wt% ZrO2, while that of the ferrite sintered with WO3 added dropped gradually from 62.0 to 47.7 MPa as the amount of WO3 was increased from 0 to 5.0 wt% due to the non-uniform microstructure. The pure Ni0.5Cu0.3Zn0.2Fe2O4 ceramic sintered at 1075 °C had an initial permeability of 356.9 and a quality factor of 71.2. The addition of ZrO2 led to a significant increase in the initial permeability (588.4 at 5.0 wt% ZrO2), but a slight decline in the quality factor (56.6 at 5.0 wt% ZrO2).

Irreversibility and critical current density of FeSr2ErCu2O6+y

NASA Astrophysics Data System (ADS)

Hata, Y.; Iida, I.; Mochiku, T.; Yasuoka, H.

2018-03-01

FeSr2ErCu2O6+y (ErFe1212) and non-superconducting FeSr2ErCu1.9Zn0.1O6+y were synthesized to study the property of the superconductivity and the irreversibility of ErFe1212. A large irreversibility in the temperature dependence of magnetization and a hysteresis in the magnetization curve were observed in ErFe1212. By comparison with non-superconducting FeSr2ErCu1.9Zn0.1O6+y, it was found that the most part of the hysteresis at high magnetic eld originates from the magnetism of Fe ion and some part of the hysteresis at low magnetic eld originates from the superconductivity. Using the magnetization curve of ErFe1212 and FeSr2ErCu1.9Zn0.1O6+y, the J c of ErFe1212 in individual grains at 10 K under 0.1 T was estimated by the Bean model and {J}\\text{c}\\text{intra} was 2.6 × 109 A/m2. The critical current density across inter-grain boundaries at 10 K estimated by V ‑ I measurement was {J}\\text{c}\\text{intra} = 5.7 × 104 A/m2. A large difference between {J}\\text{c}\\text{intra} and {J}\\text{c}\\text{intra} was observed in ErFe1212. {J}\\text{c}\\text{intra} and {J}\\text{c}\\text{intra} of ErFe1212 are 2.2 and 5.2 times larger than these of YFe1212, respectively.

An alternative approach to recovering valuable metals from zinc phosphating sludge.

PubMed

Kuo, Yi-Ming

2012-01-30

This study used a vitrification process (with good potential for commercialization) to recover valuable metals from Zn phosphating sludge. The involved vitrification process achieves two major goals: it transformed hazardous Zn phosphating sludge into inert slag and it concentrated Fe (83.5%) and Zn (92.8%) into ingot and fine particulate-phase material, respectively. The Fe content in the ingot was 278,000 mg/kg, making the ingot a potential raw material for iron making. The fine particulate-phase material (collected from flue gas) contained abundant Zn (544,000 mg/kg) in the form of ZnO. The content (67.7%) of ZnO was high, so it can be directly sold to refineries. The recovered coarse particulate-phase material, with insufficient amount of ZnO, can be recycled as a feeding material for Zn re-concentration. Therefore, the vitrification process can not only treat hazardous materials but also effectively recover valuable metals. Copyright © 2011 Elsevier B.V. All rights reserved.

Influence of Gas Atmosphere Dew Point on the Galvannealing of CMnSi TRIP Steel

NASA Astrophysics Data System (ADS)

Cho, Lawrence; Kim, Myung Soo; Kim, Young Ha; De Cooman, Bruno C.

2013-11-01

The Fe-Zn reaction occurring during the galvannealing of a Si-bearing transformation-induced plasticity (TRIP) steel was investigated by field-emission electron probe microanalysis and field-emission transmission electron microscopy. The galvannealing was simulated after hot dipping in a Zn bath containing 0.13 mass pct Al at 733 K (460 °C). The galvannealing temperature was in the range of 813 K to 843 K (540 °C to 570 °C). The kinetics and mechanism of the galvannealing reaction were strongly influenced by the gas atmosphere dew point (DP). After the galvannealing of a panel annealed in a N2+10 pct H2 gas atmosphere with low DPs [213 K and 243 K (-60 °C and -30 °C)], the coating layer consisted of δ (FeZn10) and η (Zn) phase crystals. The Mn-Si compound oxides formed during intercritical annealing were present mostly at the steel/coating interface after the galvannealing. Galvannealing of a panel annealed in higher DP [263 K and 273 K, and 278 K (-10 °C, 0 °C, and +5 °C)] gas atmospheres resulted in a coating layer consisting of δ and Г (Fe3Zn10) phase crystals, and a thin layer of Г 1 (Fe11Zn40) phase crystals at the steel/coating interface. The Mn-Si oxides were distributed homogeneously throughout the galvannealed (GA) coating layer. When the surface oxide layer thickness on panels annealed in a high DP gas atmosphere was reduced, the Fe content at the GA coating surface increased. Annealing in a higher DP gas atmosphere improved the coating quality of the GA panels because a thinner layer of oxides was formed. A high DP atmosphere can therefore significantly contribute to the suppression of Zn-alloy coating defects on CMnSi TRIP steel processed in hot dip galvanizing lines.

A Passively Q-Switched, CW-Pumped Fe:ZnSe Laser

DTIC Science & Technology

2014-03-01

passively Q-switched microchip lasers using semiconductor saturable absorbers,” J. Opt. Soc. Amer. B, Opt. Phys., vol. 16, no. 3, pp. 376–388, Mar. 1999...204 IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 50, NO. 3, MARCH 2014 A Passively Q-Switched, CW-Pumped Fe:ZnSe Laser Jonathan W. Evans, Patrick A...Berry, and Kenneth L. Schepler Abstract— We report the demonstration of high-average-power passively Q-switched laser oscillation from Fe2+ ions in zinc

Effect of Sulfur on Liquidus Temperatures in the ZnO-"FeO"-Al2O3-CaO-SiO2-S System in Equilibrium with Metallic Iron

NASA Astrophysics Data System (ADS)

Zhao, Baojun; Hayes, Peter C.; Jak, Evgueni

2011-10-01

The phase equilibria in the ZnO-"FeO"-Al2O3-CaO-SiO2-S system have been determined experimentally in equilibrium with metallic iron. A pseudoternary section of the form ZnO-"FeO"-(Al2O3+CaO+SiO2) for CaO/SiO2 = 0.71 (weight), (CaO+SiO2)/Al2O3 = 5.0 (weight), and fixed 2.0 wt pct S concentration has been constructed. It was found that the addition of 2.0 wt pct S to the liquid extends the spinel primary phase field significantly and decreases the size of the wustite primary phase field. The liquidus temperature in the wustite primary phase field is decreased by approximately 80 K and the liquidus temperature in the spinel primary phase field is decreased by approximately 10 K with addition of 2.0 wt pct S in the composition range investigated. It was also found that iron-zinc sulfides are present in some samples in the spinel primary phase field, which are matte appearing at low zinc concentrations and sphalerite (Zn,Fe)S at higher zinc concentrations. The presence of sulfur in the slag has a minor effect on the partitioning of ZnO between the wustite and liquid phases but no effect on the partitioning of ZnO between the spinel and liquid phases.

Observed And Modeled Seasonal Trends In Dissolved And Particulate Cu, Fe, Mn, And Zn In A Mining-Impacted Stream

EPA Science Inventory

North Fork Clear Creek (NFCC) in Colorado, an acid-mine drainage (AMD) impacted stream, was chosen to examine the distribution of dissolved and particulate Cu, Fe, Mn, and Zn in the water column, with respect to seasonal hydrologic controls. NFCC is a high-gradient stream with d...

Structural, dielectric and magnetic properties of ZnFe2O4-Na0.5Bi0.5TiO3 multiferroic composites

NASA Astrophysics Data System (ADS)

Bhasin, Tanvi; Agarwal, Ashish; Sanghi, Sujata; Yadav, Manisha; Tuteja, Muskaan; Singh, Jogender; Rani, Sonia

2018-04-01

Multiferroic xNa0.5Bi0.5TiO3-(1-x)ZnFe2O4 (x=0.10, 0.20) composites were prepared by conventional solid state reaction method. Rietveld analysis of XRD data shows that samples exhibit both cubic (Fd-3m) and rhombohedral (R3c) crystal structure. Structural parameters and unit cell volume of samples vary with composition. The dielectric constant and dielectric loss (tanδ) display dispersion at low frequency due to space charge polarization and inhomogeneity in the composites. Magnetic analysis depicts the antiferromagnetic behavior of composites and magnetization is enhanced with the introduction of ferrite (ZnFe2O4) phase.

Estimated daily intake of Fe, Cu, Ca and Zn through common cereals in Tehran, Iran.

PubMed

Kashian, S; Fathivand, A A

2015-06-01

This paper presents the findings of study undertaken to estimate the dietary intake of iron (Fe), copper (Cu), calcium (Ca) and zinc (Zn) through common cereals in Tehran, Iran. 100 samples of rice, wheat and barley were collected from various brands between August and October 2013. The samples were analyzed performing instrumental neutron activation analysis (INAA). The dietary intake for adults was estimated by a total cereal study. Calculations were carried out on the basis of the reported adults' average food consumption rate data. The total daily intake estimated in mgd(-1) for Tehran population were 3.6 (Fe), 10.2 (Zn), 0.3 (Cu) and 234.5 (Ca). Wheat showed the highest contribution to Zn, Cu and Ca intakes. Furthermore, intakes were compared with recommended dietary allowance (RDA). Zn total intake (10.2mgd(-1)) was comparable with RDA values for males (11mgd(-1)) and was higher than recommended value for females (8mgd(-1)). The intakes of other studied elements were below the respective RDAs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of Cu2+ substitution on the magnetic properties of co-precipitated Ni-Cu-Zn ferrite nanoparticles

NASA Astrophysics Data System (ADS)

Ramakrishna, K. S.; Srinivas, Ch.; Tirupanyam, B. V.; Ramesh, P. N.; Meena, S. S.; Potukuchi, D. M.; Sastry, D. L.

2017-05-01

Spinel ferrite nanoparticles with chemical equation NixCu0.1Zn0.9-xFe2O4 (x = 0.5, 0.6, 0.7) have been synthsized using co-precipitation method followed by heat treatment at a temperature of 200 °C for 2h. The results of XRD, FE-SEM and VSM studies are reported. XRD patterns confirm the formation of cubic spinel phase of ferrite samples along with small amount of a secondary phase of α-Fe2O3 whose concentration decreases as Ni2+ concentration increases. The crystallite sizes (in the range of 7.5-13.9 nm) increase and the lattice parameter decreases with increase in Ni2+ ion concentration. These values are comparable to those of NiZn ferrite without Cu substitution. It has been observed that there is a considerable reduction in saturation magnetisation (Ms). This and differences in other magnetic parameters are attributed to considerable changes in cation distribution or core shell interactions of NiZn ferrite with 10 mole% Cu substitution in the place of Zn.

Magnetic and crystallographic properties of ZrM 2-δZn 20+δ (M=Cr–Cu)

DOE PAGES

Svanidze, E.; II, M. Kindy; Georgen, C.; ...

2016-04-29

Single crystals of the cubic Laves ternaries ZrM 2-δZn 20+δ (M=Mn, Fe, Co, Ni and Cu, 0 ≤ δ ≤ 1) have been synthesized in this paper using a self-flux method. The magnetic properties of these compounds were compared with structurally similar cubic binaries ZrM 2 (M=Mn, Fe, Co, Ni and Cu). A transition from local to itinerant moment magnetism was observed for M=Fe and M=Mn, while all other ternaries exhibit weakly para- or diamagnetic behavior. The local-to-itinerant crossover can be explained by a nearly two-fold increase of the M–M bond length d M–M in ZrM 2-δZn 20+δ compounds, asmore » compared with the ZrM 2 binaries. Additionally, we report two new compounds in this series ZrCrZn 21 and ZrCu 2Zn 20. Finally, analysis of crystallographic and magnetic trends in these materials will aid in understanding of magnetism in general and 3d intermetallics in particular.« less

Distribution of dissolved and labile particulate trace metals in the overlying bottom water in the Vistula River plume (southern Baltic Sea).

PubMed

Sokolowski, A; Wolowicz, M; Hummel, H

2001-10-01

Overlying bottom water samples were collected in the Vistula River plume, southern Baltic Sea, (Poland) and analysed for dissolved and labile particulate (1 M HCl extractable) Cu, Pb, Zn, Mn, Fe and Ni, hydrological parameters being measured simultaneously. Particulate organic matter (POM), chlorophyll a and dissolved oxygen are key factors governing the chemical behaviour of the measured metal fractions. For the dissolved Cu, Pb, Zn, Fe and Ni two maxima, in the shallow and in the deeper part of the river plume, were found. In the shallow zone desorption from seaward fluxing metal-rich riverine particles account for markedly increased metal concentrations, as confirmed also by high particulate metal contents. For Pb, atmospheric inputs were also considered to have contributed to the elevated concentrations of dissolved Pb adjacent to the river mouth. In the deep zone desorption from detrital and/or resuspended particles by aerobic decomposition of organic material may be the main mechanism responsible for enrichment of particle-reactive metals (Cu, Pb, Zn) in the overyling bottom waters. The increased concentrations of dissolved Fe may have been due to reductive dissolution of Fe oxyhydroxides within the deep sediments by which dissolved Ni was released to the water. The distribution of Mn was related to dissolved oxygen concentrations, indicating that Mn is released to the water column under oxygen reduced conditions. However, Mn transfer to the dissolved phase from anoxic sediments in deeper part of the Vistula plume was hardly evidenced suggesting that benthic flux of Mn occurs under more severe reductive regime than is consistent with mobilization of Fe. Behaviour of Mn in a shallower part has been presumably affected by release from porewaters and by oxidization into less soluble species resulting in seasonal removal of this metal (e.g. in April) from the dissolved phase. The particulate fractions represented from about 6% (Ni) and 33% (Mn, Zn, Cu) to 80% (Fe) and 89% (Pb) of the total (labile particulate plus dissolved) concentrations. The affinity of the metals for particulate matter decreased in the following order: Pb > Fe > Zn > or = > Cu > Mn > Ni. Significant relationships between particulate Pb-Zn-Cu reflected the affinity of these metals for organic matter, and the significant relationship between Ni-Fe reflected the adsorption of Ni onto Fe-Mn oxyhydroxides. A comparison of metal concentrations with data from other similar areas revealed that the river plume is somewhat contaminated with Cu, Pb and Zn which is in agreement with previous findings on anthropogenic origin of these metals in the Polish zone of southern Baltic Sea.

Time-resolved determination of Fe(II) ions using cysteine-bridged Mn-doped ZnS quantum dots as a phosphorimetric probe.

PubMed

Jing, Wenjie; Lu, Yuexiang; Wang, Feiyang; He, Liuying; Sun, Jingwei; Liu, Yueying

2018-05-12

A time-resolved phosphorescence (TRP) is applied to the highly sensitive determination of Fe(II) ions. The method is based on the use of a phosphorescent probe consisting of cysteine-bridged Mn-doped ZnS quantum dots (Mn/ZnS QDs). The presence of cysteine enhances the phosphorescence of the QDs and also increases the efficiency of quenching caused by Fe(II) ions. This results in strongly improved selectivity for Fe(II). The linear response is obtained in the concentration range of 50-1000 nM with a 19 nM detection limit. Phosphorescence is recorded at excitation/emission peaks of 301/602 nm. The interference of short-lived fluorescent and scattering background from the biological fluids is eliminated by using the TRP mode with a delay time of 200 μs. The determination of Fe(II) in human serum samples spiked at a 150 nM level gave a 92.4% recovery when using the TRP mode, but only 52.4% when using steady-state phosphorescence. This demonstrates that this probe along with TRP detection enables highly sensitive and accurate determination of Fe(II) in serum. Graphical abstract Schematic of a novel phosphorescent method for the detection of Fe 2+ ions based on cysteine-bridged Mn-doped ZnS quantum dots. The sensitivity of this assay greatly increases due to the addition of cysteine. Interferences by short-lived auto-fluorescence and the scattering light from the biological fluids is eliminated by using time-resolved phosphorescence mode.

Photoelectron spectroscopy of the bis(dithiolene) anions [M(mnt)2]n- (M = Fe - Zn; n = 1, 2): changes in electronic structure with variation of metal center and with oxidation.

PubMed

Waters, Tom; Wang, Xue-Bin; Woo, Hin-Koon; Wang, Lai-Sheng

2006-07-24

A detailed understanding of the electronic structures of transition metal bis(dithiolene) centers is important in the context of their interesting redox, magnetic, and optical properties. The electronic structures of the series [M(mnt)2]n- (M = Fe - Zn; mnt = 1,2-S2C2(CN)2; n = 1, 2) were examined by a combination of photodetachment photoelectron spectroscopy and density functional theory calculations, providing insights into changes in electronic structure with variation of the metal center and with oxidation. Significant changes were observed for the dianions [M(mnt)2]2- due to stabilization of the metal 3d levels from Fe to Zn and the transition from square-planar to tetrahedral coordination about the metal center (Fe-Ni, D(2h) --> Cu D2 --> Zn, D(2d). Changes with oxidation from [M(mnt)2]2- to [M(mnt)2]1- were largely dependent on the nature of the redox-active orbital in the couple [M(mnt)2](2-/1-). In particular, the first detachment feature for [Fe(mnt)2]2- originated from a metal-based orbital (Fe(II) --> Fe(III)) while that for [Fe(mnt)2]1- originated from a ligand-based orbital, a consequence of stabilization of Fe 3d levels in the latter. In contrast, the first detachment feature for both of [Ni(mnt)2]2- and [Ni(mnt)2]1- originated from the same ligand-based orbital in both cases, a result of occupied Ni 3d levels being stabilized relative those of Fe 3d and occurring below the highest energy occupied ligand-based orbital for both of [Ni(mnt)2]2- and [Ni(mnt)2]1- . The combined data illustrate the subtle interplay between metal- and ligand-based redox chemistry in these species and demonstrate changes in their electronic structures with variation of metal center, oxidation, and coordination geometry.

The effect of solution pH on the electrochemical performance of nanocrystalline metal ferrites MFe2O4 (M=Cu, Zn, and Ni) thin films

NASA Astrophysics Data System (ADS)

Elsayed, E. M.; Rashad, M. M.; Khalil, H. F. Y.; Ibrahim, I. A.; Hussein, M. R.; El-Sabbah, M. M. B.

2016-04-01

Nanocrystalline metal ferrite MFe2O4 (M=Cu, Zn, and Ni) thin films have been synthesized via electrodeposition-anodization process. Electrodeposited (M)Fe2 alloys were obtained from aqueous sulfate bath. The formed alloys were electrochemically oxidized (anodized) in aqueous (1 M KOH) solution, at room temperature, to the corresponding hydroxides. The parameters controlling the current efficiency of the electrodeposition of (M)Fe2 alloys such as the bath composition and the current density were studied and optimized. The anodized (M)Fe2 alloy films were annealed in air at 400 °C for 2 h. The results revealed the formation of three ferrite thin films were formed. The crystallite sizes of the produced films were in the range between 45 and 60 nm. The microstructure of the formed film was ferrite type dependent. The corrosion behavior of ferrite thin films in different pH solutions was investigated using open circuit potential (OCP) and potentiodynamic polarization measurements. The open circuit potential indicates that the initial potential E im of ZnFe2O4 thin films remained constant for a short time, then sharply increased in the less negative direction in acidic and alkaline medium compared with Ni and Cu ferrite films. The values of the corrosion current density I corr were higher for the ZnFe2O4 films at pH values of 1 and 12 compared with that of NiFe2O4 and CuFe2O4 which were higher only at pH value 1. The corrosion rate was very low for the three ferrite films when immersion in the neutral medium. The surface morphology recommended that Ni and Cu ferrite films were safely used in neutral and alkaline medium, whereas Zn ferrite film was only used in neutral atmospheres.

Structural, spectroscopic and thermal characterization of 2-tert-butylaminomethylpyridine-6-carboxylic acid methylester and its Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO(2)(II) complexes.

PubMed

Mohamed, Gehad G; El-Gamel, Nadia E A

2005-04-01

Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO(2)(II) complexes with the ligand 2-tert-butylaminomethylpyridine-6-carboxylic acid methylester (HL(2)) have been prepared and characterized by elemental analyses, molar conductance, magnetic moment, thermal analysis and spectral data. 1:1 M:HL(2) complexes, with the general formula [M(HL(2))X(2)].nH(2)O (where M = Co(II) (X = Cl, n = 0), Ni(II) (X = Cl, n = 3), Cu(II) (grey colour, X = AcO, n = 1), Cu(II) (yellow colour, X = Cl, n = 0) and Zn(II) (X = Br, n = 0). In addition, the Fe(III) and UO(2)(II) complexes of the type 1:2 M:HL(2) and with the formulae [Fe(L(2))(2)]Cl and [UO(2)(HL(2))(2)](NO(3))(2) are prepared. From the IR data, it is seen that HL(2) ligand behaves as a terdentate ligand coordinated to the metal ions via the pyridyl N, carboxylate O and protonated NH group; except the Fe(III) complex, it coordinates via the deprotonated NH group. This is supported by the molar conductance data, which show that all the complexes are non-electrolytes, while the Fe(III) and UO(2)(II) complexes are 1:1 electrolytes. IR and H1-NMR spectral studies suggest a similar behaviour of the Zn(II) complex in solid and solution states. From the solid reflectance spectral data and magnetic moment measurements, the complexes have a trigonal bipyramidal (Co(II), Ni(II), Cu(II) and Zn(II) complexes) and octahedral (Fe(III), UO(2)(II) complexes) geometrical structures. The thermal behaviour of the complexes is studied and the different dynamic parameters are calculated applying Coats-Redfern equation.

The effect of Fe2O3 crystal phases on CO2 hydrogenation

PubMed Central

Wang, Tianqi; Chen, Hongxian; Yang, Xiazhen; Jin, Yangfu

2017-01-01

The effect of Fe2O3 crystal phases on their performance in CO2 hydrogenation was studied. α-Fe2O3 crystal was prepared by precipitation method from Fe(NO3)3·9H2O and (NH4)2CO3, and γ-Fe2O3 was prepared by grinding Fe(NO3)3·9H2O and L(+)-Tartaric acid in agate mortar completely. The crystal phases of Fe2O3 influence the distribution of promoter Zn, K and Cu on catalysts. The dispersity of K on γ-Fe2O3 surface is higher than α-Fe2O3. On the contrary, Cu and Zn are more dispersive on α-Fe2O3 surface than γ-Fe2O3. The catalyst in γ-Fe2O3 phase is easily reduced relative to the catalyst in α-Fe2O3 phase. The former presents higher CO2 conversion and C2+ hydrocarbon selectivity than the latter in CO2 hydrogenation. PMID:28806421

The effect of Fe2O3 crystal phases on CO2 hydrogenation.

PubMed

Ning, Wensheng; Wang, Tianqi; Chen, Hongxian; Yang, Xiazhen; Jin, Yangfu

2017-01-01

The effect of Fe2O3 crystal phases on their performance in CO2 hydrogenation was studied. α-Fe2O3 crystal was prepared by precipitation method from Fe(NO3)3·9H2O and (NH4)2CO3, and γ-Fe2O3 was prepared by grinding Fe(NO3)3·9H2O and L(+)-Tartaric acid in agate mortar completely. The crystal phases of Fe2O3 influence the distribution of promoter Zn, K and Cu on catalysts. The dispersity of K on γ-Fe2O3 surface is higher than α-Fe2O3. On the contrary, Cu and Zn are more dispersive on α-Fe2O3 surface than γ-Fe2O3. The catalyst in γ-Fe2O3 phase is easily reduced relative to the catalyst in α-Fe2O3 phase. The former presents higher CO2 conversion and C2+ hydrocarbon selectivity than the latter in CO2 hydrogenation.

Ferroelectric enhancement in heterostructured ZnO /BiFeO3-PbTiO3 film

NASA Astrophysics Data System (ADS)

Yu, Shengwen; Chen, Rui; Zhang, Guanjun; Cheng, Jinrong; Meng, Zhongyan

2006-11-01

The authors have prepared heterostructured ZnO /BiFeO3-PbTiO3 (BFO-PT) composite film and BFO-PT film on Pt /Ti/SiO2/Si substrates by pulsed-laser deposition. The structure and morphologies of the films were characterized by x-ray diffraction (XRD) and scanning electron microscope. XRD results show that both films are perovskite structured last with different orientations. The leakage current density in the ZnO /BFO-PT film was found to be nearly two orders of magnitude lower. This could be due to the introduced ZnO layer behaving as a Schottky barrier between the BFO-PT film and top electrodes. The dramatic ferroelectric enhancement in ZnO /BFO-PT film is mostly ascribed to the improved insulation.

Analysis of ferrite nanoparticles in the flow of ferromagnetic nanofluid.

PubMed

Muhammad, Noor; Nadeem, Sohail; Mustafa, M T

2018-01-01

Theoretical analysis has been carried out to establish the heat transport phenomenon of six different ferromagnetic MnZnFe2O4-C2H6O2 (manganese zinc ferrite-ethylene glycol), NiZnFe2O4-C2H6O2 (Nickel zinc ferrite-ethylene glycol), Fe2O4-C2H6O2 (magnetite ferrite-ethylene glycol), NiZnFe2O4-H2O (Nickel zinc ferrite-water), MnZnFe2O4-H2O (manganese zinc ferrite-water), and Fe2O4-H2O (magnetite ferrite-water) nanofluids containing manganese zinc ferrite, Nickel zinc ferrite, and magnetite ferrite nanoparticles dispersed in a base fluid of ethylene glycol and water mixture. The performance of convective heat transfer is elevated in boundary layer flow region via nanoparticles. Magnetic dipole in presence of ferrites nanoparticles plays a vital role in controlling the thermal and momentum boundary layers. In perspective of this, the impacts of magnetic dipole on the nano boundary layer, steady, and laminar flow of incompressible ferromagnetic nanofluids are analyzed in the present study. Flow is caused by linear stretching of the surface. Fourier's law of heat conduction is used in the evaluation of heat flux. Impacts of emerging parameters on the magneto-thermomechanical coupling are analyzed numerically. Further, it is evident that Newtonian heating has increasing behavior on the rate of heat transfer in the boundary layer. Comparison with available results for specific cases show an excellent agreement.

Ethnic studies of dietary intakes of zinc, copper, iron, and calcium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matthews, C.; Figueroa, M.; Tam, C.F.

1986-01-01

Immigrants, such as S.E. Asians who live in the L.A. area, often suffer high incidences of diseases. It is of interest to examine ethnic eating patterns whether they influence dietary Zn, Cu, Fe, Ca, protein and Kcal, which are essential for proper immune functions. Three-day dietary intake of adult ethnic groups, Asian(A)(N=18), Caucasian(C)(26), Black(B)(7), Latino(L)(12), Middle Easterner(ME)(9) and Filipino(F)(6) were analyzed for Zn, Cu, Fe, Ca, protein and Kcal by Ohio Data Base Foods II(ODBF) then statistically compared by PROPHET. Zn and Cu were also analyzed by hand calculation(HC). No statistical differences were observed for mean Zn between groups analyzedmore » by ODBF whereas HC of mean Zn between A vs C (A=11.3 +/- S.D.2.9 mg vs C=8.8 +/- 2.8, P<0.01) and A vs L (11.3+/-2.9 vs L=8.9+/-2.2, P<0.05) were statistically different. No differences were found for Cu between the groups. By ODBF, none of mean Cu or Zn met 2/3 RDA for any of the groups. For Fe, no differences were found between groups and only 50% of the subjects met 2/3 RDA. Significant differences were observed for Ca only between A vs C and B vs C. Both A and B had lower mean Ca than C. All groups had adequate protein. Mean Kcal of all groups were found to be at or about 2/3 RDA. Both insufficient Kcal and eating patterns contribute to inadequate Cu, Zn, and Fe intakes and hence may affect immune competency.« less

Medicago sativa--Sinorhizobium meliloti Symbiosis Promotes the Bioaccumulation of Zinc in Nodulated Roots.

PubMed

Zribi, Kais; Nouairi, Issam; Slama, Ines; Talbi-Zribi, Ons; Mhadhbi, Haythem

2015-01-01

In this study we investigated effects of Zn supply on germination, growth, inorganic solutes (Zn, Ca, Fe, and Mg) partitioning and nodulation of Medicago sativa This plant was cultivated with and without Zn (2 mM). Treatments were plants without (control) and with Zn tolerant strain (S532), Zn intolerant strain (S112) and 2 mM urea nitrogen fertilisation. Results showed that M. sativa germinates at rates of 50% at 2 mM Zn. For plants given nitrogen fertilisation, Zn increased plant biomass production. When grown with symbionts, Zn supply had no effect on nodulation. Moreover, plants with S112 showed a decrease of shoot and roots biomasses. However, in symbiosis with S532, an increase of roots biomass was observed. Plants in symbiosis with S. meliloti accumulated more Zn in their roots than nitrogen fertilised plants. Zn supply results in an increase of Ca concentration in roots of fertilised nitrogen plants. However, under Zn supply, Fe concentration decreased in roots and increased in nodules of plants with S112. Zn supply showed contrasting effects on Mg concentrations for plants with nitrogen fertilisation (increase) and plants with S112 (decrease). The capacity of M. sativa to accumulate Zn in their nodulated roots encouraged its use in phytostabilisation processes.

Influence of Aluminum on the Formation Behavior of Zn-Al-Fe Intermetallic Particles in a Zinc Bath

NASA Astrophysics Data System (ADS)

Park, Joo Hyun; Park, Geun-Ho; Paik, Doo-Jin; Huh, Yoon; Hong, Moon-Hi

2012-01-01

The shape, size, and composition of dross particles as a function of aluminum content at a fixed temperature were investigated for aluminum added to the premelted Zn-Fe melt simulating the hot-dip galvanizing bath by a sampling methodology. In the early stage, less than 30 minutes after Al addition, local supersaturation and depletion of the aluminum concentration occurred simultaneously in the bath, resulting in the nucleation and growth of both Fe2Al5Zn x and FeZn13. However, the aluminum was homogenized continuously as the reaction proceeded, and fine and stable FeZn10Al x formed after 30 minutes. An Al-depleted zone (ADZ) mechanism was newly proposed for the "η→η+ζ→δ" phase transformations. The ζ phase bottom dross partly survived for a relatively long period, i.e., 2 hours in this work, whereas the η phase disappeared after 30 minutes. In the early stage of dross formation, both Al-free large particles as well as high-Al tiny particles were formed. The dross particle size decreased slightly with increased reaction time before reaching a plateau. The opposite tendency was observed when the Al content was 0.130 mass pct; with a relatively high Al content, the nucleation of tiny η phase dross was significantly enhanced because of the high degree of supersaturation. This unstable η phase dissolved continuously and underwent simple transformation to the stable δ phase. The relationship between nucleation potential and supersaturation ratio of species is discussed based on the thermodynamics of classical nucleation theory.

Analysis of iron, zinc, selenium and cadmium in paraffin-embedded prostate tissue specimens using inductively coupled plasma mass-spectrometry

USGS Publications Warehouse

Sarafanov, A.G.; Todorov, T.I.; Kajdacsy-Balla, A.; Gray, Michael A.; MacIas, V.; Centeno, J.A.

2008-01-01

Formalin-fixed paraffin-embedded (FFPE) tissue specimens represent a valuable and abundant resource of pathologic material for various biomedical studies. In the present study, we report the application of high-resolution inductively coupled mass-spectrometry (ICP-MS) for quantification of Fe, Zn, Se and Cd in FFPE prostate tissue. These elements have a possible role in the development of prostate diseases: while Zn and Se are needed for a healthy prostate, Cd shows multiple toxic and carcinogenic effects. Excessive accumulation of Fe induces the production of highly reactive hydroxyl radical species, which may play a role in cancer etiopathogenesis. To assess whether the levels of these metals in the FFPE prostate tissue represent their original content, we compared their levels with those in the fresh tissue (on dry weight basis) in samples obtained from 15 patients. We found that in FFPE tissue, the recoveries of Se, Fe, Cd and Zn were progressively decreased, 97??11% (r=0.88), 82??22% (r=0.86), 59??23% (r=0.69) and 24??11% (r=0.38), respectively. Thus, the use of correction factors, determined as k=0.16 for Se, k=0.20 for Fe, k=0.27 for Cd and k=0.67 for Zn, is required to estimate the retrospective levels of these elements in the parental non-processed fresh (wet) prostate tissue. The technique used in this study enables the analysis of archival FFPE prostate tissue for the concentrations of Fe, Zn, Se and Cd to study association between the levels of these metals and prostate disease. ?? 2008.

Synchrotron study of metal localization in Typha latifolia  L. root sections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Yu; Feng, Huan; Gallagher, Frank J.

2015-10-13

Understanding mechanisms that control plant root metal assimilation in soil is critical to the sustainable management of metal-contaminated land. With the assistance of the synchrotron X-ray fluorescence technique, this study investigated possible mechanisms that control the localization of Fe, Cu, Mn, Pb and Zn in the root tissues ofTypha latifolia L. collected from a contaminated wetland. Metal localizations especially in the case of Fe and Pb in the dermal tissue and the vascular bundles were different. Cluster analysis was performed to divide the dermal tissue into iron-plaque-enriched dermal tissue and regular dermal tissue based on the spatial distribution of Pb andmore » Fe. Factor analysis showed that Cu and Zn were closely correlated to each other in the dermal tissues. The association of Cu, Zn and Mn with Fe was strong in both regular dermal tissue and iron-plaque-enriched dermal tissue, while significant (p< 0.05) correlation of Fe with Pb was only observed in tissues enriched with iron plaque. In the vascular bundles, Zn, Mn and Cu showed strong association, suggesting that the localization of these three elements was controlled by a similar mechanism. Iron plaque in the peripheral dermal tissues acted as a barrier for Pb and a buffer for Zn, Cu and Mn. The Casparian strip regulated the transportation of metals from dermal tissues to the vascular bundles. The results suggested that the mechanisms controlling metal localization in root tissues varied with both tissue types and metals.« less

Effect of Synthesis Temperature and NaOH Concentration on Microstructural and Magnetic Properties of Mn0.5Zn0.5Fe2O4 Nanoparticles

NASA Astrophysics Data System (ADS)

Siregar, N.; Indrayana, I. P. T.; Suharyadi, E.; Kato, T.; Iwata, S.

2017-05-01

Mn0.5Zn0.5Fe2O4 nanoparticles have been successfully synthesized through coprecipitation method by varying NaOH concentrations from 0.5 M to 6 M and synthesis temperatures from 30 to 120 °C. The X-ray diffraction (XRD) pattern indicates samples consisting of multiphase structures such as spinel of Mn0.5Zn0.5Fe2O4, α-MnO2, ZnO, λ-MnO2, and γ-Fe2O3. The crystallite size of Mn0.5Zn0.5Fe2O4 is in the range of 14.1 to 26.7 nm. The Transmission electron microscope (TEM) image shows that sample was agglomerate. The hysteresis loops confirm that nanoparticles are soft magnetic materials with low coercivity (H c) in the range of 45.9 to 68.5 Oe. Those values increased relatively with increasing particles size. For NaOH concentration variation, the maximum magnetization of the sample increased from 10.4 emu/g to 11.6 emu/g with increasing ferrite content. Meanwhile, the maximum magnetization increased from 7.9 to 15.7 emu/g for samples with various synthesis temperature. The highest coercivity of 68.5 Oe was attained for a sample of 6 M NaOH under 90 °C. The highest magnetization of 15.7 emu/g was achieved for a sample of 1.5 M NaOH under 120 °C caused by the maximum crystallinity of sample.

Probing the Structure, Stability and Hydrogen Adsorption of Lithium Functionalized Isoreticular MOF-5 (Fe, Cu, Co, Ni and Zn) by Density Functional Theory

PubMed Central

Venkataramanan, Natarajan Sathiyamoorthy; Sahara, Ryoji; Mizuseki, Hiroshi; Kawazoe, Yoshiyuki

2009-01-01

Li adsorption on isoreticular MOFs with metal Fe, Cu, Co, Ni and Zn was studied using density function theory. Li functionalization shows a considerable structural change associated with a volume change in isoreticular MOF-5 except for the Zn metal center. Hydrogen binding energies on Li functionalized MOFs are seen to be in the range of 0.2 eV, which is the desired value for an ideal reversible storage system. This study has clearly shown that Li doping is possible only in Zn-based MOF-5, which would be better candidate to reversibly store hydrogen. PMID:19468328

High-zinc rice as a breakthrough for high nutritional rice breeding program

NASA Astrophysics Data System (ADS)

Barokah, U.; Susanto, U.; Swamy, M.; Djoar, D. W.; Parjanto

2018-03-01

WHO reported climate change already takes 150,000 casualties annually, due to the emergence of various diseases and malnutrition caused by food shortages and disasters. Rice is the staple food for almost all of Indonesian citizens, therefore Zn biofortification on rice is expected to be effective, efficient, massive, and sustainable to overcome the Zn nutritional deficiency. This study aims to identify rice with high Zn content and yield for further effort in releasing this variety. Ten lines along with two varieties as a comparison (Ciherang and Inpari 5 Merawu) were tested in Plumbon Village, Mojolaban Subdistrict, Sukoharjo Regency during February-May 2017. The experiment was designed in a Randomized Completely Block Design with four replications on a 4 m x 5 m area, with 25 cm x 25 cm plant spacing using seedling transplanting techniques of 21 days old seeds. The results showed that the plant genotypes treated had differences in yield characteristics, heading date, harvest age, panicle number, filled and un-filled grain per panicle, seed set, 1000 grains weight, Zn and Iron (Fe) content in rice grain. B13884-MR-29-1-1 line (30.94 ppm Zn, 15.84 ppm Fe, 4.11 ton/ha yield) and IR 97477- 115-1-CRB-0-SKI-1-SKI-0-2 (29.61 ppm Zn, 13.49 ppm Zn, 4.4 ton/ha yield) are prospective variety to be released. Ciherang had Zn content of 23.04 ppm, 11.93 ppm Fe, and yield of 4.07 t/ha.

Photoinduced formation of reactive oxygen species and electrons from metal oxide-silica nanocomposite: An EPR spin-trapping study

NASA Astrophysics Data System (ADS)

Zhao, Hongxia; Chen, Xiuying; Li, Xintong; Shen, Chen; Qu, Baocheng; Gao, Jingsuo; Chen, Jingwen; Quan, Xie

2017-09-01

Metal oxide nanocomposites with photocatalytic activity have the potential for many applications in environmental remediation and biomedicine. In this study, we investigated the formation and stabilization of electrons/holes from three metal oxide-silica nanocomposites (CuO-SiO2, Fe2O3-SiO2 and ZnO-SiO2) under irradiation by electron paramagnetic resonance (EPR) technology. The characteristic EPR signals with g = 2.00070-2.00105, ΔHp-p = 2.17-2.37 G were determined, which corresponded to lattice-trapped electrons. Moreover, the generation of active species from CuO-SiO2, Fe2O3-SiO2 and ZnO-SiO2 in aqueous solution under irradiation was also systematically studied. The results showed that all the three nanocomposites could generate hydroxyl radical, singlet oxygen and electron. CuO-SiO2 was more effective than Fe2O3-SiO2 and ZnO-SiO2 in producing hydroxyl radical and electrons, while ZnO-SiO2 was the most efficient in generating singlet oxygen. In addition, CuO-SiO2 exhibited most obviously photocatalytic activity toward degradation of bisphenol A, followed by Fe2O3-SiO2 and ZnO-SiO2. These findings will provide vital insights into photocatalytic mechanisms and potentially photoinduced toxicity of metal oxide-silica nanocomposites.

Nano-engineering of p-n CuFeO2-ZnO heterojunction photoanode with improved light absorption and charge collection for photoelectrochemical water oxidation

NASA Astrophysics Data System (ADS)

Karmakar, Keshab; Sarkar, Ayan; Mandal, Kalyan; Gopal Khan, Gobinda

2017-08-01

The effective utilization of abundant visible solar light for photoelectrochemical water splitting is a green approach for energy harvesting, to reduce the enormous rise of carbon content in the atmosphere. Here, a novel efficient design strategy for p-n type nano-heterojunction photoanodes is demonstrated, with the goal of improving water splitting efficiency by growing low band gap p-CuFeO2 nanolayers on n-ZnO nanorods by an easy and scalable electrochemical route. The photoconversion efficiency of p-n CuFeO2/ZnO photoanodes is found to be ˜450% higher than that of pristine ZnO nanorod electrodes under visible solar light illumination (λ > 420 nm, intensity 10 mW cm-2). The p-n CuFeO2/ZnO nano-engineering not only boosts the visible light absorption but also resolves limitations regarding effective charge carrier separation and transportation due to interfacial band alignment. This photoanode also shows remarkably enhanced stability, where the formation of p-n nano-heterojunction enhances the easy migration of holes to the electrode/electrolyte interface, and of electrons to the counter electrode (Pt) for hydrogen generation. Therefore, this work demonstrates that p-n nano-engineering is a potential strategy to design light-harvesting electrodes for water splitting and clean energy generation.

Chelation of Cu(II), Zn(II), and Fe(II) by Tannin Constituents of Selected Edible Nuts

PubMed Central

Karamać, Magdalena

2009-01-01

The tannin fractions isolated from hazelnuts, walnuts and almonds were characterised by colorimetric assays and by an SE-HPLC technique. The complexation of Cu(II) and Zn(II) was determined by the reaction with tetramethylmurexide, whereas for Fe(II), ferrozine was employed. The walnut tannins exhibited a significantly weaker reaction with the vanillin/HCl reagent than hazelnut and almond tannins, but the protein precipitation capacity of the walnut fraction was high. The SE-HPLC chromatogram of the tannin fraction from hazelnuts revealed the presence of oligomers with higher molecular weights compared to that of almonds. Copper ions were most effectively chelated by the constituents of the tannin fractions of hazelnuts, walnuts and almonds. At a 0.2 mg/assay addition level, the walnut tannins complexed almost 100% Cu(II). The Fe(II) complexation capacities of the tannin fractions of walnuts and hazelnuts were weaker in comparison to that of the almond tannin fraction, which at a 2.5 mg/assay addition level, bound Fe(II) by ~90%. The capacity to chelate Zn(II) was quite varied for the different nut tannin fractions: almond tannins bound as much as 84% Zn(II), whereas the value for walnut tannins was only 8.7%; and for hazelnut tannins, no Zn(II) chelation took place at the levels tested. PMID:20054482

Chelation of Cu(II), Zn(II), and Fe(II) by tannin constituents of selected edible nuts.

PubMed

Karamać, Magdalena

2009-12-22

The tannin fractions isolated from hazelnuts, walnuts and almonds were characterised by colorimetric assays and by an SE-HPLC technique. The complexation of Cu(II) and Zn(II) was determined by the reaction with tetramethylmurexide, whereas for Fe(II), ferrozine was employed. The walnut tannins exhibited a significantly weaker reaction with the vanillin/HCl reagent than hazelnut and almond tannins, but the protein precipitation capacity of the walnut fraction was high. The SE-HPLC chromatogram of the tannin fraction from hazelnuts revealed the presence of oligomers with higher molecular weights compared to that of almonds. Copper ions were most effectively chelated by the constituents of the tannin fractions of hazelnuts, walnuts and almonds. At a 0.2 mg/assay addition level, the walnut tannins complexed almost 100% Cu(II). The Fe(II) complexation capacities of the tannin fractions of walnuts and hazelnuts were weaker in comparison to that of the almond tannin fraction, which at a 2.5 mg/assay addition level, bound Fe(II) by approximately 90%. The capacity to chelate Zn(II) was quite varied for the different nut tannin fractions: almond tannins bound as much as 84% Zn(II), whereas the value for walnut tannins was only 8.7%; and for hazelnut tannins, no Zn(II) chelation took place at the levels tested.

Phytase from Citrobacter koseri PM-7: Enhanced production using statistical method and application in ameliorating mineral bioaccessibility and protein digestibility of high-phytate food.

PubMed

Tripathi, Preeti; A, Jyothi Lakshmi; Kapoor, Mukesh

2018-01-02

The present study was aimed at enhancing phytase (Phy-Ck) production from Citrobacter koseri PM-7 using response surface methodology (RSM) and improving the bioaccessibility of minerals (Fe and Zn) and protein digestibility in high-phytate food using Phy-Ck. A five-variable and three-level central composite design of RSM using wheat bran (6.681%, w/v), inoculum level (2.5%, v/v), and triton X-100 (0.2%, v/v) resulted in up to 5.57-fold (1.047 U/ml) improvement in Phy-Ck yield from C. koseri PM-7 when compared with fermentation media I and II. The model was successfully validated in the design space by taking a random set of variable combinations. Treatment of high-phytate food with partially purified Phy-Ck showed improvement in mineral bioaccessibility maximally for defatted sesame flour (DSF) (Fe 45.5%; Zn 50.7%) followed by wheat flour (WF) (Fe 13.5%; Zn 14.4%), green gram flour (GGF) (Fe 0.7%; Zn 3.8%) and defatted groundnut flour (DGF) (Zn 5.6%). The in vitro protein digestibility (IVPD) of WF increased from 48.83 to 65.04%, GGF from 45.04 to 57.12%, and DSF from 47.34 to 55.7% after Phy-Ck treatment.

Geochemical fractionation and pollution assessment of Zn, Cu, and Fe in surface sediments from Shadegan Wildlife Refuge, southwest of Iran.

PubMed

Chaharlang, Behnam Heidari; Bakhtiari, Alireza Riyahi; Mohammadi, Jahangard; Farshchi, Parvin

2017-09-01

This research focuses on the fractionation and distribution patterns of heavy metals (Zn, Cu, and Fe) in surficial sediments collected from Shadegan Wildlife Refuge, the biggest wetland in southern part of Iran, to provide an overall classification for the sources of metals in the study area using a sequential extraction method. For this purpose, a four-step sequential extraction technique was applied to define the partitioning of the metals into different geochemical phases of the sediment. The results illustrated that the average total level of Zn, Cu, and Fe in surface sediments were 55.20 ± 16.04, 22.86 ± 5.68, and 25,979.01 ± 6917.91 μg/g dw, respectively. On the average, the chemical partitioning of all metals in most stations was in the order of residual >oxidizable-organic > acid-reducible > exchangeable. In the same way, the results of calculated geochemical indices revealed that Cu, Zn, and Fe concentrations are mainly influenced by lithogenic origins. Compared with consensus-based SQGs, Cu was likely to result in occasionally harmful biological effects on the biota.

Synthesis and characterization of Cu0.3Zn0.5Mg0.2Fe2O4 nanoparticles as a magnetic drug delivery system

NASA Astrophysics Data System (ADS)

Ansari, Mohammad; Bigham, Ashkan; Hassanzadeh-Tabrizi, S. A.; Abbastabar Ahangar, H.

2017-10-01

Mixed spinel ferrite nanoparticles are being applied in biomedical applications due to their biocompatibility, antibacterial activity, particular magnetic and electronic properties with chemical and thermal stabilities. The Cu0.3Zn0.5Mg0.2Fe2O4 nanoparticles are synthesized through the thermal treatment method. Polyvinyl alcohol (PVA) is used as the capping agent to stabilize the particles and prevent their agglomeration. The synthesized nanoparticles are characterized through X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), N2 adsorption-desorption, field emission scanning electron microscopy (FESEM), and transmission electron microscope (TEM). The magnetic characterization is made on a vibrating sample magnetometer (VSM), which displayed super-paramagnetic behavior of the synthesized sample. Potential application of the Cu0.3Zn0.5Mg0.2Fe2O4 nanoparticles as a drug delivery agent is assessed in vitro by estimating their release properties. The obtained results indicate that the amount of ibuprofen (IBU) adsorbed into the nanocarrier of Cu0.3Zn0.5Mg0.2Fe2O4 is 104 mg/g and the drug release is sustained up to 72 h.

Pilot test of pollution control and metal resource recovery for acid mine drainage.

PubMed

Yan, Bo; Mai, Ge; Chen, Tao; Lei, Chang; Xiao, Xianming

2015-01-01

The study was undertaken in order to recover the metal resources from acid mine drainage (AMD). A 300 m(3)/d continuous system was designed and fractional precipitation technology employed for the main metals Fe, Cu, Zn, and Mn recovery. The system was operated for six months using actual AMD in situ. The chemicals' input and also the retention time was optimized. Furthermore, the material balance was investigated. With the system, the heavy metals of the effluent after the Mn neutralization precipitation were below the threshold value of the Chinese integrated wastewater discharge limit. The precipitates generated contained 42%, 12%, 31%, and 18% for Fe, Cu, Zn, and Mn, respectively, and the recovery rates of Fe, Cu, Zn, and Mn were 82%, 79%, 83%, and 83%, respectively. The yield range of the precipitate had significant correlation with the influent metal content. Using the X-ray diffraction analysis, the refinement for Fe, Cu, and Zn could be achieved through the processes of roasting and floatation. Cost-benefit was also discussed; the benefit from the recycled metal was able to pay for the cost of chemical reagents used. Most important of all, through the use of this technology, the frustrating sludge problems were solved.

Effects of pH Value of the Electrolyte and Glycine Additive on Formation and Properties of Electrodeposited Zn-Fe Coatings

PubMed Central

2013-01-01

Environmentally friendly and cyanide-free sulfate bath under continuous current and the corrosion behavior of electrodeposits of zinc-iron alloys were studied by means of electrochemical tests in a solution of 3.5% NaCl in presence and absence of glycine. The effects of pH on the quality of Zn-Fe coatings were investigated in order to improve uniformity and corrosion protection performance of the coating films. The deposit morphology was analyzed using scanning electron microscopy (SEM), and X-ray diffraction (XRD) was used to determine the preferred crystallographic orientations of the deposits. It was found that the uniformity and corrosion resistance of Zn-Fe coating films were strongly associated with pH of the coating electrolyte. To obtain the effect of pH on the film quality and corrosion performances of the films, the corrosion test was performed with potentiodynamic anodic polarization method. It was also observed that uniformity and corrosion resistivity of the coating films were decreased towards pH = 5 and then improved with increasing pH value of the electrolyte. The presence of glycine in the plating bath decreases the corrosion resistance of Zn-Fe coatings. PMID:23844388

Optical, electrical and ferromagnetic studies of ZnO:Fe diluted magnetic semiconductor nanoparticles for spintronic applications.

PubMed

Elilarassi, R; Chandrasekaran, G

2017-11-05

In the present investigation, diluted magnetic semiconductor (Zn 1-x Fe x O) nanoparticles with different doping concentrations (x=0, 0.02, 0.04, 0.06, and 0.08) were successfully synthesized by sol-gel auto-combustion method. The crystal structure, morphology, optical, electrical and magnetic properties of the prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis using x-rays (EDAX), ultraviolet-visible spectrophotometer, fluorescence spectroscope (FS), vibrating sample magnetometer (VSM) and broad band dielectric spectrometer (BDS). XRD results reveal that all the samples possess hexagonal wurtzite crystal structure with good crystalline quality. The absence of impurity phases divulge that Fe ions are well incorporated into the ZnO crystal lattice. The substitutional incorporation of Fe 3+ at Zn sites is reflected in optical absorption spectra of the samples. Flouorescence spectra of the samples show a strong near-band edge related UV emission as well as defect related visible emissions. The semiconducting behavior of the samples has been confirmed through electrical conductivity measurements. Magnetic measurements indicated that all the samples possess ferromagnetism at room temperature. Copyright © 2017 Elsevier B.V. All rights reserved.

Food matrix and cooking process affect mineral bioaccessibility of enteral nutrition formulas.

PubMed

Galán, María Gimena; Drago, Silvina Rosa

2014-02-01

When enteral formulas (EF) are administered orally as a supplement to the normal diet, they are often mixed with conventional foods or included in recipes in order to seek new flavors and textures and avoid monotony. The aims of this work were to study the bioaccessibility of Fe, Zn and Ca from commercial EF and the impact upon their incorporation into sweet preparations. Twenty commercial EF, before and after inclusion in sweet food (rice pudding, RP; banana smoothie, BS; tea, T; chocolate dessert, CD) were evaluated regarding Fe, Zn and Ca dialyzability (%DFe , %DZn , %DCa ) as an estimator of mineral bioaccessibility. Fe, Zn and Ca dialyzability from EF was variable and generally low. Heating during EF-sweet food preparation (T and CD) lowered values to 44.1 %DFe , possibly due to degradation of vitamin C, and 52.7 %DZn and 25.3 %DCa , due to the interaction with food components. EF and EF-sweet foods did not represent a good supply of Fe, Zn and Ca as recommended. This study demonstrated how the bioaccessibility of these minerals is affected by the food matrix in which EF is included as well as heating during food preparation. © 2013 Society of Chemical Industry.

Biosorption of heavy metals from industrial waste water by Geobacillus thermodenitrificans.

PubMed

Chatterjee, S K; Bhattacharjee, I; Chandra, G

2010-03-15

The metal binding capacity of the thermophilic bacteria Geobacillus thermodenitrificans isolated from Damodar river, India was assessed using synthetic metal solutions and industrial waste water. Biosorption preference of dead biomass of G. thermodenitrificans for the synthetic metal solutions was in the following order Fe(+3)>Cr(+3)>Co(+2)>Cu(+2)>Zn(+2)>Cd(+2)>Ag(+)>Pb(+2). It reduced the concentration of Fe(+3) (91.31%), Cr(+3) (80.80%), Co(+2) (79.71%), Cu(+2) (57.14%), Zn(+2) (55.14%), Cd(+2) (49.02%), Ag(+) (43.25%) and Pb(+2) (36.86%) at different optimum pH within 720 min. When this strain was applied in the industrial waste water biosorption preference was in the following order Fe(+3)>Cr(+3)>Cd(+2)>Pb(+2)>Cu(+2)>Co(+2)>Zn(+2)>Ag(+) and concentrations reduced up to 43.94% for Fe(+3), 39.2% for Cr(+3), 35.88% for Cd(+2), 18.22% for Pb(+2), 13.03% for Cu(+2), 11.43% for Co(+2), 9.02% for Zn(+2) and 7.65% for Ag(+) within 120 min. (c) 2009 Elsevier B.V. All rights reserved.

Optical and superparamagnetic behavior of ZnFe2O4 nanoparticles

NASA Astrophysics Data System (ADS)

Lal, Ganesh; Punia, Khushboo; Dolia, S. N.; Kumar, Sudhish

2018-05-01

Nanoparticles of zinc ferrite have been synthesized using a low temperature citrate sol-gel route and characterized by powder X-ray diffraction (XRD), Raman & UV-Vis-NIR spectroscopic and SQUID magnetometry measurements. Analysis of XRD pattern and Raman spectrum confirmed that the synthesized ZnFe2O4 sample crystallizes in single phase fcc spinel ferrite structure and the average particle size of nanoparticles is estimated to 24nm. Optical absorption study shows that maximum photo absorption take place in the visible band and peaking in UV band at 206nm and the band gap energy is estimated to Eg = 2.1eV. Zero Field Cooled (ZFC) and Field Cooled (FC) modes of magnetization down to 5K and in fields up to 20kOe shows that ZnFe2O4 nanoparticles exhibits superparamagnetism with high magneto-crystalline anisotropy and high magnetization. Small difference of 9K between the separation temperature TS=˜30K and blocking temperature TB= 21K are suggestive of the formation of ferromagnetic clusters and a narrow particle size distribution of the nanoparticles in superparamagnetic ZnFe2O4 nanoparticles.

Distribution of trace metals in surface seawater and zooplankton of the Bay of Bengal, off Rushikulya estuary, East Coast of India.

PubMed

Srichandan, Suchismita; Panigrahy, R C; Baliarsingh, S K; Rao B, Srinivasa; Pati, Premalata; Sahu, Biraja K; Sahu, K C

2016-10-15

Concentrations of trace metals such as iron (Fe), copper (Cu), zinc (Zn), cobalt (Co), nickel (Ni), manganese (Mn), lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), vanadium (V), and selenium (Se) were determined in seawater and zooplankton from the surface waters off Rushikulya estuary, north-western Bay of Bengal. During the study period, the concentration of trace metals in seawater and zooplankton showed significant spatio-temporal variation. Cu and Co levels in seawater mostly remained non-detectable. Other elements were found at higher concentrations and exhibited marked variations. The rank order distribution of trace metals in terms of their average concentration in seawater was observed as Fe>Ni>Mn>Pb>As>Zn>Cr>V>Se>Cd while in zooplankton it was Fe>Mn>Cd>As>Pb>Ni>Cr>Zn>V>Se. The bioaccumulation factor (BAF) of Fe was highest followed by Zn and the lowest value was observed with Ni. Results of correlation analysis discerned positive affinity and good relationship among the majority of the trace metals, both in seawater and zooplankton suggesting their strong affinity and coexistence. Copyright © 2016 Elsevier Ltd. All rights reserved.

Spin canting and magnetic transition in NixZn1-xFe2O4 (x=0.0, 0.5 and 1.0) nanoparticles

NASA Astrophysics Data System (ADS)

Rani, Stuti; Raghav, Dharmendra Singh; Yadav, Prashant; Varma, G. D.

2018-04-01

Nanoparticles of NixZn1-xFe2O4(x=0.0, 0.5 and 1.0) have been synthesized via co-precipitation method and studied thestructural and magnetic properties. Rietveld refinement of X ray diffraction data of as synthesized samples revealthat the samples have mixed spinel structure with space group Fd-3m. The lattice parameter of the samples decreases as doping concentration of Ni ions increases. Magnetic measurements show paramagnetic to ferrimagnetic transition at room temperature on Ni doping in ZnFe2O4 nanoparticles. The magnetic measurements also show spin canting in samples possibly due to their nanocrystalline nature. The spin canting angles have been calculated with the help of Yafet-Kittel (Y-K) model. Furthermore, the Law of approach (LA) fitting of M-H curves indicates that the samples are highly anisotropicin nature. The Arrot plots of as synthesized samples also indicate the paramagnetic to ferrimagnetic transition. The correlation between the structural and observed magnetic properties of NixZn1-xFe2O4(x=0.0, 0.5 and 1.0) nanocrystals will be described and discussed in this paper.

Synthesis and characterization of ferrite-semiconductor nano composite for photocatalytic degradation of aqueous nitrobenzene solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Modi, K. B.; Kathad, C. R.; Raval, P. Y.

2016-05-06

Nanoparticles of semiconductor TiO{sub 2}, zinc ferrite (ZnFe{sub 2}O{sub 4}) and ZnFe{sub 2}O{sub 4}-TiO{sub 2} composite, were synthesized by auto combustion route. Subsequent characterization of synthesized photocatalysts was carried out by X-ray powder diffractometry, transmission electron microscopy, UV-Vis-Diffuse Reflectance Spectroscopy to study the structural and textural properties. The specific surface area, pore diameter and pore volume of synthesized materials were investigated by N{sub 2} adsorption analysis while the presence of TiO{sub 2} in the composite material was verified by infrared spectral analysis. The photocatalytic activity of synthesized photocatalysts was evaluated by degradation of nitrobenzene (NB) in aqueous medium under irradiationmore » of ultraviolet light. The result revealed that 77, 73 and 70% of NB was degraded using TiO{sub 2}, ZnFe{sub 2}O{sub 4} and ZnFe{sub 2}O{sub 4}-TiO{sub 2} photocatalysts after 4h in the presence of UV irradiation. The composite photocatalyst was found easy to separate from the treated solution.« less

Comparison of catalytic activities for photocatalytic and sonocatalytic degradation of organic dye in the presence of ternary Fe{sub 3}O{sub 4}/ZnO/CuO magnetic heteregenous nanocatalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taufik, Ardiansyah; Saleh, Rosari, E-mail: rosari.saleh@gmail.com, E-mail: rosari.saleh@ui.ac.id; Integrated Laboratory of Energy and Environment, Fakultas MIPA-Universitas Indonesia, 16424 Depok

2016-04-19

The Fe{sub 3}O{sub 4}/ZnO/CuO nanocatalyst with various CuO loading were synthesized by sol-gel method and were characterized by powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, UV-Vis spectroscopy, and vibrating sample magnetometry. The findings demonstrate that all samples exhibit ferromagnetic behavior at room temperatureand containa well-crystalline ternary oxide nanocatalyst. Methylene blue was taken as the model of organic dye to evaluate its photocatalytic and sonocatalytic degradation in the presence of Fe{sub 3}O{sub 4}/ZnO/CuO nanocatalyst. The observed degradation activity indicate that the order of degradation of methylene blue issonocatalysis> photocatalysis. Fe{sub 3}O{sub 4}/ZnO/CuO nanocatalyst with the lowest CuOmore » loading exhibit the highest rate of degradation of methylene blue during the sono- and photocatalytic processes. The experimental data shows that holes are the predominant oxidative species involved in the sono- and photodegradation of methylene blue.« less

Toxicity of Metals to a Freshwater Snail, Melanoides tuberculata

PubMed Central

Shuhaimi-Othman, M.; Nur-Amalina, R.; Nadzifah, Y.

2012-01-01

Adult freshwater snails Melanoides tuberculata (Gastropod, Thiaridae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed and median lethal times (LT50) and concentrations (LC50) were calculated. LT50 and LC50 increased with the decrease in mean exposure concentrations and times, respectively, for all metals. The LC50 values for the 96-hour exposures to Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.14, 1.49, 3.90, 6.82, 8.46, 8.49, 68.23, and 45.59 mg L−1, respectively. Cu was the most toxic metal to M. tuberculata, followed by Cd, Zn, Pb, Ni, Fe, Mn, and Al (Cu > Cd > Zn > Pb > Ni > Fe > Mn > Al). Metals bioconcentration in M. tuberculata increases with exposure to increasing concentrations and Cu has the highest accumulation (concentration factor) in the soft tissues. A comparison of LC50 values for metals for this species with those for other freshwater gastropods reveals that M. tuberculata is equally sensitive to metals. PMID:22666089

Recovery of manganese and zinc from waste Zn-C cell powder: Characterization and leaching.

PubMed

Biswas, Ranjit K; Karmakar, Aneek K; Kumar, Sree L; Hossain, Mohammad N

2015-12-01

A large number of waste Zn-C cells (Haquebrand) were broken down and collected as agglomerated powder. This powder was sun-dried, dry-ground and sieved down to 300 mesh size and stored. The sample was analysed and found to contain (35.4 ± 0.2)% Mn, (11.0 ± 0.1)% Zn and ∼ 2.5% Fe as major metallic constituents. The phases, ZnMn2O4 and Zn(ClO4)2 · 2H2O or MnO(OH) were identified in the hot water washed sample. The material was found to be leached effectively by a 2 mol/L sulfuric acid solution containing glucose (2g/L). However, the dissolution was dependent on (S/L) ratio; and the stage-wise leaching was not fruitful for Mn-dissolution. On leaching 5 g of powder (<53 μm) with a 250 mL of 0.5 g glucose containing 2 mol/L sulfuric acid solution (S/L=20 g/L), at 100°C and 300 rpm for 1h, a solution containing (7.08 ± 0.10)g/L Mn(2+), (2.20 ± 0.06) Zn(2+) and ∼ 0.40 g/L Fe(3+) was recovered corresponding to cent percent dissolutions of Zn and Mn and 80% dissolution of Fe. Copyright © 2015 Elsevier Ltd. All rights reserved.

Zinc tetraaminophthalocyanine-Fe3O4 nanoparticle composite for laccase immobilization

PubMed Central

Huang, Jun; Liu, Cheng; Xiao, Haiyan; Wang, Juntao; Jiang, Desheng; GU, Erdan

2007-01-01

Zinc tetraaminophthalocyanine-Fe3O4 nanoparticle composites were prepared by organic-inorganic complex technology and characterized. It has been proved that the ZnTAPc dispersed randomly onto the surface of Fe3O4 nanoparticles to form molecular dispersion layer and there was a relatively strong bond between central zinc cation and oxygen. The nanoparticle composite took the shape of roundish spheres with the mean diameter of about 15 nm. Active amino groups of magnetic carriers could be used to bind laccase via glutaraldehyde. The optimal pH for the activity of the immobilized laccases and free laccase were the same at pH 3.0 and the optimal temperature for laccase immobilization on ZnTAPc-Fe3O4 nanoparticle composite was 45°. The immobilization yields and Km value of the laccase immobilized on ZnTAPc-Fe3O4 nanoparticle composite were 25% and 20.1 μM, respectively. This kind of immobilized laccase has good thermal, storage and operation stability, and could be used as the sensing biocomponent for the fiber optic biosensor based on enzyme catalysis. PMID:18203444

Voltammetric Sensor Based on Fe-doped ZnO and TiO2 Nanostructures-modified Carbon-paste Electrode for Determination of Levodopa

NASA Astrophysics Data System (ADS)

Anaraki Firooz, Azam; Hosseini Nia, Bahram; Beheshtian, Javad; Ghalkhani, Masoumeh

2017-10-01

In this study, undoped and 1 wt.% Fe-doped with ZnO, and TiO2 nanostructures were synthesized by a simple hydrothermal method without using templates. The influence of the Fe dopant on structural, optical and electrochemical response was studied by x-ray diffraction, scanning electron microscopy, UV-Vis spectra, photoluminescence spectra and electrochemical characterization system. The electrochemical response of the carbon paste electrode modified with synthesized nanostructures (undoped ZnO and TiO2 as well as doped with Fe ions) toward levodopa (L-Dopa) was studied. Cyclic voltammetry using provided modified electrodes showed electro-catalytic properties for electro-oxidation of L-Dopa and a significant reduction was observed in the anodic overvoltage compared to the bare electrode. The results indicated the presence of the sufficient dopants. The best response was obtained in terms of the current enhancement, overvoltage reduction, and reversibility improvement of the L-Dopa oxidation reaction under experimental conditions by the modified electrode with TiO2 nanoparticles doped with Fe ions.

In-situ high-pressure x-ray diffraction study of zinc ferrite nanoparticles

DOE PAGES

Ferrari, S.; Kumar, R. S.; Grinblat, F.; ...

2016-04-23

We have studied the high-pressure structural behavior of zinc ferrite (ZnFe 2O 4) nanoparticles by powder X-ray diffraction measurements up to 47 GPa. We found that the cubic spinel structure of ZnFe 2O 4 remains up to 33 GPa and a phase transition is induced beyond this pressure. The high-pressure phase is indexed to an orthorhombic CaMn 2O 4-type structure. Upon decompression the low- and high-pressure phases coexist. The compressibility of both structures was also investigated. We have observed that the lattice parameters of the high-pressure phase behave anisotropically upon compression. Further, we predict possible phase transition around 55 GPa.more » For comparison, we also studied the compression behavior of magnetite (Fe 3O 4) nanoparticles by X-ray diffraction up to 23 GPa. Spinel-type ZnFe 2O 4 and Fe 3O 4 nanoparticles have a bulk modulus of 172 (20) GPa and 152 (9) GPa, respectively. Lastly, this indicates that in both cases the nanoparticles do not undergo a Hall-Petch strengthening.« less

In-situ high-pressure x-ray diffraction study of zinc ferrite nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferrari, S.; Kumar, R. S.; Grinblat, F.

We have studied the high-pressure structural behavior of zinc ferrite (ZnFe 2O 4) nanoparticles by powder X-ray diffraction measurements up to 47 GPa. We found that the cubic spinel structure of ZnFe 2O 4 remains up to 33 GPa and a phase transition is induced beyond this pressure. The high-pressure phase is indexed to an orthorhombic CaMn 2O 4-type structure. Upon decompression the low- and high-pressure phases coexist. The compressibility of both structures was also investigated. We have observed that the lattice parameters of the high-pressure phase behave anisotropically upon compression. Further, we predict possible phase transition around 55 GPa.more » For comparison, we also studied the compression behavior of magnetite (Fe 3O 4) nanoparticles by X-ray diffraction up to 23 GPa. Spinel-type ZnFe 2O 4 and Fe 3O 4 nanoparticles have a bulk modulus of 172 (20) GPa and 152 (9) GPa, respectively. Lastly, this indicates that in both cases the nanoparticles do not undergo a Hall-Petch strengthening.« less

The accumulation of elements in plants growing spontaneously on small heaps left by the historical Zn-Pb ore mining.

PubMed

Stefanowicz, Anna M; Stanek, Małgorzata; Woch, Marcin W; Kapusta, Paweł

2016-04-01

The study evaluated the levels of nine metals, namely Ca, Cd, Fe, K, Mg, Mn, Pb, Tl, and Zn, in soils and tissues of ten plant species growing spontaneously on heaps left by historical mining for Zn-Pb ores. The concentrations of Cd, Pb, Tl, and Zn in heap soils were much higher than in control soils. Plants growing on heaps accumulated excessive amounts of these elements in tissues, on average 1.3-52 mg Cd kg(-1), 9.4-254 mg Pb kg(-1), 0.06-23 mg Tl kg(-1) and 134-1479 mg Zn kg(-1) in comparison to 0.5-1.1 mg Cd kg(-1), 2.1-11 mg Pb kg(-1), 0.02-0.06 mg Tl kg(-1), and 23-124 mg Zn kg(-1) in control plants. The highest concentrations of Cd, Pb, and Zn were found in the roots of Euphorbia cyparissias, Fragaria vesca, and Potentilla arenaria, and Tl in Plantago lanceolata. Many species growing on heaps were enriched in K and Mg, and depleted in Ca, Fe, and Mn. The concentrations of all elements in plant tissues were dependent on species, organ (root vs. shoot), and species-organ interactions. Average concentrations of Ca, K, and Mg were generally higher in shoots than in roots or similar in the two organs, whereas Cd, Fe, Pb, Tl, and Zn were accumulated predominantly in the roots. Our results imply that heaps left by historical mining for Zn-Pb ores may pose a potential threat to the environment and human health.

Effect of adsorbed metals ions on the transport of Zn- and Ni-EDTA complexes in a sand and gravel aquifer

USGS Publications Warehouse

Kent, D.B.; Davis, J.A.; Anderson, L.C.D.; Rea, B.A.; Coston, J.A.

2002-01-01

Adsorption, complexation, and dissolution reactions strongly influenced the transport of metal ions complexed with ethylenediaminetetraacetic acid (EDTA) in a predominantly quartz-sand aquifer during two tracer tests conducted under mildly reducing conditions at pH 5.8 to 6.1. In tracer test M89, EDTA complexes of zinc (Zn) and nickel (Ni), along with excess free EDTA, were injected such that the lower portion of the tracer cloud traveled through a region with adsorbed manganese (Mn) and the upper portion of the tracer cloud traveled through a region with adsorbed Zn. In tracer test S89, Ni- and Zn-EDTA complexes, along with excess EDTA complexed with calcium (Ca), were injected into a region with adsorbed Mn. The only discernable chemical reaction between Ni-EDTA and the sediments was a small degree of reversible adsorption leading to minor retardation. In the absence of adsorbed Zn, the injected Zn was displaced from EDTA complexes by iron(III) [Fe(III)] dissolved from the sediments. Displacement of Zn by Fe(III) on EDTA became increasingly thermodynamically favorable with decreasing total EDTA concentration. The reaction was slow compared to the time-scale of transport. Free EDTA rapidly dissolved aluminum (Al) from the sediments, which was subsequently displaced slowly by Fe. In the portion of tracer cloud M89 that traveled through the region contaminated with adsorbed Zn, little displacement of Zn complexed with EDTA was observed, and Al was rapidly displaced from EDTA by Zn desorbed from the sediments, in agreement with equilibrium calculations. In tracer test S89, desorption of Mn dominated over the more thermodynamically favorable dissolution of Al oxyhydroxides. Comparison with results from M89 suggests that dissolution of Al oxyhydroxides in coatings on these sediment grains by Ca-EDTA was rate-limited whereas that by free EDTA reached equilibrium on the time-scale of transport. Rates of desorption are much faster than rates of dissolution of Fe oxyhydroxides from sediment-grain surfaces and, therefore, adsorbed metal ions can strongly influence the speciation of ligands like EDTA in soils and sediments, especially over small temporal and spatial scales. Copyright ?? 2002 Elsevier Science Ltd.

Preparation of TbCu7-type Sm-Fe powders by low-temperature HDDR treatment

NASA Astrophysics Data System (ADS)

Takagi, Kenta; Jinno, Miho; Ozaki, Kimihiro

2018-05-01

Low-temperature hydrogen-disproportionation-desorption-recombination (HDDR) treatment of Sm-Fe alloy powder was conducted to prepare a metastable TbCu7 type Sm-Fe alloy powder with a grain size of more than a few hundreds of nanometers. While a treatment temperature above 700 °C produced the familiar Th2Zn17 type alloy, one below 600 °C resulted in successful synthesis of the TbCu7 type Sm-Fe alloy with submicron-size grains. This TbCu7 type alloy powder, however, showed no significant improvement in magnetic properties compared to the Th2Zn17 type, as its composition was estimated to be near SmFe8.5 and thus did not achieve the expected Fe-rich composition. Therefore, cross-sectional transmission electron microscope observation of the unfinished TbCu7 type alloy powder was conducted in order to explore means of forming the Fe-rich phase.

Fabrication of Mg-X-O (X = Fe, Co, Ni, Cr, Mn, Ti, V, and Zn) barriers for magnetic tunnel junctions

NASA Astrophysics Data System (ADS)

Yakushiji, K.; Kitagawa, E.; Ochiai, T.; Kubota, H.; Shimomura, N.; Ito, J.; Yoda, H.; Yuasa, S.

2018-05-01

We fabricated magnetic tunnel junctions with a 3d-transition material(X)-doped MgO (Mg-X-O) barrier, and evaluated the effect of the doping on magnetoresistance (MR) and microstructure. Among the variations of X (X = Fe, Co, Ni, Cr, Mn, Ti, V, and Zn), X = Fe and Mn showed a high MR ratio of more than 100%, even at a low resistance-area product of 3 Ωμm2. The microstructure analysis revealed that (001) textured orientation formed for X = Fe and Mn despite substantial doping (about 10 at%). The elemental mappings indicated that Fe atoms in the Mg-Fe-O barrier were segregated at the interfaces, while Mn atoms were evenly involved in the Mg-Mn-O barrier. This suggests that MgO has high adaptability for Fe and Mn dopants in terms of high MR ratio.

Composite multifunctional nanostructures based on ZnO tetrapods and superparamagnetic Fe3O4 nanoparticles.

PubMed

Villani, M; Rimoldi, T; Calestani, D; Lazzarini, L; Chiesi, V; Casoli, F; Albertini, F; Zappettini, A

2013-04-05

A nanocomposite material is obtained by coupling superparamagnetic magnetite nanoparticles (Fe3O4 NP) and vapor phase grown zinc oxide nanostructures with 'tetrapod' morphology (ZnO TP). The aim is the creation of a multifunctional material which retains the attractive features of ZnO (e.g. surface reactivity, strong UV emission, piezoelectricity) together with added magnetism. Structural, morphological, optical, magnetic and functional characterization are performed. In particular, the high saturation magnetization of Fe3O4 NP (above 50 A m(2) kg(-1)), the strong UV luminescence and the enhanced photocatalytic activity of coupled nanostructures are discussed. Thus the nanocomposite turns out to be suitable for applications in energy harvesting and conversion, gas- and bio-sensing, bio-medicine and filter-free photocatalysis.

The use of novel biodegradable, optically active and nanostructured poly(amide-ester-imide) as a polymer matrix for preparation of modified ZnO based bionanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdolmaleki, Amir, E-mail: abdolmaleki@cc.iut.ac.ir; Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan 84156-83111, Islamic Republic of Iran; Mallakpour, Shadpour, E-mail: mallak@cc.iut.ac.ir

Highlights: Black-Right-Pointing-Pointer A novel biodegradable and nanostructured PAEI based on two amino acids, was synthesized. Black-Right-Pointing-Pointer ZnO nanoparticles were modified via two different silane coupling agents. Black-Right-Pointing-Pointer PAEI/modified ZnO BNCs were synthesized through ultrasound irradiation. Black-Right-Pointing-Pointer ZnO particles were dispersed homogeneously in PAEI matrix on nanoscale. Black-Right-Pointing-Pointer The effect of ZnO nanoparticles on the properties of synthesized polymer was examined. -- Abstract: A novel biodegradable and nanostructured poly(amide-ester-imide) (PAEI) based on two different amino acids, was synthesized via direct polycondensation of biodegradable N,N Prime -bis[2-(methyl-3-(4-hydroxyphenyl)propanoate)]isophthaldiamide and N,N Prime -(pyromellitoyl)-bis-L-phenylalanine diacid. The resulting polymer was characterized by FT-IR, {sup 1}H NMR,more » specific rotation, elemental analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) analysis. The synthesized polymer showed good thermal stability with nano and sphere structure. Then PAEI/ZnO bionanocomposites (BNCs) were fabricated via interaction of pure PAEI and ZnO nanoparticles. The surface of ZnO was modified with two different silane coupling agents. PAEI/ZnO BNCs were studied and characterized by FT-IR, XRD, UV/vis, FE-SEM and TEM. The TEM and FE-SEM results indicated that the nanoparticles were dispersed homogeneously in PAEI matrix on nanoscale. Furthermore the effect of ZnO nanoparticle on the thermal stability of the polymer was investigated with TGA and DSC technique.« less

Characterisation of zinc in slags originated from a contaminated sediment by coupling /μ-PIXE, /μ-RBS, /μ-EXAFS and powder EXAFS spectroscopy

NASA Astrophysics Data System (ADS)

Isaure, M. P.; Laboudigue, A.; Manceau, A.; Sarret, G.; Tiffreau, C.; Trocellier, P.

2001-07-01

Depositing dredged sediments on soils is usual but it is a hazardous practice for the local environment when these sediments are polluted by heavy metals. This chemical hazard can be assessed by determining the speciation of metals. In this study, slags highly polluted with Zn and originated from a contaminated dredged sediment were investigated. Zn speciation was studied by laterally resolved techniques such as μ-particle induced X-ray emission (μ-PIXE), μ-Rutherford backscattering spectrometry (μ-RBS), μ-extended X-ray absorption fine structure (μ-EXAFS), and bulk analyses such as powder EXAFS spectroscopy. μ-PIXE and μ-RBS results showed that high concentrations of Zn were associated with S in localised areas at the surface of the slags while moderate amounts of Zn were mainly associated with Fe in the matrix. EXAFS results allowed to identify ZnS and Zn sorbed on ferrihydrite (5Fe 2O 3·9H 2O), proxy for iron oxy-hydroxides, as the main Zn-bearing phases. The occurrence of this Zn-iron oxy-hydroxide is interpreted as a mobilisation of Zn released from ZnS oxidation.

Structural, optical, and improved field-emission properties of tetrapod-shaped Sn-doped ZnO nanostructures synthesized via thermal evaporation.

PubMed

Zhou, Xiongtu; Lin, Tihang; Liu, Yuhui; Wu, Chaoxing; Zeng, Xiangyao; Jiang, Dong; Zhang, Yong-ai; Guo, Tailiang

2013-10-23

High-quality tetrapod-shaped Sn-doped ZnO (T-SZO) nanostructures have been successfully synthesized via the thermal evaporation of mixed Zn and Sn powder. The effects of the Sn dopant on the morphology, microstructure, optical, and field-emission (FE) properties of T-SZO were investigated. It was found that the growth direction of the legs of T-SZO is parallel to the [0001] crystal c-axis direction and that the incorporation of Sn in the ZnO matrix increases the aspect ratio of the tetrapods, leads to blue shift in the UV region, and considerably improves the FE performance. The results also show that tetrapod cathodes with around a 0.84 atom % Sn dosage have the best FE properties, with a turn-on field of 1.95 V/μm, a current density of 950 μA/cm2 at a field of 4.5 V/μm, and a field-enhancement factor as high as 9556.

Effect of sintering temperature on micro structural and impedance spectroscopic properties of Ni0.5Zn0.5Fe2O4 nano ferrite

NASA Astrophysics Data System (ADS)

Venkatesh, Davuluri; Ramesh, K. V.; Sastry, C. V. S. S.

2017-07-01

Ni-Zn nanoferrite Ni0.5Zn0.5Fe2O4 is prepared by citrate gel auto combustion method and sintered at various temperatures 800, 900, 1000, 1100 and 1200°C. The room temperature x-ray diffraction conforms that the single phase spinel structure is formed. Crystallite size and density were increased with increasing of sintering temperature. From Raman spectroscopy all sintered samples are single phase with cubic spinel structure belong to Fd3m space group. From surface morphology studies it is clearly observed that the particle size increased with increasing of sintering temperature. Impedance spectroscopy revel that increasing of conductivity is due to grain resistance is decreased with increasing of sintering temperature. Cole-Cole plots are studied from impedance data. The electrical modulus analysis shows that non-Debye nature of Ni0.5Zn0.5Fe2O4 ferrite.

The phases and magnetic properties of (Ti, Co), and Cr doped Zn 2Y-type hexagonal ferrite

NASA Astrophysics Data System (ADS)

Chang, Y. H.; Wang, C. C.; Chin, T. S.; Yen, F. S.

1988-04-01

The phases and magnetic properties of Y-type hexagonal ferrite, Ba 2Zn 2 (Ti, Co) yFe 12-2 yO 22 doped with two sets of ions, (Ti, Co) and Cr were studied. In (Ti, Co) - doped ferrites the second phase appears at y ⩾ 0.6, which is a spinel type with the formula of (Zn 1-ηCo η)(Fe 2-δCo δ)O 4. Two resonant peaks are observed in ESR studies at the fields of 1020 and 2430 Oe, respectively, at a frequency of 9.684 GHz. The linewidth increases with the addition of the dopants. In chromium doped ferrite, two phases are identified as the amount of chromium is up to 0.2: spinel type of Zn(Fe 2-ɛCr ɛ)O 4 and orthorhombic BaCr 2O 4. Although the amount of Cr used does not influence the resonant field of the unique peak of the derivative curves from ESR, it eventually enlarges the linewidth.

Synthesis of ferrites obtained from heavy metal solutions using wet method.

PubMed

Yang, Ji; Peng, Juan; Liu, Kaicheng; Guo, Rui; Xu, Dianliang; Jia, Jinping

2007-05-08

Wet method was employed to the treatment of heavy metal-contaminated wastewater, and Zn(x)Fe(3-x)O(4), Ni(x)Fe(3-x)O(4) and Cr(x)Fe(3-x)O(4) (0Cr(3+) and the influence of the three ions on sample thermostability is Zn(2+)>Ni(2+)>Cr(3+).

ICP-AES Determination of Mineral Content in Boletus tomentipes Collected from Different Sites of China.

PubMed

Wang, Xue-mei; Zhang, Ji; Li, Tao; Li, Jie-qing; Wang, Yuan-zhong; Liu, Hong-gao

2015-05-01

P, Na, Ca, Cu, Fe, Mg, Zn, As, Cd, Co, Cr and Ni, contents have been examined in caps and stipes of Boletus tomentipes collected from different sites of Yunnan province, southwest China. The elements were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES) with microwave digestion. P, Ca, Mg, Fe, Zn and Cu were the most abundant amongst elements determined in Boletus tomentipes. The caps were richer in P, Mg, Zn and Cd, and the stipes in Ca, Co and Ni. Cluster analysis showed a difference between Puer (BT7 and BT8) and other places. The PCA explained about 77% of the total variance, and the minerals differentiating these places were P (PC1) together with Ca, Cu, Fe, Mg, As and Ni, Na (PC2) together with Cd, and Zn (PC3). The results of this study imply that element concentrations of a mushroom are mutative when collected from the different bedrock soil geochemistry.

Adsorption of tetracycline on Fe (hydr)oxides: effects of pH and metal cation (Cu2+, Zn2+ and Al3+) addition in various molar ratios

PubMed Central

Hsu, Liang-Ching; Liu, Yu-Ting; Syu, Chien-Hui; Huang, Mei-Hsia; Teah, Heng Yi

2018-01-01

Iron (Fe) (hydr)oxides control the mobility and bioavailability of tetracycline (TC) in waters and soils. Adsorption of TC on Fe (hydr)oxides is greatly affected by polyvalent metals; however, impacts of molar metal/TC ratios on TC adsorptive behaviours on Fe (hydr)oxides remain unclear. Results showed that maximum TC adsorption on ferrihydrite and goethite occurred at pH 5–6. Such TC adsorption was generally promoted by the addition of Cu2+, Zn2+ and Al3+. The greatest increase in TC adsorption was found in the system with molar Cu/TC ratio of 3 due to the formation of Fe hydr(oxide)–Cu–TC ternary complexes. Functional groups on TC that were responsible for the complexation with Cu2+shifted from phenolic diketone groups at Cu/TC molar ratio < 1 to amide groups at Cu/TC molar ratio ≥ 1. For the addition of Al3+, the complexation only took place with phenolic diketone groups, resulting in the enhanced TC adsorption at a molar Al/TC ratio of 1. However, TC adsorption decreased for Al/TC molar ratio > 1 as excess Al3+ led to the competitive adsorption with Al/TC complexes. For the Zn2+ addition, no significant correlation was found between TC adsorption capacity and molar Zn/TC ratios. PMID:29657795

Surfactant-assisted synthesis of polythiophene/Ni0.5Zn0.5Fe2-xCexO4 ferrite composites: study of structural, dielectric and magnetic properties for EMI-shielding applications.

PubMed

Dar, M Abdullah; Majid, Kowsar; Hanief Najar, Mohd; Kotnala, R K; Shah, Jyoti; Dhawan, S K; Farukh, M

2017-04-19

This work reports the exploitation of nanocrystalline Ni 0.5 Zn 0.5 Fe 2-x Ce x O 4 ferrite for potential application by designing quasi-spherical shaped polythiophene (PTH) composites via in situ emulsion polymerization. The structural, electronic, dielectric, magnetic, and electromagnetic interference (EMI) shielding properties of PTH/Ni 0.5 Zn 0.5 Fe 2-x Ce x O 4 composites were investigated. Our results suggest that these properties could be optimized by modulating the concentration of x (composition) in the polymer matrix. Higher values of ε' and ε'' were obtained on composite formation, and could be due to the heterogeneity developed in the material. An enhancement in the value of saturation magnetization (123 emu g -1 for x = 0.04) and Curie temperature was obtained with Ce concentration, which is useful for high density recording purposes. A low value of saturation magnetization was obtained for the PTH/Ni 0.5 Zn 0.5 Fe 2-x Ce x O 4 composite (36 emu g -1 for x = 0.04). This could be attributed to the non-magnetic nature of the polymer. A total shielding effectiveness (SE T = SE A + SE R ) up to 34 dB (≈99.9% attenuation) was recorded for PTH/Ni 0.5 Zn 0.5 Fe 2-x Ce x O 4 composites (x = 0.04) in a frequency range of 8.2-12.4 GHz (X-band), which surpasses the shielding criteria of SE T > 30 dB for commercial purposes. Such a material with high SE identifies its potential for making electromagnetic shields. The effect of Ce substitution on the microstructure, dielectric, impedance and magnetic properties of PTH/Ni 0.5 Zn 0.5 Fe 2-x Ce x O 4 ferrite composites was also investigated. X-ray diffraction analysis confirmed cubic spinel phase formation, and the broad reflection peaks indicated the formation of smaller sized particles. The smaller energy band gap (2.53 eV) of the composite indicated that this material could be used for photocatalysis in the visible region. Dielectric and impedance measurements were carried out in a frequency range of 8.2-12.4 GHz. Dielectric properties were improved considerably by the substitution of Ce 3+ ions in PTH/Ni 0.5 Zn 0.5 Fe 2-x Ce x O 4 composites. Impedance spectroscopy was used to study the effect of grain and grain boundaries on the electrical properties of PTH/Ni 0.5 Zn 0.5 Fe 2-x Ce x O 4 composites. Cole-Cole plots showed the formation of single semi-circles for all samples in the measured frequency range. This showed that the composite material was composed of good conducting grains and poorly conducting grain boundaries.

Quantitative Zn speciation in a contaminated dredged sediment by μ-PIXE, μ-SXRF, EXAFS spectroscopy and principal component analysis

NASA Astrophysics Data System (ADS)

Isaure, Marie-Pierre; Laboudigue, Agnès; Manceau, Alain; Sarret, Géraldine; Tiffreau, Christophe; Trocellier, Patrick; Lamble, Géraldine; Hazemann, Jean-Louis; Chateigner, Daniel

2002-05-01

Dredging and disposal of sediments onto agricultural soils is a common practice in industrial and urban areas that can be hazardous to the environment when the sediments contain heavy metals. This chemical hazard can be assessed by evaluating the mobility and speciation of metals after sediment deposition. In this study, the speciation of Zn in the coarse (500 to 2000 μm) and fine (<2 μm) fractions of a contaminated sediment dredged from a ship canal in northern France and deposited on an agricultural soil was determined by physical analytical techniques on raw and chemically treated samples. Zn partitioning between coexisting mineral phases and its chemical associations were first determined by micro-particle-induced X-ray emission and micro-synchrotron-based X-ray radiation fluorescence. Zn-containing mineral species were then identified by X-ray diffraction and powder and polarized extended X-ray absorption fine structure spectroscopy (EXAFS). The number, nature, and proportion of Zn species were obtained by a coupled principal component analysis (PCA) and least squares fitting (LSF) procedure, applied herein for the first time to qualitatively (number and nature of species) and quantitatively (relative proportion of species) speciate a metal in a natural system. The coarse fraction consists of slag grains originating from nearby Zn smelters. In this fraction, Zn is primarily present as sphalerite (ZnS) and to a lesser extent as willemite (Zn 2SiO 4), Zn-containing ferric (oxyhydr)oxides, and zincite (ZnO). In the fine fraction, ZnS and Zn-containing Fe (oxyhydr)oxides are the major forms, and Zn-containing phyllosilicate is the minor species. Weathering of ZnS, Zn 2SiO 4, and ZnO under oxidizing conditions after the sediment disposal accounts for the uptake of Zn by Fe (oxyhydr)oxides and phyllosilicates. Two geochemical processes can explain the retention of Zn by secondary minerals: uptake on preexisting minerals and precipitation with dissolved Fe and Si. The second process likely occurs because dissolved Zn and Si are supersaturated with respect to Zn phyllosilicate. EXAFS spectroscopy, in combination with PCA and LSF, is shown to be a meaningful approach to quantitatively determining the speciation of trace elements in sediments and soils.

Total and water-soluble trace metal content of urban background PM 10, PM 2.5 and black smoke in Edinburgh, UK

NASA Astrophysics Data System (ADS)

Heal, Mathew R.; Hibbs, Leon R.; Agius, Raymond M.; Beverland, Iain J.

Toxicological studies have implicated trace metals in airborne particles as possible contributors to respiratory and/or cardiovascular inflammation. As part of an epidemiological study, co-located 24 h samples of PM 10, PM 2.5 and black smoke (BS) were collected for 1 year at an urban background site in Edinburgh, and each sample sequentially extracted with ultra-pure water, then concentrated HNO 3/HCl, and analysed for Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd and Pb. This yields a comprehensive data set for UK urban airborne trace metal. The median ( n>349) daily water-soluble metal concentration in PM 2.5 ranged from 0.05 ng m -3 for Ti to 5.1 ng m -3 for Pb; and in PM 10 from 0.18 ng m -3 for Ti to 11.7 ng m -3 for Fe. Median daily total (i.e. water+acid-extractable) metal concentration in PM 2.5 ranged from 0.3 ng m -3 for As to 27.6 ng m -3 for Fe; and in PM 10 from 0.37 ng m -3 for As to 183 ng m -3 for Fe. The PM 2.5:PM 10 ratio varied considerably with metal, from <17%, on average, for Ti and Fe, to >70% for V, As, Cd and Pb. The 11 trace metals constituted proportionally more of the PM 10-2.5 fraction than of the PM 2.5 fraction (0.9%). The proportion of water-soluble metal in each size-fraction varied considerably, from <10% water-soluble Fe and Ti in PM 10-2.5, to >50% water-soluble V, Zn, As and Cd in PM 2.5. Although Fe generally dominated the trace metal, water-soluble metal also contained significant Zn, Pb and Cu, and for all size and solubility fractions >90% of trace metal was comprised of Fe, Zn, Pb and Cu. Statistical analyses suggested three main sources: traffic; static combustion; and crustal. The association of metals with traffic (Cu, Fe, Mn, Pb, Zn) was consistent with traffic-induced non-exhaust "resuspension" rather than direct exhaust emission. Meteorology contributed to the wide variation in daily trace metal concentration. The proportion of trace metal in particles varied significantly with the air mass source and was highest on days for trajectories traversing over land. For Mn, Fe, Cu, Zn, As and Pb there was greater correlation of metal concentration with BS mass than with either PM 10 or PM 2.5 mass, suggesting that BS reflectance monitoring could be a cost-effective surrogate measure of particle metal concentration in urban background air.

Selective ion exchange governed by the Irving-Williams series in K2Zn3[Fe(CN)6]2 nanoparticles: toward a designer prodrug for Wilson's disease.

PubMed

Kandanapitiye, Murthi S; Wang, Fan Jennifer; Valley, Benjamin; Gunathilake, Chamila; Jaroniec, Mietek; Huang, Songping D

2015-02-16

The principle of the Irving-Williams series is applied to the design of a novel prodrug based on K2Zn3[Fe(CN)6]2 nanoparticles (ZnPB NPs) for Wilson's disease (WD), a rare but fatal genetic disorder characterized by the accumulation of excess copper in the liver and other vital organs. The predetermined ion-exchange reaction rather than chelation between ZnPB NPs and copper ions leads to high selectivity of such NPs for copper in the presence of the other endogenous metal ions. Furthermore, ZnPB NPs are highly water-dispersible and noncytotoxic and can be readily internalized by cells to target intracellular copper ions for selective copper detoxification, suggesting their potential application as a new-generation treatment for WD.

Electromagnetic interference attenuation and shielding effect of quaternary Epoxy-PPy/Fe3O4-ZnO nanocomposite as a broad band microwave-absorber

NASA Astrophysics Data System (ADS)

Olad, Ali; Shakoori, Sahar

2018-07-01

An increase in the electromagnetic wave pollution generated from wireless telecommunication devices has devoted to a great request for exploiting microwave absorbing materials for themselves. The combination of inherently conducting polymers such as polypyrrole (PPy) with metal oxides has led to design ideal microwave absorbing materials which benefit both advantage effects of ICPs and metal oxide nanoparticles. Herein, the quaternary nanocomposite of Epoxy-PPy/Fe3O4-ZnO was prepared and tested for the absorption of X-band microwaves. Simultaneous application of metal oxides and conducting polypyrrole in the epoxy matrix was evaluated in order to increase the absorption intensity and broadness of microwaves in X-band region. The morphology, microstructure, and phase structure of Fe3O4, ZnO, and PPy, as well as quaternary nanocomposite were characterized and studied using FTIR, XRD, FESEM and TEM techniques. The presence of nanoparticles in the quaternary nanocomposite was confirmed by EDS. The magnetization of iron oxide was studied by VSM. The synergetic effect of iron oxide and zinc oxide nanoparticles in different weight ratios (Fe3O4/ZnO) on the electromagnetic wave absorption was evaluated. The electromagnetic parameters have been evaluated by the vector network analyzer in the frequency range of 8.2-12.4 GHz which is named as X-band region and is adequate for radar applications. The electromagnetic wave absorbing outcomes indicated that Epoxy-PPy/Fe3O4-ZnO quaternary nanocomposite has wide absorption area and high attenuation, which is believed to be due to dielectric loss properties related to the polypyrrole, magnetic loss factor of Fe3O4, and synergetic effects of components. The maximum reflection loss reached to -32.53 dB at 9.96 GHz with a nanocomposite thickness of 2 mm which is dedicated to the Epoxy-PPy/Fe3O4-ZnO with iron oxide to zinc oxide ratio of 2:1. The absorption bandwidth with the reflection loss lower than -10 dB (90% attenuation) was up to 4.2 GHz that covering a frequency range of 8.2-12.4 GHz. Results showed that absorber having %15 (w/w) polypyrrole/epoxy resin in Epoxy-PPy/Fe3O4-ZnO nanocomposite with iron oxide to zinc oxide ratio of 2:1 displays the best reflection loss properties. The loss curves illustrated the values of dielectric loss tangent and magnetic loss tangent of prepared nanocomposites which are in the range of 0.25-0.7 and -0.08 to 0.09 respectively. Therefore, microwave absorption mechanism is probably attributed to dielectric loss.

Detection of Labile Low-Molecular-Mass Transition Metal Complexes in Mitochondria

PubMed Central

McCormick, Sean P.; Moore, Michael J.; Lindahl, Paul A.

2015-01-01

Liquid chromatography was used with an on-line inductively coupled plasma mass spectrometer to detect low-molecular-mass (LMM) transition metal complexes in mitochondria isolated from fermenting yeast cells, human Jurkat cells, and mouse brain and liver. These complexes constituted 20 – 40% of total mitochondrial Mn, Fe, Zn, and Cu ions. The major LMM Mn complex in yeast mitochondria had a mass of ca. 1100 Da and a concentration of ~ 2 μM. Mammalian mitochondria contained a second Mn species with a mass of ca. 2000 Da at a comparable concentration. The major Fe complex in mitochondria isolated from exponentially growing yeast cells had a mass of ca. 580 Da; the concentration of Fe580 in mitochondria was ca. 100 μM. When mitochondria were isolated from fermenting cells in post-exponential phase, the mass of the dominant LMM Fe complex was ca. 1100 Da. Upon incubation, the intensity of Fe1100 declined and Fe580 increased, suggesting that the two are interrelated. Mammalian mitochondria contained Fe580 and 2 other Fe species (Fe2000 and Fe1100) at concentrations of ca. 50 μM each. The dominant LMM Zn species in mitochondria had a mass of ca. 1200 Da and a concentration of ca. 110 μM. Mammalian mitochondria contained a second major LMM Zn species at 1500 Da. The dominant LMM Cu species in yeast mitochondria had a mass of ca. 5000 Da and a concentration in yeast mitochondria of ca. 16 μM; Cu5000 was not observed in mammalian mitochondria. The dominant Co species in mitochondria, Co1200, had a concentration of 20 nM and was probably a cobalamin. Mammalian but not yeast mitochondria contained a LMM Mo species, Mo730, at ca. 1 μM concentration. Increasing Mn, Fe, Cu, and Zn concentrations 10 fold in the medium increased the concentration of the same element in the corresponding isolated mitochondria. Treatment with metal chelators confirmed that these LMM species were labile. The dominant S species at 1100 Da was not free GSH or GSSG. PMID:26018429

Transverse excitations in liquid Fe, Cu and Zn

NASA Astrophysics Data System (ADS)

Hosokawa, S.; Inui, M.; Kajihara, Y.; Tsutsui, S.; Baron, A. Q. R.

2015-05-01

Transverse acoustic (TA) excitation modes were observed in inelastic x-ray scattering spectra of liquid Fe, Cu and Zn. From the analysis of current correlation functions, we concluded that TA excitation modes can experimentally be detected through the quasi-TA branches in the longitudinal current correlation spectra in these liquid metals. The microscopic elastic constants are estimated and a characteristic difference from macroscopic polycrystalline value was found in Poisson's ratio of liquid Fe, which shows an extremely softer value of ∼0.38 compared with the macroscopic value of ∼0.275. The lifetime of the TA modes were determined to be ∼0.45 ps for liquid Fe and Cu and ∼0.55 ps for liquid Zn, reflecting different interatomic correlations between liquid transition metals and non-transition metals. The propagation length of the TA modes are ∼0.85 nm in all of liquid metals, corresponding to the size of icosahedral or similar size of cages formed instantaneously in these liquid metals.

Trace metals in Bermuda rainwater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jickells, T.D.; Knap, A.H.; Church, T.M.

1984-02-20

The concentration of Cd, Cu, Fe, Mn, Ni, Pb, and Zn have been measured in Bermuda rainwater. Factor analysis indicates that Fe, Mn, and Pb have similar to acidic components derived from North America. The other metals all behave simiarly but differently to the acides. Sea salt, even after allowances for fractionation, apparently contributes minor amounts of Cu, Pb, and Zn and uncertain amounts of Fe, Mn, and Cd to Atlantic Ocean precipitation. Wash out ratios, calculated from this data along with earlier measurements of atmospheric trace metal concentration on Bermuda, are of the same order as those reported frommore » other remote ocean areas. The wet depositional fluxes of Cu, Ni, Pb, and Zn to the western Atlantic Ocean are significant compared to measured oceanic flux rates. However, the wet depositional fluxes of Fe and Mn to this area are relatively small, suggesting additional inputs, while an excess wet depositional flux of Cd suggests large-scale atmospheric recycling of this element.« less

Changing the zinc:iron ratio in a cereal-based nutritional supplement has no effect on percent absorption of iron and zinc in Sri Lankan children

USDA-ARS?s Scientific Manuscript database

The Thriposha program is a community-level nutrition intervention in Sri Lanka that provides a combination of energy, protein, and micronutrients as a 'ready-to-eat' cereal-based food. We measured the bioavailability of Fe and Zn from Thriposha formula at two different molar ratios of Zn: Fe in orde...

Fabrication of a novel NiFe2O4/Zn-Al layered double hydroxide intercalated with EDTA composite and its adsorption behavior for Cr(VI) from aqueous solution

NASA Astrophysics Data System (ADS)

Deng, Lin; Shi, Zhou; Wang, Li; Zhou, Shiqing

2017-05-01

A novel magnetic NiFe2O4/Zn-Al layered double hydroxide intercalated with EDTA composite (NiFe2O4/ZnAl-EDTA LDH) was prepared through modified coprecipitation method and employed for adsorptive removal of Cr(VI) from aqueous solution. The adsorbents were characterized using Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and X-ray photoelectron spectroscopy (XPS). Factors affecting the Cr(VI) adsorption, such as initial solution pH, adsorbent dosage, contact time, initial Cr(VI) concentration, temperature and coexisting ions, were studied systematically. Experiments results show that the magnetic NiFe2O4/ZnAl-EDTA LDH exhibits high adsorption efficiency within a wide pH range of 3.0-7.0 (R>80% at Cr(VI) concentration 50 mg L-1, contact time 360 min, and adsorbent dosage 2 g/L) and quick separation property. The adsorption process is fitted well with the Langmuir isotherm and pseudo-second-order kinetic model. The maximum theoretical adsorption capacity is found to be 77.22 mg g-1 at pH 6.0 and 318 K. The positive ΔH value (2.907 kJ mol-1) and negative ΔG value (-4.722 kJ mol-1) at 298-318 K reveals that the adsorption process is feasible, spontaneous and endothermic. Coexisting anions (PO43-, SO42-, CO32-, HCO3-, Cl-, and NO3-) have no significant effect on Cr(VI) removal. The mechanism study indicates that the adsorption of Cr(VI) onto NiFe2O4/ZnAl-EDTA LDH mainly involves electrostatic attraction and ion exchange interaction. It is interesting to note that a proportion of Cr(VI) adsorbed on the adsorbent surface are reduced to Cr(III) during the adsorption process. Results from this study demonstrate the potential utility of the magnetic NiFe2O4/ZnAl-EDTA LDH that could be developed into a viable technology for efficient removal of Cr(VI) from aqueous solution.

Recovery of zinc and cadmium from spent batteries using Cyphos IL 102 via solvent extraction route and synthesis of Zn and Cd oxide nanoparticles.

PubMed

Singh, Rashmi; Mahandra, Harshit; Gupta, Bina

2017-09-01

The overall aim of this study is to separate and recover zinc and cadmium from spent batteries. For this purpose Cyphos IL 102 diluted in toluene was employed for the extraction and recovery of Zn and Cd from Zn-C and Ni-Cd batteries leach liquor. The influence of extractant concentration for the leach liquors of Zn-C (0.01-0.05mol/L) and Ni-Cd (0.04-0.20mol/L) batteries has been investigated. Composition of the leach liquor obtained from Zn-C/Ni-Cd spent batteries is Zn - 2.18g/L, Mn - 4.59g/L, Fe - 4.0×10 -3 g/L, Ni - 0.2×10 -3 g/L/Cd - 4.28g/L, Ni - 0.896×10 -1 g/L, Fe - 0.148g/L, Co - 3.77×10 -3 g/L, respectively. Two stage counter current extraction at A/O 1:1 and 3:2 with 0.04mol/L and 0.2mol/L Cyphos IL 102 for Zn and Cd, respectively provide more than 99.0% extraction of both the metal ions with almost negligible extraction of associated metal ions. A stripping efficiency of around 99.0% for Zn and Cd was obtained at O/A 1:1 using 1.0mol/L HNO 3 in two and three counter current stages, respectively. ZnO and CdO were also synthesized using the loaded organic phase and characterized using XRD, FE-SEM and EDX techniques. XRD peaks of ZnO and CdO correspond to zincite and monteponite, respectively. The average particle size was ∼27.0nm and ∼37.0nm for ZnO and CdO, respectively. The EDX analysis of ZnO and CdO shows almost 1:1 atomic percentage. Copyright © 2017. Published by Elsevier Ltd.

Removal of As, Mn, Mo, Se, U, V and Zn from groundwater by zero-valent iron in a passive treatment cell: reaction progress modeling.

PubMed

Morrison, Stan J; Metzler, Donald R; Dwyer, Brian P

2002-05-01

Three treatment cells were operated at a site near Durango, CO. One treatment cell operated for more than 3 years. The treatment cells were used for passive removal of contamination from groundwater at a uranium mill tailings repository site. Zero-valent iron [Fe(0)] that had been powdered, bound with aluminosilicate and molded into plates was used as a reactive material in one treatment cell. The others used granular Fe(0) and steel wool. The treatment cells significantly reduced concentrations of As, Mn, Mo, Se, U, V and Zn in groundwater that flowed through it. Zero-valent iron [Fe(0)], magnetite (Fe3O4), calcite (CaCO3), goethite (FeOOH) and mixtures of contaminant-bearing phases were identified in the solid fraction of one treatment cell. A reaction progress approach was used to model chemical evolution of water chemistry as it reacted with the Fe(0). Precipitation of calcite, ferrous hydroxide [Fe(OH)2] and ferrous sulfide (FeS) were used to simulate observed changes in major-ion aqueous chemistry. The amount of reaction progress differed for each treatment cell. Changes in contaminant concentrations were consistent with precipitation of reduced oxides (UO2, V2O3), sulfides (As2S3, ZnS), iron minerals (FeSe2, FeMoO4) and carbonate (MnCO3). Formation of a free gas phase and precipitation of minerals contributed to loss of hydraulic conductivity in one treatment cell.

Stable room temperature magnetocurrent in electrodeposited permeable n-type metal base transistor

NASA Astrophysics Data System (ADS)

Silva, G. V. O.; Teixeira, H. A.; Mello, S. L. A.; de Araujo, C. I. L.

2018-02-01

We investigated a permeable metal base transistor consisting of a ZnO/NiFe/Si heterostructure. Both ZnO and NiFe layers were grown by electrodeposition techniques, using only adhesive tape masks to define deposition regions. The base permeability can thus be controlled by varying the NiFe deposition time. We report here our best results obtained for the permeable NiFe base close to the electrical percolation threshold, which gives reasonable sensitivity to the device. Magnetocurrent measurements carried out at room temperature show that this permeable metal base transistor is stable and sensitive under applied magnetic fields of low intensities, ˜100 Oe, required for electronics integration.

Size-depressed critical temperatures for the order-disorder transition of FePt, CoPt, FePb, Cu2S, and ZnS nanostructures

NASA Astrophysics Data System (ADS)

Jiang, R.; Zhou, Z. F.; Yang, X. X.; Guo, N. G.; Qi, W. H.; Sun, C. Q.

2013-01-01

The size dependency of the critical temperature (TC) for the order-disorder phase transitions of both the bimetallic and the chalcogenide nanoclusters is shown to follow the rule of bond order-length-strength correlation. The loss of the cohesive energy of the undercoordinated atoms in the surface skin dictates the structural stability. Theoretical reproduction of the size TC trends of FePt, CoPt, FePb, Cu2S, and ZnS nanostructures not only confirms our expectations without involving the concepts of surface energy or entropy used for continuum bulk materials but also provides guideline for engineering nanostructured alloys or compounds.

Analysis of ferrite nanoparticles in the flow of ferromagnetic nanofluid

PubMed Central

Nadeem, Sohail; Mustafa, M. T.

2018-01-01

Theoretical analysis has been carried out to establish the heat transport phenomenon of six different ferromagnetic MnZnFe2O4—C2H6O2 (manganese zinc ferrite-ethylene glycol), NiZnFe2O4—C2H6O2 (Nickel zinc ferrite-ethylene glycol), Fe2O4—C2H6O2 (magnetite ferrite-ethylene glycol), NiZnFe2O4—H2O (Nickel zinc ferrite-water), MnZnFe2O4—H2O (manganese zinc ferrite-water), and Fe2O4—H2O (magnetite ferrite-water) nanofluids containing manganese zinc ferrite, Nickel zinc ferrite, and magnetite ferrite nanoparticles dispersed in a base fluid of ethylene glycol and water mixture. The performance of convective heat transfer is elevated in boundary layer flow region via nanoparticles. Magnetic dipole in presence of ferrites nanoparticles plays a vital role in controlling the thermal and momentum boundary layers. In perspective of this, the impacts of magnetic dipole on the nano boundary layer, steady, and laminar flow of incompressible ferromagnetic nanofluids are analyzed in the present study. Flow is caused by linear stretching of the surface. Fourier’s law of heat conduction is used in the evaluation of heat flux. Impacts of emerging parameters on the magneto—thermomechanical coupling are analyzed numerically. Further, it is evident that Newtonian heating has increasing behavior on the rate of heat transfer in the boundary layer. Comparison with available results for specific cases show an excellent agreement. PMID:29320488

Diverse Reactivity of ECp* (E = Al, Ga) toward Low-Coordinate Transition Metal Amides [TM(N(SiMe3)2)2] (TM = Fe, Co, Zn): Insertion, Cp* Transfer, and Orthometalation.

PubMed

Weßing, Jana; Göbel, Christoph; Weber, Birgit; Gemel, Christian; Fischer, Roland A

2017-03-20

The reactivity of the carbenoid group 13 metal ligands ECp* (E = Al, Ga) toward low valent transition metal complexes [TM(btsa) 2 ] (TM = Fe, Co, Zn; btsa = bis(trimethylsilyl)amide) was investigated, revealing entirely different reaction patterns for E = Al and Ga. Treatment of [Co(btsa) 2 ] with AlCp* yields [Cp*Co(μ-H)(Al(κ 2 -(CH 2 SiMe 2 )NSiMe 3 )(btsa))] (1) featuring an unusual heterometallic bicyclic structure that results from the insertion of AlCp* into the TM-N bond with concomitant ligand rearrangement including C-H activation at one amide ligand. For [Fe(btsa) 2 ], complete ligand exchange gives FeCp* 2 , irrespective of the employed stoichiometric ratio of the reactants. In contrast, treatment of [TM(btsa) 2 ] (TM = Fe, Co) with GaCp* forms the 1:1 and 1:2 adducts [(GaCp*)Co(btsa) 2 ] (2) and [(GaCp*) 2 Fe(btsa) 2 ] (3), respectively. The tendency of AlCp* to undergo Cp* transfer to the TM center appears to be dependent on the nature of the TM center: For [Zn(btsa) 2 ], no Cp* transfer is observed on reaction with AlCp*; instead, the insertion product [Zn(Al(η 2 -Cp*)(btsa)) 2 ] (4) is formed. In the reaction of [Co(btsa) 2 ] with the trivalent [Cp*AlH 2 ], transfer of the amide ligands without further ligand rearrangement is observed, leading to [Co(μ-H) 4 (Al(η 2 -Cp*)(btsa)) 2 ] (5).

The Role of Metal Oxides in Nanothermite Reactions: Evidence of Condensed Phase Initiation

DTIC Science & Technology

2010-01-01

ignition on the gaseous oxidizer release from the metal oxides CuO, Fe2O3, and ZnO .[14] However, there is uncertainty as to whether oxidizer release to the...and how it differs from some other systems. In our previous work, we studied the nanothermite reaction of Al/CuO, Al/Fe2O3, and Al/ ZnO .[9] For...Jomard, Oxygen Diffusion in Bi2O3-doped ZnO , Materials Research-Ibero-American Journal of Materials, 11 (2008) 221-225. [20] T. Ivetic, M.V. Nikolic

Single and multi-layered core-shell structures based on ZnO nanorods obtained by aerosol assisted chemical vapor deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Pizá-Ruiz, P.

2015-07-15

Core–shell nanorod structures were prepared by a sequential synthesis using an aerosol assisted chemical vapor deposition technique. Several samples consisting of ZnO nanorods were initially grown over TiO{sub 2} film-coated borosilicate glass substrates, following the synthesis conditions reported elsewhere. Later on, a uniform layer consisting of individual Al, Ni, Ti or Fe oxides was grown onto ZnO nanorod samples forming the so-called single MO{sub x}/ZnO nanorod core–shell structures, where MO{sub x} was the metal oxide shell. Additionally, a three-layer core–shell sample was developed by growing Fe, Ti and Fe oxides alternately, onto the ZnO nanorods. The microstructure of the core–shellmore » materials was characterized by grazing incidence X-ray diffraction, scanning and transmission electron microscopy. Energy dispersive X-ray spectroscopy was employed to corroborate the formation of different metal oxides. X-ray diffraction outcomes for single core–shell structures showed solely the presence of ZnO as wurtzite and TiO{sub 2} as anatase. For the multi-layered shell sample, the existence of Fe{sub 2}O{sub 3} as hematite was also detected. Morphological observations suggested the existence of an outer material grown onto the nanorods and further microstructural analysis by HR-STEM confirmed the development of core–shell structures in all cases. These studies also showed that the individual Al, Fe, Ni and Ti oxide layers are amorphous; an observation that matched with X-ray diffraction analysis where no apparent extra oxides were detected. For the multi-layered sample, the development of a shell consisting of three different oxide layers onto the nanorods was found. Overall results showed that no alteration in the primary ZnO core was produced during the growth of the shells, indicating that the deposition technique used herein was and it is suitable for the synthesis of homogeneous and complex nanomaterials high in quality and purity. In addition, materials absorptance determined from the total transmittance and reflectance spectra revealed a broader absorption interval including visible light, indicating potential uses of these nanostructures on solar energy appliances. - Graphical abstract: Display Omitted - Highlights: • Uniform ZnO nanorods (core)–metal oxide (shell) were obtained sequentially by AACVD. • Shells were structured of homogeneous single or multi-layered non-mixed metal oxides. • ZnO nanorod core was preserved during the shell synthesis. • Optical absorptance revealed visible interval absorption for FeO{sub x} shell samples. • Materials can be suitable for photocatalytic or photovoltaic applications.« less

Isotopic composition of zinc, copper, and iron in lunar samples

NASA Astrophysics Data System (ADS)

Moynier, F.; Albarède, F.; Herzog, G. F.

2006-12-01

We determined by ICP-MS the concentrations and isotopic ratios of Fe, Cu, and Zn in the Ti-rich lunar basalt 74275, in the lunar orange glass 74220, and in up to 10 lunar soils, namely, 14163, 15231, 64501, 66041, 68841, 69941, 70011, 72501, 75081, and 76501. Two analyses of zinc in lunar basalt 74275 give δ 66Zn = 0.17‰ and 0.75‰, values within the range of those measured in terrestrial basalts; copper in lunar basalt 74275 has δ 65Cu ˜ +1.4‰, which is isotopically heavier than values observed in terrestrial basalts. In the orange glass, we measured δ 56Fe = -0.24‰, δ 65Cu = -0.42‰, and δ 66Zn ˜ -3.6‰. These values of δ are more negative than those obtained for 74275 and for typical lunar basalts, but for Cu, comparable to those observed in terrestrial sulfides and meteorites. In lunar soils we found 0.11‰ ⩽ δ 56Fe ⩽ 0.51‰, 2.6‰ ⩽ δ 65Cu ⩽ 4.5‰, and 2.2‰ ⩽ δ 66Zn ⩽ 6.4‰. Insofar as we can generalize from a small sample set, S, Fe, Cu, Zn, and Cd show similar trends in isotopic fractionation on the Moon. Lunar basalts have nearly terrestrial isotopic ratios. Relative to the lunar basalt 74275, the pyroclastic glass 74220 is enriched in the lighter isotopes of Fe, Cu, and Zn, and the soils are enriched in the heavier isotopes of Fe, Cu, and Zn. The patterns in the basalts are likely inherited from the source material; the light-isotope enrichments seen in the orange glass originated during lava fountaining or, less probably, during partial condensation of vapor; and the heavy-isotope enrichments in the lunar soils were likely created by a combination of processes that included micrometeorite vaporization and sputtering. In the orange glass, the light-isotope enrichments (relative to lunar basalts) of Zn are larger than those of Cu. If these enrichments reflect accurately the isotopic composition of the gas, they suggest that Cu is more volatile than Zn in the liquid from which the gas derived. A simple model built on the known flux of micrometeorites to the lunar surface and a published estimate that micrometeorites generate 10 times their own mass of vapor, predicts heavy-isotope enrichments comparable to those observed in soils but only if the regolith gardening rate is set at about one twentieth of the generally accepted value of 1 cm/My. This discrepancy may reflect the difference in the time constants for micrometeorite milling and decimeter-scale gardening, or the importance of sputtering.

[Long-term effects of tillage methods on heavy metal accumulation and availability in purple paddy soil].

PubMed

Chang, Tong-Ju; Cui, Xiao-Qiang; Ruan, Zhen; Zhao, Xiu-Lan

2014-06-01

A long-term experiment, conducted at Southwest University since 1990, was used to evaluate the effect of tillage methods on the total and available contents of heavy metals (Fe, Mn, Cu, Zn, Pb, Cd) in the profile of purple paddy soil and the contents of those metals in root, stem leaf and brown rice. The experiment included five tillage methods: conventional tillage, paddy-upland rotation, no-tillage and fallow in winter, ridge-no-tillage and compartments-no-tillage. The results showed that the total concentrations of Fe, Cu, Zn, Pb and Cd in the soil profile had no significant differences among five treatments, but it was found that total Mn has a significant decline in 0-20 cm under conventional tillage, paddy-upland rotation and no-tillage and fallow in winter compared with ridge-no-tillage and compartments-no-tillage. The availability of Fe, Cu, Zn, Pb and Cd decreased with the increase of soil depth in all treatments, but the availability of Mn was found to be the highest in the 20-40 cm layers except those in the paddy-upland rotation. In the ploughed layer, the contents of available Fe, Mn was the highest in paddy-upland rotation, while the contents of available Zn and Pb was the highest in conventional tillage, but tillage treatments had not significant influence to the contents of available Cu. Correlation analysis showed that available Fe was significantly negatively related to the pH values and significantly negatively related to the organic matter of soils, available Mn was significantly negatively related to the pH values and organic matter of soils, whereas the available Zn was significantly positively related to total Zn. The contents of Fe, Mn in rice root, the contents of Fe, Mn, Cu and Cd in rice straw and Cu in brown rice were higher under paddy-upland rotation, ridge-no-tillage and compartments-no-tillage than those in conventional tillage and no-tillage and fellow in winter. Paddy-upland rotation can significantly lower the migration coefficient value of Cd in brown rice, and the Pb, Cd concentration in brown rice in the treatment of paddy-upland rotation was lower than the upper limit (< 0.2 mg x kg(-1)) of the National Standard for Food Hygiene for Cd concentration. The content of Fe in root was significantly and negatively related with soil pH and significantly and positively related with soil available Fe, the content of Mn in root was significantly negatively related with soil pH and significantly positively related with soil available Mn, the content of Mn in straw was significantly negatively related with soil pH, significantly positively related with soil total Mn and significantly positively related with soil available Mn, the content of Cu in straw and brown rice was significantly negatively related with soil pH, the content of Zn was significant related with soil pH and significant related with soil CEC. The content of Fe in root, Mn in root and straw and Cd in straw was positively related with soil available Fe, Mn and Cd, respectively, but was negatively related with pH in plough layer soil, Zn in straw was also negatively related with plough layer soil pH. From the results as above, it is concluded that different tillage methods can change the values of soil pH, alter the availability of heavy metal in soils, consequently affect uptake of heavy metal by rice. Of the tillage methods, paddy-upland rotation could increase the availability of Fe and Mn, but decrease the availability of Zn, Pb and Cd in purple paddy soils. Paddy-upland rotation can also increase the contents of Fe, Mn in rice root and straw, but decrease Cd content in brown rice, and could reduce the Pb, Cd contents in brown rice in a certain extent, however, attention should be given to long-term paddy-upland rotation cause of leaching of soil surface Mn.

Effect of external magnetic field on the crystal growth of nano-structured Zn xMn 1- x+ yZr yFe 2-2 yO 4 thin films

NASA Astrophysics Data System (ADS)

Anjum, Safia; Rafique, M. S.; Khaleeq-ur-Rahaman, M.; Siraj, K.; Usman, Arslan; Ahsan, A.; Naseem, S.; Khan, K.

2011-06-01

Zn 0.2Mn 0.81Zr 0.01Fe 1.98O 4 and Zn 0.2Mn 0.83Zr 0.03Fe 1.94O 4 thin films with different concentrations of Mn and Zr have been deposited on single crystal n-Si (400) at room temperature (RT) by pulse laser deposition technique (PLD). The films have been deposited under two conditions: (i) with the applied external magnetic field across the propagation of the plume (ii) without applied external magnetic field ( B=0). XRD results show the films have spinel cubic structure when deposited in the presence of magnetic field. SEM and AFM observations clearly show the effect of external applied magnetic field on the growth of films in terms of small particle size, improved uniformity and lower r.m.s. roughness. Thin films deposited under the influence of external magnetic field exhibit higher magnetization as measured by the VSM. The optical band gap energy Eg, refractive index n, reflection, absorption and the thickness of the thin films were measured by spectroscopy ellipsometer. The reflection of Zn 0.2Mn 0.83Zr 0.03Fe 1.94O 4 thin films is higher than Zn 0.2Mn 0.81Zr 0.01Fe 1.98O 4 thin films due to the greater concentration of Zr. The thicknesses of the thin films under the influence of external magnetic field are larger than the films grown without field for both samples. The optical band gap energy Eg decreases with increasing film thickness. The films with external magnetic field are found highly absorbing in nature due to the larger film thickness.

The potential of selected macroalgal species for treatment of AMD at different pH ranges in temperate regions.

PubMed

Oberholster, Paul J; Cheng, Po-Hsun; Botha, Anna-Maria; Genthe, Bettina

2014-09-01

The metal bioaccumulation potential of selected macroalgae species at different pH ranges was study for usage as part of a possible secondary passive acid mine drainage (AMD) treatment technology in algae ponds. Two separate studies were conducted to determine the suitability of macroalgae for passive treatment when metabolic processes in macrophytes and microorganisms in constructed wetlands decrease during winter months. In the field study, the bioconcentration of metals (mg/kg dry weight) measured in the benthic macroalgae mats was in the following order: site 1. Oedogonium crassum Al > Fe > Mn > Zn; site 2. Klebsormidium klebsii, Al > Fe > Mn > Zn; site 3. Microspora tumidula, Fe > Al > Mn > Zn and site 4. M. tumidula, Fe > Mn > Al > Zn. In the laboratory study, cultured macroalgae K. klebsii, O. crassum and M. tumidula isolated from the field sampling sites were exposed to three different pH values (3, 5 and 7), while bioaccumulation of the metals, Al, Fe, Mn and Zn and glutathione S-transferase (GST) activity were measured in the different selected algae species at a constant water temperature of 14 °C. Bioaccumulation of Al was the highest for O. crassum followed by K. klebsii and M. tumidula (p < 0.0001). From the study it was evident that the highest metal bioaccumulation occurred in the macroalgae O. crassum at all three tested pH values under constant low water temperature. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dissolution behavior of Cu, Fe and Zn from gold sulfide concentrate during pre-oxidation using ozone in neutral media

NASA Astrophysics Data System (ADS)

Kurniawan, Mubarok, M. Zaki

2018-04-01

The aim of this work was to observe the dissolution behaviour of Cu, Fe and Zn from gold sulfide concentrate during preoxidation with ozone as the oxidant and distillation water as the media. The preoxidation experiments were carried out in five-necked reactor with variations of retention time, percent solid, particle size and oxygen dosage injected to ozone generator. The retention time was varied at 6 hours, 8 hours, 12 hours and 24 hours. The percent solid was varied at 10%, 20% and 30% while the particle size was varied at P80 -75 mesh dan P80 -20 mesh. The dosage of oxygen injection to ozone generator was varried at 1 liter per minute and 2 liter per minute. The ozone gas was produced by using ozone generator type OZ-03 and injected to the slurry by using Mazzei injector. The soluble Cu, Fe and Zn were measured by using Atomic Absorption Spectrophotometry (AAS). The concentrates were characterized by X-Ray Diffraction (XRD), mineragraphy, fire assay and Inductively Coupled Plasma (ICP). Fire assay, ICP and XRD were used to analyse the residues and froth. The solubilition of metals (Cu, Fe and Zn) was obtained through the formation of sulphate ion and H+ which decreased the pH, released a number of heat and then was continued by the formation of elemental sulphur (S°). The interaction of particles and gas yielded the formation of froth. The highest dissolution percentage of Cu, Fe and Zn was achieved through 24 hours oxidation at 20% (w/w), P80 -20 mesh and one liter per minute of oxygen injection dosage by 83.016%, 24.7303% and 91.6808%, respectively.

Removal of Fe3+ and Zn2+ from plasma metalloproteins by iron chelating therapeutics depicted with SEC-ICP-AES.

PubMed

Sooriyaarachchi, Melani; Gailer, Jürgen

2010-08-28

The iron chelation therapy drugs desferrioxamine B (DFO) and deferiprone (DFP) are used to treat iron overload patients, but not much is known about their adverse effects on other essential metals in vivo. After the addition of a clinically relevant dose of DFP or an equimolar dose of DFO to human plasma in vitro, the mixtures were analyzed by size exclusion chromatography (SEC) coupled to an inductively coupled plasma atomic emission spectrometer (ICP-AES). Simultaneous detection of the emission lines of copper, iron and zinc allowed the visualization of changes that these drugs exerted at the metalloprotein level. After the addition of DFP, a <10 kDa novel Fe-peak was detected and identified as (DFP)(3)Fe, whereas DFO resulted in the elution of a much smaller amount of Fe in this elution range. In fact, DFP was approximately 8-times more efficient than DFO regarding the removal of Fe from plasma proteins. The addition of both iron chelators also resulted in the elution of a <10 kDa novel Zn-peak. DFP abstracted twice as much Zn from plasma proteins compared to DFO. The identification of one of these peaks as (DFP)(2)Zn establishes a feasible biomolecular basis for the etiology of Zn-deficiency in patients that undergo long-term treatment with these drugs. Our results demonstrate that the analysis of plasma by SEC-ICP-AES can simultaneously provide insight into the efficacy of chelation therapy drugs and their adverse health effects at the metalloprotein level. Thus, SEC-ICP-AES emerges as a useful analytical tool to visualize health-relevant bioinorganic chemistry-related reactions of medicinal drugs in blood plasma in vitro.

Spectroscopy investigation of nanostructured nickel–zinc ferrite obtained by mechanochemical synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lazarević, Zorica Ž., E-mail: lzorica@yahoo.com; Milutinović, Aleksandra N.; Jovalekić, Čedomir D.

2015-03-15

Highlights: • Nano powder of Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} prepared by a soft mechanochemicaly after 10 h milling. • Phase formation controlled by XRD, Raman and IR spectroscopy. • Spectroscopy measurements indicate that the prepared samples have spinel structure. • The average particles size are found to be around 20 nm. • The degree of inversion is δ = 0.36 for NZF obtained from hydroxides for 10 h. - Abstract: Nano crystalline samples of nickel–zinc ferrite, Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} were prepared by mechanochemical route in a planetary ball mill starting from two mixtures of the appropriate quantitiesmore » of the powders: case (1) oxide powders: NiO, ZnO and α-Fe{sub 2}O{sub 3} in one case, and in the second case (2) hydroxide powders: Ni(OH){sub 2}, Zn(OH){sub 2} and Fe(OH){sub 3}. In order to monitor the progress of chemical reaction and confirm phase formation, powder samples obtained after 5 h and 10 h of milling were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman, IR and Mössbauer spectroscopy. It is shown that the soft mechanochemical method, i.e. mechanochemical activation of hydroxides, produces high quality single phase Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} samples in much more efficient way. From the IR spectroscopy of single phase samples it is obvious that energy of modes depends on the ratio of cations. The deconvolution of Raman spectra allows to separate contributions of different cations to a particular type of vibration and to estimate the degree of inversion.« less

Wire-in-tube structure fabricated by single capillary electrospinning via nanoscale Kirkendall effect: the case of nickel-zinc ferrite.

PubMed

Fu, Jiecai; Zhang, Junli; Peng, Yong; Zhao, Changhui; He, Yongmin; Zhang, Zhenxing; Pan, Xiaojun; Mellors, Nigel J; Xie, Erqing

2013-12-21

Wire-in-tube structures have previously been prepared using an electrospinning method by means of tuning hydrolysis/alcoholysis of a precursor solution. Nickel-zinc ferrite (Ni0.5Zn0.5Fe2O4) nanowire-in-nanotubes have been prepared as a demonstration. The detailed nanoscale characterization, formation process and magnetic properties of Ni0.5Zn0.5Fe2O4 nanowire-in-nanotubes has been studied comprehensively. The average diameters of the outer tubes and inner wires of Ni0.5Zn0.5Fe2O4 nanowire-in-nanotubes are around 120 nm and 42 nm, respectively. Each fully calcined individual nanowire-in-nanotube, either the outer-tube or the inner-wire, is composed of Ni0.5Zn0.5Fe2O4 monocrystallites stacked along the longitudinal direction with random orientation. The process of calcining electrospun polymer composite nanofibres can be viewed as a morphologically template nucleation and precursor diffusion process. This allows the nitrates precursor to diffuse toward the surface of the nanofibres while the oxides (decomposed from hydroxides and nitrates) products diffuse to the core region of the nanofibres; the amorphous nanofibres transforming thereby into crystalline nanowire-in-nanotubes. In addition, the magnetic properties of the Ni0.5Zn0.5Fe2O4 nanowire-in-nanotubes were also examined. It is believed that this nanowire-in-nanotube (sometimes called core-shell) structure, with its uniform size and well-controlled orientation of the long nanowire-in-nanotubes, is particularly attractive for use in the field of nano-fluidic devices and nano-energy harvesting devices.

Lithium Storage Performance of Zinc Ferrite Nanoparticle Synthesized with the Assistance of Triblock Copolymer P123.

PubMed

Yao, J H; Li, Y W; Song, X B; Zhang, Y F; Yan, J

2018-05-01

The ZnFe2O4 samples with the triblock copolymer P123 (P123) additive quantity of 0 wt.%, 2 wt.%, 5 wt.%, 8 wt.% and 10 wt.% were prepared by a very facile homogeneous precipitation method followed by high temperature sintering. The microstructures of the prepared samples were analyzed by X-ray diffraction (XRD) and Field emission scanning electron microscopy (FESEM). The results revealed that the five prepared samples are all normal spinel zinc ferrite (ZnFe2O4); the sample with the P123 additive quantity of 8 wt.% has the smallest particle size among the five samples. The lithium storage performances of the prepared samples are characterized by cyclic voltammograms (CV), electrochemical impedance spectroscopy (EIS), and charge-discharge tests. The results demonstrated that adding proper amount of P123 can obviously improve the lithium storage performances of zinc ferrite spinel powder. But excessive P123 can induce the particle agglomerates so that the lithium storage performance of sample decays significantly. The ZnFe2O4 sample with the P123 additive quantity of 8 wt.% exhibited the highest electrochemical activity, the best rate performance, and superior cycling stability. For example, after 50 charge/discharge cycles under a current density of 120 mA g-1, the ZnFe2O4 sample with the P123 additive quantity of 8 wt.% can retain a specific discharge capacity of 468 mAh g-1, much higher than that of for the ZnFe2O4 sample with the P123 additive quantity of 0 wt.% (224 mAh g-1).

Heavy Metals in Soils and Vegetables Irrigated with Urban Grey Waste Water in Fagge, Kano, Nigeria.

PubMed

Chiroma, T M; Ebewele, R O; Hymore, F K

2014-01-01

There is currently an increased consumption of vegetables within the local urban community. However, contamination of these vegetables with heavy metals poses a potential health hazard. Consequently, the potential contamination problem due to the effect of levels of some heavy metals (Fe, Mg, Zn, Mn, Cu and Cr) in soils and vegetables irrigated with drainage urban grey waste water were investigated. The maximum levels of Fe, Zn, Mn, Cu and Cr in the urban grey waste waters were respectively 2.8, 2.1, 19.5, 2.3 and 143.1 times, higher than the maximum recommended concentrations of these metals: 5.0 μg/mL, 2.0 μg/mL, 0.2 μg/mL, 0.2 μg/mL and 0.1 μg/mL, respectively, for irrigation waters. The soils were found to be contaminated with these metals to levels that range between 24 to 84 percent contaminations. Although the heavy metals concentration ranking in vegetable parts vary with plant specie, the concentrations of Fe, Zn, Mn, Cu and Cr in most parts of the vegetables were above their critical concentrations of 750 - 1000 μg/g, 100 - 400 μg/g, 300 - 500 μg/g, 20 - 100 μg/g and 5 - 30 μg/g, respectively, in plants. This suggests potential toxicity of these parts of vegetables. It was however found that over 40 percent of the concentrations of Fe, Mg, Zn and Cu in Onions, Fe in Okro, Cr in Bushgreen, Cu in Roselle and Zn, Cu in Carrot leaves can be easily removed by washing the leaves with water. However, only Cu concentration in Onions and Bushgreen leaves met the acceptable permissible level in plants after washing.

PM2.5 water-soluble elements in the southeastern United States: automated analytical method development, spatiotemporal distributions, source apportionment, and implications for heath studies

NASA Astrophysics Data System (ADS)

Fang, T.; Guo, H.; Verma, V.; Peltier, R. E.; Weber, R. J.

2015-06-01

Water-soluble redox-active metals are potentially toxic due to the ability to catalytically generate reactive oxygen species (ROS) in vivo, leading to oxidative stress. As part of the Southeastern Center for Air Pollution and Epidemiology (SCAPE), we developed a method to quantify water-soluble elements, including redox-active metals, from a large number of filter samples (N = 530) in support of the Center's health studies. PM2.5 samples were collected during 2012-2013 at various sites (three urban, two rural, a near-road, and a road-side site) in the southeastern US, using high-volume samplers. Water-soluble elements (S, K, Ca, Ti, Mn, Fe, Cu, Zn, As, Se, Br, Sr, Ba, and Pb) were determined by extracting filters in deionized water and re-aerosolized for analyses by X-ray fluorescence (XRF) using an online aerosol element analyzer (Xact, Cooper Environmental). Concentrations ranged from detection limits (nominally 0.1 to 30 ng m-3) to 1.2 μg m-3, with S as the most abundant element, followed by Ca, K, Fe, Cu, Zn, and Ba. Positive Matrix Factorization (PMF) identified four factors that were associated with specific sources based on relative loadings of various tracers. These include: brake/tire wear (with tracers Ba and Cu); biomass burning (K); secondary formation (S, Se, and WSOC); and mineral dust (Ca). Of the four potentially toxic and relatively abundant metals (redox active Cu, Mn, Fe, and redox-inactive Zn), 51 % of Cu, 32 % of Fe, 17 % of Mn, and 45 % of Zn, were associated with the brake/tire factor. Mn was mostly associated with the mineral dust factor (45 %). These two factors were higher in warm (dryer) periods that favored particle re-suspension. Zn was found in a mixture of factors, with 26 % associated with mineral dust, 14 % biomass burning, and 13 % secondary formation. Roughly 50 % of Fe and 40 % of Cu was apportioned to the secondary formation factor, likely through increased solubility by sulfur-driven aerosol acidity. Linkages between sulfate and water-soluble Fe and Cu may account for some of the past observed associations between sulfate/sulfur oxide and health outcomes. For Cu, Mn, Fe, and Zn, only Fe was correlated with PM2.5 mass (r = 0.73-0.80). Overall, mobile source emissions generated through mechanical processes (re-entrained road dust, tire and break wear) and processing by secondary sulfate were major contributors to water-soluble metals known to be capable of generating ROS.

Germanium enrichment in supergene settings: evidence from the Cristal nonsulfide Zn prospect, Bongará district, northern Peru

NASA Astrophysics Data System (ADS)

Mondillo, Nicola; Arfè, Giuseppe; Herrington, Richard; Boni, Maria; Wilkinson, Clara; Mormone, Angela

2018-02-01

Supergene nonsulfide ores form from the weathering of sulfide mineralization. Given the geochemical affinity of Ge to Si4+ and Fe3+, weathering of Ge-bearing sulfides could potentially lead to Ge enrichments in silicate and Fe-oxy-hydroxide minerals, although bulk rock Ge concentrations in supergene nonsulfide deposits are rarely reported. Here, we present the results of an investigation into Ge concentrations and deportment in the Cristal supergene Zn nonsulfide prospect (Bongará, northern Peru), which formed from the weathering of a preexisting Mississippi Valley-type (MVT) sulfide deposit. Material examined in this study originates from drillcore recovered from oxidized Zn-rich bodies 15-20 m thick, containing 5-45 wt% Zn and Ge concentrations 100 ppm. Microanalysis and laser ablation-ICP-MS show that precursor sphalerite is rich in both Fe (mean Fe = 8.19 wt%) and Ge (mean Ge = 142 ppm). Using the mineral geothermometer GGIMFis—geothermometer for Ga, Ge, In, Mn, and Fe in sphalerite—proposed by Frenzel et al. (Ore Geol Rev 76:52-78, 2016), sphalerite trace element data from the Cristal prospect suggest a possible formation temperature ( T GGIMFis) of 225 ± 50 °C, anomalously high for a MVT deposit. Germanium concentrations measured in both goethite (mean values 100 to 229 ppm, max 511 ppm) and hemimorphite (mean values 39 to 137 ppm, max 258 ppm) are similar to concentrations measured in hypogene sphalerite. Additionally, the Ge concentrations recorded in bulk rock analyses of sphalerite-bearing and oxidized samples are also similar. A persistent warm-humid climate is interpreted for the region, resulting in the development of an oxidation zone favoring the formation of abundant Zn hydrosilicates and Fe hydroxides, both able to incorporate Ge in their crystal structure. In this scenario, Ge has been prevented from dispersion during the weathering of the Ge-bearing sulfide bodies and remains in the resultant nonsulfide ore.

Evaluation of heavy metal leaching from coal ash-versus conventional concrete monoliths and debris.

PubMed

Gwenzi, Willis; Mupatsi, Nyarai M

2016-03-01

Application of coal ash in construction materials is constrained by the potential risk of heavy metal leaching. Limited information is available on the comparative heavy metal leaching from coal ash-versus conventional concrete. The current study compared total and leached heavy metal concentrations in unbound coal ash, cement and sand; and investigated the effect of initial leachant pH on heavy metal leaching from coal-ash versus conventional concrete monoliths and their debris. Total Pb, Mn and Zn in coal ash were lower than or similar to that of other materials, while Cu and Fe showed the opposite trend. Leached concentrations of Zn, Pb, Mn, Cu and Fe in unbound coal ash, its concrete and debris were comparable and in some cases even lower than that for conventional concrete. In all cases, leached concentrations accounted for just <1% of the total concentrations. Log-log plots of concentration and cumulative release of Fe versus time based on tank leaching data showed that leaching was dominated by diffusion. Overall, the risk of Zn, Pb, Mn, Cu and Fe leaching from coal ash and its concrete was minimal and comparable to that of conventional concrete, a finding in contrast to widely held public perceptions and earlier results reported in other regions such as India. In the current study the coal ash, and its concrete and debris had highly alkaline pH indicative of high acid neutralizing and pH buffering capacity, which account for the stabilization of Zn, Pb, Mn, Cu and Fe. Based on the low risk of Zn, Pb, Mn, Cu and Fe leaching from the coal ash imply that such coal ash can be incorporated in construction materials such as concrete without adverse impacts on public and environmental health from these constituents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Binding of the Zn2+ ion to ferric uptake regulation protein from E. coli and the competition with Fe2+ binding: a molecular modeling study of the effect on DNA binding and conformational changes of Fur

NASA Astrophysics Data System (ADS)

Jabour, Salih; Hamed, Mazen Y.

2009-04-01

The three dimensional structure of Ferric uptake regulation protein dimer from E. coli, determined by molecular modeling, was docked on a DNA fragment (iron box) and Zn2+ ions were added in two steps. The first step involved the binding of one Zn2+ ion to what is known as the zinc site which consists of the residues Cys 92, Cys 95, Asp 137, Asp141, Arg139, Glu 140, His 145 and His 143 with an average metal-Nitrogen distance of 2.5 Å and metal-oxygen distance of 3.1-3.2 Å. The second Zn2+ ion is bound to the iron activating site formed from the residues Ile 50, His 71, Asn 72, Gly 97, Asp 105 and Ala 109. The binding of the second Zn2+ ion strengthened the binding of the first ion as indicated by the shortening of the zinc-residue distances. Fe2+, when added to the complex consisting of 2Zn2+/Fur dimer/DNA, replaced the Zn2+ ion in the zinc site and when a second Fe2+ was added, it replaced the second zinc ion in the iron activating site. The binding of both zinc and iron ions induced a similar change in Fur conformations, but shifted residues closer to DNA in a different manner. This is discussed along with a possible role for the Zn2+ ion in the Fur dimer binding of DNA in its repressor activity.

Effect of milling atmosphere on structural and magnetic properties of Ni-Zn ferrite nanocrystalline

NASA Astrophysics Data System (ADS)

Hajalilou, Abdollah; Hashim, Mansor; Ebrahimi-Kahrizsangi, Reza; Masoudi Mohamad, Taghi

2015-04-01

Powder mixtures of Zn, NiO, and Fe2O3 are mechanically alloyed by high energy ball milling to produce Ni-Zn ferrite with a nominal composition of Ni0.36Zn0.64Fe2O4. The effects of milling atmospheres (argon, air, and oxygen), milling time (from 0 to 30 h) and heat treatment are studied. The products are characterized using x-ray diffractometry, field emission scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy, and transmitted electron microscopy. The results indicate that the desired ferrite is not produced during the milling in the samples milled under either air or oxygen atmospheres. In those samples milled under argon, however, Zn/NiO/Fe2O3 reacts with a solid-state diffusion mode to produce Ni-Zn ferrite nanocrystalline in a size of 8 nm after 30-h-milling. The average crystallite sizes decrease to 9 nm and 10 nm in 30-h-milling samples under air and oxygen atmospheres, respectively. Annealing the 30-h-milling samples at 600 °C for 2 h leads to the formation of a single phase of Ni-Zn ferrite, an increase of crystallite size, and a reduction of internal lattice strain. Finally, the effects of the milling atmosphere and heating temperature on the magnetic properties of the 30-h-milling samples are investigated. Project supported by the University Putra Malaysia Graduate Research Fellowship Section.

Superoxide-Dismutase Deficient Mutants in Common Beans (Phaseolus vulgaris L.): Genetic Control, Differential Expressions of Isozymes, and Sensitivity to Arsenic

PubMed Central

Talukdar, Dibyendu; Talukdar, Tulika

2013-01-01

Two common bean (Phaseolus vulgaris L.) mutants, sodPv 1 and sodPv 2, exhibiting foliar superoxide dismutase (SOD) activity of only 25% and 40% of their mother control (MC) cv. VL 63 were isolated in EMS-mutagenized (0.15%, 8 h) M2 progeny. Native-PAGE analysis revealed occurrence of Mn SOD, Fe SOD, Cu/Zn SOD I and Cu/Zn SOD II isozymes in MC, while Fe SOD, and Mn SOD were not formed in sodPv 1 and sodPv 2 leaves, respectively. In-gel activity of individual isozymes differed significantly among the parents. SOD deficiency is inherited as recessive mutations, controlled by two different nonallelic loci. Gene expressions using qRT PCR confirmed higher expressions of Cu/Zn SOD transcripts in both mutants and the absence of Fe SOD in sodPv 1 and Mn SOD in sodPv 2. In 50 μM arsenic, Cu/Zn SODs genes were further upregulated but other isoforms downregulated in the two mutants, maintaining SOD activity in its control level. In an F2 double mutants of sodPv 1 × sodPv 2, no Fe SOD, and Mn SOD expressions were detectable, while both Cu/Zn SODs are down-regulated and arsenic-induced leaf necrosis appeared. In contrast to both mutants, ROS-imaging study revealed overaccumulation of both superoxides and H2O2 in leaves of double mutant. PMID:24078924

Zinc and selenium accumulation and their effect on iron bioavailability in common bean seeds.

PubMed

de Figueiredo, Marislaine A; Boldrin, Paulo F; Hart, Jonathan J; de Andrade, Messias J B; Guilherme, Luiz R G; Glahn, Raymond P; Li, Li

2017-02-01

Common beans (Phaseolus vulgaris) are the most important legume crops. They represent a major source of micronutrients and a target for essential trace mineral enhancement (i.e. biofortification). To investigate mineral accumulation during seed maturation and to examine whether it is possible to biofortify seeds with multi-micronutrients without affecting mineral bioavailability, three common bean cultivars were treated independently with zinc (Zn) and selenium (Se), the two critical micronutrients that can be effectively enhanced via fertilization. The seed mineral concentrations during seed maturation and the seed Fe bioavailability were analyzed. Common bean seeds were found to respond positively to Zn and Se treatments in accumulating these micronutrients. While the seed pods showed a decrease in Zn and Se along with Fe content during pod development, the seeds maintained relatively constant mineral concentrations during seed maturation. Selenium treatment had minimal effect on the seed accumulation of phytic acid and polyphenols, the compounds affecting Fe bioavailability. Zinc treatment reduced phytic acid level, but did not dramatically affect the concentrations of total polyphenols. Iron bioavailability was found not to be greatly affected in seeds biofortified with Se and Zn. In contrast, the inhibitory polyphenol compounds in the black bean profoundly reduced Fe bioavailability. These results provide valuable information for Se and Zn enhancement in common bean seeds and suggest the possibility to biofortify with these essential nutrients without greatly affecting mineral bioavailability to increase the food quality of common bean seeds. Published by Elsevier Masson SAS.

The influence of manganese treatment on the distribution of metal elements in rats and the protection by sodium para-amino salicylic acid.

PubMed

Yuan, Zong-Xiang; Chen, Hai-Bin; Li, Shao-Jun; Huang, Xiao-Wei; Mo, Yu-Huan; Luo, Yi-Ni; He, Sheng-Nan; Deng, Xiang-Fa; Lu, Guo-Dong; Jiang, Yue-Ming

2016-07-01

Manganese (Mn) overexposure induced neurological damages, which could be potentially protected by sodium para-aminosalicylic acid (PAS-Na). In this study, we systematically detected the changes of divalent metal elements in most of the organs and analyzed the distribution of the metals in Mn-exposed rats and the protection by PAS-Na. Sprague Dawley (SD) rats received intraperitoneal injections of 15mg/kg MnCl2·4H2O (5d/week for 3 weeks), followed by subcutaneous (back) injections of PAS-Na (100 and 200mg/kg, everyday for 5 weeks). The concentrations of Mn and other metal elements [Iron (Fe), Copper (Cu), Zinc (Zn), Magnesium (Mg), Calcium (Ca)] in major organs (liver, spleen, kidney, thighbone and iliac bone, cerebral cortex, hippocampus and testes) and blood by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The results showed that Mn overexposure significantly increased Mn in most organs, Fe and Zn in liver, Fe and Mg in blood; however decreased Fe, Cu, Zn, Mg and Ca in cortex, Cu and Zn in kidney, Cu and Mg in iliac bone, and Zn in blood. In contrast, PAS-Na treatment restored most changes particularly in cortex. In conclusion, excessive Mn exposure disturbed the balance of other metal elements but PAS-Na post-treatments could restore these alterations. Copyright © 2016 Elsevier GmbH. All rights reserved.

Structural and morphological study of Zn0.9Mn0.05Fe0.05O synthesized by sol-gel wet chemical precipitation route

NASA Astrophysics Data System (ADS)

Jain, S. K.; Dolia, S. N.; Choudhary, B. L.; Prashant, B. L.

2018-04-01

Transition metal substituted Zinc oxide (ZnO) has drawn a great deal of attention due to its excellent properties. Zn0.9Mn0.05Fe0.05O sample synthesized was by Sol-gel wet chemical precipitation route at temperature 350°C. The crystallinity and the structure of Zn0.9Mn0.05Fe0.05O was determined by X-ray diffraction by Cu-Kα radiations operated at 40kV and 35mA in the range of 20° to 80°. The pattern gets indexed in wurtzite (hexagonal) structure with lattice constants a=b=3.2525Å and c=5.2071Å and approves the single phase material with no impurity. The values of particle size assessed by Debye Scherer’s (DS) formula lie in the range of 13nm to 33nm indicating the nano-crystalline nature of the sample. The morphological analysis of the sample was performed by Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) measurements. The observed size of Zn0.9Mn0.05Fe0.05O nanoparticles by TEM micrograph exhibits the similar trend with the size calculated by Debye-Scherer formula. TEM image show the irregular shape of the nanoparticles and particle size lies in the range of 10-35nm. Similar to SEM image, the slight agglomeration of the nanoparticles have been observed from TEM.

Characterization of metal adsorption variability in a sand and gravel aquifer, Cape Cod, Massachusetts, U.S.A

USGS Publications Warehouse

Fuller, C.C.; Davis, J.A.; Coston, J.A.; Dixon, E.

1996-01-01

Several geochemical properties of an aquifer sediment that control metal-ion adsorption were investigated to determine their potential use as indicators of the spatial variability of metal adsorption. Over the length of a 4.5-m-long core from a sand and gravel aquifer, lead (Pb2+) and zinc (Zn2+) adsorption at constant chemical conditions (pH 5.3) varied by a factor of 2 and 4, respectively. Pb2+ and Zn2+ were adsorbed primarily by Fe- and Al-oxide coatings on quartz-grain surfaces. Per unit surface area, both Pb2+ and Zn2+ adsorption were significantly correlated with the amount of Fe and Al that dissolved from the aquifer material in a partial chemical extraction. The variability in conditional binding constants for Pb2+ and Zn2+ adsorption (log KADS) derived from a simple non-electrostatic surface complexation model were also predicted by extracted Fe and Al normalized to surface area. Because the abundance of Fe- and Al-oxide coatings that dominate adsorption does not vary inversely with grain size by a simple linear relationship, only a weak, negative correlation was found between the spatial variability of Pb2+ adsorption and grain size in this aquifer. The correlation between Zn2+ adsorption and grain size was not significant. Partial chemical extractions combined with surface-area measurements have potential use for estimating metal adsorption variability in other sand and gravel aquifers of negligible carbonate and organic carbon content.

Tululite, Ca14(Fe3+,Al)(Al,Zn,Fe3+,Si,P,Mn,Mg)15O36: a new Ca zincate-aluminate from combustion metamorphic marbles, central Jordan

NASA Astrophysics Data System (ADS)

Khoury, Hani N.; Sokol, Ella V.; Kokh, Svetlana N.; Seryotkin, Yurii V.; Nigmatulina, Elena N.; Goryainov, Sergei V.; Belogub, Elena V.; Clark, Ian D.

2016-02-01

Tululite (Ca14(Fe3+,Al)(Al,Zn,Fe3+,Si,P,Mn,Mg)15O36 (the hypothetical end-member formula Ca14{Fe3+O6}[SiO4][Zn5Al9]O26) (IMA2014-065) is a new natural Ca zincate-aluminate, identified in medium-temperature (800-850 °C) combustion metamorphic (CM) spurrite-fluorellestadite marbles from central Jordan. The type locality (Tulul Al Hammam area) is situated in the northern part of the Siwaqa complex, the largest area of the "Mottled Zone" Formation in the Dead Sea region. The marbles originated from bitumen-rich chalky marine sediments of the Maastrichtian-Paleogene Muwaqqar Chalk Marl Formation, which have low clay content (and, consequently, low Al) and high Zn, Cd, and U enrichments. The bulk CM rocks derived from the low-Al protolith have unusually high (Zn + Cd)/Al ratios ( 0.2) and, as a result, a mineralogy with negligibly small percentages of Ca aluminates having low Ca:Al molar ratios (minerals of mayenite supergroup, Ca:Al = 6:7) common to most of calcareous CM rocks in the Mottled Zone. Instead, the mineral assemblage of the Zn-rich marbles contains tululite, with high Ca:Al = 2.55 molar ratios and Zn substituting for a large portion of Al (Zn:Al = 1.1). Tululite occurs in thin clusters as irregular grains with indented outlines (20-100 μm in size), having typical open-work textures associated with rock-forming calcite, fluorellestadite, spurrite, and accessory Zn-rich periclase, lime-monteponite solid solutions, calcium uranates, and zincite. Marbles also bear brownmillerite, dorrite, fluormayenite, high-fluorine Ca aluminate, and lakargiite. Secondary phases are brucite, gel-like calcium silicate hydrates and calcium silicate aluminate hydrates, including Zn- and U-bearing and Cd-rich compounds, Si-bearing hydrated compounds after calcium uranates, and basic Cd chlorides. The empirical formula of the holotype tululite (a mean of 32 analyses) is (Ca13.29Cd0.75)Σ14.04(Al5.46Zn5.20Fe3+ 2.23Si0.95Mn3+ 1.01Mg0.78P0.41)Σ16.04O36. Tululite is cubic, space group F23; a = 14.9346(4) Å; V = 3331.07(15) Å3, Z = 4. The strongest lines of the X-ray powder-diffraction pattern [ d, Å - ( I obs )] are: 2.874(57), 2.640 (100), 2.524(42), 2.278(41), 1.760(54), 1.725(25), 1.524(33), 1.500(33). The crystal structure was solved from single-crystal X-ray diffraction data and refined to wR2 = 0.0672 on the basis of 913 unique reflections with I 0 > 2σ( I). Tululite belongs to a group of compounds with the general formula Ca14 MT 15O35+ x (0 ≤ x ≤ 1), and is a new structure type. The tetrahedral framework of tululite structure is formed by T7O13 secondary building units (SBU), which consist of four corner-linked tetrahedra sharing a common oxygen atom and three tetrahedra sharing two O atoms with the neighbor SBU. Ca2+ cations occupy three positions; two of them also contain a minor amount of Cd2+. The Ca sites surround an island (Fe3+,Al)O6 octahedron and a (Si,P)O4 tetrahedron in the centers of framework cages at the junction of eight SBUs. The (Fe3+,Al)O6 octahedron is coordinated by fourteen Ca positions into a 6-capped cube, whereas the (Si,P)O4 tetrahedron is coordinated by six Ca positions into a regular octahedron. The structural formula of tululite is Ca14{Fe3+O6}M1[(Si,P)O4]T1[(Al,Zn)7O13]2 T2-T4. The mineral is yellow with greenish tint, transparent with vitreous luster, non-fluorescent under ultraviolet light, and showing neither parting nor cleavage; Mohs hardness is 6.5. The density calculated on the basis of the empirical formula is 3.826 g/cm3. Its Raman spectrum shows strong bands at 522, 550 and 636 cm-1 and weak bands at 199, 260, 295, 456, and 754 cm-1.

A Zn isotope perspective on the rise of continents.

PubMed

Pons, M-L; Fujii, T; Rosing, M; Quitté, G; Télouk, P; Albarède, F

2013-05-01

Zinc isotope abundances are fairly constant in igneous rocks and shales and are left unfractionated by hydrothermal processes at pH < 5.5. For that reason, Zn isotopes in sediments can be used to trace the changing chemistry of the hydrosphere. Here, we report Zn isotope compositions in Fe oxides from banded iron formations (BIFs) and iron formations of different ages. Zinc from early Archean samples is isotopically indistinguishable from the igneous average (δ(66) Zn ~0.3‰). At 2.9-2.7 Ga, δ(66) Zn becomes isotopically light (δ(66) Zn < 0‰) and then bounces back to values >1‰ during the ~2.35 Ga Great Oxygenation Event. By 1.8 Ga, BIF δ(66) Zn has settled to the modern value of FeMn nodules and encrustations (~0.9‰). The Zn cycle is largely controlled by two different mechanisms: Zn makes strong complexes with phosphates, and phosphates in turn are strongly adsorbed by Fe hydroxides. We therefore review the evidence that the surface geochemical cycles of Zn and P are closely related. The Zn isotope record echoes Sr isotope evidence, suggesting that erosion starts with the very large continental masses appearing at ~2.7 Ga. The lack of Zn fractionation in pre-2.9 Ga BIFs is argued to reflect the paucity of permanent subaerial continental exposure and consequently the insignificant phosphate input to the oceans and the small output of biochemical sediments. We link the early decline of δ(66) Zn between 3.0 and 2.7 Ga with the low solubility of phosphate in alkaline groundwater. The development of photosynthetic activity at the surface of the newly exposed continents increased the oxygen level in the atmosphere, which in turn triggered acid drainage and stepped up P dissolution and liberation of heavy Zn into the runoff. Zinc isotopes provide a new perspective on the rise of continents, the volume of carbonates on continents, changing weathering conditions, and compositions of the ocean through time. © 2013 Blackwell Publishing Ltd.

ONR Tokyo Scientific Bulletin. Volume 5, Number 1, January-March 1980,

DTIC Science & Technology

1980-03-01

alloys studied are in die AI-Zn, Al -Mg, Al -Si. Al - Cu . Cu - Al . and Cu -Fe... alloys Digital processing Measuring N 20. Abstract (cont.) with certain reports also being contributed by visiting stateside scientist. Occasionally a...atomic absorption spectrophotometer with tubes for the determination of Zn, Cu , Pb, Cr, Fe, Mg, Mn, Al , Co, Cd, Si, Ti, Zr, Ga, Au, Ag, Ni, Na, and

Beta decay of exotic TZ = -1, -2 nuclei: the interesting case of 56Zn

NASA Astrophysics Data System (ADS)

Orrigo, S. E. A.; Rubio, B.; Fujita, Y.; Blank, B.; Gelletly, W.; Agramunt, J.; Algora, A.; Ascher, P.; Bilgier, B.; Cáceres, L.; Cakirli, R. B.; Fujita, H.; Ganioğlu, E.; Gerbaux, M.; Giovinazzo, J.; Grévy, S.; Kamalou, O.; Kozer, H. C.; Kucuk, L.; Kurtukian-Nieto, T.; Molina, F.; Popescu, L.; Rogers, A. M.; Susoy, G.; Stodel, C.; Suzuki, T.; Tamii, A.; Thomas, J. C.

2014-03-01

The β decay properties of the Tz = -2, 56Zn isotope and other proton-rich nuclei in the fp-shell have been investigated in an experiment performed at GANIL. The ions were produced in fragmentation reactions and implanted in a double-sided silicon strip detector surrounded by Ge EXOGAM clovers. Preliminary results for 56Zn are presented .The 56Zn decay proceeds mainly by β delayed proton emission, but β delayed gamma rays were also detected. Moreover, the exotic β delayed gamma-proton decay was observed for the first time. The 56Zn half-life and the energy levels populated in the 56Cu daughter have been determined. Knowledge of the gamma de-excitation of the mirror states in 56Co and the comparison with the results of the mirror charge exchange process, the 56Fe(3He,t) reaction (where 56Fe has Tz = +2), were important in the interpretation of the 56Zn decay data. The absolute Fermi and Gamow-Teller strengths have been deduced.

Evaluation of Trace Elements and Their Relationship with Growth and Development of Young Children.

PubMed

Cao, Jia; Gao, Zhenyan; Yan, Jin; Li, Minming; Su, Jia; Xu, Jian; Yan, Chong-Huai

2016-06-01

This study was conducted to assess the levels of trace elements and their relationship with growth and development of children in Shanghai, China, to offer scientific evidence for supplementing trace elements in children. A stratified, clustered, random sampling method was used in the study. Blood samples were taken from 2141 Shanghai children from 0 to 6.0 years old, and the concentrations of zinc (Zn), calcium (Ca), iron (Fe), copper (Cu), and magnesium (Mg) were measured using inductively coupled plasma mass spectrometry (ICP-MS). Nutritional status was determined and Z-scores of anthropometric parameters, such as height for age (HFA), weight for age (WFA), and body mass index (BMI) were calculated, indicated by HAZ, WAZ, and BMIZ, respectively. The overall median blood levels of Zn, Ca, Fe, Cu, and Mg were 8.83, 79.02, 9.49, 1.04, and 15.45 mg/L, respectively. Fe, Cu, and Mg increased with age and Zn, Fe, and Cu differed by sex. HAZ and WAZ were positively correlated with Zn (r (2) = 0.072 and 0.053, respectively; P < 0.05). Trace elements were significantly related to children's growth and development. Dietary supplementation and screening of nutritional states are potential solutions to improve children's growth and development.

Trace elements in muscle of three fish species from Todos os Santos Bay, Bahia State, Brazil.

PubMed

de Santana, Carolina Oliveira; de Jesus, Taíse Bomfim; de Aguiar, William Moura; de Jesus Sant'anna Franca-Rocha, Washington; Soares, Carlos Alberto Caroso

2017-03-01

In this study, an analysis was performed on the concentrations of the trace elements Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn in muscle of two carnivorous and one planktivorous fish species collected at Todos os Santos Bay (BTS). The accumulation order of the trace elements in Lutjanus analis was Al >Zn >Fe >Cr >Ba >Ni. In Cetengraulis edentulus, the order was Al >Fe >Zn >Cr >Ni >Mn >As. In the species Diapterus rhombeus, the order was Al >Fe >Zn >Cr >Ni >Mn >Cd. To determine the risk related to the consumption of fish, toxicity guidelines were used as standard references. It was observed that the species C. edentulus contained concentrations of As exceeding WHO limits, but these concentrations were acceptable according to the Agência Nacional de Vigilância Sanitária (ANVISA) guidelines. Cd levels were found only in D. rhombeus and in low concentrations according to the determinations of WHO and ANVISA. Pb levels were not detected in any of the three fish species. The analyzed elements did not differ statistically according to the species and feeding habits. The results point to possible risks of human contamination by As related to the consumption of the fish species C. edentulus from the BTS.

Mg-Al and Zn-Fe layered double hydroxides used for organic species storage and controlled release.

PubMed

Seftel, E M; Cool, P; Lutic, D

2013-12-01

Layered double hydroxides (LDH) containing (Mg and Al) or (Zn and Fe) were prepared by coprecipitation at constant pH, using NaOH and urea as precipitation agents. The most pure LDH phase in the Zn/Fe system was obtained with urea and in Mg/Al system when using NaOH. The incorporation of phenyl-alanine (Phe) anions in the interlayer of the LDH was performed by direct coprecipitation, ionic exchange and structure reconstruction of the mixed oxide obtained by the calcination of the coprecipitated product at 400°C. The reconstruction method and the direct coprecipitation in a medium containing Phe in the initial mixture were less successful in terms of high yields of organic-mineral composite than the ionic exchange method. A spectacular change in sample morphology and yield in exchanged solid was noticed for the Zn3Fe sample obtained by ionic exchange for 6h with Phe solution. A delivery test in PBS of pH=7.4 showed the release of the Phe in several steps up to 25 h indicating different host-guest interactions between the Phe and the LDH matrix. This behavior makes the preparation useful to obtain late delivery drugs, by the incorporation of the anion inside the LDH layer. © 2013.

Design, synthesis and photoelectrochemical properties of hexagonal metallomacrocycles based on triphenylamine: [M6(4,4'-bis(2,2':6',2''-terpyridinyl)triphenylamine)6(X)12]; [M = Fe(II), PF6- and Zn(II), BF4-].

PubMed

Hwang, Seok-Ho; Moorefield, Charles N; Wang, Pingshan; Fronczek, Frank R; Courtney, Brandy H; Newkome, George R

2006-08-07

Synthesis of a novel bis(terpyridine) ligand, 4,4'-bis(2,2':6',2''-terpyridinyl)triphenylamine, utilizing triphenylamine, as a specific angle controller, has led to the self-assembly of a unique hexagonal metallomacrocycle family, [Fe6(2)6(PF6)12] and [Zn6(2)6(BF4)12], utilizing terpyridine-metal(II)-terpyridine connectivity. The crystal structure of the novel ligand shows that the angle between the two terpyridinyl moieties is 119.69 degrees , which enabled the formation of the hexagonal-shaped macrocycles. The crystal packing architectures of this starting ligand revealed channels induced by solvent encapsulation. Following complexation of this ligand with transition metals [Fe(II) or Zn(II)] in a one-pot reaction, the resultant structures were characterized by (1)H and (13)C NMR, UV/Vis and mass spectroscopies. The expected metal-to-ligand charge transfer (MLCT; lambda(max) = 582 nm) and emission (lambda(em) = 575 nm) characteristics were exhibited by both [Fe6(2)6(PF6)12] and[Zn6(2)6(BF4)12]. The photoelectrochemical characteristics of these hexagonal metallomacrocycles demonstrate that they can be used as sensitizers in dye-sensitized solar cells.

Mechanism of γ-irradiation induced phase transformations in nanocrystalline Mn0.5Zn0.5Fe2O4 ceramics

NASA Astrophysics Data System (ADS)

Jagadeesha Angadi, V.; Anupama, A. V.; Choudhary, Harish K.; Kumar, R.; Somashekarappa, H. M.; Mallappa, M.; Rudraswamy, B.; Sahoo, B.

2017-02-01

The structural, infrared absorption and magnetic property transformations in nanocrystalline Mn0.5Zn0.5Fe2O4 samples irradiated with different doses (0, 15, 25 and 50 kGy) of γ-irradiation were investigated in this work and a mechanism of phase transformation/decomposition is provided based on the metastable nature of the Mn-atoms in the spinel lattice. The nano-powder sample was prepared by solution combustion route and the pellets of the sample were exposed to γ-radiation. Up to a dose of 25 kGy of γ-radiation, the sample retained the single phase cubic spinel (Fd-3m) structure, but the disorder in the sample increased. On irradiating the sample with 50 kGy γ-radiation, the spinel phase decomposed into new stable phases such as α-Fe2O3 and ZnFe2O4 phases along with amorphous MnO phase, leading to a change in the surface morphology of the sample. Along with the structural transformations the magnetic properties deteriorated due to breakage of the ferrimagnetic order with higher doses of γ-irradiation. Our results are important for the understanding of the stability, durability and performance of the Mn-Zn ferrite based devices used in space applications.

Spinel NixZn1-xFe2O4 (0.0 ≤ x ≤ 1.0) nano-photocatalysts: Synthesis, characterization and photocatalytic degradation of methylene blue dye

NASA Astrophysics Data System (ADS)

Padmapriya, G.; Manikandan, A.; Krishnasamy, V.; Jaganathan, Saravana Kumar; Antony, S. Arul

2016-09-01

Spinel NixZn1-xFe2O4 (x = 0.0 to 1.0) nanoparticles were successfully synthesized by a simple microwave combustion method (MCM) using metal nitrates as raw materials and glycine as the fuel. The structural, morphological and opto-magnetic properties of the spinel NixZn1-xFe2O4 ferrites were determined by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray (EDX) spectroscopy, high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED) pattern, UV-Visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM). Powder XRD, and EDX analysis was confirmed the formation of pure phase of spinel ferrites. HR-SEM and HR-TEM analysis was confirmed the formation of sphere like-particle morphology of the samples with smaller agglomeration. VSM analysis clearly showed the superparamagnetic and ferromagnetic nature of the samples. The Ms value is 3.851 emu/g for undoped ZnFe2O4 sample and it increased with increase in Ni content. Photo-catalytic degradation (PCD) of methylene blue (MB) dye using the samples were carried out and observed good PCD results.

An investigation on the potential of metal recovery from the municipal waste incinerator in Taiwan.

PubMed

Kuo, Nae-Wen; Ma, Hwong-Wen; Yang, Ya-Mei; Hsiao, Teng-Yuan; Huang, Chin-Ming

2007-01-01

This study aimed to identify distribution of metals and to estimate the amount of these metals that can be potentially recovered from incineration residues. First, the partitioning behavior of Cr, Cu, Fe, Cd, Al, Zn, and Pb in bottom ash and fly ash was investigated in one large municipal waste incinerator in Taiwan. In addition, the material flow analysis (MFA) method was used to estimate the material flux of metals within incinerator plant, and to calculate the amount of metal recovery. According to the findings of this study, six metals (Fe, Al, Cu, Zn, Cr, and Pb) concentrated in bottom ash mostly, while Cd existed primarily in fly ash. The weight percentages of Fe (4.49%), Al (5.24%), Cu (1.29%), Zn (2.21%), and Pb (0.58%) in incinerator ash are high, and even higher than the compositions of natural minerals. Finally, the amount of Cr, Cu, Fe, Cd, Al, Zn and Pb that can be potentially recovered from incineration residues will reach 2.69 x 10(2), 1.46 x 10(4), 4.91 x 10(4), 6.92 x 10(1), 5.10 x 10(4), 1.85 x 10(4) and 4.66 x 10(3) ton/yr, respectively.

Development of surface functionalized ZnO-doped LiFePO4/C composites as alternative cathode material for lithium ion batteries

NASA Astrophysics Data System (ADS)

Saroha, Rakesh; Panwar, Amrish K.; Sharma, Yogesh; Tyagi, Pawan K.; Ghosh, Sudipto

2017-02-01

Surface modified olivine-type LiFePO4/C-ZnO doped samples were synthesized using sol-gel assisted ball-milling route. In this work, the influence of ZnO-doping on the physiochemical, electrochemical and surface properties such as charge separation at solid-liquid interphase, surface force gradient, surface/ionic conductivity of pristine LiFePO4/C (LFP) has been investigated thoroughly. Synthesized samples were characterized using X-ray diffraction, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. All the synthesized samples were indexed to the orthorhombic phase with Pnma space group. Pristine LiFePO4 retain its structure for higher ZnO concentrations (i.e. 2.5 and 5.0 wt.% of LFP). Surface topography and surface force gradient measurements by EFM revealed that the kinetics of charge carriers, e-/Li+ is more in ZnO-doped LFP samples, which may be attributed to diffusion or conduction process of the charges present at the surface. Among all the synthesized samples LFP/C with 2.5 wt.% of ZnO (LFPZ2.5) displays the highest discharge capacity at all C-rates and exhibit excellent rate performance. LFPZ2.5 delivers a specific discharge capacity of 164 (±3) mAh g-1 at 0.1C rate. LFPZ2.5 shows best cycling performance as it provides a discharge capacity of 135 (±3) mAh g-1 at 1C rate and shows almost 95% capacity retention after 50 charge/discharge cycles. Energy density plot shows that LFPZ2.5 offers high energy and power density measured at high discharge rates (5C), proving its usability for hybrid vehicles application.

Enhancement of Fe diffusion in ZnSe/S laser crystals under hot isostatic pressing

NASA Astrophysics Data System (ADS)

Gafarov, Ozarfar; Martinez, Alan; Fedorov, Vladimir; Mirov, Sergey

2017-02-01

Many organic molecules have strong and narrow absorption features in the middle Infrared (mid-IR) spectral range. The ability to directly probe absorption features of molecules enables numerous mid-IR applications in non-invasive medical diagnosis, industrial processing and process control, environmental monitoring, etc. Thus, there is a strong demand for lasers operating in mid-IR spectral range. Transition metal (TM) doped II-VI semiconductors such as Fe/Cr:ZnSe/S are the material of choice for fabrication of mid-IR gain media due to favorable combination of properties: a four level energy structure, absence of excited state absorption , broad mid-IR vibronic absorption and emission bands. Despite the significant progress in post-growth thermal diffusion technology of TM:II-VI fabrication there are still some difficulties associated with diffusion of certain TM's in these materials. In this work we address the issue of poor diffusion of Fe in ZnSe/S polycrystals. It is well known that with the temperature increase the diffusion rate of impurity also increases. However, simple application of high temperatures during the diffusion process is problematic for ZnSe/S crystals due to their strong sublimation. The sublimation processes can be suppressed by application of high pressures. Hot isostatic pressing was utilized as the means for simultaneous application of high temperatures (1300°C) and high pressures (1000atm, 3000atm). It was determined that diffusion coefficient of Fe was improved 13 and 14 fold in ZnSe and ZnS, respectively, as compared to the standard diffusion at 950°C. The difference in diffusion coefficients can be due to strong increase in the grain size of polycrystals.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Yong-Min; Bang, Suhee; Yoon, Heejung

Here we report redox-inactive metal ions play important roles in tuning chemical properties of metal–oxygen intermediates. We describe the effect of water molecules on the redox properties of a nonheme iron(III)–peroxo complex binding redox-inactive metal ions. The coordination of two water molecules to a Zn 2+ ion in (TMC)Fe III-(O 2)-Zn(CF 3SO 3) 2 (1-Zn 2+) decreases the Lewis acidity of the Zn 2+ ion, resulting in the decrease of the one-electron oxidation and reduction potentials of 1-Zn 2+. This further changes the reactivities of 1-Zn 2+ in oxidation and reduction reactions; no reaction occurred upon addition of an oxidantmore » (e.g., cerium(IV) ammonium nitrate (CAN)) to 1-Zn 2+, whereas 1-Zn 2+ coordinating two water molecules, (TMC)Fe III-(O 2)-Zn(CF 3SO 3) 2-(OH 2) 2 [1-Zn 2+-(OH 2) 2], releases the O 2 unit in the oxidation reaction. In the reduction reactions, 1-Zn 2+ was converted to its corresponding iron(IV)–oxo species upon addition of a reductant (e.g., a ferrocene derivative), whereas such a reaction occurred at a much slower rate in the case of 1-Zn 2+-(OH 2) 2. Finally, the present results provide the first biomimetic example showing that water molecules at the active sites of metalloenzymes may participate in tuning the redox properties of metal–oxygen intermediates.« less

Improvement on the magnetic and dielectric behavior of hard/soft ferrite nanocomposites

NASA Astrophysics Data System (ADS)

Mansour, S. F.; Hemeda, O. M.; Abdo, M. A.; Nada, W. A.

2018-01-01

Nanocomposites from M-type hexaferrite BaFe11.7Al0.15Zn0.15O19 and spinel ferrite Mn0.8Mg0.2Fe2O4 nanoparticles according to the formula [(x)(Ba Fe11.7Al0.15 Zn0.15O19) + (1 - x)(Mn0.8 Mg0.2Fe2O4); x = 0.3, 0.4 and 0.5] have been manufactured by the citrate combustion method. The structure and morphology of the nanocomposites were appointed by X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FESEM). The remanent magnetization and coercivity of the nanocomposites became 2 and 2.5 times higher, respectively by adding BaFe11.7Al0.15 Zn0.15O19 phase. The Cole-Cole plots of the nanocomposite x = 0.4 at the selected temperatures shows two successive semicircles at all the selected temperatures. The first low frequencies semicircle elucidates the contribution of the grain boundary and the second one, at high frequencies, gives the contribution of grain to conduction process. Multilateral applications for exchange spring magnets can be manufactured using those nanocomposites.

Coexistence of Cu, Fe, Pb, and Zn oxides and chlorides as a determinant of chlorinated aromatics generation in municipal solid waste incinerator fly ash.

PubMed

Fujimori, Takashi; Tanino, Yuta; Takaoka, Masaki

2014-01-01

We investigated chemical determinants of the generation of chlorinated aromatic compounds (aromatic-Cls), such as polychlorinated biphenyls (PCBs) and chlorobenzenes (CBzs), in fly ash from municipal solid waste incineration. The influences of the following on aromatic-Cls formation in model fly ash (MFA) were systematically examined quantitatively and statistically: (i) inorganic chlorides (KCl, NaCl, CaCl2), (ii) base materials (SiO2, Al2O3, CaCO3), (iii) metal oxides (CuO, Fe2O3, PbO, ZnO), (iv) metal chlorides (CuCl2, FeCl3, PbCl2, ZnCl2), and (v) "coexisting multi-models." On the basis of aromatic-Cls concentrations, the ∑CBzs/∑PCBs ratio, and the similarity between distribution patterns, MFAs were categorized into six groups. The results and analysis indicated that the formation of aromatic-Cls depended strongly on the "coexistence condition", namely multimodels composed of not only metal chlorides, but also of metal oxides. The precise replication of metal chloride to oxide ratios, such as the precise ratios of Cu-, Fe-, Pb-, and Zn-chlorides and oxides, may be an essential factor in changing the thermochemical formation patterns of aromatic-Cls. Although CuCl2 acted as a promoter of aromatic-Cls generation, statistical analyses implied that FeCl3 also largely influenced the generation of aromatic-Cls under mixture conditions. Various additional components of fly ash were also comprehensively analyzed.

Biomonitoring Heavy Metal Pollution Using an Aquatic Apex Predator, the American Alligator, and Its Parasites

PubMed Central

Tellez, Marisa; Merchant, Mark

2015-01-01

Monitoring the bioaccumulation of chemical elements within various organismal tissues has become a useful tool to survey current or chronic levels of heavy metal exposure within an environment. In this study, we compared the bioaccumulations of As, Cd, Cu, Fe, Pb, Se, and Zn between the American alligator, Alligator mississippiensis, and its parasites in order to establish their use as bioindicators of heavy metal pollution. Concomitant with these results, we were interested to determine if parasites were more sensitive bioindicators of heavy metals relative to alligators. We found parasites collectively accumulated higher levels of As, Cu, Se, and Zn in comparison to their alligator hosts, whereas Fe, Cd, and Pb concentrations were higher in alligators. Interestingly, Fe levels were significantly greater in intestinal trematodes than their alligator hosts when analyzed independently from other parasitic taxa. Further analyses showed alligator intestinal trematodes concentrated As, Cu, Fe, Se, and Zn at significantly higher levels than intestinal nematodes and parasites from other organs. However, pentastomids also employed the role as a good biomagnifier of As. Interestingly, parasitic abundance decreased as levels of As increased. Stomach and intestinal nematodes were the poorest bioaccumulators of metals, yet stomach nematodes showed their ability to concentrate Pb at orders of magnitude higher in comparison to other parasites. Conclusively, we suggest that parasites, particularly intestinal trematodes, are superior biomagnifiers of As, Cu, Se, and Zn, whereas alligators are likely good biological indicators of Fe, Cd, and Pb levels within the environment. PMID:26555363

Biofortified indica rice attains iron and zinc nutrition dietary targets in the field

USDA-ARS?s Scientific Manuscript database

Iron (Fe) and zinc (Zn) deficiencies are the most prevalent micronutrient malnutrition globally1. Fe in rice has proven efficacious in improving serum ferritin concentration and body Fe levels2. Rapid progress in biofortification demonstrates the feasibility to enhance Fe in polished rice by expre...

Cu, Fe, and Zn Isotope Variations Within a High-Temperature Mid-Ocean Ridge Sulfide Structure

NASA Astrophysics Data System (ADS)

Ewing, S. M.; Nelson, B. K.; Kelley, D. S.; Nielsen, D. C.

2006-12-01

Hydrothermal processes at mid-ocean ridges play an important role in controlling the transition metal budget of seawater and the crust through which it circulates. Preliminary work has shown stable metal isotope variations accompany these processes. We report Cu, Zn, and Fe isotope analyses of transects through a high temperature sulfide structure ("Fin") collected during the 1998 Edifice Rex Sulfide Recovery Project. We analyzed two horizontal transects through the sulfide edifice, from inner conduit to outer surface. Transects A and F are 9 and 6 cm in length, respectively. Each displays radially zoned mineralogy progressing from a chalcopyrite (ccp) zone through zones of zinc sulfide, pyrite-anhydrite (pyr-anh) matrix, zinc sulfide-anhydrite (zns-anh) matrix, to an outer well-cemented silica (Si) zone. Additional ccp and pyr-anh zones appear in transect A resulting from a smaller breakout conduit. In transect A, Cu displays the most isotopic variation, with little variation in Fe and Zn isotopes. From the inner ccp zone outward, the Cu isotope profile shows a 0.4‰ (±0.05‰ 2σ) increase in the first pyr-anh zone over the coarse-grained ccp zone. The δ65Cu drops by 0.6‰ in the secondary ccp zone and recovers to values of the innermost wall in the following zone where it is constant until the outermost portion of the Si rich zone, which shows a 1.3‰ increase over inner zone values. The Zn isotope profile has a total variation of 0.27‰ (±0.05‰ 2σ), with a 0.2‰ increase in the first pyr- anh zone followed by a .27‰ decrease in the adjacent zone, and recovering to its heaviest values in the second pyr-anh zone. The Zn profile lacks any significant increase of the δ^{64}Zn in the outermost zones. The Fe isotope profile shows very little variation across the chimney wall, but does have a sharp 0.7‰ (±0.1‰ 2σ) increase in the δ56Fe in the well-cemented Si rich zone. In transect F, the Cu isotope profile again shows the most variation, but displays a more pronounced jump of 1.3‰ at the zinc sulfide boundary and no obvious increase of the δ65Cu in the Si rich zone. Similarly with Zn, there is a 0.35‰ increase of the δ^{64}Zn, but no outer wall increase. Fe, on the other hand, has variation of the same order as transect A, and shows a 0.6‰ increase of the δ56Fe in both the zns-anh and Si rich zones. These profiles are likely the result of a combination of diffusion and advection processes, fluid mineral equilibria, and mineral-mineral equilibria. High δ values of the outer zones likely reflect oxidation reactions with seawater. Processes responsible for isotopic variations within interior zones of the structure are ambiguous. Kinetic effects and biological activity may play a role, as Zn, which is not redox sensitive and only minimally coordination sensitive, has profiles that are qualitatively similar to Cu and Fe, but less analytically pronounced. Our findings are within the range of other published results, and further illustrate such measurable metal isotope variation exists not only on the vent field scale among chimneys, but systematically within chimney walls.

Metal-Ion Distribution and Oxygen Vacancies That Determine the Activity of Magnetically Recoverable Catalysts in Methanol Synthesis.

PubMed

Oracko, Troy; Jaquish, Rigel; Losovyj, Yaroslav B; Morgan, David Gene; Pink, Maren; Stein, Barry D; Doluda, Valentin Yu; Tkachenko, Olga P; Shifrina, Zinaida B; Grigoriev, Maxim E; Sidorov, Alexander I; Sulman, Esther M; Bronstein, Lyudmila M

2017-10-04

Here, we report on the development of novel Zn-, Zn-Cr-, and Zn-Cu-containing catalysts using magnetic silica (Fe 3 O 4 -SiO 2 ) as the support. Transmission electron microscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy (XPS) showed that the iron oxide nanoparticles are located in mesoporous silica pores and the magnetite (spinel) structure remains virtually unchanged despite the incorporation of Zn and Cr. According to XPS data, the Zn and Cr species are intermixed within the magnetite structure. In the case of the Zn-Cu-containing catalysts, a separate Cu 2 O phase was also observed along with the spinel structure. The catalytic activity of these catalysts was tested in methanol synthesis from syngas (CO + H 2 ). The catalytic experiments showed an improved catalytic performance of Zn- and Zn-Cr-containing magnetic silicas compared to that of the ZnO-SiO 2 catalyst. The best catalytic activity was obtained for the Zn-Cr-containing magnetic catalyst prepared with 1 wt % Zn and Cr each. X-ray absorption spectroscopy demonstrated the presence of oxygen vacancies near Fe and Zn in Zn-containing, and even more in Zn-Cr-containing, magnetic silica (including oxygen vacancies near Cr ions), revealing a correlation between the catalytic properties and oxygen vacancies. The easy magnetic recovery, robust synthetic procedure, and high catalytic activity make these catalysts promising for practical applications.

"Invisible" gold and PGE elements in synthetic crystals of sphalerite and covellite: A EPMA, LA-ICP-MS and XAFS study

NASA Astrophysics Data System (ADS)

Tonkacheev, Dmitry; Chareev, Dmitry; Abramova, Vera; Tagirov, Boris

2016-04-01

Sphalerite and covellite are widespread minerals in the different genetic types of deposits and forms under the various conditions. The purpose of this work is to determine the possible range of concentration and chemical state of Au and PGE (Pt, Pd, Rh) in sphalerite (Zn,Fe) S and covellite (CuS). These minerals were synthesized using gas transport and salt flux techniques. The crystals of ZnS were grown using the gas transport method at 850°C and the salt flux one using NaCl/KCl, CsCl/NaCl/KCl, and LiCl/RbCl eutectic mixtures at 850, 645 and 470°C, respectively. CuS crystals were synthesized using the salt flux method in RbCl/LiCl melt at 470 and 340°C. The trace metal activity was always controlled by the presence of pure metal or its sulfide, and, therefore, the concentration of these elements in synthesized phases represent the maximum possible value for given T/f(S2) synthesis parameters. The LA-ICP-MS and/or EPMA techniques were used to determine the Au concentration in synthesized phases. The concentration of Au in sphalerite, synthesized at 850°C with admixture of Cd, Se, In, Fe, and Mn, reached 0.3wt%, whereas the sphalerite cell parameter extremely increased up to 5.4161Å relatively to 5.4060 Å for pure ZnS. It was found that the observed high Au concentration is caused by the presence of In (2091±46 ppm Au in sample with Fe and In in comparison with 14±7 for Se-bearing ZnS, 94±12 ppm for Fe-Mn-bearing sphalerite, and 96±46 for Fe-bearing sphalerite. The concentration of Au in Fe-bearing sphalerite synthesized at 645°C does not exceed 5 ppm. Therefore, increase of temperature results in the increase of Au concentration in sphalerite. The concentration of Au in another Fe-bearing-sphalerite series synthesized using gas transport method at 850°C various from 200 to 500 ppm and depends on the iron content. This fact could be related to the oxidation state or Fe in ZnS-FeS solid solution series. The concentration of Pt and Pd, Rh in sphalerite is below the detection limit of LA-ICP-MS (~30 ppb). However, these trace elements change the cathodoluminescence properties of ZnS. The concentration or gold in covellite was determined by both LA-ICP-MS and EPMA techniques and the final values clearly fit together. The maximum concentration can be observed at 450° and equal to 0.3wt%. This value changes minor due to the increasing of the temperature. In principle, adding admixtures of In, Zn, Se, Cu, Sb, Bi did not affect on the concentration of Au. However, in experiment where sulfur is excessive and a mixture of In, Zn, Se, Cu, Sb, Bi, were added the concentration of Au is equal 0.128+0.028 ppm. The gold distribution in covellite and sphalerite is always homogeneous. According to XANES data, atoms of Au in the crystal structure covellite is in triangles, formed by the atoms of Cu. In sphalerite gold is in "invisible" state too.

Isotopic Evidence of Unaccounted for Fe and Cu Erythropoietic Pathways

NASA Astrophysics Data System (ADS)

Albarede, F.; Telouk, P.; Lamboux, A.; Jaouen, K.; Balter, V.

2011-12-01

Despite its potential importance for understanding perturbations in the Fe-Cu homeostatic pathways, the natural isotopic variability of these metals in the human body remains unexplored. We measured the Fe, Cu, and Zn isotope compositions of total blood, serum, and red blood cells of ~50 young blood donors by multiple-collector ICP-MS after separation and purification by anion exchange chromatography. Zn is on average 0.2 permil heavier in erythrocytes (δ 66Zn=0.44±0.33 permil) with respect to serum but shows much less overall isotopic variability than Fe and Cu, which indicates that isotope fractionation depends more on redox conditions than on ligand coordination. On average, Fe in erythrocytes (δ 56Fe=-2.59±0.47 permil) is isotopically light by 1-2 permil with respect to serum, whereas Cu in erythrocytes (δ 65Cu=0.56±0.50 permil) is 0.8 percent heavier. Fe and Cu isotope compositions clearly separate erythrocytes of men and women. Fe and Cu from B-type men erythrocytes are visibly more fractionated than all the other blood types. Isotope compositions provide an original method for evaluating metal mass balance and homeostasis. Natural isotope variability shows that the current models of Fe and Cu erythropoiesis, which assume that erythropoiesis is restricted to bone marrow, violate mass balance requirements. It unveils unsuspected major pathways for Fe, with erythropoietic production of isotopically heavy ferritin and hemosiderin, and for Cu, with isotopically light Cu being largely channeled into blood and lymphatic circulation rather than into superoxide dismutase-laden erythrocytes. Iron isotopes provide an intrinsic measuring rod of the erythropoietic yield, while Cu isotopes seem to gauge the relative activity of erythropoiesis and lymphatics.

Synthesis and characterization of mesoporous and hollow-mesoporous MxFe3-xO4 (M=Mg, Mn, Fe, Co, Ni, Cu, Zn) microspheres for microwave-triggered controllable drug delivery

NASA Astrophysics Data System (ADS)

Chen, Ping; Cui, Bin; Bu, Yumei; Yang, Zhenfeng; Wang, Yaoyu

2017-12-01

Spinel ferrites can be used in magnetic targeting and microwave heating and can therefore be used for targeted and controllable drug delivery. We used the cetyltrimethylammonium bromide-assisted solvothermal method to synthesize a series of spinel ferrites (MxFe3-xO4, M=Mg, Mn, Fe, Co, Ni, Cu, Zn) with a mesoporous or hollow-mesoporous structure suitable for direct drug loading and the particle diameters ranging from 200 to 350 nm. We investigated the effects of M2+ cation on the morphology and properties of these products by analyzing their transmission electron microscopy images, mesoporous properties, magnetic properties, and microwave responses. We chose hollow-mesoporous MxFe3-xO4 (M=Fe, Co, Zn) nanoparticles, which had better overall properties, for the drug VP16 (etoposide) loading and microwave-controlled release. The CoxFe3-xO4 and Fe3O4 particles trapped 61.5 and 64.8%, respectively, of the VP16, which were higher than that (60.4%) of ZnxFe3-xO4. Controllable drug release by these simple magnetic nanocarriers can be achieved by microwave irradiation, and VP16-loaded CoxFe3-xO4 released the most VP16 molecules (more than 50% after 1 h and 69.1% after 6 h) under microwave irradiation. Our results confirm the favorable drug loading and microwave-controlled delivery by these ferrites, and lay a theoretical foundation to promote clinical application of the targeted controllable drug delivery system. [Figure not available: see fulltext.

Assessment of the effects of glutamic acid decarboxylase antibodies and trace elements on cognitive performance in older adults.

PubMed

Alghadir, Ahmad H; Gabr, Sami A; Al-Eisa, Einas S

2015-01-01

Homeostatic imbalance of trace elements such as iron (Fe), copper (Cu), and zinc (Zn) demonstrated adverse effects on brain function among older adults. The present study aimed to investigate the effects of trace elements and the presence of anti-glutamic acid decarboxylase antibodies (GADAs) in human cognitive abilities among healthy older adults. A total of 100 healthy subjects (65 males, 35 females; age range; 64-96 years) were recruited for this study. Based on Loewenstein Occupational Therapy Cognitive Assessment (LOTCA) score, the participants were classified according to cognitive performance into normal (n=45), moderate (n=30), and severe (n=25). Cognitive functioning, leisure-time physical activity (LTPA), serum trace elements - Fe, Cu, Zn, Zn/Cu, and GADAs were assessed using LOTCA battery, pre-validated physical activity (PA) questionnaire, atomic absorption, and immunoassay techniques, respectively. Approximately 45% of the study population (n=45) had normal distribution of cognitive function and 55% of the study population (n=55) had abnormal cognitive function; they were classified into moderate (score 62-92) and severe (score 31-62). There was a significant reduction in the level of Zn and Zn/Cu ratio along with an increase in the level of Fe, Cu, and anti-GADAs in subjects of severe (P=0.01) and moderate (P=0.01) cognitive performance. LOTCA-cognitive scores correlated positively with sex, HbA(1c), Fe, Cu, Zn, and Zn/Cu ratio, and negatively with age, PA, body mass index, and anti-GADAs. Significant inter-correlation was reported between serum trace element concentrations and anti-GADAs which suggest producing a cognitive decline via oxidative and neural damage mechanism. This study found significant associations among trace elements, anti-GADAs, and cognitive function in older adults. The homeostatic balance of trace elements should be recommended among older adults for better cognitive performance.

Pollution characteristics, source apportionment, and health risk of heavy metals in street dust of Suzhou, China.

PubMed

Lin, Manli; Gui, Herong; Wang, Yao; Peng, Weihua

2017-01-01

To analyze the pollution characteristics, source apportionment, and health risk of heavy metals (HMs) in street dust of Suzhou, China, 23 sampling sites were selected and periodically sampled for 12 months. A total of 276 samples were collected, and the concentrations of selected HMs (e.g., Cr, Cu, Fe, Mn, Pb, V, and Zn) were examined with an X-ray fluorescence spectrum analyzer. Results showed that the mean concentrations of Cr, Cu, Fe, Mn, Pb, V, and Zn in the street dust of Suzhou were 112.9, 27.5, 19941.3, 410.3, 45.2, 75.6, and 225.3 mg kg -1 , respectively. Cr, Cu, Pb, and Zn exceeded their background values in local natural soils by 1.3-3.6-fold, whereas Fe, Mn, and V were all within their background values. However, enrichment factor analysis revealed that Cr, Cu, Mn, Pb, V, and Zn, especially Cr, Cu, Pb, and Zn, were enriched in Suzhou street dust. The HMs showed no significant seasonal changes overall, but spatial distribution analysis implied that the high values of Cr, Cu, Mn, Pb, V, and Zn were mainly distributed in areas with frequent human activities. Results of multivariate techniques (e.g., Pearson correlation, hierarchical cluster, and principal components analyses) suggested that Pb and Zn had complicated sources; Cu and V mainly originated from traffic sources; Fe and Mn mainly came from natural sources; and Cr was dominantly related to industrial district. Health risk assessment revealed that a single heavy metal might not cause both non-cancer and carcinogenic risks to local residents. Nevertheless, the sum of the hazard index of all selected HMs for children slightly exceeded the safety value, thereby implying that the HMs from Suzhou street dust can possibly produce significant risk to children. Cr was the priority pollutant in the study area because of its high concentration, high enrichment, and high contribution to non-cancer risk values.

Composition and Elution Behavior of Various Elements from Printed Circuit Boards, Cathode-ray Tube Glass, and Liquid-crystal Displays in Waste Consumer Electronics.

PubMed

Inaba, Kazuho; Murata, Tomoyoshi; Yamamura, Shigeki; Nagano, Masaaki; Iwasaki, Kazuhiro; Nakajima, Daisuke; Takigami, Hidetaka

2018-01-01

The contents and elution behavior of metals in consumer electronics parts were determined so as to understand their maximum environmental risk. Elements contained most in printed-circuit boards were Cu, Si, Br, Ca, Al, Sn, Pb, Sb, Ba, Fe, Ni, Ti, and Zn; in cathode-ray tube glass were Si, Pb, Ba, Sr, Zn, Zr, Ca, and Sb; in arsenic contained liquid-crystal displays were Si, Ca, Sr, Ba, As, and Fe; and in antimony contained liquid-crystal displays were Si, Ba, Ca, Sb, Sr, Fe, and Sn. The elements eluted most from printed-circuit boards were Zn, Pb, and Cu; from cathode-ray tube glass were Pb, Zn, B, Ba, and Si; and from liquid-crystal displays were B and Si, and the toxic As and Sb. The amount eluted was greatest at acidic pH. It was revealed that officially recommended 6-h-shaking with a pure water test was insufficient to understand the real environmental risk of waste electronics.

Optical, electrical and ferromagnetic studies of ZnO:Fe diluted magnetic semiconductor nanoparticles for spintronic applications

NASA Astrophysics Data System (ADS)

Elilarassi, R.; Chandrasekaran, G.

2017-11-01

In the present investigation, diluted magnetic semiconductor (Zn1-xFexO) nanoparticles with different doping concentrations (x = 0, 0.02, 0.04, 0.06, and 0.08) were successfully synthesized by sol-gel auto-combustion method. The crystal structure, morphology, optical, electrical and magnetic properties of the prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis using x-rays (EDAX), ultraviolet-visible spectrophotometer, fluorescence spectroscope (FS), vibrating sample magnetometer (VSM) and broad band dielectric spectrometer (BDS). XRD results reveal that all the samples possess hexagonal wurtzite crystal structure with good crystalline quality. The absence of impurity phases divulge that Fe ions are well incorporated into the ZnO crystal lattice. The substitutional incorporation of Fe3+ at Zn sites is reflected in optical absorption spectra of the samples. Flouorescence spectra of the samples show a strong near-band edge related UV emission as well as defect related visible emissions. The semiconducting behavior of the samples has been confirmed through electrical conductivity measurements. Magnetic measurements indicated that all the samples possess ferromagnetism at room temperature.

Heavy metals and polycyclic aromatic hydrocarbons: pollution and ecological risk assessment in street dust of Tehran.

PubMed

Saeedi, Mohsen; Li, Loretta Y; Salmanzadeh, Mahdiyeh

2012-08-15

50 street dust samples from four major streets in eastern and southern Tehran, the capital of Iran, were analyzed for metal pollution (Cu, Cr, Pb, Ni, Cd, Zn, Fe, Mn and Li). Hakanson's method was used to determine the Risk Index (RI) and ecological risks. Amongst these samples, 21 were also analyzed for polycyclic aromatic hydrocarbons (PAHs). Correlation, cluster and principal component analyses identified probable natural and anthropogenic sources of contaminants. The dust had elevated concentrations of Pb, Cd, Cu, Cr, Ni, Zn, Fe and PAHs. Enrichment factors of Cu, Pb, Cd and Zn showed that the dust is extremely enriched in these metals. Multivariate statistical analyses revealed that Cu, Pb, Zn, Fe and PAHs and, to a lesser extent, Cr and Ni have common anthropogenic sources. While Mn and Li were identified to have natural sources, Cd may have different anthropogenic origins. All samples demonstrated high ecological risk. Traffic and related activities, petrogenic and pyrogenic sources are likely to be the main anthropogenic sources of heavy metals and PAHs in Tehran dust. Copyright © 2012 Elsevier B.V. All rights reserved.

Photoelectrochemical enhancement of ZnO/BiVO4/ZnFe2O4/rare earth oxide hetero-nanostructures

NASA Astrophysics Data System (ADS)

She, Xuefeng; Zhang, Zhuo; Baek, Minki; Yong, Kijung

2018-01-01

Over the decades, researchers have made great efforts to turn the world into a cleaner place through efficient recycling of industrial waste and developing of green energy. Here we demonstrate a prototype heterostructure photoelectrochemical (PEC) cell fabricated using recycled industrial waste. ZnFe2O4 (ZFO) nanorod (NR) clusters were synthesized on the BiVO4@ZnO hetero-nanostructures using recycled rare earth oxide (REO) slags as Fe source. The NR-based PEC cell exhibited a significantly enhanced photon to hydrogen conversion efficiency over the entire UV and visible spectrum. Further study demonstrates that the photo-carrier separation and migration processes can be facilitated by the cascade band alignment of the heterostructure and the clustered nanostructure network. In addition, the life-time of the photo-carriers can be enhanced by the REO passivation layer, leading to a further increased PEC performance. Our results present a novel approach for high efficiency PEC cells, and offer great promises to the efficient recycling of industrial waste for clean renewable energy applications.

A multifunctional β-CD-modified Fe3O4@ZnO:Er(3+),Yb(3+) nanocarrier for antitumor drug delivery and microwave-triggered drug release.

PubMed

Peng, Hongxia; Cui, Bin; Li, Guangming; Wang, Yingsai; Li, Nini; Chang, Zhuguo; Wang, Yaoyu

2015-01-01

We constructed a novel core-shell structured Fe3O4@ZnO:Er(3+),Yb(3+)@(β-CD) nanoparticles used as drug carrier to investigate the loading and controllable release properties of the chemotherapeutic drug etoposide (VP-16). The cavity of β-cyclodextrin is chemically inert, it can store etoposide molecules by means of hydrophobic interactions. The Fe3O4 core and ZnO:Er(3+),Yb(3+) shell functioned successfully for magnetic targeting and up-conversion fluorescence imaging, respectively. In addition, the ZnO:Er(3+),Yb(3+) shell acts as a good microwave absorber with excellent microwave thermal response property for microwave triggered drug release (the VP-16 release of 18% under microwave irradiation for 15 min outclass the 2% within 6h without microwave irradiation release). The release profile could be controlled by the duration and number of cycles of microwave application. This material therefore promises to be a useful noninvasive, externally controlled drug-delivery system in cancer therapy. Copyright © 2014 Elsevier B.V. All rights reserved.

Doping effect on the structural properties of Cu1-x(Ni, Zn, Al and Fe)xO samples (0

NASA Astrophysics Data System (ADS)

Amaral, J. B.; Araujo, R. M.; Pedra, P. P.; Meneses, C. T.; Duque, J. G. S.; dos S. Rezende, M. V.

2016-09-01

In this work, the effect of insertion of transition metal, TM (=Ni, Zn, Al and Fe), ions in Cu1-xTMxO samples (0

Commentary on the sphalerite geobarometer

USGS Publications Warehouse

Toulmin, P.; Barton, P.B.; Wiggins, L.B.

1991-01-01

The FeS content of sphalerite in assemblages with pyrite and pyrrhotite has been widely used and widely criticized as a geobarometer. The commonly accepted form of the geobarometer is based on the composition of sphalerite being independent of temperature below about 550??C at all pressures up to at least 10 kbar, but strong thermodynamic arguments require a significant temperature dependence in this region. Most minor components have a negligible effect on the relevant equilibria, but the effect of CuS is somewhat more significant. Molar and partial molar volumes for binary (ZnS-FeS) and ternary (ZnS-FeS-CuS) sphalerite solutions are presented; the ternary data are consistent with charge transfer between Cu and Fe. -from Authors

Effect of Initial Iron Content in a Zinc Bath on the Dissolution Rate of Iron During a Hot Dip Galvanizing Process

NASA Astrophysics Data System (ADS)

Lee, Sang Myung; Lee, Suk Kyu; Paik, Doo-Jin; Park, Joo Hyun

2017-04-01

The mechanism of iron dissolution and the effect of initial Fe content in a Zn bath on the dissolution rate of iron were investigated using a finger rotating method (FRM). When the initial iron content, [Fe]°, in the zinc bath was less than the solubility limit, the iron content in the zinc bath showed a rapid increase, whereas a moderate increase was observed when [Fe]° was close to the solubility limit. Based on Eisenberg's kinetic model, the mass transfer coefficient of iron in the present experimental condition was calculated to be k M = 1.2 × 10-5 m/s, which was similar to the results derived by Giorgi et al. under industrial practice conditions. A dissolution of iron occurred even when the initial iron content in the zinc bath was greater than the solubility limit, which was explained by the interfacial thermodynamics in conjunction with the morphology of the surface coating layer. By analyzing the diffraction patterns using TEM, the outermost dendritic-structured coating layer was confirmed as FeZn13 ( ζ). In order to satisfy the local equilibrium based on the Gibbs-Thomson equation, iron in the dendrite-structured phase spontaneously dissolved into the zinc bath, resulting in the enrichment of iron in front of the dendrite tip. Through the diffusion boundary layer in front of the dendritic-structured layer, dissolved Fe atoms diffused out and reacted with Zn and small amounts of Al, resulting in the formation of dross particles such as FeZn10Al x ( δ). It was experimentally confirmed that the smaller the difference between the initial iron content in the zinc bath and the iron solubility limit at a given temperature, the lower the number of formed dross particles.

Effects of chemical composition of fly ash on efficiency of metal separation in ash-melting of municipal solid waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okada, Takashi, E-mail: t-okada@u-fukui.ac.jp; Tomikawa, Hiroki

2013-03-15

Highlights: ► Separation of Pb and Zn from Fe and Cu in ash-melting of municipal solid waste. ► Molar ratio of Cl to Na and K in fly ash affected the metal-separation efficiency. ► The low molar ratio and a non-oxidative atmosphere were better for the separation. - Abstract: In the process of metal separation by ash-melting, Fe and Cu in the incineration residue remain in the melting furnace as molten metal, whereas Pb and Zn in the residue are volatilized. This study investigated the effects of the chemical composition of incineration fly ash on the metal-separation efficiency of themore » ash-melting process. Incineration fly ash with different chemical compositions was melted with bottom ash in a lab-scale reactor, and the efficiency with which Pb and Zn were volatilized preventing the volatilization of Fe and Cu was evaluated. In addition, the behavior of these metals was simulated by thermodynamic equilibrium calculations. Depending on the exhaust gas treatment system used in the incinerator, the relationships among Na, K, and Cl concentrations in the incineration fly ash differed, which affected the efficiency of the metal separation. The amounts of Fe and Cu volatilized decreased by the decrease in the molar ratio of Cl to Na and K in the ash, promoting metal separation. The thermodynamic simulation predicted that the chlorination volatilization of Fe and Cu was prevented by the decrease in the molar ratio, as mentioned before. By melting incineration fly ash with the low molar ratio in a non-oxidative atmosphere, most of the Pb and Zn in the ash were volatilized leaving behind Fe and Cu.« less