21 CFR 184.1298 - Ferric citrate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Reg. No. 2338-05-8) is prepared from reaction of citric acid with ferric hydroxide. It is a compound of indefinite ratio of citric acid and iron. (b) The ingredient must be of a purity suitable for its...

21 CFR 184.1298 - Ferric citrate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Reg. No. 2338-05-8) is prepared from reaction of citric acid with ferric hydroxide. It is a compound of indefinite ratio of citric acid and iron. (b) The ingredient must be of a purity suitable for its...

Magnetotactic bacteria form magnetite from a phosphate-rich ferric hydroxide via nanometric ferric (oxyhydr)oxide intermediates.

PubMed

Baumgartner, Jens; Morin, Guillaume; Menguy, Nicolas; Perez Gonzalez, Teresa; Widdrat, Marc; Cosmidis, Julie; Faivre, Damien

2013-09-10

The iron oxide mineral magnetite (Fe3O4) is produced by various organisms to exploit magnetic and mechanical properties. Magnetotactic bacteria have become one of the best model organisms for studying magnetite biomineralization, as their genomes are sequenced and tools are available for their genetic manipulation. However, the chemical route by which magnetite is formed intracellularly within the so-called magnetosomes has remained a matter of debate. Here we used X-ray absorption spectroscopy at cryogenic temperatures and transmission electron microscopic imaging techniques to chemically characterize and spatially resolve the mechanism of biomineralization in those microorganisms. We show that magnetite forms through phase transformation from a highly disordered phosphate-rich ferric hydroxide phase, consistent with prokaryotic ferritins, via transient nanometric ferric (oxyhydr)oxide intermediates within the magnetosome organelle. This pathway remarkably resembles recent results on synthetic magnetite formation and bears a high similarity to suggested mineralization mechanisms in higher organisms.

RATES OF HYDROUS FERRIC OXIDE CRYSTALLIZATION AND THE INFLUENCE ON COPRECIPITATED ARSENATE

EPA Science Inventory

Arsenate coprecipitated with hydrous ferric oxide (HFO) was stabilized against dissolution during transformation of HFO to more crystalline iron (hydr)oxides. The rate of arsenate stabilization approximately coincided with the rate of HFO transformation at pH 6 and 40 ?C. Compa...

PHYSICAL SOLUTIONS FOR ACID MINE DRAINAGE AT REMOTE MINE SITES

EPA Science Inventory

After completing extensive bench-scale testing to determine optimum treatment approaches, the technology has been taken to the field. Preliminary results show that calcium hydroxide precipitates the bulk of the arsenic and zinc; the granular ferric hydroxide removes the rest of ...

Methods of using adsorption media for separating or removing constituents

DOEpatents

Tranter, Troy J [Idaho Falls, ID; Herbst, R Scott [Idaho Falls, ID; Mann, Nicholas R [Blackfoot, ID; Todd, Terry A [Aberdeen, ID

2011-10-25

Methods of using an adsorption medium to remove at least one constituent from a feed stream. The method comprises contacting an adsorption medium with a feed stream comprising at least one constituent and removing the at least one constituent from the feed stream. The adsorption medium comprises a polyacrylonitrile (PAN) matrix and at least one metal hydroxide homogenously dispersed therein. The adsorption medium may comprise from approximately 15 wt % to approximately 90 wt % of the PAN and from approximately 10 wt % to approximately 85 wt % of the at least one metal hydroxide. The at least one metal hydroxide may be selected from the group consisting of ferric hydroxide, zirconium hydroxide, lanthanum hydroxide, cerium hydroxide, titanium hydroxide, copper hydroxide, antimony hydroxide, and molybdenum hydroxide.

21 CFR 184.1296 - Ferric ammonium citrate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... citrate (iron (III) ammonium citrate) is prepared by the reaction of ferric hydroxide with citric acid... 18.5 percent iron, approximately 9 percent ammonia, and 65 percent citric acid and occurs as reddish... composed of 14.5 to 16 percent iron, approximately 7.5 percent ammonia, and 75 percent citric acid and...

21 CFR 184.1296 - Ferric ammonium citrate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... citrate (iron (III) ammonium citrate) is prepared by the reaction of ferric hydroxide with citric acid... 18.5 percent iron, approximately 9 percent ammonia, and 65 percent citric acid and occurs as reddish... composed of 14.5 to 16 percent iron, approximately 7.5 percent ammonia, and 75 percent citric acid and...

21 CFR 184.1296 - Ferric ammonium citrate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... prepared by the reaction of ferric hydroxide with citric acid, followed by treatment with ammonium..., approximately 9 percent ammonia, and 65 percent citric acid and occurs as reddish brown or garnet red scales or..., approximately 7.5 percent ammonia, and 75 percent citric acid and occurs as thin transparent green scales, as...

21 CFR 184.1296 - Ferric ammonium citrate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... citrate (iron (III) ammonium citrate) is prepared by the reaction of ferric hydroxide with citric acid... 18.5 percent iron, approximately 9 percent ammonia, and 65 percent citric acid and occurs as reddish... composed of 14.5 to 16 percent iron, approximately 7.5 percent ammonia, and 75 percent citric acid and...

21 CFR 184.1296 - Ferric ammonium citrate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... citrate (iron (III) ammonium citrate) is prepared by the reaction of ferric hydroxide with citric acid... 18.5 percent iron, approximately 9 percent ammonia, and 65 percent citric acid and occurs as reddish... composed of 14.5 to 16 percent iron, approximately 7.5 percent ammonia, and 75 percent citric acid and...

PHYSICAL SOLUTIONS FOR ACID MINE DRAINAGE AT REMOTE MINE SITES (SLIDES)

EPA Science Inventory

After completing extensive bench-scale testing to determine optimum treatment approaches, the technology has been taken to the field. Preliminary results show that calcium hydroxide precipitates the bulk of the arsenic and zinc; the granular ferric hydroxide removes the rest of ...

Rational design of interfacial properties of ferric (hydr)oxide nanoparticles by adsorption of fatty acids from aqueous solutions.

PubMed

Ponnurangam, Sathish; Chernyshova, Irina V; Somasundaran, Ponisseril

2012-07-24

Notwithstanding the great practical importance, still open are the questions how, why, and to what extent the size, morphology, and surface charge of metal (hydr)oxide nanoparticles (NPs) affect the adsorption form, adsorption strength, surface density, and packing order of organic (bio)molecules containing carboxylic groups. In this article, we conclusively answer these questions for a model system of ferric (hydr)oxide NPs and demonstrate applicability of the established relationships to manipulating their hydrophobicity and dispersibility. Employing in situ Fourier transform infrared (FTIR) spectroscopy and adsorption isotherm measurements, we study the interaction of 150, 38, and 9 nm hematite (α-Fe(2)O(3)) and ∼4 nm 2-line ferrihydrite with sodium laurate (dodecanoate) in water. We discover that, independent of morphology, an increase in size of the ferric (hydr)oxide NPs significantly improves their adsorption capacity and affinity toward fatty acids. This effect favors the formation of bilayers, which in turn promotes dispersibility of the larger NPs in water. At the same time, the local order in self-assembled monolayer (SAM) strongly depends on the morphological compatibility of the NP facets with the geometry-driven well-packed arrangements of the hydrocarbon chains as well as on the ratio of the chemisorbed to the physically adsorbed carboxylate groups. Surprisingly, the geometrical constraints can be removed, and adsorption capacity can be increased by negatively polarizing the NPs due to promotion of the outer-sphere complexes of the fatty acid. We interpret these findings and discuss their implications for the nanotechnological applications of surface-functionalized metal (hydr)oxide NPs.

Reactions of metal ions at surfaces of hydrous iron oxide

USGS Publications Warehouse

Hem, J.D.

1977-01-01

Cu, Ag and Cr concentrations in natural water may be lowered by mild chemical reduction involving ferric hydroxide-ferrous ion redox processes. V and Mo solubilities may be controlled by precipitation of ferrous vanadate or molybdate. Concentrations as low as 10-8.00 or 10-9.00 M are readily attainable for all these metals in oxygen-depleted systems that are relatively rich in Fe. Deposition of manganese oxides such as Mn3O4 can be catalyzed in oxygenated water by coupling to ferrous-ferric redox reactions. Once formed, these oxides may disproportionate, giving Mn4+ oxides. This reaction produces strongly oxidizing conditions at manganese oxide surfaces. The solubility of As is significantly influenced by ferric iron only at low pH. Spinel structures such as chromite or ferrites of Cu, Ni, and Zn, are very stable and if locally developed on ferric hydroxide surfaces could bring about solubilities much below 10-9.00 M for divalent metals near neutral pH. Solubilities calculated from thermodynamic data are shown graphically and compared with observed concentrations in some natural systems. ?? 1977.

Process for the synthesis of iron powder

DOEpatents

Not Available

1982-03-06

A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder.

Process for the synthesis of iron powder

DOEpatents

Welbon, William W.

1983-01-01

A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder.

Process for the synthesis of iron powder

DOEpatents

Welbon, W.W.

1983-11-08

A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder. 2 figs.

Molecular dynamics simulation study of the early stages of nucleation of iron oxyhydroxide nanoparticles in aqueous solutions

DOE PAGES

Zhang, Hengzhong; Waychunas, Glenn A.; Banfield, Jillian F.

2015-07-29

Nucleation is a fundamental step in crystal growth. Of environmental and materials relevance are reactions that lead to nucleation of iron oxyhydroxides in aqueous solutions. These reactions are difficult to study experimentally due to their rapid kinetics. Here, we used classical molecular dynamics simulations to investigate nucleation of iron hydroxide/oxyhydroxide nanoparticles in aqueous solutions. Results show that in a solution containing ferric ions and hydroxyl groups, iron–hydroxyl molecular clusters form by merging ferric monomers, dimers, and other oligomers, driven by strong affinity of ferric ions to hydroxyls. When deprotonation reactions are not considered in the simulations, these clusters aggregate tomore » form small iron hydroxide nanocrystals with a six-membered ring-like layered structure allomeric to gibbsite. By comparison, in a solution containing iron chloride and sodium hydroxide, the presence of chlorine drives cluster assembly along a different direction to form long molecular chains (rather than rings) composed of Fe–O octahedra linked by edge sharing. Further, in chlorine-free solutions, when deprotonation reactions are considered, the simulations predict ultimate formation of amorphous iron oxyhydroxide nanoparticles with local atomic structure similar to that of ferrihydrite nanoparticles. Overall, our simulation results reveal that nucleation of iron oxyhydroxide nanoparticles proceeds via a cluster aggregation-based nonclassical pathway.« less

Simultaneous separation of copper, cadmium and cobalt from sea-water by co-flotation with octadecylamine and ferric hydroxide as collectors.

PubMed

Cabezon, L M; Caballero, M; Cela, R; Perez-Bustamante, J A

1984-08-01

A method is proposed for the simultaneous quantitative separation of traces ofCu(II), Cd(II) and Co(II) from sea-water samples by means of the co-flotation (adsorbing colloid flotation) technique with ferric hydroxide as co-precipitant and octadecylamine as collector. The experimental parameters have been studied and optimized. The drawbacks arising from the low solubility of octadecylamine and the corresponding sublates in water have been avoided by use of a 6M hydrochloric acid-MIBK-ethanol (1:2:2 v v ) mixture. The results obtained by means of the proposed method have been compared with those given by the usual ammonium pyrrolidine dithiocarbamate/MIBK extraction method.

Attenuation of dissolved metals in neutral mine drainage in the Zambian Copperbelt.

PubMed

Sracek, Ondra; Filip, Jan; Mihaljevič, Martin; Kříbek, Bohdan; Majer, Vladimír; Veselovský, František

2011-01-01

Behaviour of metals like Cu and Co was studied in nearly neutral (pH ≥ 6.4) mine drainage seepage in a stream downgradient of a tailing dam at Chambishi site in the Copperbelt of Zambia. They are attenuated by precipitation of ferruginous ochres that incorporate significant quantities of metals. Using chemical analysis, X-ray powder diffraction and Mössbauer spectroscopy, we show that the ochres are composed mostly of amorphous ferric hydroxide. Close to the seepage face, the total Fe content of ochres increases due to precipitation of amorphous ferric hydroxide, but total Fe in sediment decreases further downstream. The stream then flows through wetland (dambo) where the remaining fraction of metals is removed. During rainy periods, increased flow rate may result in re-suspension of ochres, increasing thus the mobility of metals. Major ions like sulphate are conservative at the start of the dry period (May), but gypsum may probably precipitate later at the end of the dry period. Sequential extractions of bulk sediments indicate that Mn behaves differently to Fe, with a trend of increasing Mn with distance from the tailing dam. There is much more Fe than Mn in residual (Aqua Regia) fraction, indicating that amorphous ferric hydroxides are transformed to more crystalline phases deeper in sediment. Environmental impact of mine drainage is relatively limited due to its neutral character.

Central Heating Plant Coal Use Handbook. Volume 1: Technical Reference.

DTIC Science & Technology

1996-11-01

variation of a dry desulfurization system simply uses dry calcium hydroxide that is injected into the flue gas stream before entry to a fabric filter...97/14, Voll 173 competitive capital and operating costs compared with conventional technology using flue gas desulfurization reduced NOx emissions...ferric iron in slag, expressed as a percentage of the total iron calculated as ferric iron FGD: Flue gas desulfurization filter: A device for

Different arsenate and phosphate incorporation effects on the nucleation and growth of iron(III) (Hydr)oxides on quartz.

PubMed

Neil, Chelsea W; Lee, Byeongdu; Jun, Young-Shin

2014-10-21

Iron(III) (hydr)oxides play an important role in the geochemical cycling of contaminants in natural and engineered aquatic systems. The ability of iron(III) (hydr)oxides to immobilize contaminants can be related to whether the precipitates form heterogeneously (e.g., at mineral surfaces) or homogeneously in solution. Utilizing grazing incidence small-angle X-ray scattering (GISAXS), we studied heterogeneous iron(III) (hydr)oxide nucleation and growth on quartz substrates for systems containing arsenate and phosphate anions. For the iron(III) only system, the radius of gyration (Rg) of heterogeneously formed precipitates grew from 1.5 to 2.5 (± 1.0) nm within 1 h. For the system containing 10(-5) M arsenate, Rg grew from 3.6 to 6.1 (± 0.5) nm, and for the system containing 10(-5) M phosphate, Rg grew from 2.0 to 4.0 (± 0.2) nm. While the systems containing these oxyanions had more growth, the system containing only iron(III) had the most nucleation events on substrates. Ex situ analyses of homogeneously and heterogeneously formed precipitates indicated that precipitates in the arsenate system had the highest water content and that oxyanions may bridge iron(III) hydroxide polymeric embryos to form a structure similar to ferric arsenate or ferric phosphate. These new findings are important because differences in nucleation and growth rates and particle sizes will impact the number of available reactive sites and the reactivity of newly formed particles toward aqueous contaminants.

Life cycle assessment of sustainable raw material acquisition for functional magnetite bionanoparticle production.

PubMed

Sadhukhan, Jhuma; Joshi, Nimisha; Shemfe, Mobolaji; Lloyd, Jonathan R

2017-09-01

Magnetite nanoparticles (MNPs) have several applications, including use in medical diagnostics, renewable energy production and waste remediation. However, the processes for MNP production from analytical-grade materials are resource intensive and can be environmentally damaging. This work for the first time examines the life cycle assessment (LCA) of four MNP production cases: (i) industrial MNP production system; (ii) a state-of-the-art MNP biosynthesis system; (iii) an optimal MNP biosynthesis system and (iv) an MNP biosynthesis system using raw materials sourced from wastewaters, in order to recommend a sustainable raw material acquisition pathway for MNP synthesis. The industrial production system was used as a benchmark to compare the LCA performances of the bio-based systems (cases ii-iv). A combination of appropriate life cycle impact assessment methods was employed to analyse environmental costs and benefits of the systems comprehensively. The LCA results revealed that the state-of-the-art MNP biosynthesis system, which utilises analytical grade ferric chloride and sodium hydroxide as raw materials, generated environmental costs rather than benefits compared to the industrial MNP production system. Nevertheless, decreases in environmental impacts by six-fold were achieved by reducing sodium hydroxide input from 11.28 to 1.55 in a mass ratio to MNPs and replacing ferric chloride with ferric sulphate (3.02 and 2.59, respectively, in a mass ratio to MNPs) in the optimal biosynthesis system. Thus, the potential adverse environmental impacts of MNP production via the biosynthesis system can be reduced by minimising sodium hydroxide and substituting ferric sulphate for ferric chloride. Moreover, considerable environmental benefits were exhibited in case (iv), where Fe(III) ions were sourced from metal-containing wastewaters and reduced to MNPs by electrons harvested from organic substrates. It was revealed that 14.4 kJ and 3.9 kJ of primary fossil resource savings could be achieved per g MNP and associated electricity recoveries from wastewaters, respectively. The significant environmental benefits exhibited by the wastewater-fed MNP biosynthesis system shows promise for the sustainable production of MNPs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Implementation of ferric hydroxide-based media for removal of toxic metalloids

NASA Astrophysics Data System (ADS)

Szlachta, Małgorzata; Wójtowicz, Patryk

2017-11-01

Effective removal of inorganic arsenic species is possible by application of the sorption technique with the use of iron-based sorbents. This study investigates the removal of arsenic(III) and arsenic(V) from an aqueous solution by application of a granular ferric hydroxide-based sorbent. The performance of tested media was evaluated based on the batch and fixed-bed adsorption studies. The efficiency of the process was determined with various treatment times, adsorbent doses, initial concentrations of arsenic and various solution temperatures. The obtained adsorption data were fitted with pseudo-first and second-order kinetic models and Langmuir and Freundlich isotherm equations. It was observed that the overall arsenite removal was lower when compared to the arsenate, and all tested operating parameters influenced the process efficiency. The experiments under dynamic conditions showed high treatment capacity and stability of tested adsorbent over a long period of time.

Geochemistry and microbiology of iron-related well-screen encrustation and aquifer biofouling in Suffolk County, Long Island, New York

USGS Publications Warehouse

Walter, D.A.

1997-01-01

Iron-related well-screen encrustation and aquifer biofouling has decreased the specific capacity of several production wells in Suffolk County, N.Y., and has forced the Suffolk County Water Authority to adopt a costly well-reconditioning and replacement program. The specific-capacity declines are the result of the precipitation of iron oxyhydroxides and the growth of iron bacteria on the well screens and in the pore spaces of the surrounding formation. Mineralogic and chemical analyses indicate that the inorganic part of the encrusting material consists primarily of amorphous ferric hydroxide (Fe(OH)3 ); minor components of the material include goethite (FeOOH), hematite (Fe2 O 3 ), and quartz (SiO 2 ). The weight percent of ferric hydroxide in the material ranged from 32.3 to 98.6 percent and averaged 64.3 percent. Equilibrium modeling indicated that during pumping the well waters were supersaturated with respect to goethite, hematite, magnetite, and quartz and were under-saturated with respect to ferric hydroxide. Theoretical Eh values computed for the ferrous/ferric-iron redox couple and the oxygen/water redox couple averaged 390 millivolts and 810 millivolts, respectively, indicating that the waters were in a state of redox disequilibrium. The disequilibrium condition arises from the mixing of ground water with a low dissolved-oxygen concentration with oxygenated ground water during operation of the well. The low pH of the ground water contributes to the disequilibrium condition by slowing the rate of iron oxidation after the introduction of oxygen. Chemical and mineralogical data indicate that most of the encrusting material in the wells was deposited while the wells were shut down, probably in response to the use of treated water of higher pH to keep pump turbines wet while the wells were not in operation; the increased pH of water in the static water column increases the rate of ferrous-iron oxidation and causes the well water to become increasingly saturated with respect to ferric hydroxide. The median half-time of oxidation in samples of untreated ground water (pH 4-5) was 4.19 days, whereas the average half-time of oxidation in treated water (pH 7-8) was 11.9 minutes Equilibrium modeling indicated that treated waters generally were supersaturated with respect to ferric hydroxide, whereas untreated well waters were not. Field and laboratory data indicate that iron bacteria play an important role in the encrustation and biofouling process in Suffolk County. Filamentous iron bacteria were common in the affected wells. The most common species was Gallionella ferruginea, an effective biofouling agent that prefers water with low, but detectable, dissolved-oxygen concentrations and high dissolved-iron concentrations; this species was more common in biofilm samples from the Magothy aquifer than in those from the upper glacial aquifer. Iron bacteria also were found in sediment cores from several locations in the aquifer and in drilling water. Lignite could act as a carbon source for heterotrophic iron bacteria, which could accelerate the formation of iron-bacteria biofilms in wells screened in some parts of the Magothy aquifer. Iron-bacteria biofilms alter the chemistry of well water by removing iron, manganese, and sulfate from solution and by increasing the pH. Sulfur-reducing bacteria and iron-sulfide mineral phases were observed in some samples of encrusting material, indicating that these bacteria could contribute to well-screen encrustation in some geochemical environments.

Metals removal from aqueous solution by iron-based bonding agents.

PubMed

Deliyanni, Eleni A; Lazaridis, Nikolaos K; Peleka, Efrosini N; Matis, Konstantinos A

2004-01-01

GOAL AND SCOPE AND BACKGROUND: The application of a promising method, termed sorptive flotation, for the removal of chromium(VI) and zinc ions was the aim of the present paper. A special case of sorptive flotation is adsorbing colloid flotation. Suitable sorbent preparation techniques have been developed in the laboratory. Sorptive flotation, consisting of the sorption and flotation processes combined in series, has proved to give fast and satisfactory treatment of the industrial streams and effluents bearing dilute aqueous solutions of zinc and chromium(VI). Goethite has proved to be effective for the removal of chromium(VI) and zinc ions. Also, adsorbing colloid flotation with ferric hydroxide (as the co-precipitant) could be an alternative method to the above-mentioned separation of metal ions. In both cases, chromium(VI) (pH=4) and zinc (pH=7) removal was about 100%. The reasons for selecting the iron-based bonding materials, like goethite and/or in-situ produced ferric hydroxide, are that they are cheap, easily synthesized, suitable both for cation and anion sorption, and, furthermore, that they present low risks for adding a further pollutant to the system. Promising results were obtained. The application of goethite and in-situ produced ferric hydroxide has demonstrated their effectiveness in the removal of heavy metal ions, such as chromium anions and zinc cations. A proposed continuation of current work is the utilization of similar iron oxides, for instance synthesized akaganeite. The comparison between the results reported in this paper with the results reported in the literature, also deserves attention.

Bacterial Formation of As(V) and As(III) Ferric Oxyhydroxides in Acid Mine Drainage.

NASA Astrophysics Data System (ADS)

Morin, G.; Juillot, F.; Lebrun, S.; Casiot, C.; Elbaz-Poulichet, F.; Bruneel, O.; Personne, J.; Leblanc, M.; Ildefonse, P.; Calas, G.

2002-12-01

The oxidation of dissolved Fe(II) which is often promoted by acidophilic bacteria in acid mine drainage (AMD) and some hot springs, leads to the precipitation of Fe(III) oxy-hydroxides which incorporate toxic elements within their structure or adsorb them at their surface, thus limiting their mobility. In such complex natural systems, synchrotron-based techniques as X-ray absorption spectroscopy offer the opportunity to monitor surface/solution interactions as well as redox changes affecting the mobility and toxicity of trace elements as arsenic. Spatial and seasonal variations of the (bio-) oxidation of Fe(II) and As(III), and the subsequent precipitation of As-Fe gels, were followed by XANES, XRD, and SEM along the CarnoulŠs AMD (Gard, France). Chemical and mineralogical data collected on sediments, stromatolite, and bioassay samples showed that some indigenous bacteria living in the As-rich CarnoulŠs water ([As] = up to 350 mg.l-1) play an important role in the nature and composition of the solid phases that sequester arsenic at the site. The formation of nano-crystalline and amorphous As(III) ferric oxy-hydroxides has been related to the presence of bacteria able to oxidize Fe(II) but not As(III), which are only present in winter in the upstream area. A rare ferric arsenite sulfate oxy-hydroxide mineral was discovered in this context. Other types of bacteria, occurring in the downstream area whatever the season, are able to catalyze As(III) to As(V) oxidation and, provided that enough Fe(II) oxidizes, promote the formation of amorphous As(V) rich ferric oxy-hydroxides. These bacterially mediated reactions significantly reduce the concentration of dissolved As(III), which is more toxic and mobile than As(V), and might thus be helpful for designing As-removal processes. This work was supported by the French PEVS and ACI Ecologie Quantitative Programs and the PIRAMID EC program. ?Deceased, 26 October 1999 Juillot F., Ildefonse Ph., Morin G., Calas G., De Kersabiec A.M. and Benedetti M. Applied Geochemistry 8, 1031-1048 (1999). Morin G., Lecocq D., Juillot F., Ildefonse Ph., Calas Bull. Soc. Géol. Fr. 173, 281-291 (2002). Morin G., Juillot F., Casiot C., Bruneel O., Personné J-C., Elbaz-Poulichet F., Leblanc M., Ildefonse P. and Calas G. Environ. Sci. Technol (in review.)

Woody Plant Invasion of Grassland: Lignin and Aliphatic Biopolymer Chemistry and Carbon Isotope Composition in Physical Fractions

NASA Astrophysics Data System (ADS)

Gamblin, D.; Boutton, T.; Liao, J.; Jastrow, J.; Filley, T.

2003-12-01

Significant changes in the apportionment of organic carbon in grassland and savanna soils have been document as a result of woody plant encroachment. In the Rio Grande Plains of Texas, C4 grasslands (d13C = -14 0/00) have undergone succession to trees and shrubs of a subtropical thorn woodland (d13C = -27 0/00) over the past 150 y which has resulted in increased soil organic carbon storage. Large differences in the turnover times of physical fractions in this system indicate selective preservation mechanisms which may include physical protection or inherent biochemical recalcitrance. To elucidate mechanisms of SOC sequestration during woody plant succession in this system, we are investigating the chemistry and compound-specific stable carbon isotope composition of lignin and aliphatic biopolymers in specific physical (size, density) soil fractions within a chronosequence that includes remnant grasslands (Time 0) and woody plant stands ranging in age from 10-130 y. The soil fraction data is being compared to biopolymer and isotope chemistry of the root, stem and/or leaf tissue of 20 of the dominant genus of plants in the system. Lignin phenols and suberin and cutin-derived hydroxyfatty acids are being isolated using alkaline CuO oxidation and tetramethylammonium hydroxide thermochemolysis. A comparison of the macroaggregate (greater than 250 um), microaggregate (53-250 um), and free silt and clay fractions in the oldest stand indicates that lignin is the most concentrated (organic carbon normalized values) in macroaggregates and is significantly less degraded, as determined by relative yields of oxidized and reduced lignin phenols. Additionally, the intra-aggregate silt and clay fraction from the macroaggregates contains less than half of the organic carbon normalized lignin phenols and is relatively more oxidized than what is found in the total macroaggregate pool. From these preliminary results it appears that the bulk macroaggregate pool contains the least degraded/freshest lignin of the physical fractions. This is consistent with the relatively shorter residence times determined for this fraction in this system. Continuing work includes compound specific isotope analysis of isolated lignin and hydroxyl fatty acids to elucidate biopolymer-specific turnover times which will provide important clues into the mechanisms of SOM storage and biopolymer recalcitrance.

Chemical properties of ground water and their corrosion and encrustation effects on wells

USGS Publications Warehouse

Barnes, Ivan; Clarke, Frank Eldridge

1969-01-01

Well waters in Egypt, Nigeria, and West Pakistan were studied for their chemical properties and corrosive or encrusting behavior. From the chemical composition of the waters, reaction states with reference to equilibrium were tested for 29 possible coexisting oxides, carbonates, sulfides, and elements. Of the 29 solids considered, only calcite, CaCO3, and ferric hydroxide, Fe(OH)3, showed any correlation with the corrosiveness of the waters to mild steel (iron metal). All 39 of the waters tested were out of equilibrium with iron metal, but those waters in equilibrium or supersaturated with both calcite and ferric hydroxide were the least corrosive. Supersaturation with other solid phases apparently was unrelated to corrosion. A number of solids may form surface deposits in wells and lead to decreased yields by fouling well intakes (screens and gravel packs) or increasing friction losses in casings. Calcite, CaCO3; ferric hydroxide, Fe(OH)3; magnetite, Fe3O4; siderite, FeCO3; hausmannite, Mn304 (tetragonal); manganese spinel, Mn3O4 (isometric); three iron sulfides mackinawite, FeS (tetragonal); greigite, Fe3S4 (isometric); and smythite, Fe3S4 (rhombohedral)-copper hydroxide, Co(OH)2; and manganese hydroxide, Mn(OH)2, were all at least tentatively identified in the deposits sampled. Of geochemical interest is the demonstration that simple stable equilibrium models fail in nearly every case to predict compositions of water yielded by the wells studied. Only one stable phase (calcite) was found to exhibit behavior approximately predictable from stable equilibrium considerations. No other stable phase was found to behave as would be predicted from equilibrium considerations. All the solids found to precipitate (except calcite) are metastable in that they are not the least soluble phases possible in the systems studied. In terms of metastable equilibrium, siderite and ferric hydroxide behave approximately as would be predicted from equilibrium considerations, but both are metastable and the presence of neither would be anticipated if only the most stable phases were considered. The behaviors of none of the other solids would be predictable from either stable or metastable equilibrium considerations. An unanswered problem raised by the study reported here is how, or by what paths, truly stable phases form if first precipitates are generally metastable.The utility of the findings in well design and operation is in no way impaired by the general lack of equilibrium. Conditions leading to either corrosion (which is related to lack of supersaturation with protective phases), or encrustation (supersaturation with phases that were found to precipitate), or both, apparently can be identified. The application of the methods described can be of great importance in developing unexploited ground-water resources in that certain practical problems can be identified before extensive well construction and unnecessary well failure.

Transformation of Chlorinated Hydrocarbons on Synthetic Green Rusts

EPA Science Inventory

Green rusts (GRs) are layered double hydroxides that contain both ferrous and ferric ions in their structure. GRs can potentially serve as a chemical reductant for degradation of chlorinated hydrocarbons. GRs are found in zerovalent iron based permeable reactive barriers and in c...

ARSENIC CONTAMINATION AT THE INDUSTRI-PLEX SUPERFUND SITE, WOBURN, MA

EPA Science Inventory

Arsenate coprecipitated with hydrous ferric oxide (HFO) was stabilized against dissolution during transformation of HFO to more crystalline iron (hydr)oxides. The rate of arsenate stabilization approximately coincided with the rate of HFO transformation at pH 6 and 40 ?C. Compa...

Iron (III) Matrix Effects on Mineralization and Immobilization of Actinides

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

Cynthia-May S. Gong; Tyler A. Sullens; Kenneth R. Czerwinski

2006-01-01

Abstract - A number of models for the Yucca Mountain Project nuclear waste repository use studies of actinide sorption onto well-defined iron hydroxide materials. In the case of a waste containment leak, however, a complex interaction between dissolved waste forms and failed containment vessel components can lead to immediate precipitation of migratory iron and uranyl in the silicate rich near-field environment. Use of the Fe(III) and UO22+ complexing agent acetohydroxamic acid (AHA) as a colorimetric agent for visible spectrophotometry is well-known. Using the second derivative of these spectra a distinct shift in iron complexation in the presence of silicate ismore » seen that is not seen with uranyl or alone. Silica also decreases the ability of uranyl and ferric solutions to absorb hydroxide, hastening precipitation. These ferric silicate precipitates are highly amorphous and soluble. Precipitates formed in the presence of uranyl below ~1 mol% exhibit lower solubility than precipitates from up to 50 mol % and of uranyl silicates alone.« less

Evaluation of geotextile filtration applying coagulant and flocculant amendments for aquaculture biosolids dewatering and phosphorus removal

USDA-ARS?s Scientific Manuscript database

Wastes contained in the microscreen backwash discharged from intensive recirculating aquaculture systems were removed and dewatered in simple geotextile bag filters. Three chemical coagulation aids, (aluminum sulfate (alum), ferric chloride, and calcium hydroxide (hydrated lime)), were tested in com...

The Speciation of Sulfur in an Ocean on Europa

NASA Technical Reports Server (NTRS)

Zolotov, M. Yu.; Shock, E. L.

2002-01-01

Stability of native sulfur, iron sulfides, and aqueous sulfur compounds is evaluated at assumed P-T conditions of the Europa's ocean floor. Pyrite, gypsum, and ferric hydroxides can coexist in contact with sulfate-rich oceanic water. Additional information is contained in the original extended abstract.

IRON PRECIPITATION AND ARSENIC ATTENUATION - ASSESSMENT OF ARSENIC NATURAL ATTENUATION OF THE SUBSURFACE USING A GEOCHEMICAL MODEL (PHREEQC)

EPA Science Inventory

Laboratory experiments show that amorphous and poorly crystallized ferric iron hydroxides have much greater capacity to attenuate arsenic compared to clays and other aluminosilicate minerals. Studies (e.g., Lin and Qvarfort, 1996) showed that a sudden change in geochemical condit...

EFFECTS OF FERRIC HYDROXIDE ON THE ANAEROBIC BIODEGRADATION KINETICS AND TOXICITY OF VEGETABLE OIL IN FRESHWATER SEDIMENTS

EPA Science Inventory

Biodegradation of vegetable oil in freshwater sediments exhibits self-inhibitory characteristics when it occurs under methanogenic conditions but not under iron-reducing conditions. The basis of the protective effect of iron was investigated by comparing its effects on oil biodeg...

21 CFR 172.370 - Iron-choline citrate complex.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Iron-choline citrate complex. 172.370 Section 172... CONSUMPTION Special Dietary and Nutritional Additives § 172.370 Iron-choline citrate complex. Iron-choline citrate complex made by reacting approximately equimolecular quantities of ferric hydroxide, choline, and...

Checking Studies on Zones of Siting Feasibility for Dredged Material in Puget Sound.

DTIC Science & Technology

1986-01-01

priority pollutants in the ZSFs including copper, lead, mercury , HPAH, LPAH, PCBs and DDT. The area around Fourmile Rock dump site was classified in a...sediment contains ferric hydroxide (an olive color when associated with organic particles), while the reduced hydrogen sulphide sediments below this

POLLUTION PREVENTION IN THE SEMICONDUCTOR INDUSTRY THROUGH RECOVERY AND RECYCLING OF GALLIUM AND ARSENIC FROM GAAS POLISHING WASTES

EPA Science Inventory

A process was developed for the recovery of both arsenic and gallium from gallium arsenide polishing wastes. The economics associated with the current disposal techniques utilizing ferric hydroxide precipitation dictate that sequential recovery of toxic arsenic and valuble galliu...

Performance evaluation of ALCAN-AASF50-ferric coated activated alumina and granular ferric hydroxide (GFH) for arsenic removal in the presence of competitive ions in an active well :Kirtland field trial - initial studies.

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

Neidel, Linnah L.; Krumhansl, James Lee; Siegel, Malcolm Dean

This report documents a field trial program carried out at Well No.15 located at Kirtland Air Force Base, Albuquerque, New Mexico, to evaluate the performance of two relatively new arsenic removal media, ALCAN-AASF50 (ferric coated activated alumina) and granular ferric hydroxide (US Filter-GFH). The field trial program showed that both media were able to remove arsenate and meet the new total arsenic maximum contaminant level (MCL) in drinking water of 10 {micro}g/L. The arsenate removal capacity was defined at a breakthrough effluent concentration of 5 {micro}g/L arsenic (50% of the arsenic MCL of 10 {micro}g/L). At an influent pH ofmore » 8.1 {+-} 0.4, the arsenate removal capacity of AASF50 was 33.5 mg As(V)/L of dry media (29.9 {micro}g As(V)/g of media on a dry basis). At an influent pH of 7.2 {+-} 0.3, the arsenate removal capacity of GFH was 155 mg As(V)/L of wet media (286 {micro}g As(V)/g of media on a dry basis). Silicate, fluoride, and bicarbonate ions are removed by ALCAN AASF50. Chloride, nitrate, and sulfate ions were not removed by AASF50. The GFH media also removed silicate and bicarbonate ions; however, it did not remove fluoride, chloride, nitrate, and sulfate ions. Differences in the media performance partly reflect the variations in the feed-water pH between the 2 tests. Both the exhausted AASF50 and GFH media passed the Toxicity Characteristic Leaching Procedure (TCLP) test with respect to arsenic and therefore could be disposed as nonhazardous waste.« less

Facile Synthesis of Radial-Like Macroporous Superparamagnetic Chitosan Spheres with In-Situ Co-Precipitation and Gelation of Ferro-Gels

PubMed Central

Yang, Chih-Hui; Wang, Chih-Yu; Huang, Keng-Shiang; Yeh, Chen-Sheng; Wang, Andrew H. -J.; Wang, Wei-Ting; Lin, Ming-Yu

2012-01-01

Macroporous chitosan spheres encapsulating superparamagnetic iron oxide nanoparticles were synthesized by a facile and effective one-step fabrication process. Ferro-gels containing ferrous cations, ferric cations and chitosan were dropped into a sodium hydroxide solution through a syringe pump. In addition, a sodium hydroxide solution was employed for both gelation (chitosan) and co-precipitation (ferrous cations and ferric cations) of the ferro-gels. The results showed that the in-situ co-precipitation of ferro-ions gave rise to a radial morphology with non-spheroid macro pores (large cavities) inside the chitosan spheres. The particle size of iron oxide can be adjusted from 2.5 nm to 5.4 nm by tuning the concentration of the sodium hydroxide solution. Using Fourier Transform Infrared Spectroscopy and X-ray diffraction spectra, the synthesized nanoparticles were illustrated as Fe3O4 nanoparticles. In addition, the prepared macroporous chitosan spheres presented a super-paramagnetic behaviour at room temperature with a saturation magnetization value as high as ca. 18 emu/g. The cytotoxicity was estimated using cell viability by incubating doses (0∼1000 µg/mL) of the macroporous chitosan spheres. The result showed good viability (above 80%) with alginate chitosan particles below 1000 µg/mL, indicating that macroporous chitosan spheres were potentially useful for biomedical applications in the future. PMID:23226207

IMPACTS OF IRON, NUTRIENTS, AND MINERAL FINES ON ANAEROBIC BIODEGRADATION OF CANOLA OIL IN FRESHWATER SEDIMENTS

EPA Science Inventory

Factors affecting anaerobic biodegradation kinetics of canola oil in freshwater sediments were investigated. An optimum dose of ferric hydroxide (10.5 g Fe(III)·kg^-1 sediment) was found to stimulate anaerobic biodegradation of canola oil (18.6 g oil kg^-1). ...

SYNTHESIS OF A POLYMERIC HYBRID ION EXCHANGER WITH RECOVERED IRON(III) TOWARDS THE REMOVAL OF ARSENIC

EPA Science Inventory

Every year, millions of tons of ferric hydroxide loaded water treatment residuals are disposed of under current EPA regulations into landfills and other waste sites. Meanwhile, half way around the world, millions of people are drinking arsenic contaminated water on a daily bas...

Novel chemoselective hydrogenation of aromatic nitro compounds over ferric hydroxide supported nanocluster gold in the presence of CO and H2O.

PubMed

Liu, Lequan; Qiao, Botao; Chen, Zhengjian; Zhang, Juan; Deng, Youquan

2009-02-14

Chemoselective hydrogenation of aromatic nitro compounds were first efficiently achieved over Au/Fe(OH)(x) at 100-120 degrees C for 1.5-6 h (depending on different substrates) in the presence of CO and H(2)O.

Effects of management and pore characteristics on organic matter composition of macroaggregates: evidence from characterization of organic matter and imaging: Pore characteristics and OM composition of macroaggregates

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

Toosi, E. R.; Kravchenko, A. N.; Mao, J.

Macroaggregates are of interest because of their fast response to land management and their role in the loss or restoration of soil organic carbon (SOC). The study included two experiments. In Experiment I, we investigated the effect of long-term (27 years) land management on the chemical composition of organic matter (OM) of macroaggregates. Macroaggregates were sampled from topsoil under conventional cropping, cover cropping and natural succession systems. The OM of macroaggregates from conventional cropping was more decomposed than that of cover cropping and especially natural succession, based on larger δ 15N values and decomposition indices determined by multiple magic-angle spinningmore » nuclear magnetic resonance ( 13C CP/MAS NMR) and Fourier transform infrared (FTIR) spectroscopy. Previous research at the sites studied suggested that this was mainly because of reduced diversity and activity of the decomposer community, change in nutrient stoichiometry from fertilization and contrasting formation pathways of macroaggregates in conventional cropping compared with cover cropping and, specifically, natural succession. In Experiment II, we investigated the relation between OM composition and pore characteristics of macroaggregates. Macroaggregates from the natural succession system only were studied. We determined 3-D pore-size distribution of macroaggregates with X-ray microtomography, for which we cut the macroaggregates into sections that had contrasting dominant pore sizes. Then, we characterized the OM of macroaggregate sections with FTIR and δ15N methods. The results showed that within a macroaggregate, the OM was less decomposed in areas where the small (13–32 µm) or large (136–260 µm) pores were abundant. This was attributed to the role of large pores in supplying fresh OM and small pores in the effective protection of OM in macroaggregates. Previous research at the site studied had shown increased abundance of large and small intra-aggregate pores following adoption of less intensive management systems. It appears that land management can alter the OM composition of macroaggregates, partly by the regulation of OM turnover at the intra-aggregate scale.« less

Effect Of Iron On The Sensitivity Of Hydrogen, Acetate, And Butyrate Metabolism To Inhibition By Long-Chain Fatty Acids In Vegetable-Oil-Enriched Freshwater Sediments

EPA Science Inventory

Freshwater sediment microbial communities enriched by growth on vegetable oil in the presence of a substoichiometric amount of ferric hydroxide (sufficient to accept about 12% of the vegetable-oil-derived electrons) degrade vegetable oil to methane faster than similar microbial c...

Prebiotic Oxidative Polymerization of 2,3 Dimercaptopropanol on the Surface of Iron(III) Hydroxide Oxide

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1994-01-01

The oxidation of 2,3-Dimercapto-1-propanol by ferric ions on the surface of iron (III) hydroxide oxide yielded polydisulfide polymers. This polymerization occured readily at low dithiol concentration under mild aqueous conditions. Polydisulfide polymers up to the 15-mer were synthesized from 1 mM dithiol in 5 ml water reacted with iron (III) hydroxide oxide (20 mg, 160 micro mole Fe) for 3 days under anaerobic conditions at 40 C and pH 4. About 91% of the dithiol was converted to short soluble oligomers and 9% to insoluble larger oligomers that were isolated with the mineral phase. Reactions at higher dithiol concentrations with the same ratio of dithiol to mineral gave a higher yield of the larger insoluble oligomers. The relationship of these results to prebiotic polymer synthesis will be discussed.

Mineral saturation states in natural waters and their sensitivity to thermodynamic and analytical errors

USGS Publications Warehouse

Nordstrom, D. Kirk; Ball, James W.

1989-01-01

Saturation indices computed with WATEQ4F chemical analyses from a groundwater in crystalline bedrock and a surface water receiving acid mine drainage are frequently at or above saturation with respect to calcite, fluorite, barite, gibbsite and ferrihydrite. Deep granitic groundwaters from Stripa, Sweden, are supersaturated with respect to calcite and fluorite. Acid mine waters from the Leviathan Mine drainage basin in California are supersaturated with respect to barite by about a factor of three. These mine waters also are 10 times supersaturated with respect to the most soluble form of ferric hydroxide but are near saturation with respect to microcrystalline gibbsite. A sensitivity analysis has been performed by varying the analytic and thermodynamic parameters for which the saturation indices are most sensitive. For calcite, fluorite and barite, the supersaturation effect appears to be real because it is only slightly decreased by sources of uncertainty. Apparent supersaturation for gibbsite is most likely caused by the degree of crystallinity on solubility behavior. Apparent supersaturation for ferric hydroxide is likely caused by small colloidal particles (< 0.1 µm) in the water sample that cannot be removed by standard field filtration, although several other possible explanations cannot be easily excluded.

Prebiotic Polymerization: Oxidative Polymerization of 2,3 Dimercapto-1- Propanol on the Surface of Iron(III) Hydroxide Oxide

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1995-01-01

The oxidation of 2,3-dimercapto-1-propanol by ferric ions on the surface of iron(III) hydroxide oxide (Fe(OH)O) yielded polydisulfide oligomers. This polymerization occurred readily at low dithiol concentration under mild aqueous conditions. Polydisulfide polymers up to the 15-mer were synthesized from 1 mM dithiol in 5 ml water reacted with iron(III) hydroxide oxide (20 mg, 160 micromole Fe) for 3 days under anaerobic conditions at 40 C and pH 4. About 91% of the dithiol was converted to short soluble oligomers and 9% to insoluble larger oligomers that were isolated with the FE(OH)O phase. Reactions carried out at the same ratio of dithiol to FE(OH)O but at higher dithiol concentrations gave higher yields of the larger insoluble oligomers. The relationship of these results to prebiotic polymer synthesis is discussed.

Prebiotic polymerization: Oxidative polymerization of 2, 3-dimercapto-1-propanol on the surface of iron(III) hydroxide oxide

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1995-01-01

The oxidation of 2, 3-dimercapto-1-propanol by ferric ions on the surface of iron(III) hydroxide oxide (Fe(OH)O) yielded polydisulfide oligomers. This polymerization occurred readily at low dithiol concentration under mild aqueous conditions. Polydisulfide polymers up to the 15-mer were synthesized from 1 mM dithiol in 5 ml water reacted with iron(III) hydroxide oxide (20 mg, 160 micromole Fe) for 3 days under anaerobic conditions at 40 C and pH 4. About 91% of the dithiol was converted to short soluble oligomers and 9% to insoluble larger oligomers that were isolated with the Fe(OH)O phase. Reactions carried out at the same ratio of dithiol to Fe(OH)O but at higher dithiol concentrations gave higher yields of the larger insoluble oligomers. The relationship of these results to prebiotic polymer synthesis is discussed.

In situ remediation process using divalent metal cations

DOEpatents

Brady, Patrick V.; Khandaker, Nadim R.; Krumhansl, James L.; Teter, David M.

2004-12-14

An in situ process for treating ambient solid materials (e.g., soils, aquifer solids, sludges) by adding one or more divalent metal cations to the ambient solid material. The added divalent metal cations, such as Cu.sup.2+ or Zn.sup.2+, combine with metal oxide/hydroxides (e.g., ferric oxide/hydroxide or aluminum oxide/hydroxide) already present in the ambient solid material to form an effective sorbent material having a large number of positively-charged surface complexes that binds and immobilizes anionic contaminant species (e.g., arsenic or chromate). Divalent metal cations can be added, for example, by injecting an aqueous solution of CuSO.sub.4 into an aquifer contaminated with arsenic or chromate. Also, sludges can be stabilized against leaching of anionic contaminants through the addition of divalent metal cations. Also, an inexpensive sorbent material can be easily formed by mixing divalent metal cations with soil that has been removed from the ground.

Iron crystallization in a fluidized-bed Fenton process.

PubMed

Boonrattanakij, Nonglak; Lu, Ming-Chun; Anotai, Jin

2011-05-01

The mechanisms of iron precipitation and crystallization in a fluidized-bed reactor were investigated. Within the typical Fenton's reagent dosage and pH range, ferric ions as a product from ferrous ion oxidation would be supersaturated and would subsequently precipitate out in the form of ferric hydroxide after the initiation of the Fenton reaction. These precipitates would simultaneously crystallize onto solid particles in a fluidized-bed Fenton reactor if the precipitation proceeded toward heterogeneous nucleation. The heterogeneous crystallization rate was controlled by the fluidized material type and the aging/ripening period of the crystallites. Iron crystallization onto the construction sand was faster than onto SiO(2), although the iron removal efficiencies at 180 min, which was principally controlled by iron hydroxide solubility, were comparable. To achieve a high iron removal rate, fluidized materials have to be present at the beginning of the Fenton reaction. Organic intermediates that can form ferro-complexes, particularly volatile fatty acids, can significantly increase ferric ion solubility, hence reducing the crystallization performance. Therefore, the fluidized-bed Fenton process will achieve exceptional performance with respect to both organic pollutant removal and iron removal if it is operated with the goal of complete mineralization. Crystallized iron on the fluidized media could slightly retard the successive crystallization rate; thus, it is necessary to continuously replace a portion of the iron-coated bed with fresh media to maintain iron removal performance. The iron-coated construction sand also had a catalytic property, though was less than those of commercial goethite. Copyright © 2011 Elsevier Ltd. All rights reserved.

Authigenic vivianite in Potomac River sediments: control by ferric oxy-hydroxides.

USGS Publications Warehouse

Hearn, P.P.; Parkhurst, D.L.; Callender, E.

1983-01-01

Sand-size aggregates of vivianite crystals occur in the uppermost sediments of the Potomac River estuary immediately downstream from the outfall of a sewage treatment plant at the southernmost boundary of the District of Columbia, USA. They are most abundant in a small area of coarse sand (dredge spoil) which contrasts with the adjacent, much finer sediments. The sewage outfall supplies both reducing conditions and abundant phosphate. Analyses and calculations indicate that the pore waters in all the adjacent sediments are supersaturated with respect to vivianite. Its concentration in the coarse sand is attributed to the absence there of amorphous ferric oxyhydroxides, which are present in the finer sediments and preferentially absorb the phosphate ion. -H.R.B.

REMOVAL OF FISSION PRODUCTS FROM WATER

DOEpatents

Rosinski, J.

1961-12-19

A process is given for precipitating fission products from a body of water having a pH of above 6.5. Calcium permanganate and ferrous sulfate are added in a molar ratio of l: 3, whereby a mixed precipitate of manganese dioxide, ferric hydroxide and calcium sulfate is formed; the precipitate carries the fisston products and settles to the bottom of the body of water. (AEC)

The relationship between dissolved humic acids and soluble iron in estuaries

NASA Technical Reports Server (NTRS)

Fox, L. E.

1984-01-01

Dissolved humic acid and soluble iron appear to be chemically unassociated in estuaries despite their coincident removal. This conclusion is supported by differences in the aggregation kinetics of soluble iron and dissolved humic acid, the inability of extracted humic acid to stabilize laboratory preparations of ferric hydroxide, and decreasing ratios of humic acid carbon to soluble iron along the axes of some estuaries.

Application of granular ferric hydroxides for removal elevated concentrations of arsenic from mine waters

NASA Astrophysics Data System (ADS)

Szlachta, Małgorzata; Włodarczyk, Paweł; Wójtowicz, Patryk

2015-04-01

Arsenic is naturally occurring element in the environment. Over three hundred minerals are known to contain some form of arsenic and among them arsenopyrite is the most common one. Arsenic-bearing minerals are frequently associated with ores containing mined metals such as copper, tin, nickel, lead, uranium, zinc, cobalt, platinum and gold. In the aquatic environment arsenic is typically present in inorganic forms, mainly in two oxidation states (+5, +3). As(III) is dominant in more reduced conditions, whereas As(V) is mostly present in an oxidizing environment. However, due to certain human activities the elevated arsenic levels in aquatic ecosystems are arising to a serious environmental problem. High arsenic concentrations found in surface and groundwaters, in some regions originate from mining activities and ore processing. Therefore, the major concern of mining industry is to maintain a good quality of effluents discharged in large volumes. This requires constant monitoring of effluents quality that guarantee the efficient protection of the receiving waters and reacting to possible negative impact of contamination on local communities. A number of proven technologies are available for arsenic removal from waters and wastewaters. In the presented work special attention is given to the adsorption method as a technically feasible, commonly applied and effective technique for the treatment of arsenic rich mine effluents. It is know that arsenic has a strong affinity towards iron rich materials. Thus, in this study the granular ferric hydroxides (CFH 12, provided by Kemira Oyj, Finland) was applied to remove As(III) and As(V) from aqueous solutions. The batch adsorption experiments were carried out to assess the efficiency of the tested Fe-based material under various operating parameters, including composition of treated water, solution pH and temperature. The results obtained from the fixed bed adsorption tests demonstrated the benefits of applying granular ferric hydroxides for treatment As-contaminated waters. This research is a part of the study supported by the National Centre for Research and Development grant (2014-2017) "Sustainable and responsible supply of primary resources - SUSMIN" (http://projects.gtk.fi/susmin), within the EU ERA-NET ERA-MIN program.

Leaching of Arsenic from Granular Ferric Hydroxide Residuals under Mature Landfill Conditions

PubMed Central

Ghosh, Amlan; Mukiibi, Muhammed; Sáez, A. Eduardo; Ela, Wendell P.

2008-01-01

Most arsenic bearing solid residuals (ABSR) from water treatment will be disposed in non-hazardous landfills. The lack of an appropriate leaching test to predict arsenic mobilization from ABSR creates a need to evaluate the magnitude and mechanisms of arsenic release under landfill conditions. This work studies the leaching of arsenic and iron from a common ABSR, granular ferric hydroxide, in a laboratory-scale column that simulates the biological and physicochemical conditions of a mature, mixed solid waste landfill. The column operated for approximately 900 days and the mode of transport as well as chemical speciation of iron and arsenic changed with column age. Both iron and arsenic were readily mobilized under the anaerobic, reducing conditions. During the early stages of operation, most arsenic and iron leaching (80% and 65%, respectively) was associated with suspended particulate matter and iron was lost proportionately faster than arsenic. In later stages, while the rate of iron leaching declined, the arsenic leaching rate increased greater than 7-fold. The final phase was characterized by dissolved species leaching. Future work on the development of standard batch leaching tests should take into account the dominant mobilization mechanisms identified in this work: solid associated transport, reductive sorbent dissolution, and microbially mediated arsenic reduction. PMID:17051802

Leaching of arsenic from granular ferric hydroxide residuals under mature landfill conditions.

PubMed

Ghosh, Amlan; Mukiibi, Muhammed; Sáez, A Eduardo; Ela, Wendell P

2006-10-01

Most arsenic bearing solid residuals (ABSR) from water treatment will be disposed in nonhazardous landfills. The lack of an appropriate leaching test to predict arsenic mobilization from ABSR creates a need to evaluate the magnitude and mechanisms of arsenic release under landfill conditions. This work studies the leaching of arsenic and iron from a common ABSR, granular ferric hydroxide, in a laboratory-scale column that simulates the biological and physicochemical conditions of a mature, mixed solid waste landfill. The column operated for approximately 900 days and the mode of transport as well as chemical speciation of iron and arsenic changed with column age. Both iron and arsenic were readily mobilized under the anaerobic, reducing conditions. During the early stages of operation, most arsenic and iron leaching (80% and 65%, respectively) was associated with suspended particulate matter, and iron was lost proportionately faster than arsenic. In later stages, while the rate of iron leaching declined, the arsenic leaching rate increased greater than 7-fold. The final phase was characterized by dissolved species leaching. Future work on the development of standard batch leaching tests should take into account the dominant mobilization mechanisms identified in this work: solid associated transport, reductive sorbent dissolution, and microbially mediated arsenic reduction.

Redox Reactions of Phenazine Antibiotics with Ferric (Hydr)oxides and Molecular Oxygen

PubMed Central

Wang, Yun; Newman, Dianne K.

2009-01-01

Phenazines are small redox-active molecules produced by a variety of bacteria. Beyond merely serving as antibiotics, recent studies suggest that phenazines play important physiological roles, including one in iron acquisition. Here we characterize the ability of four electrochemically reduced natural phenazines—pyocyanin (PYO), phenazine-1-carboxylate (PCA), phenazine-1-carboxamide, and 1-hydroxyphenazine (1-OHPHZ)—to reductively dissolve ferrihydrite and hematite in the pH range 5–8. Generally, the reaction rate is higher for a phenazine with a lower reduction potential, with the reaction between PYO and ferrihydrite at pH 5 being an exception; the rate decreases as the pH increases; the rate is higher for poorly crystalline ferrihydrite than for highly crystalline hematite. Ferric (hydr)oxide reduction by reduced phenazines can potentially be inhibited by oxygen, where O2 competes with Fe(III) as the final oxidant. The reactivity of reduced phenazines with O2 decreases in the order: PYO > 1-OHPHZ > PCA. Strikingly, reduced PYO, which is the least reactive phenazine with ferrihydrite and hematite at pH 7, is the most reactive phenazine with O2. These results imply that different phenazines may perform different functions in environments with gradients of iron and O2. PMID:18504969

Macroaggregation and soil organic carbon restoration in a highly weathered Brazilian Oxisol after two decades under no-till.

PubMed

de Oliveira Ferreira, Ademir; de Moraes Sá, João Carlos; Lal, Rattan; Tivet, Florent; Briedis, Clever; Inagaki, Thiago Massao; Gonçalves, Daniel Ruiz Potma; Romaniw, Jucimare

2018-04-15

Conclusions based on studies of the impacts of soil organic carbon (SOC) fractions and soil texture on macroaggregation and SOC stabilization in long-term (>20years) no-till (NT) fields remain debatable. This study was based on the hypothesis that the amount and frequency of biomass-C input associated with NT can be a pathway to formation of macroaggregates and to SOC buildup. The objectives were to: 1) assess the macroaggregate distribution (proportional mass, class mass) and the SOC and particulate organic carbon (POC) stocks of extra-large (8-19mm), large (2-8mm) and small (0.25-2mm) macroaggregate size classes managed for two decades by NT, and 2) assess the recovery of SOC stocks in extra-large macroaggregates compared to adjacent native vegetation (Andropogon sp., Aristida sp., Paspalum sp., and Panicum sp.). The crop rotation systems were: soybean (Glycine max L.), maize (Zea mays L.) and beans (Phaseolus vulgaris L.) in summer; and black oat (Avena strigosa Schreb), white oat (Avena sativa), vetch (Vicia sativa L.), black oat.+vetch (Avena strigosa Schreb+vetch) and wheat (Triticum aestivum L.) in winter. The experimental was laid out as 2×2 randomized block factorial with 12 replicates of a NT experiment established in 1997 on two highly weathered Oxisols. The factors comprised of: (a) two soil textural types: clay loam and sandy clay, and (b) two sampling depths: 0-5 and 5-20cm. The three classes of macroaggregates were obtained by wet sieving, and the SOC content was determined by the dry combustion method. The extra-large macroaggregate classes in 0-20cm depth for sandy clay (SdC) and clay loam (CL) Oxisol represented 75.2 and 72.4% of proportional mass, respectively. The SOC and POC stocks among macroaggregate classes in 0-5 and 5-20cm depths decreased in the order: 8-19mm>2-8mm ≈ 0.25-2mm. The SdC plots under soybean/maize at 3:1 ratio recovered 58.3%, while those at 1:1 ratio (high maize frequency) in CL recovered 73.1% of SOC stock in the extra-large macroaggregates compared with the same under native vegetation for 0-20cm depth. Thus, partial restoration of the SOC stock in original extra-large macroaggregate confirms the hypothesis that NT through higher maize cultivation frequency can be a pathway to fomation of macroaggregates and SOC buildup. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrogen sulfide removal from sediment and water in box culverts/storm drains by iron-based granules.

PubMed

Sun, J L; Shang, C; Kikkert, G A

2013-01-01

A renewable granular iron-based technology for hydrogen sulfide removal from sediment and water in box culverts and storm drains is discussed. Iron granules, including granular ferric hydroxide (GFH), granular ferric oxide (GFO) and rusted waste iron crusts (RWIC) embedded in the sediment phase removed aqueous hydrogen sulfide formed from sedimentary biological sulfate reduction. The exhausted iron granules were exposed to dissolved oxygen and this regeneration process recovered the sulfide removal capacities of the granules. The recovery is likely attributable to the oxidation of the ferrous iron precipitates film and the formation of new reactive ferric iron surface sites on the iron granules and sand particles. GFH and RWIC showed larger sulfide removal capacities in the sediment phase than GFO, likely due to the less ordered crystal structures on their surfaces. This study demonstrates that the iron granules are able to remove hydrogen sulfide from sediment and water in box culverts and storm drains and they have the potential to be regenerated and reused by contacting with dissolved oxygen.

Processing of metallurgical residues by flotation - bench-scale studies on two industrial products.

PubMed

Rao, S R; Finch, J A

2006-01-01

Resource recovery from two metallurgical residues by flotation was investigated applying an electrostatic model to select initial conditions. The first, a sulphation roast/water leach residue, was processed to float lead sulphate, comparing dodecylamine and xanthate collectors. From the second, a neutralization residue, gypsum, was recovered by reverse flotation of ferric hydroxide, comparing oleate and sulphonate collectors. In both cases, further upgrading by acid leaching was considered.

Tillage and crop residue management methods had minor effects on the stock and stabilization of topsoil carbon in a 30-year field experiment.

PubMed

Singh, Pooja; Heikkinen, Jaakko; Ketoja, Elise; Nuutinen, Visa; Palojärvi, Ansa; Sheehy, Jatta; Esala, Martti; Mitra, Sudip; Alakukku, Laura; Regina, Kristiina

2015-06-15

We studied the effects of tillage and straw management on soil aggregation and soil carbon sequestration in a 30-year split-plot experiment on clay soil in southern Finland. The experimental plots were under conventional or reduced tillage with straw retained, removed or burnt. Wet sieving was done to study organic carbon and soil composition divided in four fractions: 1) large macroaggregates, 2) small macroaggregates, 3) microaggregates and 4) silt and clay. To further estimate the stability of carbon in the soil, coarse particulate organic matter, microaggregates and silt and clay were isolated from the macroaggregates. Total carbon stock in the topsoil (equivalent to 200 kg m(-2)) was slightly lower under reduced tillage (5.0 kg m(-2)) than under conventional tillage (5.2 kg m(-2)). Reduced tillage changed the soil composition by increasing the percentage of macroaggregates and decreasing the percentage of microaggregates. There was no evidence of differences in the composition of the macroaggregates or carbon content in the macroaggregate-occluded fractions. However, due to the higher total amount of macroaggregates in the soil, more carbon was bound to the macroaggregate-occluded microaggregates in reduced tillage. Compared with plowed soil, the density of deep burrowing earthworms (Lumbricus terrestris) was considerably higher under reduced tillage and positively associated with the percentage of large macroaggregates. The total amount of microbial biomass carbon did not differ between the treatments. Straw management did not have discernible effects either on soil aggregation or soil carbon stock. We conclude that although reduced tillage can improve clay soil structure, generally the chances to increase topsoil carbon sequestration by reduced tillage or straw management practices appear limited in cereal monoculture systems of the boreal region. This may be related to the already high C content of soils, the precipitation level favoring decomposition and aggregate turnover in the winter with topsoil frost. Copyright © 2015. Published by Elsevier B.V.

Novel strategy to engineer trachea cartilage graft with marrow mesenchymal stem cell macroaggregate and hydrolyzable scaffold.

PubMed

Liu, Liangqi; Wu, Wei; Tuo, Xiaoye; Geng, Wenxin; Zhao, Jie; Wei, Jing; Yan, Xingrong; Yang, Wei; Li, Liwen; Chen, Fulin

2010-05-01

Limited donor sites of cartilage and dedifferentiation of chondrocytes during expansion, low tissue reconstruction efficiency, and uncontrollable immune reactions to foreign materials are the main obstacles to overcome before cartilage tissue engineering can be widely used in the clinic. In the current study, we developed a novel strategy to fabricate tissue-engineered trachea cartilage grafts using marrow mesenchymal stem cell (MSC) macroaggregates and hydrolyzable scaffold of polylactic acid-polyglycolic acid copolymer (PLGA). Rabbit MSCs were continuously cultured to prepare macroaggregates in sheet form. The macroaggregates were studied for their potential for chondrogenesis. The macroaggregates were wrapped against the PLGA scaffold to make a tubular composite. The composites were incubated in spinner flasks for 4 weeks to fabricate trachea cartilage grafts. Histological observation and polymerase chain reaction array showed that MSC macroaggregates could obtain the optimal chondrogenic capacity under the induction of transforming growth factor-beta. Engineered trachea cartilage consisted of evenly spaced lacunae embedded in a matrix rich in proteoglycans. PLGA scaffold degraded totally during in vitro incubation and the engineered cartilage graft was composed of autologous tissue. Based on this novel, MSC macroaggregate and hydrolyzable scaffold composite strategy, ready-to-implant autologous trachea cartilage grafts could be successfully fabricated. The strategy also had the advantages of high efficiency in cell seeding and tissue regeneration, and could possibly be used in future in vivo experiments.

Regeneration of strong-base anion-exchange resins by sequential chemical displacement

DOEpatents

Brown, Gilbert M.; Gu, Baohua; Moyer, Bruce A.; Bonnesen, Peter V.

2002-01-01

A method for regenerating strong-base anion exchange resins utilizing a sequential chemical displacement technique with new regenerant formulation. The new first regenerant solution is composed of a mixture of ferric chloride, a water-miscible organic solvent, hydrochloric acid, and water in which tetrachloroferrate anion is formed and used to displace the target anions on the resin. The second regenerant is composed of a dilute hydrochloric acid and is used to decompose tetrachloroferrate and elute ferric ions, thereby regenerating the resin. Alternative chemical displacement methods include: (1) displacement of target anions with fluoroborate followed by nitrate or salicylate and (2) displacement of target anions with salicylate followed by dilute hydrochloric acid. The methodology offers an improved regeneration efficiency, recovery, and waste minimization over the conventional displacement technique using sodium chloride (or a brine) or alkali metal hydroxide.

Linking Intra-Aggregate Pore Size Distribution with Organic Matter Decomposition Status, Evidence from FTIR and X-Ray Tomography

NASA Astrophysics Data System (ADS)

Toosi, E. R.; Quigley, M.; Kravchenko, A. N.

2014-12-01

It has been reported that conversion of intensively cultivated lands to less disturbed systems enhances soil OM storage capacity, primarily through OM stabilization in macroaggregates. We hypothesized that the potential for OM stabilization inside macro-aggregates is influenced by presence and abundance of intra-aggregate pores. Pores determine microbial access to OM and regulate diffusion of solution/gases within aggregates which drives microbial functioning. We investigated the influence of longterm disturbance intensity on soil OM composition and its relation to pore size distribution within macroaggregates. We used quantitative FTIR to determine OM decomposition status and X-ray micro-tomography to assess pore size distribution in macroaggregates as affected by management and landuse. Macroaggregates 4-6 mm in size where selected from topsoil under long term conventional tillage (CT), cover-crop (CC), and native succession vegetation (NS) treatments at Kellogg Biological Station, Michigan. Comparison of main soil OM functional groups suggested that with increasing disturbance intensity, the proportion of aromatic and carboxylic/carbohydrates associated compounds increased and it was concomitant with a decrease in the proportion of aliphatic associated compounds and lignin derivatives. Further, FTIR-based decomposition indices revealed that overall decomposition status of macroaggregates followed the pattern of CT > CC ≈ NS. X-ray micro-tomography findings suggested that greater OM decomposition within the macroaggregates was associated with i) greater percent of pores >13 micron in size within the aggregates, as well as ii) greater proportion of small to medium pores (13-110 micron). The results develop previous findings, suggesting that shift in landuse or management indirectly affects soil OM stabilization through alteration of pore size distribution within macroaggregates that itself, is coupled with OM decomposition status.

The effect of granular ferric hydroxide amendment on the reduction of nitrate in groundwater by zero-valent iron.

PubMed

Song, Hocheol; Jeon, Byong-Hun; Chon, Chul-Min; Kim, Yongje; Nam, In-Hyun; Schwartz, Franklin W; Cho, Dong-Wan

2013-11-01

The feasibility of using granular ferric hydroxide (GFH) with zero-valent iron (Fe(0)) for its potential utility in enhancing nitrate reduction was investigated. The addition of 10gL(-1) GFH to 25gL(-1) Fe(0) significantly enhanced nitrate removal, resulting in 93% removal of 52.2mg-NL(-1) in 36-h as compared to 23% removal with Fe(0) alone. Surface analyses of the reacted Fe(0)/GFH revealed the presence of magnetite on the Fe(0) surface, which probably served as an electron mediator for nitrate reduction. Addition of GFH to Fe(0) also resulted in lower solution pH compared to Fe(0). The rate enhancing effect of GFH on nitrate reduction was attributed to the combined effects of magnetite formation and pH buffering by GFH. GFH amendment (100gL(-1)) significantly increased reduction capacity and longevity of Fe(0) to complete several nitrate reduction cycles before inactivation, giving a total nitrate removal of 205mg-NL(-1), while unamended Fe(0) gave only 20mg-NL(-1) before inactivation during the first reduction cycle. The overall result demonstrated the potential utility of Fe(0)/GFH system that may be developed into a viable technology for removal of nitrate from groundwater. Copyright © 2013 Elsevier Ltd. All rights reserved.

Extraction and physicochemical characterization of chitin and chitosan from Zophobas morio larvae in varying sodium hydroxide concentration.

PubMed

Soon, Chu Yong; Tee, Yee Bond; Tan, Choon Hui; Rosnita, Abdul Talib; Khalina, Abdan

2018-03-01

Large amount of sodium hydroxide (NaOH) is consumed to remove the protein content in chitin biomass during deproteinization. However, excessive NaOH concentration used might lead to the reduction of cost effectiveness during chitin extraction. Hence, the present study aimed to extract and evaluate the physicochemical properties of chitin and chitosan isolated from superworm (Zophobas morio) larvae using 0.5M-2.0M of NaOH. The extracted chitin and chitosan were subjected to Fourier Transform Infrared Spectroscopy (FT-IR), elemental analysis, Scanning Electron Microscope (SEM), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and X-ray Diffraction (XRD). The 0.5M NaOH treatment resulted in the highest yield of chitin (5.43%), but produced the lowest yield (65.84%) of chitosan. The extracted chitin samples had relatively high degree of acetylation (DA) (82.39%-101.39%). Both chitin and chitosan showed smooth surface with tiny pores. The extracted chitin samples were confirmed as α-chitin based on the FT-IR and TGA. The chitin samples were amorphous with low degree of crystallinity. From TGA, the Chitosan 3 extracted was partially deacetylated. Both DPPH radical scavenging and ferric-chelating assay showed positive correlation with DD of chitosan isolates. However, the chitosan isolates were not fully dissolved, resulting in lower radical scavenging and ferric-chelating ability compared to commercial chitosan. Copyright © 2017. Published by Elsevier B.V.

Preloading hydrous ferric oxide into granular activated carbon for arsenic removal.

PubMed

Jang, Min; Chen, Weifang; Cannon, Fred S

2008-05-01

Arsenic is of concern in water treatment because of its health effects. This research focused on incorporating hydrous ferric oxide (HFO) into granular activated carbon (GAC) for the purpose of arsenic removal. Iron was incorporated into GAC via incipient wetness impregnation and cured at temperatures ranging from 60 to 90 degrees C. X-ray diffractions and arsenic sorption as a function of pH were conducted to investigate the effect of temperature on final iron oxide (hydroxide) and their arsenic removal capabilities. Results revealed that when curing at 60 degrees C, the procedure successfully created HFO in the pores of GAC, whereas at temperatures of 80 and 90 degrees C, the impregnated iron oxide manifested a more crystalline form. In the column tests using synthetic water, the HFO-loaded GAC prepared at 60 degrees C also showed higher sorption capacities than media cured at higher temperatures. These results indicated that the adsorption capacity for arsenic was closely related to the form of iron (hydr)oxide for a given iron content For the column test using a natural groundwater, HFO-loaded GAC (Fe, 11.7%) showed an arsenic sorption capacity of 26 mg As/g when the influent contained 300 microg/L As. Thus, the preloading of HFO into a stable GAC media offered the opportunity to employ fixed carbon bed reactors in water treatment plants or point-of-use filters for arsenic removal.

Breakthrough behavior of granular ferric hydroxide (GFH) fixed-bed adsorption filters: modeling and experimental approaches.

PubMed

Sperlich, Alexander; Werner, Arne; Genz, Arne; Amy, Gary; Worch, Eckhard; Jekel, Martin

2005-03-01

Breakthrough curves (BTC) for the adsorption of arsenate and salicylic acid onto granulated ferric hydroxide (GFH) in fixed-bed adsorbers were experimentally determined and modeled using the homogeneous surface diffusion model (HSDM). The input parameters for the HSDM, the Freundlich isotherm constants and mass transfer coefficients for film and surface diffusion, were experimentally determined. The BTC for salicylic acid revealed a shape typical for trace organic compound adsorption onto activated carbon, and model results agreed well with the experimental curves. Unlike salicylic acid, arsenate BTCs showed a non-ideal shape with a leveling off at c/c0 approximately 0.6. Model results based on the experimentally derived parameters over-predicted the point of arsenic breakthrough for all simulated curves, lab-scale or full-scale, and were unable to catch the shape of the curve. The use of a much lower surface diffusion coefficient D(S) for modeling led to an improved fit of the later stages of the BTC shape, pointing on a time-dependent D(S). The mechanism for this time dependence is still unknown. Surface precipitation was discussed as one possible removal mechanism for arsenate besides pure adsorption interfering the determination of Freundlich constants and D(S). Rapid small-scale column tests (RSSCT) proved to be a powerful experimental alternative to the modeling procedure for arsenic.

Selective removal of arsenic and monovalent ions from brackish water reverse osmosis concentrate.

PubMed

Xu, Pei; Capito, Marissa; Cath, Tzahi Y

2013-09-15

Concentrate disposal and management is a considerable challenge for the implementation of desalination technologies, especially for inland applications where concentrate disposal options are limited. This study has focused on selective removal of arsenic and monovalent ions from brackish groundwater reverse osmosis (RO) concentrate for beneficial use and safe environmental disposal using in situ and pre-formed hydrous ferric oxides/hydroxides adsorption, and electrodialysis (ED) with monovalent permselective membranes. Coagulation with ferric salts is highly efficient at removing arsenic from RO concentrate to meet a drinking water standard of 10 μg/L. The chemical demand for ferric chloride however is much lower than ferric sulfate as coagulant. An alternative method using ferric sludge from surface water treatment plant is demonstrated as an efficient adsorbent to remove arsenic from RO concentrate, providing a promising low cost, "waste treat waste" approach. The monovalent permselective anion exchange membranes exhibit high selectivity in removing monovalent anions over di- and multi-valent anions. The transport of sulfate and phosphate through the anion exchange membranes was negligible over a broad range of electrical current density. However, the transport of divalent cations such as calcium and magnesium increases through monovalent permselective cation exchange membranes with increasing current density. Higher overall salt concentration reduction is achieved around limiting current density while higher normalized salt removal rate in terms of mass of salt per membrane area and applied energy is attained at lower current density because the energy unitization efficiency decreases at higher current density. Copyright © 2013 Elsevier B.V. All rights reserved.

An integrated wastewater reuse concept combining natural reclamation techniques, membrane filtration and metal oxide adsorption.

PubMed

Sperlich, A; Zheng, X; Ernst, M; Jekel, M

2008-01-01

In a Sino-German research project, a sustainable water reclamation concept was developed for different applications of municipal water reuse at the Olympic Green 2008 in Beijing, China. Results from pilot-scale experiments in Beijing and Berlin show that selective nutrient removal by adsorption onto granular ferric hydroxide (GFH) after a membrane bioreactor (MBR) can maintain a total phosphorus concentration of <0.03 microg L(-1) P, thus preventing eutrophication of artificial lakes. Operation time of GFH adsorption columns can be extended by regeneration using sodium hydroxide solution. A subsequent ultrafiltration (UF) membrane after bank filtration creates an additional barrier for pathogens and allows for further urban reuse applications such as toilet flushing. Short term bank / bio-filtration prior to UF is shown to effectively remove biopolymers and reduce membrane fouling. Copyright IWA Publishing 2008.

Accumulation of organic C components in soil and aggregates

PubMed Central

Yu, Hongyan; Ding, Weixin; Chen, Zengming; Zhang, Huanjun; Luo, Jiafa; Bolan, Nanthi

2015-01-01

To explore soil organic carbon (SOC) accumulation mechanisms, the dynamics of C functional groups and macroaggregation were studied synchronously through aggregate fractionation and 13C NMR spectroscopy in sandy loam soil following an 18-year application of compost and fertilizer in China. Compared with no fertilizer control, both compost and fertilizer improved SOC content, while the application of compost increased macroaggregation. Fertilizer application mainly increased the levels of recalcitrant organic C components characterized by methoxyl/N-alkyl C and alkyl C, whereas compost application mainly promoted the accumulation of methoxyl/N-alkyl C, phenolic C, carboxyl C, O-alkyl C and di-O-alkyl C in bulk soil. The preferential accumulation of organic C functional groups in aggregates depended on aggregate size rather than nutrient amendments. These groups were characterized by phenolic C and di-O-alkyl C in the silt + clay fraction, carboxyl C in microaggregates and phenolic C, carboxyl C and methoxyl/N-alkyl C in macroaggregates. Thus, the differences in accumulated organic C components in compost- and fertilizer-amended soils were primarily attributable to macroaggregation. The accumulation of methoxyl/N-alkyl C in microaggregates effectively promoted macroaggregation. Our results suggest that organic amendment rich in methoxyl/N-alkyl C effectively improved SOC content and accelerated macroaggregation in the test soil. PMID:26358660

A redox beginning: Which came first phosphoryl, acyl, or electron transfer ?. [Abstract only

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1994-01-01

Thermodynamic and kinetic information available on the synthesis of prebiotic monomers and polymers will be examined in order to illuminate the prebiotic plausibility of polymer syntheses based on (a) phosphoryl transfer that yields phosphodiester polymers, (b) acyl transfer that gives polyamides, and (c) electron transfer that produces polydisulfide or poly(thio)ester polymers. New experimental results on the oxidative polymerization of 2,3-dimercaptopropanol by ferric ions on the surface of ferric hydroxide oxide will be discussed as a chemical model of polymerization by electron transfer. This redox polymerization that yields polymers with a polydisulfide backbone was found to give oligomers up to the 15-mer from 1 mM of 2,3-dimercaptopropanol after one day at 25 C. High pressure liquid chromatography (HPLC) analysis of the oligomers was carried out on an Alltech OH-100 column eluted with acetonitrile-water.

Evaluating and Improving Water Treatment Plant Processes at Fixed Army Installations.

DTIC Science & Technology

1985-05-01

blender with variable speeds to handle different flow rates through the plant. * A coagulant feed system using orifices (facing upstream) may help achieve...cause the pipe to rupture. Tubercules are formed on pipe surfaces when iron ions are oxidized and ferric hydroxide precipitates: 2 + 2Fe + 5H20 + 1/20...2 2Fe (01)3 + 4H + " The tubercules interfere with flow and reduce the carrying capacity of the pipe . Several factors affect the rate of corrosion

Proceedings of REMR Workshop on Research Priorities for Drainage System and Relief Well Problems. Repair, Evaluation, Maintenance, and Rehabilitation Research Program

DTIC Science & Technology

1989-07-01

were checked by means of a cone penetrometer. Because of concerns that clogging would occur in the ran- dom zones, a special filter cloth sock was...that surrounded the pipes was dirty Figure 3. Old 24-in. BCCMP from toe drain; perforations are essentially plugged due to incrustation 46 Figure 4...associated deposits of ferric hydroxide have resulted in discolored water, unpalatable taste and odors , and reductions in flow through pipes. Additionally

CESIUM RECOVERY FROM AQUEOUS SOLUTIONS

DOEpatents

Schneider, R.A.

1961-06-20

Cesium may be precipitated from an aqueous solution whose acidity ranges between a pH of 1.5 and a molarity of 5 on cobaltous, zinc, cadmium, nickel, or ferrous cobalticyanide. This precipitation brings about a separation from most fission products. Ruthenium which coprecipitates to a great degree can be removed by dissolving in sulfuric acid and boiling the solution in the presence of periodic acid for volatilization; other coprecipitated fission products can then be precipitated from the sulfuric acid solution with a ferric hydroxide carrier.

Magnetic particles

NASA Technical Reports Server (NTRS)

Chang, Manchium (Inventor); Colvin, Michael S. (Inventor)

1989-01-01

Magnetic polymer particles are formed by swelling porous, polymer particles and impregnating the particles with an aqueous solution of precursor magnetic metal salt such as an equimolar mixture of ferrous chloride and ferric chloride. On addition of a basic reagent such as dilute sodium hydroxide, the metal salts are converted to crystals of magnetite which are uniformly contained througout the pores of the polymer particle. The magnetite content can be increased and neutral buoyancy achieved by repetition of the impregnaton and neutralization steps to adjust the magnetite content to a desired level.

Microscale speciation of arsenic and iron in ferric-based sorbents subjected to simulated landfill conditions

PubMed Central

Root, Robert A.; Fathordoobadi, Sahar; Alday, Fernando; Ela, Wendell; Chorover, Jon

2013-01-01

During treatment for potable use, water utilities generate arsenic-bearing ferric wastes that are subsequently dispatched to landfills. The biogeochemical weathering of these residuals in mature landfills affects the potential mobilization of sorbed arsenic species via desorption from solids subjected to phase transformations driven by abundant organic matter and bacterial activity. Such processes are not simulated with the Toxicity Characteristic Leaching Procedure (TCLP) currently used to characterize hazard. To examine the effect of sulfate on As retention in landfill leachate, columns of As(V) loaded amorphous ferric hydroxide were reacted biotically at two leachate sulfate concentrations (0.064 mM and 2.1 mM). After 300 d, ferric sorbents were reductively dissolved. Arsenic released to porewaters was partially co-precipitated in mixed-valent secondary iron phases whose speciation was dependent on sulfate concentration. As and Fe XAS showed that, in the low sulfate column, 75–81% of As(V) was reduced to As(III), and 53–68% of the Fe(III) sorbent was transformed, dominantly to siderite and green rust. In the high sulfate column, Fe(III) solids were reduced principally to FeS(am), whereas As(V) was reduced to a polymeric sulfide with local atomic structure of realgar. Multi-energy micro-X-ray fluorescence (ME-μXRF) imaging at Fe and As K-edges showed that As formed surface complexes with ferrihydrite > siderite > green rust in the low sulfate column; while discrete realgar-like phases formed in the high sulfate systems. Results indicate that landfill sulfur chemistry exerts strong control over the potential mobilization of As from ferric sorbent residuals by controlling secondary As and Fe sulfide co-precipitate formation. PMID:24102155

Zirconium doped nano-dispersed oxides of Fe, Al and Zn for destruction of warfare agents

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

Stengl, Vaclav, E-mail: stengl@uach.cz; Houskova, Vendula; Bakardjieva, Snejana

2010-11-15

Zirconium doped nano dispersive oxides of Fe, Al and Zn were prepared by a homogeneous hydrolysis of the respective sulfate salts with urea in aqueous solutions. Synthesized metal oxide hydroxides were characterized using Brunauer-Emmett-Teller (BET) surface area and Barrett-Joiner-Halenda porosity (BJH), X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDX). These oxides were taken for an experimental evaluation of their reactivity with sulfur mustard (HD or bis(2-chloroethyl)sulfide), soman (GD or (3,3'-Dimethylbutan-2-yl)-methylphosphonofluoridate) and VX agent (S-[2-(diisopropylamino)ethyl]-O-ethyl-methylphosphonothionate). The presence of Zr{sup 4+} dopant can increase both the surface area and the surface hydroxylation of the resultingmore » doped oxides, decreases their crystallites' sizes thereby it may contribute in enabling the substrate adsorption at the oxide surface thus it can accelerate the rate of degradation of warfare agents. Addition of Zr{sup 4+} converts the product of the reaction of ferric sulphate with urea from ferrihydrite to goethite. We found out that doped oxo-hydroxides Zr-FeO(OH) - being prepared by a homogeneous hydrolysis of ferric and zirconium oxo-sulfates mixture in aqueous solutions - exhibit a comparatively higher degradation activity towards chemical warfare agents (CWAs). Degradation of soman or VX agent on Zr-doped FeO(OH) containing ca. 8.3 wt.% of zirconium proceeded to completion within 30 min.« less

Effect of Arsenic on the Formation and Adsorption Property of Ferric Hydroxide Precipitates in ZVI Treatment

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

Peng, Xing; Xi, Beidou; Zhao, Ying

Treatment of arsenic by zerovalent iron (ZVI) has been studied extensively. However, the effect of arsenic on the formation of ferric hydroxide precipitates in the ZVI treatment has not been investigated. We discovered that the specific surface area (ca. 187 m2/g) and arsenic content (ca. 67 mg/g) of the suspended solids (As-containing solids) generated in the ZVI treatment of arsenic solutions were much higher than the specific surface area (ca. 37 m2/g) and adsorption capacity (ca.12 mg/g) of the suspended solids (As-free solids) generated in the arsenic-free solutions. Arsenic in the As-containing solids was much more stable than the adsorbedmore » arsenic in As-free solids. XRD, SEM, TEM, and selected area electron diffraction (SAED) analyses showed that the As-containing solids consisted of amorphous nanoparticles, while the As-free solids were composed of micron particles with weak crystallinity. Extended X-ray absorption fine structure (EXAFS) analysis determined that As(V) was adsorbed on the As-containing suspended solids and magnetic solid surfaces through bidentate binuclear complexation; and As(V) formed a mononuclear complex on the As-free suspended solids. The formation of the surface As(V) complexes retarded the bonding of free FeO6 octahedra to the oxygen sites on FeO6 octahedral clusters and prevented the growth of the clusters and their development into 3-dimensional crystalline phases.« less

On the origin of an unusual dependence of (bio)chemical reactivity of ferric hydroxides on nanoparticle size.

PubMed

Chernyshova, I V; Ponnurangam, S; Somasundaran, P

2010-11-14

Application of in situ UV-Vis absorption spectroscopy and ex situ X-ray photoelectron spectroscopy (XPS) makes it possible to resolve the controversies about the electronic properties of hematite (α-Fe(2)O(3)) nanoparticles (NPs) and, on this basis, to rationalize the unusual dependence of aquatic (bio)chemistry of these NPs on NP size. 2-Line ferrihydrite (FH) is also included in the study as the end polymorph of the size-driven phase transformation of hematite NPs in aqueous media. It is shown that the absorption edge of all NPs studied is due to the direct O 2p-Fe 3d charge transfer (CT) process, while a manifold of weak bands superimposed onto two main p-d CT bands is attributed to the d-d ligand field transitions. The band gap decreases from 2.95 to 2.18 eV with increasing NP size from 7 nm to 120 nm. This effect is attributed to restoration of hematite lattice structure, which ultimately results in an increase in the O 2p-Fe 3d hybridization, stabilization of the valence band, and delocalization of valence electrons, as confirmed by XPS. Finally, we show that the optical effects such as the Mie resonance significantly distort absorption spectra of hematite NPs larger than ∼120 nm. Possible impacts of these findings on (photo)catalytic and biochemical properties of ferric (hydr)oxide NPs are discussed.

Phenazines and Other Redox-Active Antibiotics Promote Microbial Mineral Reduction

PubMed Central

Hernandez, Maria E.; Kappler, Andreas; Newman, Dianne K.

2004-01-01

Natural products with important therapeutic properties are known to be produced by a variety of soil bacteria, yet the ecological function of these compounds is not well understood. Here we show that phenazines and other redox-active antibiotics can promote microbial mineral reduction. Pseudomonas chlororaphis PCL1391, a root isolate that produces phenazine-1-carboxamide (PCN), is able to reductively dissolve poorly crystalline iron and manganese oxides, whereas a strain carrying a mutation in one of the phenazine-biosynthetic genes (phzB) is not; the addition of purified PCN restores this ability to the mutant strain. The small amount of PCN produced relative to the large amount of ferric iron reduced in cultures of P. chlororaphis implies that PCN is recycled multiple times; moreover, poorly crystalline iron (hydr)oxide can be reduced abiotically by reduced PCN. This ability suggests that PCN functions as an electron shuttle rather than an iron chelator, a finding that is consistent with the observation that dissolved ferric iron is undetectable in culture fluids. Multiple phenazines and the glycopeptidic antibiotic bleomycin can also stimulate mineral reduction by the dissimilatory iron-reducing bacterium Shewanella oneidensis MR1. Because diverse bacterial strains that cannot grow on iron can reduce phenazines, and because thermodynamic calculations suggest that phenazines have lower redox potentials than those of poorly crystalline iron (hydr)oxides in a range of relevant environmental pH (5 to 9), we suggest that natural products like phenazines may promote microbial mineral reduction in the environment. PMID:14766572

Insights into solar photo-Fenton reaction parameters in the oxidation of a sanitary landfill leachate at lab-scale.

PubMed

Silva, Tânia F C V; Ferreira, Rui; Soares, Petrick A; Manenti, Diego R; Fonseca, Amélia; Saraiva, Isabel; Boaventura, Rui A R; Vilar, Vítor J P

2015-12-01

This work evaluates the effect of the main photo-Fenton (PF) reaction variables on the treatment of a sanitary landfill leachate collected at the outlet of a leachate treatment plant, which includes aerated lagooning followed by aerated activated sludge and a final coagulation-flocculation step. The PF experiments were performed in a lab-scale compound parabolic collector (CPC) photoreactor using artificial solar radiation. The photocatalytic reaction rate was determined while varying the total dissolved iron concentration (20-100 mg Fe(2+)/L), solution pH (2.0-3.6), operating temperature (10-50 °C), type of acid used for acidification (H2SO4, HCl and H2SO4 + HCl) and UV irradiance (22-68 W/m(2)). This work also tries to elucidate the role of ferric hydroxides, ferric sulphate and ferric chloride species, by taking advantage of ferric speciation diagrams, in the efficiency of the PF reaction when applied to leachate oxidation. The molar fraction of the most photoactive ferric species, FeOH(2+), was linearly correlated with the PF pseudo-first order kinetic constants obtained at different solution pH and temperature values. Ferric ion speciation diagrams also showed that the presence of high amounts of chloride ions negatively affected the PF reaction, due to the decrease of ferric ions solubility and scavenging of hydroxyl radicals for chlorine radical formation. The increment of the PF reaction rates with temperature was mainly associated with the increase of the molar fraction of FeOH(2+). The optimal parameters for the photo-Fenton reaction were: pH = 2.8 (acidification agent: H2SO4); T = 30 °C; [Fe(2+)] = 60 mg/L and UV irradiance = 44 WUV/m(2), achieving 72% mineralization after 25 kJUV/L of accumulated UV energy and 149 mM of H2O2 consumed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of the individual or combined application of biochar and slurry on soil macro-aggregate formation under varying moisture conditions

NASA Astrophysics Data System (ADS)

Kaiser, Michael; Grunwald, Dennis; Koch, Heinz-Josef; Rauber, Rolf; Ludwig, Bernard

2017-04-01

The formation of aggregates is of large importance for the structure and the storage of organic matter (OM) in soil. Although positive effects of organic soil additives on the formation of macro-aggregates (> 250 µm) have been reported, the influence of biochar especially applied in combination with other organic amendments remains unclear. Furthermore, studies on the effect of varying soil moisture conditions in form of drying-rewetting cycles on soil aggregate dynamics in the presence of biochar are almost missing. The objectives of this study were to analyze the effects of biochar and slurry applied to the soil individually or in combination on the formation of macro-aggregates under constant and under varying moisture conditions. We sampled four silty loam soils, carefully crushed the soil macro-aggregates, and incubated the soil at 15 °C for 60 days with the following additions: (i) none (control), (ii) biochar (12 % of dry soil mass), (iii) slurry (150 kg N ha-1), (iv) biochar (6 %) + slurry (75 kg N ha-1), (v) biochar (12 %) + slurry (75 kg N ha-1), (vi) biochar (6 %) + slurry (150 kg N ha-1) and (vii) biochar (12 %) + slurry (150 kg N ha-1). The samples were further subdivided into two groups that were incubated under conditions of constant soil moisture and of three drying-rewetting cycles. The CO2 fluxes were continuously measured during the incubation period and the samples were analyzed for microbial biomass C, macro-aggregate yields and macro-aggregate-associated C after finishing the experiment. We found the application of biochar to result in lower macro-aggregate yields with or without slurry compared to the control or the individual slurry application. In contrast, similar or higher C contents in the macro-aggregate fraction of the biochar treatments as compared to the control or slurry treatments were found indicating an occlusion of biochar in macro-aggregates. Due to the sorption characteristics of biochar, we assume the aggregate formation to be partially abiotic with direct interactions between biochar, (adsorbed) slurry, and the mineral phase of the soil. Therefore, in the presence of slurry, a prolonged period of microbial processing does not seem to be necessary to render the biochar suitable to form aggregates. Drying and rewetting of the samples resulted in significantly lower aggregate yields especially for the biochar/slurry mixtures. The drying of slurry as thought to be the most important macro-aggregate binding agent in these treatments might irreversibly disrupt large amounts of the macro-aggregates formed. Additionally, the general lower microbial biomass C and CO2 emissions for the samples experiencing drying-rewetting cycles compared to the constantly moist soils point toward less microbial activity under varying moisture conditions. This might have led to less microbial derived aggregate binding agents contributing to the lower aggregate yields found for the samples from the drying-rewetting treatments. Beside the amount and type of binding agents derived from organic soil additives, the formation and stability of soil macro-aggregate seem also to be controlled by climatically controlled soil moisture conditions.

How active site protonation state influences the reactivity and ligation of the heme in chlorite dismutase

PubMed Central

Streit, Bennett R.; Blanc, Béatrice; Lukat-Rodgers, Gudrun S.; Rodgers, Kenton R.; DuBois, Jennifer L.

2010-01-01

Chlorite dismutase catalyzes O2 release from chlorite with exquisite efficiency and specificity. The spectroscopic properties, ligand binding affinities, and steady state kinetics of chlorite dismutase from Dechloromonas aromatica were examined over pH 3–11.5 to gain insight into how the protonation state of the heme environment influences dioxygen formation. An acid/base transition was observed by UV/visible and resonance Raman spectroscopy with a pKa of 8.7, 2–3 pH units below analogous transitions observed in typical His-ligated peroxidases. This transition marks the conversion of a five coordinate high spin Fe(III) to a mixed high/low spin ferric-hydroxide, as confirmed by resonance Raman (rR) spectroscopy. The two Fe–OH stretching frequencies are quite low, consistent with a weak Fe–OH bond, despite the nearly neutral imidazole side chain of the proximal histidine ligand. The hydroxide is proposed to interact strongly with a distal H-bond donor, thereby weakening the Fe–OH bond. The rR spectra of Cld-CO as a function of pH reveal two forms of the complex, one in which there is minimal interaction of distal residues with the carbonyl oxygen and another, acidic form in which the oxygen is under the influence of positive charge. Recent crystallographic data reveal arginine 183 as the lone H-bond donating residue in the distal pocket. It is likely that this Arg is the strong, positively charged H-bond donor implicated by vibrational data to interact with exogenous axial heme ligands. The same Arg in its neutral (pKa ~ 6.5) form also appears to act as the active site base in binding reactions of protonated ligands, such as HCN, to ferric Cld. The steady state profile for the rate of chlorite decomposition is characterized by these same pKas. The 5 coordinate high spin acidic Cld is more active than the alkaline hydroxide-bound form. The acid form decomposes chlorite most efficiently when the distal Arg is protonated/cationic (maximum kcat = 2.0 (±0.6) × 105 s−1, kcat/KM = 3.2 (±0.4) × 107 M−1s−1, pH 5.2, 4 °C) and to a somewhat lesser extent when it acts as a H-bond donor to the axial hydroxide ligand under alkaline conditions. PMID:20356038

99M-technetium labeled macroaggregated human serum albumin pharmaceutical

DOEpatents

Winchell, Harry S.; Barak, Morton; Van Fleet, III, Parmer

1977-05-17

A reagent comprising macroaggregated human serum albumin having dispersed therein particles of stannous tin and a method for instantly making a labeled pharmaceutical therefrom, are disclosed. The labeled pharmaceutical is utilized in organ imaging.

Relation of laboratory and remotely sensed spectral signatures of ocean-dumped acid waste

NASA Technical Reports Server (NTRS)

Lewis, B. W.

1978-01-01

Results of laboratory transmission and remotely sensed ocean upwelled spectral signatures of acid waste ocean water solutions are presented. The studies were performed to establish ocean-dumped acid waste spectral signatures and to relate them to chemical and physical interactions occurring in the dump plume. The remotely sensed field measurements and the laboratory measurements were made using the same rapid-scanning spectrometer viewing a dump plume and with actual acid waste and ocean water samples, respectively. Laboratory studies showed that the signatures were produced by soluble ferric iron being precipitated in situ as ferric hydroxide upon dilution with ocean water. Sea-truth water samples were taken and analyzed for pertinent major components of the acid waste. Relationships were developed between the field and laboratory data both for spectral signatures and color changes with concentration. The relationships allow for the estimation of concentration of the indicator iron from remotely sensed spectral data and the laboratory transmission concentration data without sea-truth samples.

Thermodynamics at work - on the limits and potentials of biogeochemical processes

NASA Astrophysics Data System (ADS)

Peiffer, Stefan

2017-04-01

The preferential use of high potential electron acceptors by microorganisms has lead to the classical concept of a redox sequence with a sequential use of O2 nitrate, Fe(III), sulfate, and finally CO2 as electron acceptors for respiration (Stumm & Morgan, 1996). Christian Blodau has rigourously applied this concept to constrain the thermodynamical limits at which specific aquatic systems operate. In sediments from acidic mining lakes his analysis revealed that sulfate reducers are not competitive as long as low-crystallinity ferric oxides are available for organic matter decomposition (Blodau et al, 1998). This analysis opened up the possibility to generalize the linkage between the iron and sulphur cycle in such systems and to constrain the biogeochemical limits for remediation (e. g. Peine et al, 2000). In a similar approach, Beer & Blodau (2007) were able to demonstrate that constraints on the removal of products from acetoclastic methanogenesis in deeper peat layers are inhibiting organic matter decomposition and provide a thermodynamic argument for peat accumulation. In this contribution I will review such ideas and further refine the limits and potentials of biogeochemical reactions in terms of redox-active metastable phases (RAMPS) that are typically mixed-valent carbon-, iron-, and sulfur-containing compounds and which allow for the occurrence of a number of enigmatic reactions, e. g. limited greenhouse gas emission (CH4) under dynamic redox conditions. It is proposed that redox equivalents are generated, stored and recycled during oxidation and reduction cycles thus suppressing methanogenesis (Blodau, 2002). Such RAMPS will preferentially occur at dynamic interfaces being exposed to frequent redox cycles. The concept of RAMPS will be illustrated along the interaction between ferric (hydr)oxides and dissolved sulphide. Recent studies using modern analytical tools revealed the formation of a number of amorphous products within a short time scale (days) both on the Fe and S side (Peiffer & Wan, 2016; Wan et al, 2014) which will allow for the occurrence of cryptic sulphur cycles, i. e. high turnover of sulphide and sulfate without the appearance of dissolved sulphide species. References Beer, J; Blodau, C (2007): Transport and thermodynamics constrain belowground carbon turover in a northern peatland, Geochim. Cosmochim. Acta, 71, 2989-3002 Blodau, C. (2002). "Carbon cycling in peatlands: A review of processes and controls." Environmental Reviews 10(2): 111-134. Blodau, C; Hoffmann, S; Peine, A; Peiffer, S (1998): Iron and sulfate reduction in the sediments of acid mine lake 116 (Brandenburg, Germany): Rates and geochemical evaluation, Water, Air and Soil Pollution, 108, 249-270 Peiffer, S., Wan M. (2016) Reductive Dissolution and Reactivity of Ferric (Hydr)oxides, in Faivre, D., Iron Oxides: From Nature to Applications, Wiley-VCH, chapter 3, 29-51 Peine, A; Küsel, K; Tritschler, A; Peiffer, S (2000): Electron flow in an iron-rich acidic sedimant - evidence for an acidity-driven iron cycle, Limnol. Oceanogr., 45(5), 1077-1087 Stumm, W.; Morgan, J. J. (1996): Aquatic Chemistry, Wiley Wan, M., Shchukarev, A., Lohmayer, R., Planer-Friedrich, B., Peiffer, S. (2014) Occurrence of surface polysulfides during the interaction between ferric (hydr)oxides and aqueous sulfide. Environmental Science and Technology, 48, 5076-5084

Effect of Surface Oxidation on Interfacial Water Structure at a Pyrite (100) Surface as Studied by Molecular Dynamics Simulation

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

Jin, Jiaqi; Miller, Jan D.; Dang, Liem X.

2015-06-01

In the first part of this paper, a Scanning Electron Microscopy and contact angle study of a pyrite surface (100) is reported describing the relationship between surface oxidation and the hydrophilic surface state. In addition to these experimental results, the following simulated surface states were examined using Molecular Dynamics Simulation (MDS): fresh unoxidized (100) surface; polysulfide at the (100) surface; elemental sulfur at the (100) surface. Crystal structures for the polysulfide and elemental sulfur at the (100) surface were simulated using Density Functional Theory (DFT) quantum chemical calculations. The well known oxidation mechanism which involves formation of a metal deficientmore » layer was also described with DFT. Our MDS results of the behavior of interfacial water at the fresh and oxidized pyrite (100) surfaces without/with the presence of ferric hydroxide include simulated contact angles, number density distribution for water, water dipole orientation, water residence time, and hydrogen-bonding considerations. The significance of the formation of ferric hydroxide islands in accounting for the corresponding hydrophilic surface state is revealed not only from experimental contact angle measurements but also from simulated contact angle measurements using MDS. The hydrophilic surface state developed at oxidized pyrite surfaces has been described by MDS, on which basis the surface state is explained based on interfacial water structure. The Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences (BES), of the DOE funded work performed by Liem X. Dang. Battelle operates the Pacific Northwest National Laboratory for DOE. The calculations were carried out using computer resources provided by BES.« less

Regeneration and reuse of iron catalyst for Fenton-like reactions.

PubMed

Cao, Guo-min; Sheng, Mei; Niu, Wen-feng; Fei, Yu-lei; Li, Dong

2009-12-30

Fenton and Fenton-like reactions employed for oxidative treatment of a typical industrial wastewater generate a large amount of ferric hydroxide sludge which has to be properly disposed at a high cost. This paper presents a simple and cost-effective method for recovering the iron catalyst from the iron hydroxide sludge for oxidative treatment of industrial wastewaters. The sludge was dewatered, dried and baked at 350-400 degrees C for 20-30 min; the residual solids were dissolved in sulfuric acid to form the reusable catalyst for Fenton and Fenton-like reactions. The recovered catalyst was highly effective for the oxidative pretreatment of a fine chemical wastewater to improve its biodegradability; the resulting COD removal and BOD(5)/COD ratio of the treated stream remained nearly unchanged during the time period when the regenerated catalyst was reused six times. The simple and effective catalyst regeneration method will make Fenton and Fenton-like oxidation a more cost-effective wastewater treatment alternative.

Spectral reflectance properties (0.4-2.5 um) of secondary Fe-oxide, Fe-hydroxide, and Fe-sulfate-hydrate minerals associated with sulfide-bearing mine waste

USGS Publications Warehouse

Crowley, J.K.; Williams, D.E.; Hammarstrom1, J.M.; Piatak, N.; Mars, J.C.; Chou, I-Ming

2006-01-01

Fifteen Fe-oxide, Fe-hydroxide, and Fe-sulphate-hydrate mineral species commonly associated with sulphide bearing mine wastes were characterized by using X-ray powder diffraction and scanning electron microscope methods. Diffuse reflectance spectra of the samples show diagnostic absorption features related to electronic processes involving ferric and/or ferrous iron, and to vibrational processes involving water and hydroxyl ions. Such spectral features enable field and remote sensing based studies of the mineral distributions. Because secondary minerals are sensitive indicators of pH, Eh, relative humidity, and other environmental conditions, spectral mapping of these minerals promises to have important applications to mine waste remediation studies. This report releases digital (ascii) spectra (spectral_data_files.zip) of the fifteen mineral samples to facilitate usage of the data with spectral libraries and spectral analysis software. The spectral data are provided in a two-column format listing wavelength (in micrometers) and reflectance, respectively.

Low molecular weight carboxylic acids in oxidizing porphyry copper tailings.

PubMed

Dold, Bernhard; Blowes, David W; Dickhout, Ralph; Spangenberg, Jorge E; Pfeifer, Hans-Rudolf

2005-04-15

The distribution of low molecular weight carboxylic acids (LMWCA) was investigated in pore water profiles from two porphyry copper tailings impoundments in Chile (Piuquenes at La Andina and Cauquenes at El Teniente mine). The objectives of this study were (1) to determine the distribution of LMWCA, which are interpreted to be the metabolic byproducts of the autotroph microbial community in this low organic carbon system, and (2) to infer the potential role of these acids in cycling of Fe and other elements in the tailings impoundments. The speciation and mobility of iron, and potential for the release of H+ via hydrolysis of the ferric iron, are key factors in the formation of acid mine drainage in sulfidic mine wastes. In the low-pH oxidation zone of the Piuquenes tailings, Fe(III) is the dominant iron species and shows high mobility. LMWCA, which occur mainly between the oxidation front down to 300 cm below the tailings surface at both locations (e.g., max concentrations of 0.12 mmol/L formate, 0.17 mmol/L acetate, and 0.01 mmol/L pyruvate at Piuquenes and 0.14 mmol/L formate, 0.14 mmol/L acetate, and 0.006 mmol/L pyruvate at Cauquenes), are observed at the same location as high Fe concentrations (up to 71.2 mmol/L Fe(II) and 16.1 mmol/L Fe(III), respectively). In this zone, secondary Fe(III) hydroxides are depleted. Our data suggest that LMWCA may influence the mobility of iron in two ways. First, complexation of Fe(III), through formation of bidentate Fe(III)-LMWCA complexes (e.g., pyruvate, oxalate), may enhance the dissolution of Fe(III) (oxy)hydroxides or may prevent precipitation of Fe(III) (oxy)hydroxides. Soluble Fe(III) chelate complexes which may be mobilized downward and convert to Fe(II) by Fe(III) reducing bacteria. Second, monodentate LMWCA (e.g., acetate and formate) can be used by iron-reducing bacteria as electron donors (e.g., Acidophilum spp.), with ferric iron as the electron acceptor. These processes may, in part, explain the low abundances of secondary Fe(III) hydroxide precipitates below the oxidation front and the high concentrations of Fe(II) observed in the pore waters of some low-sulfide systems. The reduction of Fe(III) and the subsequent increase of iron mobility and potential acidity transfer (Fe(II) oxidation can result in the release of H+ in an oxic environment) should be taken in account in mine waste management strategies.

Arsenic Adsorption Equilibrium Concentration and Adsorption Rate of Activated Carbon Coated with Ferric-Aluminum Hydroxides

NASA Astrophysics Data System (ADS)

Zhang, M.; Sugita, H.; Oguma, T.; Hara, J.; Takahashi, S.

2015-12-01

In some areas of developing countries, ground or well water contaminated with arsenic has been reluctantly used as drinking water. It is highly desirable that effective and inexpensive arsenic removal agents should be developed and provided to reduce the potential health risk. Previous studies demonstrated that activated carbon coated with ferric-aluminum hydroxides (Fe-Al-C) has high adsorptive potential for removal of arsenic. In this study, a series of experiments using Fe-Al-C were carried to discuss adsorption equilibrium time, adsorption equilibrium concentration and adsorption rate of arsenic for Fe-Al-C. Fe-Al-C used in this study was provided by Astec Co., Ltd. Powder reagent of disodium hydrogen arsenate heptahydrate was dissolved into ion-exchanged water. The solution was then further diluted with ion-exchanged water to be 1 and 10 mg/L as arsenic concentration. The pH of the solution was adjusted to be around 7 by adding HCl and/or NaOH. The solution was used as artificial arsenic contaminated water in two types of experiments (arsenic adsorption equilibrium and arsenic adsorption rate tests). The results of the arsenic equilibrium tests were showed that a time period of about 3 days to reach apparent adsorption equilibrium for arsenic. The apparent adsorption equilibrium concentration and adsorbed amount of arsenic on Fe-Al-C adsorbent could be estimated by application of various adsorption isotherms, but the distribution coefficient of arsenic between solid and liquid varies with experimental conditions such as initial concentration of arsenic and addition concentration of adsorbent. An adsorption rate equation that takes into account the reduction in the number of effective adsorption sites on the adsorbent caused by the arsenic adsorption reaction was derived based on the data obtained from the arsenic adsorption rate tests.

Arsenic Re-Mobilization in Water Treatment Adsorbents Under Reducing Conditions: Part II, XAS and Modeling Study

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

Liu,S.; Jing, C.; Meng, X.

2008-01-01

The mechanism of arsenic re-mobilization in spent adsorbents under reducing conditions was studied using X-ray absorption spectroscopy and surface complexation model calculations. X-ray absorption near edge structure (XANES) spectroscopy demonstrated that As(V) was partially reduced to As(III) in spent granular ferric hydroxide (GFH), titanium dioxide (TiO2), activated alumina (AA) and modified activated alumina (MAA) adsorbents after 2 years of anaerobic incubation. As(V) was completely reduced to As(III) in spent granular ferric oxide (GFO) under 2-year incubation. The extended X-ray absorption fine structure (EXAFS) spectroscopy analysis showed that As(III) formed bidentate binuclear surface complexes on GFO as evidenced by an averagemore » As(III)-O bond distance of 1.78 Angstroms and As(III)-Fe distance of 3.34 Angstroms . The release of As from the spent GFO and TiO2 was simulated using the charge distribution multi-site complexation (CD-MUSIC) model. The observed redox ranges for As release and sulfate mobility were described by model calculations.« less

Green rusts synthesis by coprecipitation of Fe II-Fe III ions and mass-balance diagram

NASA Astrophysics Data System (ADS)

Ruby, Christian; Aïssa, Rabha; Géhin, Antoine; Cortot, Jérôme; Abdelmoula, Mustapha; Génin, Jean-Marie

2006-06-01

A basic solution is progressively added to various mixed Fe II-Fe III solutions. The nature and the relative quantities of the compounds that form can be visualised in a mass-balance diagram. The formation of hydroxysulphate green rust {GR( SO42-)} is preceded by the precipitation of a sulphated ferric basic salt that transforms in a badly ordered ferric oxyhydroxide. Then octahedrally coordinated Fe II species and SO42- anions are adsorbed on the FeOOH surface and GR( SO42-) is formed at the solid/solution interface. By using the same method of preparation, other types of green rust were synthesised, e.g. hydroxycarbonate green rust {GR( CO32-)}. Like other layered double hydroxides, green rusts obey the general chemical formula [ṡ[ṡmHO]x+ with x⩽1/3. Al-substituted hydroxysulphate green rust consists of small hexagonal crystals with a lateral size ˜50 nm, which is significantly smaller than the size of the GR( SO42-) crystals (˜500 nm). To cite this article: C. Ruby et al., C. R. Geoscience 338 (2006).

Do aggregate stability and soil organic matter content increase following organic inputs?

NASA Astrophysics Data System (ADS)

Lehtinen, Taru; Gísladóttir, Guðrún; van Leeuwen, Jeroen P.; Bloem, Jaap; Steffens, Markus; Vala Ragnarsdóttir, Kristin

2014-05-01

Agriculture is facing several challenges such as loss of soil organic matter (SOM); thus, sustainable farming management practices are needed. Organic farming is growing as an alternative to conventional farming; in Iceland approximately 1% and in Austria 16% of utilized agricultural area is under organic farming practice. We analyzed the effect of different farming practices (organic, and conventional) on soil physicochemical and microbiological properties in grassland soils in Iceland and cropland soils in Austria. Organic farms differed from conventional farms by absence of chemical fertilizers and pesticide use. At these farms, we investigated soil physicochemical (e.g. soil texture, pH, CAL-extractable P and K) and microbiological properties (fungal and bacterial biomass and activity). The effects of farming practices on soil macroaggregate stability and SOM quantity, quality and distribution between different fractions were studied following a density fractionation. In Iceland, we sampled six grassland sites on Brown (BA) and Histic (HA) Andosols; two sites on extensively managed grasslands, two sites under organic and two sites under conventional farming practice. In Austria, we sampled four cropland sites on Haplic Chernozems; two sites under organic and two sites under conventional farming practice. We found significantly higher macroaggregate stability in the organic compared to the conventional grasslands in Iceland. In contrast, slightly higher macroaggregation in conventional compared to the organic farming practice was found in croplands in Austria, although the difference was not significant. Macroaggregates were positively correlated with fungal biomass in Iceland, and with Feo and fungal activity in Austria. In Austria, SOM content and nutrient status (except for lower CAL-extractable P at one site) were similar between organic and conventional farms. Our results show that the organic inputs may have enhanced macroaggregation in organic farming practice compared to conventional in the permanent grassland soils in Iceland but were only enough to maintain the SOM content and macroaggregation in the cropland soils in Austria.

Limited protection of macro-aggregate-occluded organic carbon in Siberian steppe soils

NASA Astrophysics Data System (ADS)

Bischoff, Norbert; Mikutta, Robert; Shibistova, Olga; Puzanov, Alexander; Silanteva, Marina; Grebennikova, Anna; Fuß, Roland; Guggenberger, Georg

2017-05-01

Macro-aggregates especially in agricultural steppe soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal timescale. While most research on soil OC stabilization in steppes focused on North American prairie soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural steppes in southwestern Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate-protected OC under different land use as function of land use intensity and time since land use change (LUC) from pasture to arable land in Siberian steppe soils, we determined OC mineralization rates of intact (250-2000 µm) and crushed (< 250 µm) macro-aggregates in long-term incubations over 401 days (20 °C; 60 % water holding capacity) along two agricultural chronosequences in the Siberian Kulunda steppe. Additionally, we incubated bulk soil (< 2000 µm) to determine the effect of LUC and subsequent agricultural use on a fast and a slow soil OC pool (labile vs. more stable OC), as derived from fitting exponential-decay models to incubation data. We hypothesized that (i) macro-aggregate crushing leads to increased OC mineralization due to an increasing microbial accessibility of a previously occluded labile macro-aggregate OC fraction, and (ii) bulk soil OC mineralization rates and the size of the fast OC pool are higher in pasture than in arable soils with decreasing bulk soil OC mineralization rates and size of the fast OC pool as land use intensity and time since LUC increase. Against our hypothesis, OC mineralization rates of crushed macro-aggregates were similar to those of intact macro-aggregates under all land use regimes. Macro-aggregate-protected OC was almost absent and accounted for < 1 % of the total macro-aggregate OC content and to a maximum of 8 ± 4 % of mineralized OC. In accordance to our second hypothesis, highest bulk soil OC mineralization rates and sizes of the fast OC pool were determined under pasture, but mineralization rates and pool sizes were unaffected by land use intensity and time since LUC. However, at one chronosequence mean residence times of the fast and slow OC pool tended to decrease with increasing time since establishment of arable use. We conclude that the tillage-induced breakdown of macro-aggregates has not reduced the OC contents in the soils under study. The decline of OC after LUC is probably attributed to the faster soil OC turnover under arable land as compared to pasture at a reduced plant residue input.

Observational evidence of crystalline iron oxides on Mars

NASA Technical Reports Server (NTRS)

Bell, James F., III; Mccord, Thomas B.; Owensby, Pamela D.

1990-01-01

A series of new spectral observations of Mars was obtained at Mauna Kea Observatory in the 0.4-1.0-micron wavelength range during the extremely favorable 1988 opposition, which yielded new spectral reflectance and relative reflectance data for a number of distinct spots on the Martian surface at 500-600 km spatial resolution. The new spectra revealed absorptions at 0.62-0.72 micron and at 0.81-0.94 micron, both seen clearly for the first time. These absorption features are interpreted as Fe(3+) electronic transition bands that indicate the presence of crystalline ferric oxide or hydroxide minerals on the Martian surface.

A modular continuous flow reactor system for the selective bio-oxidation of iron and precipitation of schwertmannite from mine-impacted waters.

PubMed

Hedrich, Sabrina; Johnson, D Barrie

2012-02-01

A novel modular bioremediation system which facilitates the selective removal of soluble iron from extremely acidic (pH ∼2) metal-rich wastewaters by ferrous iron oxidation and selective precipitation of the ferric iron produced is described. In the first of the three modules, rapid ferrous iron oxidation was mediated by the recently-characterized iron-oxidizing autotrophic acidophile, "Ferrovum myxofaciens", which grew as long "streamers" within the reactor. Over 90% of the iron present in influent test liquors containing 280mg/L iron was oxidized at a dilution rate of 0.41h(-1), in a proton-consuming reaction. The ferric iron-rich solutions produced were pumped into a second reactor where controlled addition of sodium hydroxide caused the water pH to increase to 3.5 and ferric iron to precipitate as the mineral schwertmannite. Addition of a flocculating agent promoted rapid aggregation and settling of the fine-grain schwertmannite particles. A third passive module (a packed-bed bioreactor, also inoculated with "Fv. myxofaciens") acted as a polishing reactor, lowering soluble iron concentrations in the processed water to <1mg/L. The system was highly effective in selectively removing iron from a synthetic acidic (pH 2.1) mine water that contained soluble aluminum, copper, manganese and zinc in addition to iron. Schwertmannite was again produced, with little or no co-precipitation of other metals. Copyright © 2011 Elsevier Ltd. All rights reserved.

[Stabilization of Cadmium Contaminated Soils by Ferric Ion Modified Attapulgite (Fe/ATP)--Characterizations and Stabilization Mechanism].

PubMed

Rong, Yang; Li, Rong-bo; Zhou, Yong-li; Chen, Jing; Wang, Lin-ling; Lu, Xiao-hua

2015-08-01

Ferric ion modified attapulgite (Fe/ATP) was prepared by impregnation and its structure and morphology were characterized. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the effect of Cadmium( Cd) stabilization in soil with the addition of attapulgite (ATP) and Fe/ATP. The stabilization mechanism of Cd was further elucidated by comparing the morphologies and structure of ATP and Fe/ATP before and after Cd adsorption. Fe/ATP exhibited much better adsorption capacity than ATP, suggesting different adsorption mechanisms occurred between ATP and Fe/ATP. The leaching concentrations of Cd in soil decreased by 45% and 91% respectively, with the addition of wt. 20% ATP and Fe/ATP. The former was attributed to the interaction between Cd2 and --OH groups by chemical binding to form inner-sphere complexes in ATP and the attachment between Cd2+ and the defect sites in ATP framework. Whereas Cd stabilization with Fe/ATP was resulted from the fact that the active centers (--OH bonds or O- sites) on ATP could react with Fe3+ giving Fe--O--Cd-- bridges, which helped stabilize Cd in surface soil. What'more, the ferric oxides and metal hydroxides on the surface of ATP could interact with Cd, probably by the formation of cadmium ferrite. In conclusion, Fe/ATP, which can be easily prepared, holds promise as a potential low-cost and environmental friendly stabilizing agent for remediation of soil contaminated with heavy metals.

[Distribution of soil organic carbon, total nitrogen, total phosphorus and water stable aggregates of cropland with different soil textures on the Loess Plateau, Northwest China].

PubMed

Ge, Nan Nan; Shi, Yun; Yang, Xian Long; Zhang, Qing Yin; Li, Xue Zhang; Jia, Xiao Xu; Shao, Ming An; Wei, Xiao Rong

2017-05-18

In this study, combined with field investigation and laboratory analyses, we assessed the distribution of soil organic carbon, nitrogen, phosphorous contents and their stoichiometric ratios, and the distribution of soil water stable aggregates along a soil texture gradient in the cropland of the Loess Plateau to understand the effect of soil texture and the regulation of soil aggregates on soil fertility in cropland. The results showed that, with the change from fine soils to coarse soils along the texture gradient (loam clay→ clay loam→ sandy loam), the contents of macroaggregates, organic carbon, nitrogen, phosphorous and their stoichiometric ratios decreased, while pH value and microaggregates content showed an opposite changing pattern. The contents of macroaggregates, organic carbon, nitrogen, phosphorous, and C/P and N/P were significantly increased, but pH value and microaggregates content were significantly decreased with increasing the soil clay content. Furthermore, the contents of organic carbon, nitrogen, phosphorous, and C/P and N/P increased with the increase of macroaggregates content. These results indicated that soil fertility in croplands at a regional scale was mainly determined by soil texture, and was regulated by soil macroaggregates.

Electron Transfer Strategies Regulate Carbonate Mineral and Micropore Formation

NASA Astrophysics Data System (ADS)

Zeng, Zhirui; Tice, Michael M.

2018-01-01

Some microbial carbonates are robust biosignatures due to their distinct morphologies and compositions. However, whether carbonates induced by microbial iron reduction have such features is unknown. Iron-reducing bacteria use various strategies to transfer electrons to iron oxide minerals (e.g., membrane-bound enzymes, soluble electron shuttles, nanowires, as well as different mechanisms for moving over or attaching to mineral surfaces). This diversity has the potential to create mineral biosignatures through manipulating the microenvironments in which carbonate precipitation occurs. We used Shewanella oneidensis MR-1, Geothrix fermentans, and Geobacter metallireducens GS-15, representing three different strategies, to reduce solid ferric hydroxide in order to evaluate their influence on carbonate and micropore formation (micro-size porosity in mineral rocks). Our results indicate that electron transfer strategies determined the morphology (rhombohedral, spherical, or long-chained) of precipitated calcium-rich siderite by controlling the level of carbonate saturation and the location of carbonate formation. Remarkably, electron transfer strategies also produced distinctive cell-shaped micropores in both carbonate and hydroxide minerals, thus producing suites of features that could potentially serve as biosignatures recording information about the sizes, shapes, and physiologies of iron-reducing organisms.

On the mineral core of ferritin-like proteins: structural and magnetic characterization

NASA Astrophysics Data System (ADS)

García-Prieto, A.; Alonso, J.; Muñoz, D.; Marcano, L.; Abad Díaz de Cerio, A.; Fernández de Luis, R.; Orue, I.; Mathon, O.; Muela, A.; Fdez-Gubieda, M. L.

2015-12-01

It is generally accepted that the mineral core synthesized by ferritin-like proteins consists of a ferric oxy-hydroxide mineral similar to ferrihydrite in the case of horse spleen ferritin (HoSF) and an oxy-hydroxide-phosphate phase in plant and prokaryotic ferritins. The structure reflects a dynamic process of deposition and dissolution, influenced by different biological, chemical and physical variables. In this work we shed light on this matter by combining a structural (High Resolution Transmission Electron Microscopy (HRTEM) and Fe K-edge X-ray Absorption Spectroscopy (XAS)) and a magnetic study of the mineral core biomineralized by horse spleen ferritin (HoSF) and three prokaryotic ferritin-like proteins: bacterial ferritin (FtnA) and bacterioferritin (Bfr) from Escherichia coli and archaeal ferritin (PfFtn) from Pyrococcus furiosus. The prokaryotic ferritin-like proteins have been studied under native conditions and inside the cells for the sake of preserving their natural attributes. They share with HoSF a nanocrystalline structure rather than an amorphous one as has been frequently reported. However, the presence of phosphorus changes drastically the short-range order and magnetic response of the prokaryotic cores with respect to HoSF. The superparamagnetism observed in HoSF is absent in the prokaryotic proteins, which show a pure atomic-like paramagnetic behaviour attributed to phosphorus breaking the Fe-Fe exchange interaction.It is generally accepted that the mineral core synthesized by ferritin-like proteins consists of a ferric oxy-hydroxide mineral similar to ferrihydrite in the case of horse spleen ferritin (HoSF) and an oxy-hydroxide-phosphate phase in plant and prokaryotic ferritins. The structure reflects a dynamic process of deposition and dissolution, influenced by different biological, chemical and physical variables. In this work we shed light on this matter by combining a structural (High Resolution Transmission Electron Microscopy (HRTEM) and Fe K-edge X-ray Absorption Spectroscopy (XAS)) and a magnetic study of the mineral core biomineralized by horse spleen ferritin (HoSF) and three prokaryotic ferritin-like proteins: bacterial ferritin (FtnA) and bacterioferritin (Bfr) from Escherichia coli and archaeal ferritin (PfFtn) from Pyrococcus furiosus. The prokaryotic ferritin-like proteins have been studied under native conditions and inside the cells for the sake of preserving their natural attributes. They share with HoSF a nanocrystalline structure rather than an amorphous one as has been frequently reported. However, the presence of phosphorus changes drastically the short-range order and magnetic response of the prokaryotic cores with respect to HoSF. The superparamagnetism observed in HoSF is absent in the prokaryotic proteins, which show a pure atomic-like paramagnetic behaviour attributed to phosphorus breaking the Fe-Fe exchange interaction. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04446d

Influence of 20–Year Organic and Inorganic Fertilization on Organic Carbon Accumulation and Microbial Community Structure of Aggregates in an Intensively Cultivated Sandy Loam Soil

PubMed Central

Zhang, Huanjun; Ding, Weixin; He, Xinhua; Yu, Hongyan; Fan, Jianling; Liu, Deyan

2014-01-01

To evaluate the long–term effect of compost (CM) and inorganic fertilizer (NPK) application on microbial community structure and organic carbon (OC) accumulation at aggregate scale, soils from plots amended with CM, NPK and no fertilizer (control) for 20 years (1989–2009) were collected. Soil was separated into large macroaggregate (>2,000 μm), small macroaggregate (250–2,000 μm), microaggregate (53–250 μm), silt (2–53 μm) and clay fraction (<2 μm) by wet-sieving, and their OC concentration and phospholipid fatty acids (PLFA) were measured. The 20-year application of compost significantly (P<0.05) increased OC by 123–134% and accelerated the formation of macroaggregates, but decreased soil oxygen diffusion coefficient. NPK mainly increased OC in macroaggregates and displayed weaker influence on aggregation. Bacteria distributed in all aggregates, while fungi and actinobacteria were mainly in macroaggregates and microaggregates. The ratio of monounsaturated to branched (M/B) PLFAs, as an indicator for the ratio of aerobic to anaerobic microorganisms, increased inversely with aggregate size. Both NPK and especially CM significantly (P<0.05) decreased M/B ratios in all aggregates except the silt fraction compared with the control. The increased organic C in aggregates significantly (P<0.05) negatively correlated with M/B ratios under CM and NPK. Our study suggested that more efficient OC accumulations in aggregates under CM–treated than under NPK–treated soil was not only due to a more effective decrease of actinobacteria, but also a decrease of monounsaturated PLFAs and an increase of branched PLFAs. Aggregations under CM appear to alter micro-habitats to those more suitable for anaerobes, which in turn boosts OC accumulation. PMID:24667543

Microbial reduction of iron ore

DOEpatents

Hoffmann, M.R.; Arnold, R.G.; Stephanopoulos, G.

1989-11-14

A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry. 11 figs.

Microbial reduction of iron ore

DOEpatents

Hoffmann, Michael R.; Arnold, Robert G.; Stephanopoulos, Gregory

1989-01-01

A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry.

Carbohydrates as a source of energy and matter for the origin of life

NASA Technical Reports Server (NTRS)

Weber, A. L.

1991-01-01

Recently, we proposed a new model of early glycolysis in which the oxidation of glyceraldehyde self-hemiacetals yielded energy rich polyglyceric acid instead of energy rich thioesters. In this model, polyglyceric acid not only acts as an energy source for phosphoanhydride synthesis, but also as an autocatalyst that can replicate the sequence of D and L residues in its structure. We began our investigation of this new hypothesis - the triose model - by developing a thermal method for the racemization-free synthesis of polyglyceric acid. The hydrolytic stability and the role of chirality in interactions of polyglyceric acid were studied using this thermal polymer. Next, we established that the 2- and 3-glycerol esters of polyglyceric acid are energy rich by measuring the Gibbs free energy change of hydrolysis of the 2- and 3-glycerol esters of 2 and 3-O-L glyceroyl-glyceric acid methyl ester - a model of polyglyceric acid. Recently, we discovered that glyceraldehyde is bound and oxidized to glyceric acid on the surface of ferric hydroxide and that soluble ferric ion catalyzes the rearrangement of glyceraldehyde to lactic acid. We are exploring the possibility that these reactions could yield polyglyceric acid and polylactic acid under plausible prebiotic conditions.

Experimental investigation and modeling of dissolved organic carbon removal by coagulation from seawater.

PubMed

Jeong, Sanghyun; Sathasivan, Arumugam; Kastl, George; Shim, Wang Geun; Vigneswaran, Saravanamuthu

2014-01-01

Coagulation removes colloidal matters and dissolved organic carbon (DOC) which can cause irreversible membrane fouling. However, how DOC is removed by coagulant is not well-known. Jar test was used to study the removal of hydrophobic and hydrophilic DOC fractions at various doses (0.5-8.0 mg-Fe(+3) L(-1)) of ferric chloride (FeCl3) and pH (5.0-9.0). Natural organic matter (NOM) in seawater and treated seawater were fractionated by liquid chromatography-organic carbon detector (LC-OCD). Compared to surface water, the removal of DOC in seawater by coagulation was remarkably different. Majority of DOC could be easily removed with very low coagulant dose (<5.0 mg-Fe(+3) L(-1)) and the removal efficiency did not vary with pH, but the DOC composition in treated water had significantly changed. Hydrophobic fraction (HB) was better removed at high pH while hydrophilic fraction (HF) was better removed at low pH. A modified model of Kastl et al. (2004) which assumed that the removal occurred by adsorption of un-dissociated compounds onto ferric hydroxide was formulated and successfully validated against the jar test data. Copyright © 2013 Elsevier Ltd. All rights reserved.

Iron solubility driven by speciation in dust sources to the ocean

USGS Publications Warehouse

Schroth, A.W.; Crusius, John; Sholkovitz, E.R.; Bostick, B.C.

2009-01-01

Although abundant in the Earths crust, iron is present at trace concentrations in sea water and is a limiting nutrient for phytoplankton in approximately 40% of the ocean. Current literature suggests that aerosols are the primary external source of iron to offshore waters, yet controls on iron aerosol solubility remain unclear. Here we demonstrate that iron speciation (oxidation state and bonding environment) drives iron solubility in arid region soils, glacial weathering products (flour) and oil combustion products (oil fly ash). Iron speciation varies by aerosol source, with soils in arid regions dominated by ferric (oxy)hydroxides, glacial flour by primary and secondary ferrous silicates and oil fly ash by ferric sulphate salts. Variation in iron speciation produces systematic differences in iron solubility: less than 1% of the iron in arid soils was soluble, compared with 2-3% in glacial products and 77-81% in oil combustion products, which is directly linked to fractions of more soluble phases. We conclude that spatial and temporal variations in aerosol iron speciation, driven by the distribution of deserts, glaciers and fossil-fuel combustion, could have a pronounced effect on aerosol iron solubility and therefore on biological productivity and the carbon cycle in the ocean. ?? 2009 Macmillan Publishers Limited.

Biotransformation of arsenic species by activated sludge and removal of bio-oxidised arsenate from wastewater by coagulation with ferric chloride.

PubMed

Andrianisa, Harinaivo Anderson; Ito, Ayumi; Sasaki, Atsushi; Aizawa, Jiro; Umita, Teruyuki

2008-12-01

The potential of activated sludge to catalyse bio-oxidation of arsenite [As(III)] to arsenate [As(V)] and bio-reduction of As(V) to As(III) was investigated. In batch experiments (pH 7, 25 degrees C) using activated sludge taken from a treatment plant receiving municipal wastewater non-contaminated with As, As(III) and As(V) were rapidly biotransformed to As(V) under aerobic condition and As(III) under anaerobic one without acclimatisation, respectively. Sub-culture of the activated sludge using a minimal liquid medium containing 100mg As(III)/L and no organic carbon source showed that aerobic arsenic-resistant bacteria were present in the activated sludge and one of the isolated bacteria was able to chemoautotrophically oxidise As(III) to As(V). Analysis of arsenic species in a full-scale oxidation ditch plant receiving As-contaminated wastewater revealed that both As(III) and As(V) were present in the influent, As(III) was almost completely oxidised to As(V) after supply of oxygen by the aerator in the oxidation ditch, As(V) oxidised was reduced to As(III) in the anaerobic zone in the ditch and in the return sludge pipe, and As(V) was the dominant species in the effluent. Furthermore, co-precipitation of As(V) bio-oxidised by activated sludge in the plant with ferric hydroxide was assessed by jar tests. It was shown that the addition of ferric chloride to mixed liquor as well as effluent achieved high removal efficiencies (>95%) of As and could decrease the residual total As concentrations in the supernatant from about 200 microg/L to less than 5 microg/L. It was concluded that a treatment process combining bio-oxidation with activated sludge and coagulation with ferric chloride could be applied as an alternative technology to treat As-contaminated wastewater.

Speciation and characterization of arsenic in Ketza River mine tailings using X-ray absorption spectroscopy.

PubMed

Paktunc, Dogan; Foster, Andrea; Laflamme, Gilles

2003-05-15

Ketza River mine tailings deposited underwater and those exposed near the tailings impoundment contain approximately 4 wt % As. Column-leaching tests indicated the potential for high As releases from the tailings. The tailings are composed dominantly of iron oxyhydroxides, quartz, calcite, dolomite, muscovite, ferric arsenates, and calcium-iron arsenates. Arsenopyrite and pyrite are trace constituents. Chemical compositions of iron oxyhydroxide and arsenate minerals are highly variable. The XANES spectra indicate that arsenic occurs as As(V) in tailings, but air-drying prior to analysis may have oxidized lower-valent As. The EXAFS spectra indicate As-Fe distances of 3.35-3.36 A for the exposed tailings and 3.33-3.35 A for the saturated tailings with coordination numbers of 0.96-1.11 and 0.46-0.64, respectively. The As-Ca interatomic distances ranging from 4.15 to 4.18 A and the coordination numbers of 4.12-4.58 confirm the presence of calcium-iron arsenates in the tailings. These results suggest that ferric arsenates and inner-sphere corner sharing or bidentate-binuclear attachment of arsenate tetrahedra onto iron hydroxide octahedra are the dominant form of As in the tailings. EXAFS spectra indicate that the exposed tailings are richer in arsenate minerals whereas the saturated tailings are dominated by the iron oxyhydroxides, which could help explain the greater release of As from the exposed tailings during leaching tests. It is postulated that the dissolution of ferric arsenates during flow-through experiments caused the high As releases from both types of tailings. Arsenic tied to iron oxyhydroxides as adsorbed species are considered stable; however, iron oxyhydroxides having low Fe/As molar ratios may not be as stable. Continued As releases from the tailings are likely due to dissolution of both ferric and calcium-iron arsenates and desorption of As from high-As bearing iron oxyhydroxides during aging.

Speciation and characterization of arsenic in Ketza River mine tailings using x-ray absorption spectroscopy

USGS Publications Warehouse

Paktunc, D.; Foster, A.; Laflamme, G.

2003-01-01

Ketza River mine tailings deposited underwater and those exposed near the tailings impoundment contain approximately 4 wt % As. Column-leaching tests indicated the potential for high As releases from the tailings. The tailings are composed dominantly of iron oxyhydroxides, quartz, calcite, dolomite, muscovite, ferric arsenates, and calcium-iron arsenates. Arsenopyrite and pyrite are trace constituents. Chemical compositions of iron oxyhydroxide and arsenate minerals are highly variable. The XANES spectra indicate that arsenic occurs as As(V) in tailings, but air-drying prior to analysis may have oxidized lower-valent As. The EXAFS spectra indicate As-Fe distances of 3.35-3.36 A?? for the exposed tailings and 3.33-3.35 A?? for the saturated tailings with coordination numbers of 0.96-1.11 and 0.46-0.64, respectively. The As-Ca interatomic distances ranging from 4.15 to 4.18 A?? and the coordination numbers of 4.12-4.58 confirm the presence of calcium-iron arsenates in the tailings. These results suggest that ferric arsenates and inner-sphere corner sharing or bidentatebinuclear attachment of arsenate tetrahedra onto iron hydroxide octahedra are the dominant form of As in the tailings. EXAFS spectra indicate that the exposed tailings are richer in arsenate minerals whereas the saturated tailings are dominated by the iron oxyhydroxides, which could help explain the greater release of As from the exposed tailings during leaching tests. It is postulated that the dissolution of ferric arsenates during flow-through experiments caused the high As releases from both types of tailings. Arsenic tied to iron oxyhydroxides as adsorbed species are considered stable; however, iron oxyhydroxides having low Fe/As molar ratios may not be as stable. Continued As releases from the tailings are likely due to dissolution of both ferric and calcium-iron arsenates and desorption of As from high-As bearing iron oxyhydroxides during aging.

Microbial reduction of ferric iron oxyhydroxides as a way for remediation of grey forest soils heavily polluted with toxic metals by infiltration of acid mine drainage

NASA Astrophysics Data System (ADS)

Georgiev, Plamen; Groudev, Stoyan; Spasova, Irena; Nicolova, Marina

2015-04-01

The abandoned uranium mine Curilo is a permanent source of acid mine drainage (AMD) which steadily contaminated grey forest soils in the area. As a result, the soil pH was highly acidic and the concentration of copper, lead, arsenic, and uranium in the topsoil was higher than the relevant Maximum Admissible Concentration (MAC) for soils. The leaching test revealed that approximately half of each pollutant was presented as a reducible fraction as well as the ferric iron in horizon A was presented mainly as minerals with amorphous structure. So, the approach for remediation of the AMD-affected soils was based on the process of redoxolysis carried out by iron-reducing bacteria. Ferric iron hydroxides reduction and the heavy metals released into soil solutions was studied in the dependence on the source of organic (fresh or silage hay) which was used for growth and activity of soil microflora, initial soil pH (3.65; 4.2; and 5.1), and the ion content of irrigation solutions. The combination of limestone (2.0 g/ kg soil), silage addition (at rate of 45 g dry weight/ kg soil) in the beginning and reiterated at 6 month since the start of soil remediation, and periodical soil irrigation with slightly acidic solutions containing CaCl2 was sufficient the content of lead and arsenic in horizon A to be decreased to concentrations similar to the relevant MAC. The reducible, exchangeable, and carbonate mobile fractions were phases from which the pollutants was leached during the applied soil remediation. It determined the higher reduction of the pollutants bioavailability also as well as the process of ferric iron reduction was combined with neutralization of the soil acidity to pH (H2O) 6.2.

Key Roles of Size and Crystallinity of Nanosized Iron Hydr(oxides) Stabilized by Humic Substances in Iron Bioavailability to Plants.

PubMed

Kulikova, Natalia A; Polyakov, Alexander Yu; Lebedev, Vasily A; Abroskin, Dmitry P; Volkov, Dmitry S; Pankratov, Denis A; Klein, Olga I; Senik, Svetlana V; Sorkina, Tatiana A; Garshev, Alexey V; Veligzhanin, Alexey A; Garcia Mina, Jose M; Perminova, Irina V

2017-12-27

Availability of Fe in soil to plants is closely related to the presence of humic substances (HS). Still, the systematic data on applicability of iron-based nanomaterials stabilized with HS as a source for plant nutrition are missing. The goal of our study was to establish a connection between properties of iron-based materials stabilized by HS and their bioavailability to plants. We have prepared two samples of leonardite HS-stabilized iron-based materials with substantially different properties using the reported protocols and studied their physical chemical state in relation to iron uptake and other biological effects. We used Mössbauer spectroscopy, XRD, SAXS, and TEM to conclude on iron speciation, size, and crystallinity. One material (Fe-HA) consisted of polynuclear iron(III) (hydr)oxide complexes, so-called ferric polymers, distributed in HS matrix. These complexes are composed of predominantly amorphous small-size components (<5 nm) with inclusions of larger crystalline particles (the mean size of (11 ± 4) nm). The other material was composed of well-crystalline feroxyhyte (δ'-FeOOH) NPs with mean transverse sizes of (35 ± 20) nm stabilized by small amounts of HS. Bioavailability studies were conducted on wheat plants under conditions of iron deficiency. The uptake studies have shown that small and amorphous ferric polymers were readily translocated into the leaves on the level of Fe-EDTA, whereas relatively large and crystalline feroxyhyte NPs were mostly sorbed on the roots. The obtained data are consistent with the size exclusion limits of cell wall pores (5-20 nm). Both samples demonstrated distinct beneficial effects with respect to photosynthetic activity and lipid biosynthesis. The obtained results might be of use for production of iron-based nanomaterials stabilized by HS with the tailored iron availability to plants. They can be applied as the only source for iron nutrition as well as in combination with the other elements, for example, for industrial production of "nanofortified" macrofertilizers (NPK).

Plant-mediated effects on extracellular enzyme activities in distinct soil aggregate size classes in field

NASA Astrophysics Data System (ADS)

Kumar, Amit; Dorodnikov, Maxim; Splettstößer, Thomas; Kuzyakov, Yakov; Pausch, Johanna

2017-04-01

Soil aggregation and microbial activities within the aggregates are important factors regulating soil carbon (C) turnover. A reliable and sensitive proxy for microbial activity is activity of extracellular enzymes (EEA). In the present study, effects of soil aggregates on EEA were investigated under three maize plant densities (Low, Normal, and High). Bulk soil was fractionated into three aggregate size classes (>2000 µm large macroaggregates; 2000-250 µm small macroaggregates; <250 µm microaggregates) by optimal-moisture sieving. Microbial biomass and EEA (β-1,4-glucosidase (BG), β-1,4-N-acetylglucosaminidase (NAG), L-leucine aminopeptidase (LAP) and acid phosphatase (acP)) catalyzing soil organic matter (SOM) decomposition were measured in rooted soil of maize and soil from bare fallow. Microbial biomass C (Cmic) decreased with decreasing aggregate size classes. Potential and specific EEA (per unit of Cmic) increased from macro- to microaggregates. In comparison with bare fallow soil, specific EEA of microaggregates in rooted soil was higher by up to 73%, 31%, 26%, and 92% for BG, NAG, acP and LAP, respectively. Moreover, high plant density decreased macroaggregates by 9% compared to bare fallow. Enhanced EEA in three aggregate size classes demonstrated activation of microorganisms by roots. Strong EEA in microaggregates can be explained by microaggregates' localization within the soil. Originally adhering to surfaces of macroaggregates, microaggregates were preferentially exposed to C substrates and nutrients, thereby promoting microbial activity.

Aggregation and C dynamics along an elevation gradient in carbonate-containing grassland soils of the Alps

NASA Astrophysics Data System (ADS)

Garcia-Franco, Noelia; Wiesmeier, Martin; Kiese, Ralf; Dannenmann, Michael; Wolf, Benjamin; Zistl-Schlingmann, Marcus; Kögel-Knabner, Ingrid

2017-04-01

C sequestration in mountainous grassland soils is regulated by physical, chemical and biological soil process. An improved knowledge of the relationship between these stabilization mechanisms is decisive to recommend the best management practices for climate change mitigation. In this regard, the identification of a successful indicator of soil structural improvement and C sequestration in mountainous grassland soils is necessary. Alpine and pre-alpine grassland soils in Bavaria represent a good example for mountainous grassland soils faced with climate change. We sampled grassland soils of the northern limestone alps in Bavaria along an elevation gradient from 550 to 1300 m above sea level. We analyzed C dynamics by a comparative analysis of the distribution of C according to aggregate size classes: large-macroaggregates (> 2000 µm), small-macroaggregates (250-2000 µm), microaggregates (63-250 µm), silt plus clay particles (<63 µm) and bulk soil. Our preliminary results showed higher C content and changed water-stable aggregate distribution in the high elevation sites compared to lower elevations. Magnesium carbonate seem to play an important role in stabilizing macroaggregates formed from fresh OM. In addition, the isolation of occluded microaggregates within macroaggregates will help us to improve our understanding on the effects of climate change on soil structure and on the sensitivity of different C stabilization mechanisms present in mountainous soils.

Electron Transfer Strategies Regulate Carbonate Mineral and Micropore Formation.

PubMed

Zeng, Zhirui; Tice, Michael M

2018-01-01

Some microbial carbonates are robust biosignatures due to their distinct morphologies and compositions. However, whether carbonates induced by microbial iron reduction have such features is unknown. Iron-reducing bacteria use various strategies to transfer electrons to iron oxide minerals (e.g., membrane-bound enzymes, soluble electron shuttles, nanowires, as well as different mechanisms for moving over or attaching to mineral surfaces). This diversity has the potential to create mineral biosignatures through manipulating the microenvironments in which carbonate precipitation occurs. We used Shewanella oneidensis MR-1, Geothrix fermentans, and Geobacter metallireducens GS-15, representing three different strategies, to reduce solid ferric hydroxide in order to evaluate their influence on carbonate and micropore formation (micro-size porosity in mineral rocks). Our results indicate that electron transfer strategies determined the morphology (rhombohedral, spherical, or long-chained) of precipitated calcium-rich siderite by controlling the level of carbonate saturation and the location of carbonate formation. Remarkably, electron transfer strategies also produced distinctive cell-shaped micropores in both carbonate and hydroxide minerals, thus producing suites of features that could potentially serve as biosignatures recording information about the sizes, shapes, and physiologies of iron-reducing organisms. Key Words: Microbial iron reduction-Micropore-Electron transfer strategies-Microbial carbonate. Astrobiology 18, 28-36.

Influence of pore structure on carbon retention/loss in soil macro-aggregates

NASA Astrophysics Data System (ADS)

Quigley, Michelle; Kravchenko, Alexandra; Rivers, Mark

2017-04-01

Carbon protection within soil macro-aggregates is an important component of soil carbon sequestration. Pores, as the transportation network for microorganisms, water, air and nutrients within macro-aggregates, are among the factors controlling carbon protection through restricting physical accessibility of carbon to microorganisms. The understanding of how the intra-aggregate pore structure relates to the degree of carbon physical protection, however, is currently lacking. This knowledge gap can lead to potentially inaccurate models and predictions of soil carbon's fate and storage in future changing climates. This study utilized the natural isotopic difference between C3 and C4 plants to trace the location of newly added carbon within macro-aggregates before and after decomposition and explored how location of this carbon relates to characteristics of intra-aggregate pores. To mimic the effect of decomposition, aggregates were incubated at 23˚ C for 28 days. Computed micro-tomographic images were used to determine pore characteristics at 6 μm resolution before and after incubation. Soil (0-10 cm depth) from a 20 year continuous corn (C4 plant) experiment was used. Two soil treatments were considered: 1) "destroyed-structure", where 1 mm sieved soil was used and 2) "intact-structure", where intact blocks of soil were used. Cereal rye (Secale cereale L.) (C3 plant) was grown in the planting boxes (2 intact, 3 destroyed, and one control) for three months in a greenhouse. From each box, ˜5 macro-aggregates of ˜5 mm size were collected for a total of 27 macro-aggregates. Half of the aggregates were cut into 5-11 sections, with relative positions of the sections within the aggregate recorded, and analyzed for δ13C. The remaining aggregates were incubated and then subjected to cutting and δ13C analysis. While there were no significant differences between the aggregate pore size distributions of the two treatments, the roles that specific pores sizes played in carbon protect were disparate. In intact-structure aggregates, prior to incubation, there was no association between carbon distribution and pores. After incubation, significant correlations (α=0.05) were observed between abundance of 6-40 μm pores and both soil organic carbon (SOC) and δ13C. Sections containing more 6-40 μm pores also had increased amounts of SOC (r2=0.23) with higher presence of C4 carbon (r2=0.27). This indicates preferential preservation of older carbon in the pores of this size range. Prior to incubation, destroyed-structure aggregates had higher amounts of C3 carbon associated with 40-95 μm pores (r2=0.14), pointing to a greater presence of newly added carbon within these pores. However, after incubation there was a significant loss of SOC from these pores (r2=0.22) and, specifically, the loss of C3 carbon (r2=0.16). In the studied soil, pores of 6-40 μm size range appeared to control the preservation of older carbon, while 40-95 μm pores controlled the fate of newly added carbon. Older carbon preservation in 6-40 μm pores was mostly observed in macro-aggregates from the soil with intact structure, while the associations between 40-95 μm pores and gains and losses of newly added carbon were primarily observed in the macro-aggregates that were formed anew in the sieved soil during the plant growing experiment.

Aggregate distribution and associated organic carbon influenced by cover crops

NASA Astrophysics Data System (ADS)

Barquero, Irene; García-González, Irene; Benito, Marta; Gabriel, Jose Luis; Quemada, Miguel; Hontoria, Chiquinquirá

2013-04-01

Replacing fallow with cover crops during the non-cropping period seems to be a good alternative to diminish soil degradation by enhancing soil aggregation and increasing organic carbon. The aim of this study was to analyze the effect of replacing fallow by different winter cover crops (CC) on the aggregate distribution and C associated of an Haplic Calcisol. The study area was located in Central Spain, under semi-arid Mediterranean climate. A 4-year field trial was conducted using Barley (Hordeum vulgare L.) and Vetch (Vicia sativa L.) as CC during the intercropping period of maize (Zea mays L.) under irrigation. All treatments were equally irrigated and fertilized. Maize was directly sown over CC residues previously killed in early spring. Composite samples were collected at 0-5 and 5-20 cm depths in each treatment on autumn of 2010. Soil samples were separated by wet sieving into four aggregate-size classes: large macroaggregates ( >2000 µm); small macroaggregates (250-2000 µm); microaggregates (53-250 µm); and < 53 µm (silt + clay size). Organic carbon associated to each aggregate-size class was measured by Walkley-Black Method. Our preliminary results showed that the aggregate-size distribution was dominated by microaggregates (48-53%) and the <53 µm fraction (40-44%) resulting in a low mean weight diameter (MWD). Both cover crops increased aggregate size resulting in a higher MWD (0.28 mm) in comparison with fallow (0.20 mm) in the 0-5 cm layer. Barley showed a higher MWD than fallow also in 5-20 cm layer. Organic carbon concentrations in aggregate-size classes at top layer followed the order: large macroaggregates > small macroaggregates > microaggregates > silt + clay size. Treatments did not influence C concentration in aggregate-size classes. In conclusion, cover crops improved soil structure increasing the proportion of macroaggregates and MWD being Barley more effective than Vetch at subsurface layer.

Technologies for Extracting Valuable Metals and Compounds from Geothermal Fluids

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

Harrison, Stephen

2014-04-30

Executive Summary Simbol Materials studied various methods of extracting valuable minerals from geothermal brines in the Imperial Valley of California, focusing on the extraction of lithium, manganese, zinc and potassium. New methods were explored for managing the potential impact of silica fouling on mineral extraction equipment, and for converting silica management by-products into commercial products.` Studies at the laboratory and bench scale focused on manganese, zinc and potassium extraction and the conversion of silica management by-products into valuable commercial products. The processes for extracting lithium and producing lithium carbonate and lithium hydroxide products were developed at the laboratory scale andmore » scaled up to pilot-scale. Several sorbents designed to extract lithium as lithium chloride from geothermal brine were developed at the laboratory scale and subsequently scaled-up for testing in the lithium extraction pilot plant. Lithium The results of the lithium studies generated the confidence for Simbol to scale its process to commercial operation. The key steps of the process were demonstrated during its development at pilot scale: 1. Silica management. 2. Lithium extraction. 3. Purification. 4. Concentration. 5. Conversion into lithium hydroxide and lithium carbonate products. Results show that greater than 95% of the lithium can be extracted from geothermal brine as lithium chloride, and that the chemical yield in converting lithium chloride to lithium hydroxide and lithium carbonate products is greater than 90%. The product purity produced from the process is consistent with battery grade lithium carbonate and lithium hydroxide. Manganese and zinc Processes for the extraction of zinc and manganese from geothermal brine were developed. It was shown that they could be converted into zinc metal and electrolytic manganese dioxide after purification. These processes were evaluated for their economic potential, and at the present time Simbol Materials is evaluating other products with greater commercial value. Potassium Silicotitanates, zeolites and other sorbents were evaluated as potential reagents for the extraction of potassium from geothermal brines and production of potassium chloride (potash). It was found that zeolites were effective at removing potassium but the capacity of the zeolites and the form that the potassium is in does not have economic potential. Iron-silica by-product The conversion of iron-silica by-product produced during silica management operations into more valuable materials was studied at the laboratory scale. Results indicate that it is technically feasible to convert the iron-silica by-product into ferric chloride and ferric sulfate solutions which are precursors to a ferric phosphate product. However, additional work to purify the solutions is required to determine the commercial viability of this process. Conclusion Simbol Materials is in the process of designing its first commercial plant based on the technology developed to the pilot scale during this project. The investment in the commercial plant is hundreds of millions of dollars, and construction of the commercial plant will generate hundreds of jobs. Plant construction will be completed in 2016 and the first lithium products will be shipped in 2017. The plant will have a lithium carbonate equivalent production capacity of 15,000 tonnes per year. The gross revenues from the project are expected to be approximately $ 80 to 100 million annually. During this development program Simbol grew from a company of about 10 people to over 60 people today. Simbol is expected to employ more than 100 people once the plant is constructed. Simbol Materials’ business is scalable in the Imperial Valley region because there are eleven geothermal power plants already in operation, which allows Simbol to expand its business from one plant to multiple plants. Additionally, the scope of the resource is vast in terms of potential products such as lithium, manganese and zinc and potentially potassium.« less

A key role for green rust in the Precambrian oceans and the genesis of iron formations

NASA Astrophysics Data System (ADS)

Halevy, I.; Alesker, M.; Schuster, E. M.; Popovitz-Biro, R.; Feldman, Y.

2017-01-01

Iron formations deposited in marine settings during the Precambrian represent large sinks of iron and silica, and have been used to reconstruct environmental conditions at the time of their formation. However, the observed mineralogy in iron formations, which consists of iron oxides, silicates, carbonates and sulfides, is generally thought to have arisen from diagenesis of one or more mineral precursors. Ferric iron hydroxides and ferrous carbonates and silicates have been identified as prime candidates. Here we investigate the potential role of green rust, a ferrous-ferric hydroxy salt, in the genesis of iron formations. Our laboratory experiments show that green rust readily forms in early seawater-analogue solutions, as predicted by thermodynamic calculations, and that it ages into minerals observed in iron formations. Dynamic models of the iron cycle further indicate that green rust would have precipitated near the iron redoxcline, and it is expected that when the green rust sank it transformed into stable phases within the water column and sediments. We suggest, therefore, that the precipitation and transformation of green rust was a key process in the iron cycle, and that the interaction of green rust with various elements should be included in any consideration of Precambrian biogeochemical cycles.

Arsenic cycling in hydrocarbon plumes: secondary effects of natural attenuation

USGS Publications Warehouse

Cozzarelli, Isabelle M.; Schreiber, Madeline E.; Erickson, Melinda L.; Ziegler, Brady A.

2016-01-01

Monitored natural attenuation is widely applied as a remediation strategy at hydrocarbon spill sites. Natural attenuation relies on biodegradation of hydrocarbons coupled with reduction of electron acceptors, including solid phase ferric iron (Fe(III)). Because arsenic (As) adsorbs to Fe-hydroxides, a potential secondary effect of natural attenuation of hydrocarbons coupled with Fe(III) reduction is a release of naturally occurring As to groundwater. At a crude-oil-contaminated aquifer near Bemidji, Minnesota, anaerobic biodegradation of hydrocarbons coupled to Fe(III) reduction has been well documented. We collected groundwater samples at the site annually from 2009 to 2013 to examine if As is released to groundwater and, if so, to document relationships between As and Fe inside and outside of the dissolved hydrocarbon plume. Arsenic concentrations in groundwater in the plume reached 230 µg/L, whereas groundwater outside the plume contained less than 5 µg/L As. Combined with previous data from the Bemidji site, our results suggest that (1) naturally occurring As is associated with Fe-hydroxides present in the glacially derived aquifer sediments; (2) introduction of hydrocarbons results in reduction of Fe-hydroxides, releasing As and Fe to groundwater; (3) at the leading edge of the plume, As and Fe are removed from groundwater and retained on sediments; and (4) downgradient from the plume, patterns of As and Fe in groundwater are similar to background. We develop a conceptual model of secondary As release due to natural attenuation of hydrocarbons that can be applied to other sites where an influx of biodegradable organic carbon promotes Fe(III) reduction.

Arsenic Cycling in Hydrocarbon Plumes: Secondary Effects of Natural Attenuation.

PubMed

Cozzarelli, Isabelle M; Schreiber, Madeline E; Erickson, Melinda L; Ziegler, Brady A

2016-01-01

Monitored natural attenuation is widely applied as a remediation strategy at hydrocarbon spill sites. Natural attenuation relies on biodegradation of hydrocarbons coupled with reduction of electron acceptors, including solid phase ferric iron (Fe(III)). Because arsenic (As) adsorbs to Fe-hydroxides, a potential secondary effect of natural attenuation of hydrocarbons coupled with Fe(III) reduction is a release of naturally occurring As to groundwater. At a crude-oil-contaminated aquifer near Bemidji, Minnesota, anaerobic biodegradation of hydrocarbons coupled to Fe(III) reduction has been well documented. We collected groundwater samples at the site annually from 2009 to 2013 to examine if As is released to groundwater and, if so, to document relationships between As and Fe inside and outside of the dissolved hydrocarbon plume. Arsenic concentrations in groundwater in the plume reached 230 µg/L, whereas groundwater outside the plume contained less than 5 µg/L As. Combined with previous data from the Bemidji site, our results suggest that (1) naturally occurring As is associated with Fe-hydroxides present in the glacially derived aquifer sediments; (2) introduction of hydrocarbons results in reduction of Fe-hydroxides, releasing As and Fe to groundwater; (3) at the leading edge of the plume, As and Fe are removed from groundwater and retained on sediments; and (4) downgradient from the plume, patterns of As and Fe in groundwater are similar to background. We develop a conceptual model of secondary As release due to natural attenuation of hydrocarbons that can be applied to other sites where an influx of biodegradable organic carbon promotes Fe(III) reduction. © 2015, National Ground Water Association.

Effects of earthworms and plants on the soil structure, the physical stabilization of soil organic matter and the microbial abundance and diversity in soil aggregates in a long term study

NASA Astrophysics Data System (ADS)

Zangerlé, Anne; Hissler, Christophe; Lavelle, Patrick

2014-05-01

Earthworms and plant roots, as ecosystem engineers, have large effects on biotic and abiotic properties of the soil system. They create biogenic soil macroaggregates (i.e. earthworm casts and root macroaggregates) with specific physical, chemical and microbiological properties. Research to date has mainly considered their impacts in isolation thereby ignoring potential interactions between these organisms. On the other hand, most of the existing studies focused on short to midterm time scale. We propose in this study to consider effect of earthworms and plants on aggregate dynamics at long time scale. A 24 months macrocosm experiment, under semi-controlled conditions, was conducted to assess the impacts of corn and endogeic plus anecic earthworms (Apporectodea caliginosa and Lumbricus terrestris) on soil structure, C stabilization and microbial abundance and biodiversity. Aggregate stability was assessed by wet-sieving. Macroaggregates (>2 mm) were also visually separated according to their biological origin (e.g., earthworms, roots). Total C and N contents were measured in aggregates of all size classes and origins. Natural abundances of 13C of corn, a C4 plant, were used as a supplemental marker of OM incorporation in aggregates. The genetic structure and the abundance of the bacterial and fungal communities were characterized by using respectively the B- and F-ARISA fingerprinting approach and quantitative PCR bacteria (341F/515R) and fungi (FF330/FR1). They significantly impacted the soil physical properties in comparison to the other treatments: lower bulk density in the first 10cm of the soil with 0.95 g/cm3 in absence of corn plants and 0.88 g/cm3 in presence of corn plants compared to control soil (1.21g/cm3). The presence of earthworms increased aggregate stability (mean weight diameter) by 7.6 %, while plants alone had no simple impacts on aggregation. A significant interaction revealed that earthworms increased aggregate stability in the presence of roots by 2.4% when compared to macrocosms without plants. Additionally, the presence of roots increased the total C and N concentration in earthworm casts, while earthworms increased C storage in microaggregates within root-derived aggregates. Analyses of 13C abundances revealed that OM had been incorporated in earthworm casts from the fifth month of the experiment. Earthworms showed an impact on bacterial abundance of 26.7% of increase in single species macroaggregates and 35.5% in mixt species macroaggregates after the first harvest of corn plants. Trends however changed on the long term since bacterial abundances decreased dramatically (67.1% in single species treatments and 59.3% in mixed species treatments) during the second year and fungal abundances, stable during the first 5 months of the experiment, later increased 80% and 73.2% in earthworm and mixed species macroaggregates. This experiment showed how interactions between plants and earthworms can influence the soil structure and the soil aggregates dynamics by cooperating in macroaggregate formation. Both organisms need to be considered simultaneously for proper management of soils.

Partitioning of uranyl between ferrihydrite and humic substances at acidic and circum-neutral pH

DOE PAGES

Dublet, Gabrielle; Lezama Pacheco, Juan; Bargar, John R.; ...

2017-07-14

As part of a larger study of the reactivity and mobility of uranyl (U(VI)O 2 2+) cations in subsurface environments containing natural organic matter (NOM) and hydrous ferric oxides, we have examined the effect of reference humic and fulvic substances on the sorption of uranyl on 2-line ferrihydrite (Fh), a common, naturally occurring nano-Fe(III)-hydroxide. Uranyl was reacted with Fh at pH 4.6 and 7.0 in the presence and absence of Elliott Soil Humic Acid (ESHA) (0–835 ppm) or Suwanee River Fulvic Acid (SRFA) (0–955 ppm). Here, no evidence was found for reduction of uranyl by either form of NOM aftermore » 24 h of exposure.« less

The Purification and Concentration of Hog Cholera Virus*

PubMed Central

Cunliffe, H. R.; Rebers, P. A.

1968-01-01

Partial purification of hog cholera virus (HCV) using a simple batch-type chromatographic procedure with magnetic ferric oxide (MFO) is described. Infectious HCV was adsorbed from isotonic solutions to MFO and was eluted under conditions of low ionic strength and high pH. Aqueous solutions of 0.01 M sodium cyanide or 0.0003 M ammonium hydroxide effectively dissociated MFO-HCV complexes. The data indicate that 50 to 100% of the original HCV infectivity was recovered concomitant with a 90 to 95% reduction of extraneous organic nitrogen. MFO-purified HCV was concentrated by density gradient type centrifugations in buffered solutions of cesium chloride and sucrose. Prolonged isodensity centrifugations of concentrated MFO-purified HCV indicated a buoyant density of 1.14 to 1.15 gm/ml for the strain of virus used. PMID:15846899

Partitioning of uranyl between ferrihydrite and humic substances at acidic and circum-neutral pH

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

Dublet, Gabrielle; Lezama Pacheco, Juan; Bargar, John R.

As part of a larger study of the reactivity and mobility of uranyl (U(VI)O 2 2+) cations in subsurface environments containing natural organic matter (NOM) and hydrous ferric oxides, we have examined the effect of reference humic and fulvic substances on the sorption of uranyl on 2-line ferrihydrite (Fh), a common, naturally occurring nano-Fe(III)-hydroxide. Uranyl was reacted with Fh at pH 4.6 and 7.0 in the presence and absence of Elliott Soil Humic Acid (ESHA) (0–835 ppm) or Suwanee River Fulvic Acid (SRFA) (0–955 ppm). Here, no evidence was found for reduction of uranyl by either form of NOM aftermore » 24 h of exposure.« less

Influence of cations on the partition behavior of perfluoroheptanoate (PFHpA) and perfluorohexanesulfonate (PFHxS) on wastewater sludge.

PubMed

Wang, Fei; Shih, Kaimin; Ma, Ruowei; Li, Xiao-yan

2015-07-01

The effects of different cations on the sorption behavior of PFHpA and PFHxS on two types of sludge were investigated in this study. The sodium and potassium ions did not significantly affect PFHpA and PFHxS sorption on different sludge. For calcium and magnesium, the sorption amount of PFAS increased with calcium and magnesium concentration increasing from 1 to 30 mM and then decreased with those increasing from 30 to 100 mM. The sorption level of PFHxS or PFHpA greatly increased with increasing Al3+ and Fe3+ cation concentrations due to the strong sorption and coagulation effects by the formation of aluminum hydroxide (or ferric hydroxide) colloids or precipitates. After the organics in sludge has been removed by thermal treatment, the PFAS sorption on sludge was greatly reduced. Such finding indicated that sorption to organic matter is more important for anionic PFASs than adsorption to mineral surfaces. However, due to the higher content of biological organics, a secondary activated sludge has higher affinity toward PFAS species than chemically enhanced primary treatment sludge. It indicated that the organic types in sludge were also crucial to the sorption levels of PFASs by sludge. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Impact of land use type on stability and organic carbon of soil aggregates in Jinyun Mountain].

PubMed

Li, Jian-Lin; Jiang, Chang-Sheng; Hao, Qing-Ju

2014-12-01

Soil aggregates have the important effect on soil fertility, soil quality and the sustainable utilization of soil, and they are the mass bases of water and fertilizer retention ability of soil and the supply or release of soil nutrients. In this paper, in order to study the impact of land use type on stability and organic carbon of soil aggregates in Jinyun Mountain, we separated four land use types of soil, which are woodland, abandoned land, orchard and sloping farmland by wet sieving method, then we got the proportion of large macroaggregates (> 2 mm), small macroaggregates (0.25-2 mm), microaggregates (53 μm-0.25 mm) and silt + clay (< 53 μm) and measured the content of organic carbon in each aggregate fraction in soil depth of 0-60 cm and calculated the total content of organic carbon of all aggregates fraction in each soil. The results showed that reclamation of woodland will lead to fragmentation of macroaggregates and deterioration of soil structure, and the proportion of macroaggrgates (> 0.25 mm) were 44.62% and 32.28% respectively in the soils of orchard and sloping farmland, which reduced 38.58% (P < 0.05) and 91.52% (P < 0.05) compared with woodland. While after changing the sloping farmland to abandoned land, which lead to the conversion of soil fraction from silt + clay to large macroaggregates and small macroaggregates, so it will improve the soil structure. MWD (mean weight diameter) and GMD (geometric mean diameter) are important indicators of evaluating the stability of soil aggregates. We found the MWD and GWD in soil depth of 0-60 cm in orchards and sloping farmland were significantly lower than those in woodland (P < 0.05), while after changing the sloping farmland to abandoned land, the MWD and GWD increased significantly (P < 0.05), which indicated that reclamation of woodland will lead to the decrease of stability of soil aggregates, and they will be separated more easily by water. However, after changing the sloping farmland to abandoned land will enhance the stability of soil aggregates, and improve the ability of soil to resist external damage. The organic carbon content in each soil aggregate of four land use types decreased with the increase of soil depth. In soil depth of 0-60 cm, the storage of organic carbon of large macroaggregates in each soil are in orders of woodland (14.98 Mg x hm(-2)) > abandoned land (8.71 Mg x hm(-2)) > orchard (5.82 Mg x hm(-2)) > sloping farmland (2.13 Mg x hm(-2)), and abandoned land (35.61 Mg x hm(-2)) > woodland (20.38 Mg x hm-(-2)) > orchard (13.83 Mg x hm(-2)) > sloping farmland (6.77 Mg x hm(-2)) in small macroaggregates, and abandoned land (22.44 Mg x hm(-2)) > woodland (10.20 Mg x hm(-2)) > orchard (6.80 Mg x hm(-2)) > sloping farmland (5. 60 Mg x hm(-2)) in microaggregates, and abandoned land (22.21 Mg x hm(-2)) > woodland (17.01 Mg x hm(-2)) > orchard (16.70 Mg x hm(-2)) > sloping farmland (9.85 Mg x hm(-2)) in silt and clay fraction. Storage of organic carbon in each aggregate in the soils of woodland and abandoned land were higher than those in the soils of orchard and sloping farmland, which indicated that reclamation of woodland will lead to a loss of organic carbon in each soil aggregate fraction, while after changing the sloping farmland to abandoned land will contribute to restore and sequestrate the soil organic carbon. In addition, it showed that most organic carbon accumulated in small macroaggregate in soils of woodland and abandoned land, while they are in silt and clay in soils of orchard and sloping farmland, indicating that organic carbon in larger aggregates is unstable and is easier to convert during the land use change.

Antioxidant and cytoprotective activities of Piper betle, Areca catechu, Uncaria gambir and betel quid with and without calcium hydroxide.

PubMed

Sazwi, Nordin Nur; Nalina, Thurairajah; Abdul Rahim, Zubaidah Haji

2013-12-11

Betel quid chewing is a popular habit in Southeast Asia. It is believed that chewing betel quid could reduce stress, strengthen teeth and maintain oral hygiene. The aim of this study was to investigate the antioxidant and cytoprotective activities of each of the ingredients of betel quid and compared with betel quid itself (with and without calcium hydroxide). The correlation of their cytoprotective and antioxidant activities with phenolic content was also determined. Five samples (betel leaf, areca nut, gambir, betel quid and betel quid containing calcium hydroxide) were extracted in deionized distilled water for 12 hours at 37°C. Antioxidant activities were evaluated for radical scavenging activity using DPPH assay, ferric reducing activity using FRAP assay and lipid peroxidation inhibition activity using FTC assay. Total phenolic content (TPC) was determined using Folin-Ciocalteu procedure. Phenolic composition was analyzed using LC-MS/MS. Cytoprotective activity towards human gingival fibroblast cells was examined using MTT assay. Among the ingredients of betel quid, gambir demonstrated the highest antioxidant (DPPH - IC50 = 6.4 ± 0.8 μg/mL, FRAP - 5717.8 ± 537.6 μmol Fe(II)/mg), total phenolic content (TPC - 1142.5 ± 106.8 μg TAE/mg) and cytoprotective (100.1 ± 4.6%) activities. Betel quid when compared with betel quid containing calcium hydroxide has higher antioxidant (DPPH - IC50 =59.4 ± 4.4 μg/mL, FRAP - 1022.2 ± 235.7 μmol Fe(II)/mg), total phenolic content (TPC - 140.0 ± 22.3 μg TAE/mg), and cytoprotective (113.5 ± 15.9%) activities. However, all of the five samples showed good lipid peroxidation inhibition compared to vitamin E. LC-MS/MS analysis revealed the presence of quinic acid as the major compound of gambir and betel quid. A positive correlation was observed between TPC and radical scavenging (r = 0.972), reducing power (r = 0.981) and cytoprotective activity (r = 0.682). The betel quid has higher TPC, and antioxidant and cytoprotective activities than betel quid with calcium hydroxide. The quinic acid in betel quid may play an important role in the oral health protection.

Spectral reflectance properties (0.4-2.5 μm) of secondary Fe-oxide, Fe-hydroxide, and Fe-sulphate-hydrate minerals associated with sulphide-bearing mine wastes

USGS Publications Warehouse

Crowley, J.K.; Williams, D.E.; Hammarstrom, J.M.; Piatak, N.; Chou, I.-Ming; Mars, J.C.

2003-01-01

Diffuse reflectance spectra of 15 mineral species commonly associated with sulphide-bearing mine wastes show diagnostic absorption bands related to electronic processes involving ferric and/or ferrous iron, and to vibrational processes involving water and hydroxyl. Many of these absorption bands are relatively broad and overlapping; however, spectral analysis methods, including continuum removal and derivative analysis, permit most of the minerals to be distinguished. Key spectral differences between the minerals are illustrated in a series of plots showing major absorption band centres and other spectral feature positions. Because secondary iron minerals are sensitive indicators of pH, Eh, relative humidity, and other environmental conditions, spectral mapping of mineral distributions promises to have important application to mine waste remediation studies.

Use of modified diatomaceous earth for removal and recovery of viruses in water.

PubMed Central

Farrah, S R; Preston, D R; Toranzos, G A; Girard, M; Erdos, G A; Vasuhdivan, V

1991-01-01

Diatomaceous earth was modified by in situ precipitation of metallic hydroxides. Modification decreased the negative charge on the diatomaceous earth and increased its ability to adsorb viruses in water. Electrostatic interactions were more important than hydrophobic interactions in virus adsorption to modified diatomaceous earth. Filters containing diatomaceous earth modified by in situ precipitation of a combination of ferric chloride and aluminum chloride adsorbed greater than 80% of enteroviruses (poliovirus 1, echovirus 5, and coxsackievirus B5) and coliphage MS2 present in tap water at ambient pH (7.8 to 8.3), even after filtration of 100 liters of tap water. Viruses adsorbed to the filters could be recovered by mixing the modified diatomaceous earth with 3% beef extract plus 1 M NaCl (pH 9). Images PMID:1768124

Vertebral Uptake of Tc-99m Macroaggregated Albumin (MAA) with SPECT/CT Occurring in Superior Vena Cava Obstruction.

PubMed

Karls, Shawn; Hassoun, Hani; Derbekyan, Vilma

2016-09-01

A 67-year-old male presented with dyspnea for which lung scintigraphy was ordered to rule out pulmonary embolus. Planar images demonstrated abnormal midline uptake of Tc-99m macroaggregated albumin, which SPECT/CT localized to several thoracic vertebrae. Thoracic vertebral uptake on perfusion lung scintigraphy was previously described on planar imaging. Radionuclide venography and contrast-enhanced CT subsequently demonstrated superior vena cava (SVC) obstruction with collateralization through the azygous/hemiazygous system and vertebral venous plexus. SPECT/CT differentiated residual esophageal/tracheal ventilation activity, a clinically insignificant finding, from vertebral uptake indicative of SVC obstruction, a potentially life-threatening condition.

Hydrogeochemistry and microbiology of mine drainage: An update

USGS Publications Warehouse

Nordstrom, D. Kirk; Blowes, D.W; Ptacek, C.J.

2015-01-01

The extraction of mineral resources requires access through underground workings, or open pit operations, or through drillholes for solution mining. Additionally, mineral processing can generate large quantities of waste, including mill tailings, waste rock and refinery wastes, heap leach pads, and slag. Thus, through mining and mineral processing activities, large surface areas of sulfide minerals can be exposed to oxygen, water, and microbes, resulting in accelerated oxidation of sulfide and other minerals and the potential for the generation of low-quality drainage. The oxidation of sulfide minerals in mine wastes is accelerated by microbial catalysis of the oxidation of aqueous ferrous iron and sulfide. These reactions, particularly when combined with evaporation, can lead to extremely acidic drainage and very high concentrations of dissolved constituents. Although acid mine drainage is the most prevalent and damaging environmental concern associated with mining activities, generation of saline, basic and neutral drainage containing elevated concentrations of dissolved metals, non-metals, and metalloids has recently been recognized as a potential environmental concern. Acid neutralization reactions through the dissolution of carbonate, hydroxide, and silicate minerals and formation of secondary aluminum and ferric hydroxide phases can moderate the effects of acid generation and enhance the formation of secondary hydrated iron and aluminum minerals which may lessen the concentration of dissolved metals. Numerical models provide powerful tools for assessing impacts of these reactions on water quality.

Following iron speciation in the early stages of magnetite magnetosome biomineralization

DOE PAGES

Firlar, Emre; Perez-Gonzalez, Teresa; Olszewska, Agata; ...

2016-02-26

Understanding magnetosome magnetite biomineralization is of fundamental interest to devising the strategies for bioinspired synthesis of magnetic materials at the nanoscale. Thus, we investigated the early stages of magnetosome formation in this work and correlated the size and emergent crystallinity of magnetosome nanoparticles with the changes in chemical environment of iron and oxygen by utilizing advanced analytical electron microscopy techniques. We observed that magnetosomes in the early stages of biomineralization with the sizes of 5–10 nm were amorphous, with a majority of iron present as Fe 3+, indicative of ferric hydroxide. The magnetosomes with intermediate sizes showed partially crystalline structuremore » with a majority of iron present as Fe 3+ and trace amounts of Fe 2+. The fully maturated magnetosomes were indexed to magnetite. Furthermore, our approach provides spatially resolved structural and chemical information of individual magnetosomes with different particle sizes, attributed to magnetosomes at different stages of biomineralization.« less

Role of iron and aluminum coagulant metal residuals and lead release from drinking water pipe materials.

PubMed

Knowles, Alisha D; Nguyen, Caroline K; Edwards, Marc A; Stoddart, Amina; McIlwain, Brad; Gagnon, Graham A

2015-01-01

Bench-scale experiments investigated the role of iron and aluminum residuals in lead release in a low alkalinity and high (> 0.5) chloride-to-sulfate mass ratio (CSMR) in water. Lead leaching was examined for two lead-bearing plumbing materials, including harvested lead pipe and new lead: tin solder, after exposure to water with simulated aluminum sulfate, polyaluminum chloride and ferric sulfate coagulation treatments with 1-25-μM levels of iron or aluminum residuals in the water. The release of lead from systems with harvested lead pipe was highly correlated with levels of residual aluminum or iron present in samples (R(2) = 0.66-0.88), consistent with sorption of lead onto the aluminum and iron hydroxides during stagnation. The results indicate that aluminum and iron coagulant residuals, at levels complying with recommended guidelines, can sometimes play a significant role in lead mobilization from premise plumbing.

Iron oxide and hydroxide precipitation from ferrous solutions and its relevance to Martian surface mineralogy

NASA Technical Reports Server (NTRS)

Posey-Dowty, J.; Moskowitz, B.; Crerar, D.; Hargraves, R.; Tanenbaum, L.

1986-01-01

Experiments were performed to examine if the ubiquitousness of a weak magnetic component in all Martian surface fines tested with the Viking Landers can be attributed to ferric iron precipitation in aqueous solution under oxidizing conditions at neutral pH. Ferrous solutions were mixed in deionized water and various minerals were added to separate liquid samples. The iron-bearing additives included hematite, goethite, magnetite, maghemite, lepidocrocite and potassium bromide blank at varying concentrations. IR spectroscopic scans were made to identify any precipitates resulting from bubbling oxygen throughout the solutions; the magnetic properties of the precipitates were also examined. The data indicated that the lepidocrocite may have been preferentially precipitated, then aged to maghemite. The process would account for the presumed thin residue of maghemite on the present Martian surface, long after abundant liquid water on the Martian surface vanished.

Fe2O3 hollow sphere nanocomposites for supercapacitor applications

NASA Astrophysics Data System (ADS)

Zhao, Yu; Wen, Yang; Xu, Bing; Lu, Lu; Ren, Reiming

2018-02-01

Nanomaterials have attracted increasing interest in electrochemical energy storage and conversion. Hollow sphere Fe2O3 nanocomposites were successfully prepared through facile low temperature water-bath method with carbon sphere as hard template. The morphology and microstructure of samples were characterized by X-ray diffraction (XRD) and Scanning electron microscope (SEM), respectively. Through hydrolysis mechanism, using ferric chloride direct hydrolysis, iron hydroxide coated on the surface of carbon sphere, after high temperature calcination can form the hollow spherical iron oxide materials. Electrochemical performances of the hollow sphere Fe2O3 nanocomposites electrodes were investigated by cyclic voltammery (CV) and galvanostatic charge/discharge. The Pure hollow sphere Fe2O3 nanocomposites achieves a specific capacitance of 125 F g-1 at the current density of 85 mA g-1. The results indicate that the uniform dispersion of hollow ball structure can effectively reduce the particle reunion in the process of charging and discharging.

Arsenic removal from water employing a combined system: photooxidation and adsorption.

PubMed

Lescano, Maia; Zalazar, Cristina; Brandi, Rodolfo

2015-03-01

A combined system employing photochemical oxidation (UV/H2O2) and adsorption for arsenic removal from water was designed and evaluated. In this work, a bench-scale photochemical annular reactor was developed being connected alternately to a pair of adsorption columns filled with titanium dioxide (TiO2) and granular ferric hydroxide (GFH). The experiences were performed by varying the relation of As concentration (As (III)/As (V) weight ratio) at constant hydrogen peroxide concentration and incident radiation. Experimental oxidation results were compared with theoretical predictions using an intrinsic kinetic model previously obtained. In addition, the effectiveness of the process was evaluated using a groundwater sample. The mathematical model of the entire system was developed. It could be used as an effective tool for the design and prediction of the behaviour of these types of systems. The combined technology is efficient and promising for arsenic removal to small and medium scale.

Modeling of copper sorption onto GFH and design of full-scale GFH adsorbers.

PubMed

Steiner, Michele; Pronk, Wouter; Boller, Markus A

2006-03-01

During rain events, copper wash-off occurring from copper roofs results in environmental hazards. In this study, columns filled with granulated ferric hydroxide (GFH) were used to treat copper-containing roof runoff. It was shown that copper could be removed to a high extent. A model was developed to describe this removal process. The model was based on the Two Region Model (TRM), extended with an additional diffusion zone. The extended model was able to describe the copper removal in long-term experiments (up to 125 days) with variable flow rates reflecting realistic runoff events. The four parameters of the model were estimated based on data gained with specific column experiments according to maximum sensitivity for each parameter. After model validation, the parameter set was used for the design of full-scale adsorbers. These full-scale adsorbers show high removal rates during extended periods of time.

Study on treatment technology of wastewater from hydrolysis of acid oil

NASA Astrophysics Data System (ADS)

Li, Yuejin; Lin, Zhiyong; Han, Yali

2017-06-01

In this paper, the degumming of ferric chloride, calcium hydroxide after the removal of acid acidification hydrolysis of waste oil as raw material, through the treatment process to purify the wastewater. Choose different chemical additives, investigation of different temperature, pH value and other factors, find the best extraction condition. Through the orthogonal test of sodium carbonate, sodium oxalate, barium carbonate, compared with three kinds of chemical additives. The best chemical assistant is sodium carbonate, the best treatment temperature is 80 degrees Celsius, pH value is 8.0. After the reaction, the content of calcium and iron ions were determined by suitable methods. The removal rate of calcium ion is 98%, the removal rate of iron ion is 99%, and the effect of calcium and iron ion precipitation on the subsequent evaporation operation is reduced. Finally, the comparison is made to clarify the Dilute Glycerol water solution.

How rice roots form their surrounding: Distinctive sub-zones of oxides, silicates and organic matter

NASA Astrophysics Data System (ADS)

Koelbl, Angelika; Mueller, Carsten; Hoeschen, Carmen; Lugmeier, Johann; Said-Pullicino, Daniel; Romani, Marco; Koegel-Knabner, Ingrid

2016-04-01

Most of the rice (Oryza sativa) worldwide is grown under flooded conditions in bunded fields (paddies). Inundation during long periods of the year leads to anoxic conditions in the soil. The rice plant is well adapted to these conditions by being able to transport oxygen via aerenchyma from the atmosphere to the roots. This plant mediated O2 transport also influences the adjacent soil. Driven by the O2 leakage into the rhizosphere, reddish ferric oxides and ferric hydroxides precipitate along the root channels. Thus, radial gradients of ferric Fe and with it co-precipitated organic substances form. Detailed investigations of element gradients on a submicron scale within the oxide coatings are still missing. Nano-scale secondary ion mass spectrometry (NanoSIMS) analyses can help to visualize and study the interplay of the various soil components at a submicron scale like, e.g., the attachment of organic material to minerals or the architecture of microstructures. The aim of the present study was to evaluate the composition and size of oxide coatings around rice roots concerning the distribution of organic matter and its spatial relation to oxides and silicates. Samples were taken from the plough pan of a paddy field close to the National Rice Research Centre, Castello d'Agogna (Pavia, Italy). Intact soil aggregates were air-dried, embedded in epoxy resin and then cut and polished in order to obtain a surface with low topography. Reflected-light microscopy was used (mm to μm scale) to visualize the aggregate architecture and to identify root channels in the embedded aggregate. In the next step, scanning electron microscopy (SEM) was applied to obtain images of high resolution and to define distinctive spots for subsequent NanoSIMS analyses. Using the Cameca NanoSIMS 50L at TU München, we simultaneously detected 12C-, 12C14N-, 28Si-, 32S-, 27Al16O- and 56Fe16O- at several areas around root channels in order to distinguish between organic material and different mineral particles (e.g. oxides, clay minerals). Beside single 40 x 40 μm sized spots, mosaics of 20 x 20 μm sized images were combined to investigate the region from the surface of the root channels into the soil matrix. The image data of all detected secondary ions was analysed using line scans and designation of regions of interest (ROI) to evaluate relative occurrences and spatial distributions. The results revealed that the oxic zone around rice roots can be subdivided in distinctive sub-zones. We identified a distinctive zone of approx. 20 μm around the root channels, where exclusively oxide-associated organic matter occurred. This zone can be clearly distinguished from a clay mineral-dominated zone. In addition, oxide-incrusted root cells revealed coexisting regions of Fe (hydr)oxides and Al-organic complexes.

Soil aggregate mediates the impacts of land uses on organic carbon, total nitrogen, and microbial activity in a Karst ecosystem

NASA Astrophysics Data System (ADS)

Xiao, Shuangshuang; Zhang, Wei; Ye, Yingying; Zhao, Jie; Wang, Kelin

2017-02-01

Understanding the effect of land use on soil carbon, nitrogen, and microbial activity associated with aggregates is critical for thorough comprehension of the C and N dynamics of karst landscapes/ecosystems. We monitored soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC), and Cmic: Corg ratio in large macro- (>2 mm), small macro- (0.25-2 mm), and micro- (0.053-0.25 mm) aggregates to determine the changes in soil properties under different land uses in the karst area of Southwest China. Five common land-use types—enclosure land (natural system, control), prescribed-burning land, fuel-wood shrubland, pasture and maize fields—were selected. Results showed that pasture and maize fields remarkably decreased the SOC and TN concentrations in aggregates. Conversion of natural system to other land uses decreased MBC (except for prescribed-burning) and increased Cmic: Corg ratios in aggregates. The extent of the response to land uses of SOC and TN concentrations was similar whereas that of MBC and Cmic: Corg ratios differed across the three aggregate sizes. Further, the SOC concentrations were significantly higher in macro-aggregates than micro-aggregates; the MBC and Cmic: Corg ratios were highest in small macro-aggregates. Therefore, small macro-aggregates might have more active C dynamics.

Deep horizons: Soil Carbon sequestration and storage potential in grassland soils

NASA Astrophysics Data System (ADS)

Torres-Sallan, Gemma; Schulte, Rogier; Lanigan, Gary J.; Byrne, Kenneth A.; Reidy, Brian; Creamer, Rachel

2016-04-01

Soil Organic Carbon (SOC) enhances soil fertility, holding nutrients in a plant-available form. It also improves aeration and water infiltration. Soils are considered a vital pool for C (Carbon) sequestration, as they are the largest pool of C after the oceans, and contain 3.5 more C than the atmosphere. SOC models and inventories tend to focus on the top 30 cm of soils, only analysing total SOC values. Association of C with microaggregates (53-250 μm) and silt and clay (<53 μm) is considered C sequestration as these fractions offer the greatest protection against mineralization. This study assessed the role of aggregation in C sequestration throughout the profile, down to 1 m depth, of 30 grassland sites divided in 6 soil types. One kg sample was collected for each horizon, sieved at 8 mm and dried at 40 °C. Through a wet sieving procedure, four aggregate sizes were isolated: large macroaggregates (>2000 μm); macroaggregates (250-2000 μm); microaggregates and silt & clay. Organic C associated to each aggregate fraction was analysed on a LECO combustion analyser. Sand-free C was calculated for each aggregate size. For all soil types, 84% of the SOC located in the first 30 cm was contained inside macroaggregates and large macroaggregates. Given that this fraction has a turnover time of 1 to 10 years, sampling at that depth only provides information on the labile fraction in soil, and does not consider the longer term C sequestration potential. Only when looking at the whole profile, two clear trends could be observed: 1) soils with a clay increase at depth had most of their C located in the silt and clay fractions, which indicate their enhanced C sequestration capacity, 2) free-draining soils had a bigger part of their SOC located in the macroaggregate fractions. These results indicate that current C inventories and models that focus on the top 30 cm, do not accurately measure soil C sequestration potential in soils, but rather the more labile fraction. However, at depth soil forming processes have been identified as a major factor influencing C sequestration potential in soils. This has a major impact in further quantifying and sustaining C sequestration into the future. Soils with a high sequestration potential at depth need to be managed to enhance the residence time to contribute to future off-setting of greenhouse gas emissions.

Antioxidant and cytoprotective activities of Piper betle, Areca catechu, Uncaria gambir and betel quid with and without calcium hydroxide

PubMed Central

2013-01-01

Background Betel quid chewing is a popular habit in Southeast Asia. It is believed that chewing betel quid could reduce stress, strengthen teeth and maintain oral hygiene. The aim of this study was to investigate the antioxidant and cytoprotective activities of each of the ingredients of betel quid and compared with betel quid itself (with and without calcium hydroxide). The correlation of their cytoprotective and antioxidant activities with phenolic content was also determined. Methods Five samples (betel leaf, areca nut, gambir, betel quid and betel quid containing calcium hydroxide) were extracted in deionized distilled water for 12 hours at 37°C. Antioxidant activities were evaluated for radical scavenging activity using DPPH assay, ferric reducing activity using FRAP assay and lipid peroxidation inhibition activity using FTC assay. Total phenolic content (TPC) was determined using Folin-Ciocalteu procedure. Phenolic composition was analyzed using LC-MS/MS. Cytoprotective activity towards human gingival fibroblast cells was examined using MTT assay. Results Among the ingredients of betel quid, gambir demonstrated the highest antioxidant (DPPH - IC50 = 6.4 ± 0.8 μg/mL, FRAP - 5717.8 ± 537.6 μmol Fe(II)/mg), total phenolic content (TPC - 1142.5 ± 106.8 μg TAE/mg) and cytoprotective (100.1 ± 4.6%) activities. Betel quid when compared with betel quid containing calcium hydroxide has higher antioxidant (DPPH - IC50 =59.4 ± 4.4 μg/mL, FRAP - 1022.2 ± 235.7 μmol Fe(II)/mg), total phenolic content (TPC - 140.0 ± 22.3 μg TAE/mg), and cytoprotective (113.5 ± 15.9%) activities. However, all of the five samples showed good lipid peroxidation inhibition compared to vitamin E. LC-MS/MS analysis revealed the presence of quinic acid as the major compound of gambir and betel quid. A positive correlation was observed between TPC and radical scavenging (r = 0.972), reducing power (r = 0.981) and cytoprotective activity (r = 0.682). Conclusions The betel quid has higher TPC, and antioxidant and cytoprotective activities than betel quid with calcium hydroxide. The quinic acid in betel quid may play an important role in the oral health protection. PMID:24330738

Mobilization of arsenite by dissimilatory reduction of adsorbed arsenate

USGS Publications Warehouse

Zobrist, J.; Dowdle, P.R.; Davis, J.A.; Oremland, R.S.

2000-01-01

Sulfurospirillum barnesii is capable of anaerobic growth using ferric iron or arsenate as electron acceptors. Cell suspensions of S. barnesii were able to reduce arsenate to arsenite when the former oxyanion was dissolved in solution, or when it was adsorbed onto the surface of ferrihydrite, a common soil mineral, by a variety of mechanisms (e.g., coprecipitation, presorption). Reduction of Fe(III) in ferrihydrite to soluble Fe(II) also occurred, but dissolution of ferrihydrite was not required in order for adsorbed arsenate reduction to be achieved. This was illustrated by bacterial reduction of arsenate coprecipitated with aluminum hydroxide, a mineral that does not undergo reductive dissolution. The rate of arsenate reduction was influenced by the method in which arsenate became associated with the mineral phases and may have been strongly coupled with arsenate desorption rates. The extent of release of arsenite into solution was governed by adsorption of arsenite onto the ferrihydrite or alumina phases. The results of these experiments have interpretive significance to the mobilization of arsenic in large alluvial aquifers, such as those of the Ganges in India and Bangladesh, and in the hyporheic zones of contaminated streams.Sulfurospirillum barnesii is capable of anaerobic growth using ferric iron or arsenate as electron acceptors. Cell suspensions of S. barnesii were able to reduce arsenate to arsenite when the former oxyanion was dissolved in solution, or when it was adsorbed onto the surface of ferrihydrite a common soil mineral, by a variety of mechanisms (e.g., coprecipitation, presorption). Reduction of Fe(III) in ferrihydrite to soluble Fe(II) also occurred, but dissolution of ferrihydrite was not required in order for adsorbed arsenate reduction to be achieved. This was illustrated by bacterial reduction of arsenate coprecipitated with aluminum hydroxide, a mineral that does not undergo reductive dissolution. The rate of arsenate reduction was influenced by the method in which arsenate became associated with the mineral phases and may have been strongly coupled with arsenate desorption rates. The extent of release of arsenite into solution was governed by adsorption of arsenite onto the ferrihydrite or alumina phases. The results of these experiments have interpretive significance to the mobilization of arsenic in large alluvial aquifers, such as those of the Ganges in India and Bangladesh, and in the hyporheic zones of contaminated streams.

Local Structure of Sb in Cretaceous-Tertiary Boundary Clays from Stevns Klint By the XAFS Method

NASA Astrophysics Data System (ADS)

Hongu, H.; Yoshiasa, A.; Tobase, T.; Hiratoko, T.; Isobe, H.; Arima, H.; Sugiyama, K.; Okube, M.

2014-12-01

The Cretaceous-Tertiary (K-T) mass extinctions has been thought to be due to the asteroid impact since Ir anomalies was found by Alvarez et al. (1980) . The boundary clay is also enriched in Cr, Co, Ni, Cu, Zn, As and Sb. Especially concentrations of Sb and As are unusually large. However, the origins and concentration processes of Sb are unknown. In this study, local structure around antimony atoms in K-T boundary clay from Stevns Klint, Denmark, was determined by Sb K-edge XAFS spectroscopy. The XAFS analyses give the information about the chemical state and coordination environment around Sb atoms and help identify of the concentration phase, and also may provide various kinds of information about the asteroid impact and mass extinction. The XAFS measurements were performed at the BL-NW10A beamline at the Photon Factory in KEK, Tsukuba, Japan. The XANES spectra and radial structure function (RSF) showed that Sb in K-T boundary clays is high oxidation state Sb5+ and occupies a SbO6 octahedral site. The Sb-O interatomic distance in K-T clay sample is 2.08(1) A. It is known that Sb5+ is stable form in soil and soil water under an equilibrium situation within the Earth's surface environment. Antimony belongs to group 15 in the periodic table below arsenic, and the chemical behavior of Sb5+ is similar to that of As5+. Because there is a close correlation on co-precipitation between As and Fe (Ebihara and Miura, 1996; Sakai et al., 2007) , it is considered that Sb also correlates closely with Fe compounds (e.g., ferric hydroxides). Abundant ferric hydroxides occur in K-T boundary clays. It is considered that one of the reasons of abnormal high concentrations of Sb and As in K-T boundary clays is a lot of dust from impact ejecta falls with iron ions and deposits on surface of the Earth for a short period of time after the asteroid impact. ReferencesL. W. Alvarez, Science, 208, 1095-1108 (1980) M. Ebihara and T. Miura, Geochimica et Cosmochimica Acta, 60, 5133-5144 (1996) S. Sakai et al., The American Institute of Physics, Conference Proceeding, 882, 274-276 (2007)

Aggregate-scale heterogeneity in iron (hydr)oxide reductive transformations

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

Tufano, K.J.; Benner, S.G.; Mayer, K.U.

There is growing awareness of the complexity of potential reaction pathways and the associated solid-phase transformations during the reduction of Fe (hydr)oxides, especially ferrihydrite. An important observation in static and advective-dominated systems is that microbially produced Fe(II) accelerates Ostwald ripening of ferrihydrite, thus promoting the formation of thermodynamically more stable ferric phases (lepidocrocite and goethite) and, at higher Fe(II) surface loadings, the precipitation of magnetite; high Fe(II) levels can also lead to green rust formation, and with high carbonate levels siderite may also be formed. This study expands this emerging conceptual model to a diffusion-dominated system that mimics an idealizedmore » micropore of a ferrihydrite-coated soil aggregate undergoing reduction. Using a novel diffusion cell, coupled with micro-x-ray fluorescence and absorption spectroscopies, we determined that diffusion-controlled gradients in Fe{sup 2+}{sub (aq)} result in a complex array of spatially distributed secondary mineral phases. At the diffusive pore entrance, where Fe{sup 2+} concentrations are highest, green rust and magnetite are the dominant secondary Fe (hydr)oxides (30 mol% Fe each). At intermediate distances from the inlet, green rust is not observed and the proportion of magnetite decreases from approximately 30 to <10%. Across this same transect, the proportion of goethite increases from undetectable up to >50%. At greater distances from the advective-diffusive boundary, goethite is the dominant phase, comprising between 40 and 95% of the Fe. In the presence of magnetite, lepidocrocite forms as a transient-intermediate phase during ferrihydrite-to-goethite conversion; in the absence of magnetite, conversion to goethite is more limited. These experimental observations, coupled with results of reactive transport modeling, confirm the conceptual model and illustrate the potential importance of diffusion-generated concentration gradients in dissolved Fe{sup 2+} on the fate of ferrihydrite during reduction in structured soils.« less

Aluminium substitution in iron(II-III)-layered double hydroxides: Formation and cationic order

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

Ruby, Christian; Abdelmoula, Mustapha; Aissa, Rabha

The formation and the modifications of the structural properties of an aluminium-substituted iron(II-III)-layered double hydroxide (LDH) of formula Fe{sub 4}{sup II}Fe{sub (2-6y)}{sup III}Al{sub 6y}{sup III} (OH){sub 12} SO{sub 4}, 8H{sub 2}O are followed by pH titration curves, Moessbauer spectroscopy and high-resolution X-ray powder diffraction using synchrotron radiation. Rietveld refinements allow to build a structural model for hydroxysulphate green rust, GR(SO{sub 4}{sup 2-}), i.e. y=0, in which a bilayer of sulphate anions points to the Fe{sup 3+} species. A cationic order is proposed to occur in both GR(SO{sub 4}{sup 2-}) and aluminium-substituted hydroxysulphate green rust when y<0.08. Variation of the cellmore » parameters and a sharp decrease in average crystal size and anisotropy are detected for an aluminium content as low as y=0.01. The formation of Al-GR(SO{sub 4}{sup 2-}) is preceded by the successive precipitation of Fe{sup III} and Al{sup III} (oxy)hydroxides. Adsorption of more soluble Al{sup III} species onto the initially formed ferric oxyhydroxide may be responsible for this slowdown of crystal growth. Therefore, the insertion of low aluminium amount (y{approx}0.01) could be an interesting way for increasing the surface reactivity of iron(II-III) LDH that maintains constant the quantity of the reactive Fe{sup II} species of the material. - Graphical abstract: (a) Crystallographical structure of sulphated green rust: SO{sub 4}{sup 2-} point to the Fe{sup 3+} cations (red) that form an ordered array with the Fe{sup 2+} cations (green). (b) Width and asymmetry of the synchrotron XRD peaks increase rapidly when some Al{sup 3+} species substitute the Fe{sup 3+} cations; z is molar ratio Al{sup 3+}/Fe{sup 3+}.« less

Corrosion fatigue crack growth behavior of titanium alloys in aqueous solutions

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

Shipilov, S.A.

1998-01-01

The corrosion fatigue crack growth (FCG) behavior, the effect of applied potential on corrosion FCG rates, and the fracture surfaces of VT20 (near-{alpha}) and TS6 (near-{beta}) titanium alloys were studied. Environments were aqueous solutions of sodium chloride (NaCl), sodium hydroxide (NaOH), potassium hydroxide (KOH), ferric chloride (FeCl{sub 3}), and chromic acid (H{sub 2}CrO{sub 4}) with and without NaCl. Depending upon solution composition, corrosion FCG rates were found to be higher or lower than those in air. Cathodic polarization retarded the corrosion FCG, while anodic polarization accelerated insignificantly or almost did not influence it in most of the solutions investigated. However,more » cathodic polarization accelerated corrosion FCG in 0.6 M FeCl{sub 3} and 0.5 M to 2 M H{sub 2}CrO{sub 4} + 0.01 M to 0.1 M NaCl solutions by a dozen times when the maximum stress intensity (K{sub max}) exceeded certain critical values. When K{sub max} was lower than the critical values, the same cathodic polarization (with all other /conditions being equal) retarded corrosion FCG. Results suggested the accelerated crack growth at cathodic potentials resulted from hydrogen-induced cracking (HIC). Therefore, critical values of K{sub max}, as well as the stress intensity range ({Delta}K) were regarded as corresponding to the beginning of corrosion FCG according to a HIC mechanism and designated as K{sub HIC} and {Delta}K{sub HIC}.« less

Structural stability of coprecipitated natural organic matter and ferric iron under reducing conditions

USGS Publications Warehouse

Henneberry, Yumiko K.; Kraus, Tamara E.C.; Nico, Peter S.; Horwath, William R.

2012-01-01

The objective was to assess the interaction of Fe coprecipitated with dissolved organic matter (DOM) and its effect on Fe (hydr)oxide crystallinity and DOM retention under abiotic reducing conditions. A Fe-based coagulant was reacted with DOM from an agricultural drain and the resulting precipitate (floc) was exposed to S(-II) and Fe(II). Solution concentrations of Fe(II/III) and DOM were monitored, floc crystallinity was determined using X-ray diffraction, and the composition and distribution of functional groups were assessed using scanning transmission X-ray microscopy (STXM) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Results indicate coprecipitation of Fe(III) with DOM forms a non-crystalline floc that withstands crystallization regardless of change in pH, Fe:DOM ratio and type of reductant added. There was no evidence that exposure to reducing conditions led to release of DOM from the floc, indicating that coprecipitation with complex natural DOM in aquatic environments may stabilize Fe (hydr)oxides against crystallization upon reaction with reduced species and lead to long term sequestration of the DOM. STXM analysis identified spatially distinct regions with remarkable functional group purity, contrary to the model of DOM as a relatively uniform complex polymer lacking identifiable organic compounds. Polysaccharide-like OM was strongly and directly correlated with the presence of Fe but showed different Fe binding strength depending on the presence of carboxylic acid functional groups, whereas amide and aromatic functional groups were inversely correlated with Fe content.

Microbial exudate promoted dissolution and transformation of chromium containing minerals

NASA Astrophysics Data System (ADS)

Saad, E. M.; Sun, J.; Tang, Y.

2015-12-01

Because of its utility in many industrial processes, chromium has become the second most common metal contaminant in the United States. The two most common oxidation states of chromium in nature are Cr(III), which is highly immobile, and Cr(VI), which is highly mobile and toxic. In both natural and engineered environments, the most common remediation of Cr(VI) is through reduction, which results in chromium sequestration in the low solubility mixed Cr(III)-Fe(III) (oxy)hydroxide phases. Consequently, the stability of these minerals must be examined to assess the fate of chromium in the subsurface. We examined the dissolution of mixed Cr(III)-Fe(III) (oxy)hydroxides in the presence of common microbial exudates, including the siderophore desferrioxamine B (DFOB; a common organic ligand secreted by most microbes with high affinity for ferric iron and other trivalent metal ions) and oxalate (a common organic acid produced by microbes). The solids exhibited incongruent dissolution with preferential leaching of Fe from the solid phase. Over time, this leads to a more Cr rich mineral, which is known to be more soluble than the corresponding mixed mineral phase. We are currently investigating the structure of the reacted mineral phases and soluble Cr(III) species, as well as the potential oxidation and remobilization of the soluble Cr species. Results from this study will provide insights regarding the long term transport and fate of chromium in the natural environment in the presence of microbial activities.

Long-term manure amendments reduced soil aggregate stability via redistribution of the glomalin-related soil protein in macroaggregates

PubMed Central

Xie, Hongtu; Li, Jianwei; Zhang, Bin; Wang, Lianfeng; Wang, Jingkuan; He, Hongbo; Zhang, Xudong

2015-01-01

Glomalin-related soil protein (GRSP) contributes to the formation and maintenance of soil aggregates, it is however remains unclear whether long-term intensive manure amendments alter soil aggregates stability and whether GRSP regulates these changes. Based on a three-decade long fertilization experiment in northeast China, this study examined the impact of long-term manure input on soil organic carbon (SOC), total and easily extractable GRSP (GRSPt and GRSPe) and their respective allocations in four soil aggregates (>2000 μm; 2000–250 μm; 250–53 μm; and <53 μm). The treatments include no fertilization (CK), low and high manure amendment (M1, M2), chemical nitrogen, phosphorus and potassium fertilizers (NPK), and combined manure and chemical fertilizers (NPKM1, NPKM2). Though SOC, GRSPe and GRSPt in soil and SOC in each aggregate generally increased with increasing manure input, GRSPt and GRSPe in each aggregate showed varying changes with manure input. Both GRSP in macroaggregates (2000–250 μm) were significantly higher under low manure input, a pattern consistent with changes in soil aggregate stability. Constituting 38~49% of soil mass, macroaggregates likely contributed to the nonlinear changes of aggregate stability under manure amendments. The regulatory process of GRSP allocations in soil aggregates has important implications for manure management under intensive agriculture. PMID:26423355

Physical soil architectural traits are functionally linked to carbon decomposition and bacterial diversity.

PubMed

Rabbi, S M F; Daniel, H; Lockwood, P V; Macdonald, C; Pereg, L; Tighe, M; Wilson, B R; Young, I M

2016-09-12

Aggregates play a key role in protecting soil organic carbon (SOC) from microbial decomposition. The objectives of this study were to investigate the influence of pore geometry on the organic carbon decomposition rate and bacterial diversity in both macro- (250-2000 μm) and micro-aggregates (53-250 μm) using field samples. Four sites of contrasting land use on Alfisols (i.e. native pasture, crop/pasture rotation, woodland) were investigated. 3D Pore geometry of the micro-aggregates and macro-aggregates were examined by X-ray computed tomography (μCT). The occluded particulate organic carbon (oPOC) of aggregates was measured by size and density fractionation methods. Micro-aggregates had 54% less μCT observed porosity but 64% more oPOC compared with macro-aggregates. In addition, the pore connectivity in micro-aggregates was lower than macro-aggregates. Despite both lower μCT observed porosity and pore connectivity in micro-aggregates, the organic carbon decomposition rate constant (Ksoc) was similar in both aggregate size ranges. Structural equation modelling showed a strong positive relationship of the concentration of oPOC with bacterial diversity in aggregates. We use these findings to propose a conceptual model that illustrates the dynamic links between substrate, bacterial diversity, and pore geometry that suggests a structural explanation for differences in bacterial diversity across aggregate sizes.

Physical soil architectural traits are functionally linked to carbon decomposition and bacterial diversity

PubMed Central

Rabbi, S. M. F.; Daniel, H.; Lockwood, P. V.; Macdonald, C.; Pereg, L.; Tighe, M.; Wilson, B. R.; Young, I. M.

2016-01-01

Aggregates play a key role in protecting soil organic carbon (SOC) from microbial decomposition. The objectives of this study were to investigate the influence of pore geometry on the organic carbon decomposition rate and bacterial diversity in both macro- (250–2000 μm) and micro-aggregates (53–250 μm) using field samples. Four sites of contrasting land use on Alfisols (i.e. native pasture, crop/pasture rotation, woodland) were investigated. 3D Pore geometry of the micro-aggregates and macro-aggregates were examined by X-ray computed tomography (μCT). The occluded particulate organic carbon (oPOC) of aggregates was measured by size and density fractionation methods. Micro-aggregates had 54% less μCT observed porosity but 64% more oPOC compared with macro-aggregates. In addition, the pore connectivity in micro-aggregates was lower than macro-aggregates. Despite both lower μCT observed porosity and pore connectivity in micro-aggregates, the organic carbon decomposition rate constant (Ksoc) was similar in both aggregate size ranges. Structural equation modelling showed a strong positive relationship of the concentration of oPOC with bacterial diversity in aggregates. We use these findings to propose a conceptual model that illustrates the dynamic links between substrate, bacterial diversity, and pore geometry that suggests a structural explanation for differences in bacterial diversity across aggregate sizes. PMID:27615807

Soil aggregate mediates the impacts of land uses on organic carbon, total nitrogen, and microbial activity in a Karst ecosystem

PubMed Central

Xiao, Shuangshuang; Zhang, Wei; Ye, Yingying; Zhao, Jie; Wang, Kelin

2017-01-01

Understanding the effect of land use on soil carbon, nitrogen, and microbial activity associated with aggregates is critical for thorough comprehension of the C and N dynamics of karst landscapes/ecosystems. We monitored soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC), and Cmic: Corg ratio in large macro- (>2 mm), small macro- (0.25–2 mm), and micro- (0.053–0.25 mm) aggregates to determine the changes in soil properties under different land uses in the karst area of Southwest China. Five common land-use types—enclosure land (natural system, control), prescribed-burning land, fuel-wood shrubland, pasture and maize fields—were selected. Results showed that pasture and maize fields remarkably decreased the SOC and TN concentrations in aggregates. Conversion of natural system to other land uses decreased MBC (except for prescribed-burning) and increased Cmic: Corg ratios in aggregates. The extent of the response to land uses of SOC and TN concentrations was similar whereas that of MBC and Cmic: Corg ratios differed across the three aggregate sizes. Further, the SOC concentrations were significantly higher in macro-aggregates than micro-aggregates; the MBC and Cmic: Corg ratios were highest in small macro-aggregates. Therefore, small macro-aggregates might have more active C dynamics. PMID:28211507

Removal of inorganic mercury and methylmercury from surface waters following coagulation of dissolved organic matter with metal-based salts

USGS Publications Warehouse

Henneberry, Y.K.; Kraus, T.E.C.; Fleck, J.A.; Krabbenhoft, D.P.; Bachand, P.M.; Horwath, W.R.

2011-01-01

The presence of inorganic mercury (IHg) and methylmercury (MeHg) in surface waters is a health concern worldwide. This study assessed the removal potential use of metal-based coagulants as a means to remove both dissolved IHg and MeHg from natural waters and provides information regarding the importance of Hg associations with the dissolved organic matter (DOM) fraction and metal hydroxides. Previous research indicated coagulants were not effective at removing Hg from solution; however these studies used high concentrations of Hg and did not reflect naturally occurring concentrations of Hg. In this study, water collected from an agricultural drain in the Sacramento-San Joaquin Delta was filtered to isolate the dissolved organic matter (DOM) fraction. The DOM was then treated with a range of coagulant doses to determine the efficacy of removing all forms of Hg from solution. Three industrial-grade coagulants were tested: ferric chloride, ferric sulfate, and polyaluminum chloride. Coagulation removed up to 85% of DOM from solution. In the absence of DOM, all three coagulants released IHg into solution, however in the presence of DOM the coagulants removed up to 97% of IHg and 80% of MeHg. Results suggest that the removal of Hg is mediated by DOM-coagulant interactions. There was a preferential association of IHg with the more aromatic, higher molecular weight fraction of DOM but no such relationship was found for MeHg. This study offers new fundamental insights regarding large-scale removal of Hg at environmentally relevant regarding large-scale removal of Hg at environmentally relevant concentrations.

Mechanisms of interaction between arsenian pyrite and aqueous arsenite under anoxic and oxic conditions

NASA Astrophysics Data System (ADS)

Qiu, Guohong; Gao, Tianyu; Hong, Jun; Luo, Yao; Liu, Lihu; Tan, Wenfeng; Liu, Fan

2018-05-01

Pyrite affects the conversion and migration processes of arsenic in soils and waters. Adsorption and redox reactions of arsenite (As(III)) occur on the surface of pyrite, and the interaction processes are influenced by the arsenic incorporated into pyrite. This work examined the effects of arsenic content, pH and oxygen on the interaction between arsenian pyrite and aqueous As(III) and investigated the underlying mechanisms. The results indicated that arsenic incorporation led to a high content of Fe(III) in pyrite, and that As(III) was mainly adsorbed on pyrite surface and part of As(III) was oxidized to As(V) by the newly formed intermediates including hydroxyl radicals and hydrogen peroxide. The oxidation rate increased with increasing arsenic content in the pyrite and the presence of air (oxygen), and first decreased and then increased with increasing pH from 3.0 to 11.0. Hydroxyl radicals and hydrogen peroxide significantly contributed to the oxidation of pyrite and aqueous As(III) in acidic and alkaline solutions, respectively. Although pyrite oxidation increased with increasing arsenic content as indicated by the elevated concentrations of elemental S and SO42-, the percentage of released arsenic in total arsenic of the arsenian pyrite decreased due to the adsorption of arsenic on the surface of newly formed ferric (hydr)oxides, especially the ferric arsenate precipitate formed in high pH solutions. The present study enables a better understanding of the important interaction process of dissolved arsenite and natural pyrites in the study of groundwater contamination, arsenic migration/sequestration, and acid mine drainage formation.

Influence of humic acid on the removal of arsenate and arsenic by ferric chloride: effects of pH, As/Fe ratio, initial As concentration, and co-existing solutes.

PubMed

Kong, Yanli; Kang, Jing; Shen, Jimin; Chen, Zhonglin; Fan, Leitao

2017-01-01

The influence of humic acid (HA) on the removal of arsenic by FeCl 3 was systematically studied in this paper. Jar tests were performed to investigate the influence on arsenic during FeCl 3 coagulation of the pH adjusting method, the initial As/Fe ratio, the equilibrium As concentration, and co-occurring anions and cations. Compared with results in HA-free systems, the removal trends of arsenic in HA solutions were quite different. It was found that As(V) removal was higher at low equilibrium concentration, yet the opposite was true for As(III) removal. The presence of HA influenced the effective number of active sites for arsenic removal by FeCl 3 flocculation. In addition, in the presence of HA, the impacts of co-existing solutions on arsenic removal were also different from that of an HA-free system. This study examined the influence of co-occurring anions, such as phosphate, sulfate, and silicate on arsenic removal, depending on their ability to compete for sorption sites and to hinder or facilitate the aggregation of ferric hydroxide flocs. The presence of Ca 2+ or Cd 2+ significantly increased arsenic removal at higher pH. Low concentrations of dissolved HA and high concentrations of colloid affected the adsorption of arsenic onto iron oxide. The influence of HA on the adsorption of arsenic onto iron oxide primarily depended on the relative content of the dissolved and mineral combination states of HA and the interface combination forms.

[Impact of Land Utilization Pattern on Distributing Characters of Labile Organic Carbon in Soil Aggregates in Jinyun Mountain].

PubMed

Li, Rui; Jiang, Chang-sheng; Hao, Qing-ju

2015-09-01

Four land utilization patterns were selected for this study in Jinyun mountain, including subtropical evergreen broad-leaved forest (abbreviation: forest), sloping farmland, orchard and abandoned land. Soil samples were taken every 10 cm in the depth of 60 cm soil and proportions of large macroaggregates (> 2 mm), small macroaggregates (0. 25-2 mm), microaggregates (0. 053 - 0. 25 mm) and silt + clay (<0. 053 mm) were obtained by wet sieving method to measure the content of organic carbon and labile organic carbon in each aggregate fraction and analyze impacts of land uses on organic carbon and labile organic carbon of soil aggregates. LOC content of four soil aggregates were significantly reduced with the increase of soil depth; in layers of 0-60 cm soil depth, our results showed that LOC contents of forest and abandoned land were higher than orchard and sloping farmland. Reserves of labile organic carbon were estimated by the same soil quality, it revealed that forest (3. 68 Mg.hm-2) > abandoned land (1. 73 Mg.hm-2) > orchard (1. 43 Mg.hm-2) >sloping farmland (0.54 Mg.hm-2) in large macroaggregates, abandoned land (7.77, 5. 01 Mg.hm-2) > forest (4. 96, 2.71 Mg.hm-2) > orchard (3. 33, 21. 10 Mg.hm-2) > sloping farmland (1. 68, 1. 35 Mg.hm-2) in small macroaggregates and microaggregates, and abandoned land(4. 32 Mg.hm-2) > orchard(4. 00 Mg.hm-2) > forest(3. 22 Mg.hm-2) > sloping farmland (2.37 Mg.hm-2) in silt + clay, forest and abandoned land were higher than orchard and sloping farmland in other three soil aggregates except silt + clay. It was observed that the level of organic carbon and labile organic carbon were decreased when bringing forest under cultivation to orchard or farmland, and augments on organic carbon and labile organic carbon were found after exchanging farmland to abandoned land. The most reverses of forest and abandoned land emerged in small macroaggregates, orchard and sloping farmland were in microaggregates. That was, during the transformations of land utilization pattern, soil aggregates with bigger size were easier to accumulate or lose labile organic carbon. Allocation ratios of labile organic carbon to soil organic carbon under four land uses were decreased as the soil depth added. Allocation ratios of orchard and sloping farmland were a bit higher than forest and abandoned land, which indicated that organic carbon of forest and abandoned land were more steady and available for soil as a carbon sink, meanwhile, the forest and abandoned land would avoid more CO2 diffusing to the atmosphere from the decomposition of soil organic carbon.

Electron-paramagnetic-resonance studies of leghaemoglobins from soya-bean and cowpea root nodules. Identification of nitrosyl-leghaemoglobin in crude leghaemoglobin preparations

PubMed Central

Maskall, C. Sidney; Gibson, John F.; Dart, Peter J.

1977-01-01

1. Leghaemoglobins from soya-bean (Glycine max) and cowpea (Vigna unguiculata) root nodules were purified by chromatography on DEAE-cellulose phosphate columns at pH8.0 and pH5.8, to avoid the relatively low pH (5.2) commonly used to purify these proteins. 2. E.p.r. (electron-paramagnetic-resonance) spectra of the fluoride, azide, hydroxide and cyanide complexes of these ferric leghaemoglobins were very similar to the spectra of the corresponding myoglobin derivatives, indicating that the immediate environment of the iron in leghaemoglobin and myoglobin is similar, an imidazole moiety of histidine being the proximal ligand to the haem iron [cf. Appleby, Blumberg, Peisach, Wittenberg & Wittenberg (1976) J. Biol. Chem. 251, 6090–6096]. 3. E.p.r. spectra of the acid-metleghaemoglobins showed prominent high-spin features very near g=6 and g=2 and, unlike myoglobin, small low-spin absorptions near g=2.26, 2.72 and 3.14. The width of the g=6 absorption derivative at 10–20K was about 4–4.5mT, similar to the value for acid-methaemoglobin. In contrast, a recently published (Appleby et al., 1976) spectrum of acid-metleghaemoglobin a had less high-spin character and a much broader absorption derivative around g=6. 4. E.p.r. spectra of ferric leghaemoglobin nicotinate and imidazole complexes suggest that the low-spin absorption near g=3.14 can be attributed to a trace of ferric leghaemoglobin nicotinate, and those near g=2.26 and 2.72 are from an endogenous dihistidyl haemichrome. 5. A large e.p.r. signal at g=2 in all samples of crude leghaemoglobin was shown to be from nitrosyl-leghaemoglobin. A soya-bean sample contained 27±3% of the latter. A previously unidentified form of soya-bean ferrous leghaemoglobin a was shown to be its nitrosyl derivative. If this is not an artifact, and occurs in the root nodule, the nitrosyl radical may interfere with the function of leghaemoglobin. PMID:23110

Assessing the Potential for Ancient Habitable Environments in Gusev Crater, Mars

NASA Astrophysics Data System (ADS)

Des Marais, D. J.; Athena Science Team

2007-12-01

In order to be habitable for microbial life as we know it, an environment must provide nutrient elements, energy and liquid water. We assess the potential for habitable environments in the areas explored by the MER rover Spirit. These areas include the basaltic plains near Columbia Memorial Station, West Spur, Husband Hill, and the inner basin south of Husband Hill. Little aqueous activity apparently occurred in Gusev crater since the basaltic plains were emplaced in Hesperian times, therefore the basaltic plains were highly unlikely to have sustained habitable environments. The Columbia Hills, located ~3 km southeast of the landing site, are older than the surrounding basaltic plains. Aqueous processes have extensively altered bedrock in the Columbia Hills. Ferrous iron in the original, unaltered parent rock of hills materials has typically been oxidized extensively to form ferric oxides, hydroxides, and other ferric minerals. Migrating fluids have removed Ca and other cations, allowing residual Al to become relatively more abundant, and fluids added sulfates and chlorides. In subsurface environments on Earth, microorganisms can obtain key nutrients from the weathering of basalts. Materials examined in the Columbia Hills have comparable or greater abundances of these elements than do MORB. Wishstone rock and Watchtower outcrop have very high contents of phosphorous. Chemoautotrophs ("chemical- feeders" that obtain energy from inorganic chemicals) can thrive in subsurface environments. Mixing oxidized constituents from surface environments with generally more reduced constituents from subsurface rocks and thermal emanations provides energy to sustain microorganisms. Ferrous iron in parent materials in the Columbia Hills has been oxidized to form a variety of ferric minerals. On Earth, microbial processes have been documented to contribute to the production of goethite, hematite and other iron oxides. Observations by Spirit are consistent with the possibility that liquid water, nutrients and sources of chemical energy were simultaneously available to sustain habitable conditions in subsurface Columbia Hills materials at least some time in the distant (Noachian?) past. There is as yet no evidence that these conditions ever existed at the surface. Future research must seek to determine whether ancient migrating fluids in Gusev ever achieved the water activity necessary to sustain life.

AggModel: A soil organic matter model with measurable pools for use in incubation studies

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

Segoli, Moran; De Gryze, S.; Dou, Fugen

2013-01-01

Current soil organic matter (SOM) models are empirical in nature by employing few conceptual SOM pools that have a specific turnover time, but that are not measurable and have no direct relationship with soil structural properties. Most soil particles are held together in aggregates and the number, size and stability of these aggregates significantly affect the size and amount of organic matter contained in these aggregates, and its susceptibility to decomposition. While it has been shown that soil aggregates and their dynamics can be measured directly in the laboratory and in the field, the impact of soil aggregate dynamics onmore » SOM decomposition has not been explicitly incorporated in ecosystem models. Here, we present AggModel, a conceptual and simulation model that integrates soil aggregate and SOM dynamics. In AggModel, we consider unaggregated and microaggregated soil that can exist within or external to macroaggregated soil. Each of the four aggregate size classes contains particulate organic matter and mineral-associated organic matter fractions. We used published data from laboratory incubations to calibrate and validate the biological and environmental effects on the rate of formation and breakdown of macroaggregates and microaggregates, and the organic matter dynamics within these different aggregate fractions. After calibration, AggModel explained more than 70% of the variation in aggregate masses and over 90% of the variation in aggregate-associated carbon. The model estimated the turnover time of macroaggregates as 32 days and 166 days for microaggregates. Sensitivity analysis of AggModel parameterization supported the notion that macroaggregate turnover rate has a strong control over microaggregate masses and, hence, carbon sequestration. In addition to AggModel being a proof-of-concept, the advantage of a model that is based on measurable SOM fractions is that its internal structure and dynamics can be directly calibrated and validated by using experimental data. In conclusion, AggModel successfully incorporates the explicit representation for the turnover of soil aggregates and their influence on SOM dynamics and can form the basis for new SOM modules within existing ecosystem models.« less

Gastric air contrast: useful adjunct to hepatic artery scintigraphy

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

Wahl, R.L.; Ziessman, H.A.; Juni, J.

The utility of scintigraphic views obtained after administration of sodium bicarbonate-citric acid-simethicone crystals (E-Z-GAS) for the determination of gastric extrahepatic perfusion was evaluated in 20 technetium-99m macroaggregated albumin hepatic arterial perfusion studies performed in 19 patients. These crystals produce carbon dioxide gas, distend the stomach, and allow better delineation of gastric activity (extrahepatic perfusion to the stomach). Conversely, a lack of change in activity in the left upper quadrant after the effervescent crystals have been ingested suggests no gastric activity (and no extrahepatic perfusion to the stomach). These air-contrast views added useful information in 16 of 20 studies. Air contrastmore » views of the stomach can be extremely helpful in verifying or excluding the diagnosis of gastric extrahepatic perfusion on technetium-99m macroaggregated albumin hepatic arterial perfusion studies.« less

Dynamics of Soil Organic Carbon and Aggregate Stability with Grazing Exclusion in the Inner Mongolian Grasslands

PubMed Central

Wen, Ding; He, Nianpeng; Zhang, Jinjing

2016-01-01

Grazing exclusion (GE) has been deemed as an important approach to enhance the soil carbon storage of semiarid grasslands in China; however, it remains unclear how different organic carbon (OC) components in soils vary with the duration of GE. Here, we observed the changing trends of different OC components in soils with increased GE duration in five grassland succession series plots, ranging from free grazing to 31-year GE. Specifically, we measured microbial biomass carbon (MBC), easily oxidizable OC (EOC), water-soluble OC (WSOC), and OC in water stable aggregates (macroaggregates [250–2000 μm], microaggregates [53–250 μm], and mineral fraction [< 53 μm]) at 0–20 cm soil depths. The results showed that GE significantly enhanced EOC and WSOC contents in soils, but caused a decline of MBC at the three decade scale. Macroaggregate content (F = 425.8, P < 0.001), OC stored in macroaggregates (F = 84.1, P < 0.001), and the mean weight diameter (MWD) of soil aggregates (F = 371.3, P < 0.001) increased linearly with increasing GE duration. These findings indicate that OC stored in soil increases under three-decade GE with soil organic matter (SOM) stability improving to some extent. Long-term GE practices enhance the formation of soil aggregates through higher SOM input and an exclusion of animal trampling. Therefore, the practice of GE may be further encouraged to realize the soil carbon sequestration potential of semi-arid grasslands, China. PMID:26751370

Dynamics of Soil Organic Carbon and Aggregate Stability with Grazing Exclusion in the Inner Mongolian Grasslands.

PubMed

Wen, Ding; He, Nianpeng; Zhang, Jinjing

2016-01-01

Grazing exclusion (GE) has been deemed as an important approach to enhance the soil carbon storage of semiarid grasslands in China; however, it remains unclear how different organic carbon (OC) components in soils vary with the duration of GE. Here, we observed the changing trends of different OC components in soils with increased GE duration in five grassland succession series plots, ranging from free grazing to 31-year GE. Specifically, we measured microbial biomass carbon (MBC), easily oxidizable OC (EOC), water-soluble OC (WSOC), and OC in water stable aggregates (macroaggregates [250-2000 μm], microaggregates [53-250 μm], and mineral fraction [< 53 μm]) at 0-20 cm soil depths. The results showed that GE significantly enhanced EOC and WSOC contents in soils, but caused a decline of MBC at the three decade scale. Macroaggregate content (F = 425.8, P < 0.001), OC stored in macroaggregates (F = 84.1, P < 0.001), and the mean weight diameter (MWD) of soil aggregates (F = 371.3, P < 0.001) increased linearly with increasing GE duration. These findings indicate that OC stored in soil increases under three-decade GE with soil organic matter (SOM) stability improving to some extent. Long-term GE practices enhance the formation of soil aggregates through higher SOM input and an exclusion of animal trampling. Therefore, the practice of GE may be further encouraged to realize the soil carbon sequestration potential of semi-arid grasslands, China.

UV Catalysis, Cyanotype Photography, and Sunscreens

NASA Astrophysics Data System (ADS)

Lawrence, Glen D.; Fishelson, Stuart

1999-09-01

This laboratory experiment is intended for a chemistry course for non-science majors. The experiment utilizes one of the earliest photographic processes, the cyanotype process, to demonstrate UV catalysis of chemical reactions. In addition to making photographic prints from negatives, the process can be used to test the effectiveness of sunscreens and the relative efficacy of the SPF (sun protection factor) rating of sunscreens. This is an inexpensive process, requiring solutions of ammonium ferric citrate and potassium ferricyanide, with options to use hydrogen peroxide and ammonium hydroxide solutions. Students can prepare their own UV-sensitized paper with the indicated chemicals and watch the photographic image appear as it is exposed to sunlight or fluorescent UV lamps in a light box designed for use in this experiment. The laboratory experiment should stimulate discussion of UV catalysis, photographic processes and photochemistry, sunscreens, and UV damage to biological organisms. The chemicals used are relatively nontoxic, and the procedure is simple enough to be used by groups of diverse ages and abilities.

Friction and Wear of Iron in Corrosive Media

NASA Technical Reports Server (NTRS)

Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

1982-01-01

Friction and wear experiments were conducted with elemental iron exposed to various corrosive media including two acids, base, and a salt. Studies involved various concentrations of nitric and sulfuric acids, sodium hydroxide, and sodium chloride. Load and reciprocating sliding speed were kept constant. With the base NaOH an increase in normality beyond 0.01 N resulted in a decrease in both friction and wear. X-ray photoelectron spectroscopy (XPS) analysis of the surface showed a decreasing concentration of ferric oxide (Fe2O3) on the iron surface with increasing NaOH concentration. With nitric acid (HNO3) friction decreased in solutions to 0.05 N, beyond which no further change in friction was observed. The concentration of Fe2O3 on the surface continued to increase with increasing normality. XPS analysis revealed the presence of sulfates in addition of Fe2O3 on surfaces exposed to sulfuric acid and iron chlorides but no sodium on surfaces exposed to NaCl.

Nucleation of Iron Oxide Nanoparticles Mediated by Mms6 Protein in Situ

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

Kashyap, Sanjay; Woehl, Taylor J; Liu, Xunpei

2014-09-23

Biomineralization proteins are widely used as templating agents in biomimetic synthesis of a variety of organic–inorganic nanostructures. However, the role of the protein in controlling the nucleation and growth of biomimetic particles is not well understood, because the mechanism of the bioinspired reaction is often deduced from ex situ analysis of the resultant nanoscale mineral phase. Here we report the direct visualization of biomimetic iron oxide nanoparticle nucleation mediated by an acidic bacterial recombinant protein, Mms6, during an in situ reaction induced by the controlled addition of sodium hydroxide to solution-phase Mms6 protein micelles incubated with ferric chloride. Using inmore » situ liquid cell scanning transmission electron microscopy we observe the liquid iron prenucleation phase and nascent amorphous nanoparticles forming preferentially on the surface of protein micelles. Our results provide insight into the early steps of protein-mediated biomimetic nucleation of iron oxide and point to the importance of an extended protein surface during nanoparticle formation.« less

Preparation of biocompatible magnetite-carboxymethyl cellulose nanocomposite: characterization of nanocomposite by FTIR, XRD, FESEM and TEM.

PubMed

Habibi, Neda

2014-10-15

The preparation and characterization of magnetite-carboxymethyl cellulose nano-composite (M-CMC) material is described. Magnetite nano-particles were synthesized by a modified co-precipitation method using ferrous chloride tetrahydrate and ferric chloride hexahydrate in ammonium hydroxide solution. The M-CMC nano-composite particles were synthesized by embedding the magnetite nanoparticles inside carboxymethyl cellulose (CMC) using a freshly prepared mixture of Fe3O4 with CMC precursor. Morphology, particle size, and structural properties of magnetite-carboxymethyl cellulose nano-composite was accomplished using X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. As a result, magnetite nano-particles with an average size of 35nm were obtained. The biocompatible Fe3O4-carboxymethyl cellulose nano-composite particles obtained from the natural CMC polymers have a potential range of application in biomedical field. Copyright © 2014 Elsevier B.V. All rights reserved.

Cr6+-containing phases in the system CaO-Al2O3-CrO42--H2O at 23 °C

NASA Astrophysics Data System (ADS)

Pöllmann, Herbert; Auer, Stephan

2012-01-01

Synthesis and investigation of lamellar calcium aluminium hydroxy salts was performed to study the incorporation of chromate ions in the interlayer of lamellar calcium aluminium hydroxy salts. Different AFm-phases (calcium aluminate hydrate with alumina, ferric oxide, mono-anion phase) containing chromate were synthesized. These AFm-phases belong to the group of layered double hydroxides (LDHs). 3CaO·Al2O3·CaCrO4·nH2O and C3A·1/2Ca(OH)2·1/2CaCrO4·12H2O were obtained as pure phases and their different distinct interlayer water contents and properties determined. Solid solution of chromate-containing phases and tetracalcium-aluminate-hydrate (TCAH) were studied. The uptake of chromate into TCAH from solutions was proven. Chromate contents in solution decrease to <0.2 mg/l.

Ferric Iron Precipitation in the Nagahama Bay, Satsuma Iwo-Jima Island, Kagoshima

NASA Astrophysics Data System (ADS)

Nagata, T.; Kiyokawa, S.; Ikehara, M.; Oguri, K.; Goto, S.; Ito, T.; Yamaguchi, K. E.; Ueshiba, T.

2010-12-01

Satsuma-Iwojima island is active volcanic island and 6 x 3 km in size, located 38km south of Kyushu island, Japan. The reddish brown water along the coast of the Iwo-dake volcano at the center of the island formed by neutralization through mixing of shallow hydrothermal fluid and seawater. The reddish brown water contains reddish ferrihydrite (Fe3+) that is derived from oxidation of Fe2+ from acidic hot spring (Shikaura and Tazaki, 2001). In the Nagahama Bay with its opening to the south, red-colored Fe-rich water is affected by tidal current, but sedimentation of the ferric hydroxide is confirmed to occur in the ocean bottom (Ninomiya and Kiyokawa, 2009). Here we focus other lines of evidence from long term observations and meteorological records as important factor to form thick iron rich sediments. Meteorological and stationary observations: We used weather record in the Satsuma Iwo-jima and cross-checked with stationary observations, which enabled us to observe color changes of the surface of Nagahama Bay. It was made clear that north wind condition in the Nagahama Bay resulted in changes of the color of its surface, from red to green, by intrusion of ocean water coming from outside. Long term temperature monitoring: The temperature of seawater in the Nagahama Bay fluctuated synchronically with the air temperature. But that of hot spring water rather remained constant regardless of the seasonal change. We observed that seawater temperature in the Nagahama Bay is low at high tide and high at low tide, and the rage of temperature change is maximum at the spring tide and minimum at the neap tide. In other words, the amount of discharge of hot spring and that of seawater inflow vary inversely. Core sample: In the Nagahama Bay, iron rich sediments that is more than 1 m thick were identified. The core sample shows lithology as following; upper part, 10-20cm thick, formed loose Fe-rich deposit, lower portion formed alteration of weakly consolidated Fe-rich orange-colored mud, the organic-rich black mud and volcanic ash layers. The basal part has distinctive pink ash layer, which was identified as 1997 volcanic activity. Therefore, the core samples have records of the past 12 years and show average deposition rate of 8cm/year. Sediment trap: There accumulated 7.5cm-thick materials, dominated by ferrihydrite, during the 82 days experiment (2009/July/12~Oct./03). Sedimentation rate is 2.8cm/month (33.3cm/year). Estimated deposition rate of the core sample is 8cm/year. These differences suggest that about three-forth of Fe-hydroxide formed the Nagahama Bay would have been flashed to the open ocean by tidal and storm effects. These lines of evidence suggest that neap tide supports relatively quiet and has enough supply of hot spring into seawater and south wind works as a cap. The fine-grained iron Fe-hydroxide in the Nagahama Bay is provided and deposited at neap tide and south wind condition.

Combined Hydrous Ferric Oxide and Quaternary Ammonium Surfactant Tailoring of Granular Activated Carbon for Concurrent Arsenate and Perchlorate Removal

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

Jang, M.; Cannon, F; Parette, R

2009-01-01

Activated carbon was tailored with both iron and quaternary ammonium surfactants so as to concurrently remove both arsenate and perchlorate from groundwater. The iron (hydr)oxide preferentially removed the arsenate oxyanion but not perchlorate; while the quaternary ammonium preferentially removed the perchlorate oxyanion, but not the arsenate. The co-sorption of two anionic oxyanions via distinct mechanisms has yielded intriguing phenomena. Rapid small-scale column tests (RSSCTs) with these dually prepared media employed synthetic waters that were concurrently spiked with arsenate and perchlorate; and these trial results showed that the quaternary ammonium surfactants enhanced arsenate removal bed life by 25-50% when compared tomore » activated carbon media that had been preloaded merely with iron (hydr)oxide; and the surfactant also enhanced the diffusion rate of arsenate per the Donnan effect. The authors also employed natural groundwater from Rutland, MA which contained 60 microg/L As and traces of silica, and sulfate; and the authors spiked this with 40 microg/L perchlorate. When processing this water, activated carbon that had been tailored with iron and cationic surfactant could treat 12,500 bed volumes before 10 microg/L arsenic breakthrough, and 4500 bed volumes before 6 microg/L perchlorate breakthrough. Although the quaternary ammonium surfactants exhibited only a slight capacity for removing arsenate, these surfactants did facilitate a more favorably positively charged avenue for the arsenate to diffuse through the media to the iron sorption site (i.e. via the Donnan effect).« less

Arsenite and Ferrous Iron Oxidation Linked to Chemolithotrophic Denitrification for the Immobilization of Arsenic in Anoxic Environments

PubMed Central

Sun, Wenjie; Sierra-Alvarez, Reyes; Milner, Lily; Oremland, Ron; Field, Jim A.

2014-01-01

The objective of this study was to explore a bioremediation strategy based on injecting NO3− to support the anoxic oxidation of ferrous iron (Fe(II)) and arsenite (As(III)) in the subsurface as a means to immobilize As in the form of arsenate (As(V)) adsorbed onto biogenic ferric (Fe(III)) (hydr)oxides. Continuous flow sand filled columns were used to simulate a natural anaerobic groundwater and sediment system with co-occurring As(III) and Fe(II) in the presence (SF1) or absence (SF2) of nitrate, respectively. During operation for 250 days, the average influent arsenic concentration of 567 µg l−1 was reduced to 10.6 (±9.6) µg l−1 in the effluent of column SF1. The cumulative removal of Fe(II) and As(III) in SF1 was 6.5–10-fold higher than that in SF2. Extraction and measurement of the mass of iron and arsenic immobilized on the sand packing of the columns was close to the iron and arsenic removed from the aqueous phase during column operation. The dominant speciation of the immobilized iron and arsenic was Fe(III) and As(V) in SF1, compared with Fe(II) and As(III) in SF2. The speciation was confirmed by XRD and XPS. The results indicate that microbial oxidation of As(III) and Fe(II) linked to denitrification resulted in the enhanced immobilization of aqueous arsenic in anaerobic environments by forming Fe(III) (hydr)oxides coated sands with adsorbed As(V). PMID:19764221

[Effects of Land Use Type on Soil Microbial Biomass Carbon and Nitrogen in Water-Stable Aggregates in Jinyun Mountain].

PubMed

Li, Zeng-quan; Jiang, Chang-sheng; Hao, Qing-ju

2015-11-01

In this study, four land use types including subtropical evergreen broad-leaved forest (abbreviation: forest), sloping farmland, orchard and abandoned land were selected to collect soil samples from 0 to 60 cm depth at the same altitude in Jinyun Mountain. Four sizes of large macroaggregates (> 2 mm), small macroaggregates (0.25-2 mm), microaggregates (0.053-0.25 mm) and silt + clay (< 0.053 mm) were achieved by wet sieving method and the contents of microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) in each aggregate fraction were measured to study the impacts of the different land use types on MBC and MBN in soil aggregates. The results showed that the contents of MBC and MBN in all aggregates in the four land use types decreased with the increasing soil depth. Except large macroaggregetes, the contents of MBC and MBN in the other three soil aggregates decreased when the forest was reclamated into orchard and sloping farmland. MBC and MBN contents in large macroaggregates, small macroaggregates and microaggregates all increased when the sloping farmland was abandoned. The storages of organic carbon and nitrogen in soil depth of 0-60 cm in the four proportions were calculated by the equivalent soil mass method. The results revealed that MBC storages in the other three sizes except silt + clay were higher in the forest than those in orchard and sloping land. And MBC storages in the all aggregates were higher in the abandoned land than those in the sloping land. MBN storages in small macroaggregates and microaggregates were higher in the forest than those in orchard and sloping land. And MBN storages in the other three aggregates except silt + clay were higher in the abandoned land than those in the sloping land. Generally speaking, the storages of MBC in soil aggregates of forest and abandoned land were higher than in orchard and sloping land, MBN storage in soil aggregates of forest was nearly equal to the storage in orchard. However, the storages of MBN in soil aggregates of forest and abandoned land were higher than those in sloping land. The results showed that the reclamation of the forest resulted in the loss of MBC and MBN in soil aggregates of sloping land. However, the abandon of the sloping land contributed to the acumulation of MBC and MBN in soil aggregates. In the process of land use change, the direction and quantity of change in MBC in the soil aggregates were not consistent with those of the total soil organic carbon, which meant the microbial quotient in soil aggregates was not suitable for using to evaluate the impact of land use change on soil quality, using the total organic carbon as an index to express the sensitivity of the land use change may be better.

21 CFR 73.1299 - Ferric ferrocyanide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Ferric ferrocyanide. 73.1299 Section 73.1299 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1299 Ferric ferrocyanide. (a) Identity. (1) The color additive ferric ferrocyanide is a ferric hexacyanoferrate pigment characterized by the structual...

Evaluation of Nasal Mucociliary Transport Rate byTc-Macroaggregated Albumin Rhinoscintigraphy in Woodworkers.

PubMed

Dostbil, Zeki; Polat, Cahit; Uysal, Ismail Önder; Bakır, Salih; Karakuş, Askeri; Altındağ, Serdar

2011-01-01

Woodworkers in the furniture industry are exposed to wood dust in their workplaces. The aim of this study is to investigate the effect of occupational wood dust exposure on the nasal mucociliary transport rates (NMTRs) in woodworkers. Twenty five woodworkers and 30 healthy controls were included in this study. Wood dust concentration in workplaces was measured using the sampling device. (99m) Tc-macroaggregated albumin ((99m)Tc-MAA) rhinoscintigraphy was performed, and NMTR was calculated in all cases. In statistical analysis, an independent samples t-test was used to compare NMTR of woodworkers and control subjects. We found that the mean NMTR of the woodworkers was lower than that of the healthy controls. However, there was not a statistically significant difference between them (P = 0.066). In conclusion, our findings suggested that wood dust exposure may not impair nasal mucociliary transport rate in woodworkers employed in joinery workshops.

Evaluation of Nasal Mucociliary Transport Rate by99mTc-Macroaggregated Albumin Rhinoscintigraphy in Woodworkers

PubMed Central

Dostbil, Zeki; Polat, Cahit; Uysal, İsmail Önder; Bakır, Salih; Karakuş, Askeri; Altındağ, Serdar

2011-01-01

Woodworkers in the furniture industry are exposed to wood dust in their workplaces. The aim of this study is to investigate the effect of occupational wood dust exposure on the nasal mucociliary transport rates (NMTRs) in woodworkers. Twenty five woodworkers and 30 healthy controls were included in this study. Wood dust concentration in workplaces was measured using the sampling device. 99m Tc-macroaggregated albumin (99mTc-MAA) rhinoscintigraphy was performed, and NMTR was calculated in all cases. In statistical analysis, an independent samples t-test was used to compare NMTR of woodworkers and control subjects. We found that the mean NMTR of the woodworkers was lower than that of the healthy controls. However, there was not a statistically significant difference between them (P = 0.066). In conclusion, our findings suggested that wood dust exposure may not impair nasal mucociliary transport rate in woodworkers employed in joinery workshops. PMID:21804940

Pulmonary delivery of respiratory syncytial virus DNA vaccines using macroaggregated albumin particles.

PubMed

Harcourt, Jennifer L; Anderson, Larry J; Sullender, Wayne; Tripp, Ralph A

2004-06-02

At present there is no safe and effective vaccine for respiratory syncytial virus (RSV). DNA vaccines encoding RSV surface glycoproteins are one option being examined. Current methods to deliver DNA vaccines generally require repeated high dose intramuscular or intradermal administration for effectiveness. In this study, we examine the efficacy of pulmonary DNA vaccination using low dose DNA vaccines encoding the RSV F glycoprotein conjugated to macroaggregated albumin (MAA-F). Single vaccination of BALB/c mice with 1 microg MAA-F was ineffective, however mice boosted with an additional 1 microg MAA-F, or vaccinated a single time with 10 microg MAA-F, developed substantially improved immunity associated with reduced viral titers, increased anti-F antibody responses, and enhanced Th1 and Th2 intracellular cytokine responses. This study shows that MAA may be a useful carrier for RSV DNA vaccines.

Carbon Storage in Soil Size Fractions Under Two Cacao Agroforestry Systems in Bahia, Brazil

NASA Astrophysics Data System (ADS)

Gama-Rodrigues, Emanuela F.; Ramachandran Nair, P. K.; Nair, Vimala D.; Gama-Rodrigues, Antonio C.; Baligar, Virupax C.; Machado, Regina C. R.

2010-02-01

Shaded perennial agroforestry systems contain relatively high quantities of soil carbon (C) resulting from continuous deposition of plant residues; however, the extent to which the C is sequestered in soil will depend on the extent of physical protection of soil organic C (SOC). The main objective of this study was to characterize SOC storage in relation to soil fraction-size classes in cacao ( Theobroma cacao L.) agroforestry systems (AFSs). Two shaded cacao systems and an adjacent natural forest in reddish-yellow Oxisols in Bahia, Brazil were selected. Soil samples were collected from four depth classes to 1 m depth and separated by wet-sieving into three fraction-size classes (>250 μm, 250-53 μm, and <53 μm)—corresponding to macroaggregate, microaggregate, and silt-and-clay size fractions—and analyzed for C content. The total SOC stock did not vary among systems (mean: 302 Mg/ha). On average, 72% of SOC was in macroaggregate-size, 20% in microaggregate-size, and 8% in silt-and-clay size fractions in soil. Sonication of aggregates showed that occlusion of C in soil aggregates could be a major mechanism of C protection in these soils. Considering the low level of soil disturbances in cacao AFSs, the C contained in the macroaggregate fraction might become stabilized in the soil. The study shows the role of cacao AFSs in mitigating greenhouse gas (GHG) emission through accumulation and retention of high amounts of organic C in the soils and suggests the potential benefit of this environmental service to the nearly 6 million cacao farmers worldwide.

Carbon storage in soil size fractions under two cacao agroforestry systems in Bahia, Brazil.

PubMed

Gama-Rodrigues, Emanuela F; Ramachandran Nair, P K; Nair, Vimala D; Gama-Rodrigues, Antonio C; Baligar, Virupax C; Machado, Regina C R

2010-02-01

Shaded perennial agroforestry systems contain relatively high quantities of soil carbon (C) resulting from continuous deposition of plant residues; however, the extent to which the C is sequestered in soil will depend on the extent of physical protection of soil organic C (SOC). The main objective of this study was to characterize SOC storage in relation to soil fraction-size classes in cacao (Theobroma cacao L.) agroforestry systems (AFSs). Two shaded cacao systems and an adjacent natural forest in reddish-yellow Oxisols in Bahia, Brazil were selected. Soil samples were collected from four depth classes to 1 m depth and separated by wet-sieving into three fraction-size classes (>250 microm, 250-53 microm, and <53 microm)-corresponding to macroaggregate, microaggregate, and silt-and-clay size fractions-and analyzed for C content. The total SOC stock did not vary among systems (mean: 302 Mg/ha). On average, 72% of SOC was in macroaggregate-size, 20% in microaggregate-size, and 8% in silt-and-clay size fractions in soil. Sonication of aggregates showed that occlusion of C in soil aggregates could be a major mechanism of C protection in these soils. Considering the low level of soil disturbances in cacao AFSs, the C contained in the macroaggregate fraction might become stabilized in the soil. The study shows the role of cacao AFSs in mitigating greenhouse gas (GHG) emission through accumulation and retention of high amounts of organic C in the soils and suggests the potential benefit of this environmental service to the nearly 6 million cacao farmers worldwide.

Rapid assay for microbially reducible ferric iron in aquatic sediments

USGS Publications Warehouse

Lovely, Derek R.; Philips , Elizabeth J.P.

1987-01-01

The availability of ferric iron for microbial reduction as directly determined by the activity of iron-reducing organisms was compared with its availability as determined by a newly developed chemical assay for microbially reducible iron. The chemical assay was based on the reduction of poorly crystalline ferric iron by hydroxylamine under acidic conditions. There was a strong correlation between the extent to which hydroxylamine could reduce various synthetic ferric iron forms and the susceptibility of the iron to microbial reduction in an enrichment culture of iron-reducing organisms. When sediments that contained hydroxylamine-reducible ferric iron were incubated under anaerobic conditions, ferrous iron accumulated as the concentration of hydroxylamine-reducible ferric iron declined over time. Ferrous iron production stopped as soon as the hydroxylamine-reducible ferric iron was depleted. In anaerobic incubations of reduced sediments that did not contain hydroxylamine-reducible ferric iron, there was no microbial iron reduction, even though the sediments contained high concentrations of oxalate-extractable ferric iron. A correspondence between the presence of hydroxylamine-reducible ferric iron and the extent of ferric iron reduction in anaerobic incubations was observed in sediments from an aquifer and in fresh- and brackish-water sediments from the Potomac River estuary. The assay is a significant improvement over previously described procedures for the determination of hydroxylamine-reducible ferric iron because it provides a correction for the high concentrations of solid ferrous iron which may also be extracted from sediments with acid. This is a rapid, simple technique to determine whether ferric iron is available for microbial reduction.

21 CFR 184.1307 - Ferric sulfate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ferric sulfate. 184.1307 Section 184.1307 Food and....1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS Reg. No. 10028-22-5) is a yellow substance that may be prepared by oxidizing iron (II) sulfate or by treating ferric oxide or...

21 CFR 184.1297 - Ferric chloride.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ferric chloride. 184.1297 Section 184.1297 Food and... Substances Affirmed as GRAS § 184.1297 Ferric chloride. (a) Ferric chloride (iron (III) chloride, FeC13, CAS Reg. No. 7705-08-0) may be prepared from iron and chlorine or from ferric oxide and hydrogen chloride...

In situ characterization of green rust in the presence of arsenate and phosphate in simulated oxidized and reduced environments.

NASA Astrophysics Data System (ADS)

Root, R. A.; O'Day, P. A.

2008-12-01

Nano- to micron-scale particles of mixed-valent iron hydroxide, specifically green rust (GR [FeII6- x(OH)y FeIIIx(OH)12-y]x+[Anionx- + H2O]x-), have been identified and studied as corrosion products of steel, and recently rediscovered in hydromorphic soils and sediments. Green rusts are intermediate phases produced by biotic and abiotic reductive dissolution of ferric oxyhydroxides, or by oxidation of dissolved ferrous iron. Adsorbed oxyanions can stabilize GR phases and inhibit the formation of thermodynamically favored iron phases such as magnetite or lepidocrocite in subsurface environments. This study used synchrotron XRD to characterize iron (hydr)oxide minerals precipitated from solution and subsequent aging products under different environmental conditions of pH and Eh. Here we show the in situ abiotic development of green rust and its stabilization by the addition of adsorbed oxyanions or alternatively, subsequent rapid transformation to magnetite or lepidocrocite in the absence of added anions. A closed batch reactor with an in-line capillary was used to expose the reaction products to continuous synchrotron radiation. Laue patterns were collected at time intervals of 3-5 minutes and used to detect the formation of crystalline iron (hydr)oxide minerals that precipitate as a function time and chemical perturbations to the system, i.e. changing the pH, redox potential, ratio of Fe2+ to OH- , and addition of an oxyanion, arsenate or phosphate. The reactions were monitored by observing the development of diagnostic green rust XRD d-spacing peak at 10.9 Å (300), the 3.29 Å (210) d- spacing for lepidocrocite, and the 2.53 Å (100) d-spacing for magnetite, with continuous in-line measurement of pH and ORP. We found that green rust was stabilized by the adsorption of arsenate and phosphate. In the presence of arsenate or phosphate at pH =7, green rust transformed to lepidocrocite after several hours when anoxic controls were removed. When pH and Eh were constant, GR did not transform to magnetite or lepidocrocite. However, without arsenate or phosphate, the transformation occurred in less than 1 hour. At pH > 7.5, green rust transformed to magnetite within 1 hour. In the presence of phosphate or arsenate, the transformation was retarded and took up to 8 hours. The rates of transformation and meta- stability of iron (hydr)oxide phases in natural redoximorphic sediments play important roles in the cycling of contaminants and nutrients.

Ferric Citrate Controls Phosphorus and Delivers Iron in Patients on Dialysis

PubMed Central

Sika, Mohammed; Koury, Mark J.; Chuang, Peale; Schulman, Gerald; Smith, Mark T.; Whittier, Frederick C.; Linfert, Douglas R.; Galphin, Claude M.; Athreya, Balaji P.; Nossuli, A. Kaldun Kaldun; Chang, Ingrid J.; Blumenthal, Samuel S.; Manley, John; Zeig, Steven; Kant, Kotagal S.; Olivero, Juan Jose; Greene, Tom; Dwyer, Jamie P.

2015-01-01

Patients on dialysis require phosphorus binders to prevent hyperphosphatemia and are iron deficient. We studied ferric citrate as a phosphorus binder and iron source. In this sequential, randomized trial, 441 subjects on dialysis were randomized to ferric citrate or active control in a 52-week active control period followed by a 4-week placebo control period, in which subjects on ferric citrate who completed the active control period were rerandomized to ferric citrate or placebo. The primary analysis compared the mean change in phosphorus between ferric citrate and placebo during the placebo control period. A sequential gatekeeping strategy controlled study-wise type 1 error for serum ferritin, transferrin saturation, and intravenous iron and erythropoietin-stimulating agent usage as prespecified secondary outcomes in the active control period. Ferric citrate controlled phosphorus compared with placebo, with a mean treatment difference of −2.2±0.2 mg/dl (mean±SEM) (P<0.001). Active control period phosphorus was similar between ferric citrate and active control, with comparable safety profiles. Subjects on ferric citrate achieved higher mean iron parameters (ferritin=899±488 ng/ml [mean±SD]; transferrin saturation=39%±17%) versus subjects on active control (ferritin=628±367 ng/ml [mean±SD]; transferrin saturation=30%±12%; P<0.001 for both). Subjects on ferric citrate received less intravenous elemental iron (median=12.95 mg/wk ferric citrate; 26.88 mg/wk active control; P<0.001) and less erythropoietin-stimulating agent (median epoetin-equivalent units per week: 5306 units/wk ferric citrate; 6951 units/wk active control; P=0.04). Hemoglobin levels were statistically higher on ferric citrate. Thus, ferric citrate is an efficacious and safe phosphate binder that increases iron stores and reduces intravenous iron and erythropoietin-stimulating agent use while maintaining hemoglobin. PMID:25060056

Ferric oxide quantum dots in stable phosphate glass system and their magneto-optical study

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

Garaje, Sunil N.; Apte, Sanjay K.; Kumar, Ganpathy

2013-02-15

Graphical abstract: We report synthesis of ferric oxide embedded low melting phosphate glass nanocomposite and also the effect of ferric oxide nanoparticles (NCs) content on the optical and magneto-optical properties of the glasses. Faraday rotation of the glass nanocomposites was measured and showed variation in Verdet constant with concentration of ferric oxide. Interestingly, the host glass itself showed fairly good Verdet constant (11.5°/T cm) and there is a threefold enhancement in the Verdet constant of ferric oxide quantum dot-glass nanocomposite. Highlights: ► We synthesize ferric oxide embedded low melting stable phosphate glass nanocomposite. ► Glasses doped with 0.25 and 2%more » ferric oxide show particle size in the range of 4–12 nm. ► The host phosphate glass itself shows fairly good Verdet constant (11.5°/T cm). ► Glasses doped with 0.25% ferric oxide show high Verdet constant (30.525°/T cm). ► The as synthesis glasses may have potential application in magneto optical devices. -- Abstract: Herein, we report the synthesis of ferric oxide embedded low melting phosphate glass nanocomposite and also the effect of ferric oxide nanoparticles content on the optical and magneto-optical properties of the glasses. The optical study clearly showed red shift in optical cut off with increasing ferric oxide concentration. The band gap of the host glass was observed to be 3.48 eV and it shifted to 3.14 eV after doping with ferric oxide. The glasses doped with 0.25 and 2% ferric oxide showed particle size of 4–6 nm and 8–12 nm, respectively. Faraday rotation of the glass nanocomposites was measured and showed variation in the Verdet constant as per increasing concentration of ferric oxide. Interestingly, the host glass itself showed fairly good Verdet constant (11.5°/T cm) and threefold enhancement was observed in the Verdet constant of ferric oxide quantum dot-glass nanocomposite.« less

Effect of sustainable land management practices on soil aggregation and stabilization of organic carbon in semiarid mediterranean ecosystems

NASA Astrophysics Data System (ADS)

Garcia-Franco, Noelia; Albaladejo, Juan; Almagro, María; Wiesmeier, Martin; Martínez-Mena, María

2016-04-01

Arid and semiarid regions represent about 47% of the total land area of the world (UNEP, 1992). At present, there is a priority interest for carbon (C) sequestration in drylands. These areas are considered as very fragile ecosystems with low organic carbon (OC) saturation, and potentially, high capacity for soil OC sequestration. In addition, the restoration of these areas is one of the major challenges for scientists, who will be able to identify and recommended the best land uses and sustainable land management (SLM) practices for soil conservation and mitigation of climate change in these environments. In this regard, in semiarid Mediterranean ecosystems there is an urgent need for the implementation of SLM practices regardless of land-use type (forest, agricultural and shrubland) to maintain acceptable levels of soil organic matter (SOM) and the physico-chemical protection of the OC. Long- and short-term effects of SLM practices on soil aggregation and SOC stabilization were studied in two land uses. The long-term experiment was conducted in a reforestation area with Pinus halepensis Mill., where two afforestation techniques were implemented 20 years ago: a) mechanical terracing with a single application of organic waste of urban soil refuse, and b) mechanical terracing without organic amendment. An adjacent shrubland was considered as the reference plot. The short-term experiment was conducted in a rain-fed almond (Prunus dulcis Mill., var. Ferragnes) orchard where two SLM practices were introduced 4 years ago: a) reduced tillage plus green manure, and b) no tillage. Reduced tillage was considered as the reference plot given that it is the habitual management practice. Four aggregate size classes were differentiated by sieving (large and small macroaggregates, microaggregates, and the silt plus clay fraction), and the microaggregates occluded within small macroaggregates (SMm) were isolated. In addition, different organic C fractions corresponding with active, slow and passive pools were separated using a density fractionation method. Our results showed that the chemical stabilization of OC, was the main mechanisms of C sequestration in the two study sites, which occurred through the formation of complexes with silt and clay particles and its physical protection in microaggregates formed within macroaggregates. In addition, the chemical stabilization was promoted by the mineral composition of the soil matrix. Both studied sites, especially that involving organic soil amendment in the forest system, and the green manure treatment in the agricultural system exhibited an increase in the labile pool of OC in the soil. This increase promoted the formation of macroaggregates, in two ways: 1) directly, by acting as a binding agent between soil particles, and 2) indirectly, by stimulating the microbiological activity, especially that of the fungi - which "package" the particles with their hyphae. The establishment of these new macroaggregates favors the formation of microaggregates. In addition, in the agricultural soils, minimum tillage seems to be necessary, from the point of view of carbon sequestration, since it promotes the incorporation of plant material and the formation of aggregates into deeper layers

Magnetite solubility and phase stability in alkaline media at elevated temperatures

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

Ziemniak, S.E.; Jones, M.E.; Combs, K.E.S.

Magnetite, Fe{sub 3}O{sub 4}, is the dominant oxide constituent of the indigenous corrosion layers that form on iron base alloys in high purity, high temperature water. The apparent simultaneous stability of two distinct oxidation states of iron in this metal oxide is responsible for its unique solubility behavior. The present work was undertaken to extend the experimental and theoretical bases for estimating solubilities of an iron corrosion product (Fe{sub 3}O{sub 4}/Fe(OH){sub 2}) over a broader temperature range and in the presence of complexing, pH-controlling reagents. These results indicate that a surface layer of ferrous hydroxide controls magnetite solubility behavior atmore » low temperatures in much the same manner as a surface layer of nickel(II) hydroxide was previously reported to control the low temperature solubility behavior of NiO. The importance of Fe(III) ion complexes implies not only that most previously-derived thermodynamic properties of the Fe(OH){sub 3}{sup {minus}} ion are incorrect, but that magnetite phase stability probably shifts to favor a sodium ferric hydroxyphosphate compound in alkaline sodium phosphate solutions at elevated temperatures. The test methodology involved pumping alkaline solutions of known composition through a bed of Fe{sub 3}O{sub 4} granules and analyzing the emerging solution for Fe. Two pH-controlling reagents were tested: sodium phosphate and ammonia. Equilibria for the following reactions were described in thermodynamic terms: (a) Fe(OH){sub 2}/Fe{sub 3}O{sub 4} dissolution and transformation, (b) Fe(II) and Fe(III) ion hydroxocomplex formation (hydrolysis), (c) Fe(II) ion amminocomplex formation, and (d) Fe(II) and Fe(III) ion phosphatocomplex formation. 36 refs.« less

Coupling of the Distal H-bond Network to the Exogenous Ligand in Substrate-bound, Resting State Human Heme Oxygenase ‡

PubMed Central

Peng, Dungeng; Ogura, Hiroshi; Zhu, Wenfeng; Ma, Li-Hua; Evans, John P.; Ortiz de Montellano, Paul R.; La Mar, Gerd N.

2010-01-01

Mammalian heme oxygenase, HO, possesses catalytically implicated distal ordered water molecules within an extended H-bond network, with one of the ordered water molecules (#1) providing a bridge between the iron-coordinated ligand and the catalytically critical Asp140, that, in turn, serves as an acceptor for the Tyr58 OH H-bond. The degree of H-bonding by the ligated water molecule and the coupling of this water molecule to the H-bond network are of current interest and are herein investigated by 1H NMR. 2D NMR allowed sufficient assignments to provide both the H-bond strength and hyperfine shifts, the latter of which were used to quantify the magnetic anisotropy in both the ferric high-spin aquo and low-spin hydroxo complexes. The anisotropy in the aquo complex indicates that the H-bond donation to water #1 is marginally stronger than in a bacterial HO, while the anisotropy for the hydroxo complex reveals a conventional (dxz, dyz)1 ground state indicative of only moderate to weak H-bond acceptance by the ligated hydroxide. Mapping out the changes of the H-bond strengths in the network during the ligated water → hydroxide conversion by correcting for the effects of magnetic anisotropy, reveals a very substantial change in H-bond strength for Tyr58 OH, and lesser effects on nearby H-bonds. The effect of pH on the H-bonding network in human HO is much larger and transmitted much further from the iron than in a pathogenic bacterial HO. The implications for the HO mechanism of the H-bond of Tyr58 to Asp140 are discussed. PMID:19842713

Arsenite and ferrous iron oxidation linked to chemolithotrophic denitrification for the immobilization of arsenic in anoxic environments

USGS Publications Warehouse

Sun, W.; Sierra-Alvarez, R.; Milner, L.; Oremland, R.; Field, J.A.

2009-01-01

The objective of this study was to explore a bioremediation strategy based on injecting NO3- to support the anoxic oxidation of ferrous iron (Fe(II)) and arsenite (As(III)) in the subsurface as a means to immobilize As in the form of arsenate (As(V)) adsorbed onto biogenic ferric (Fe(III)) (hydr)oxides. Continuous flows and filled columns were used to simulate a natural anaerobic groundwater and sediment system with co-occurring As(III) and Fe(II) in the presence (column SF1) or absence (column SF2) of nitrate, respectively. During operation for 250 days, the average influent arsenic concentration of 567 ??g L-1 was reduced to 10.6 (??9.6) ??g L-1 in the effluent of column SF1. The cumulative removal of Fe(II) and As(III) in SF1 was 6.5 to 10-fold higher than that in SF2. Extraction and measurement of the mass of iron and arsenic immobilized on the sand packing of the columns were close to the iron and arsenic removed from the aqueous phase during column operation. The dominant speciation of the immobilized iron and arsenic was Fe(III) and As(V) in SF1, compared with Fe(II) and As(III) in SF2. The speciation was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicate that microbial oxidation of As(III) and Fe(II) linked to denitrification resulted in the enhanced immobilization of aqueous arsenic in anaerobic environments by forming Fe(III) (hydr)oxide coated sands with adsorbed As(V). ?? 2009 American Chemical Society.

XAS analysis of iron and palladium bonded to a polysaccharide produced anaerobically by a strain of Klebsiella oxytoca.

PubMed

Arčon, Iztok; Paganelli, Stefano; Piccolo, Oreste; Gallo, Michele; Vogel-Mikuš, Katarina; Baldi, Franco

2015-09-01

Klebsiella oxytoca BAS-10 ferments citrate to acetic acid and CO2, and secretes a specific exopolysaccharide (EPS), which is able to bind different metallic species. These biomaterials may be used for different biotechnological purposes, including applications as innovative green biogenerated catalysts. In production of biogenerated Pd species, the Fe(III) as ferric citrate is added to anaerobic culture of K. oxytoca BAS-10, in the presence of palladium species, to increase the EPS secretion and improve Pd-EPS yield. In this process, bi-metallic (FePd-EPS) biomaterials were produced for the first time. The morphology of bi-metallic EPS, and the chemical state of the two metals in the FePd-EPS, are investigated by transmission electron microscopy, Fourier transform infra-red spectroscopy, micro-X-ray fluorescence, and X-ray absorption spectroscopy methods (XANES and EXAFS), and compared with mono-metallic Pd-EPS and Fe-EPS complexes. Iron in FePd-EPS is in the mineralized form of iron oxides/hydroxides, predominantly in the form of Fe(3+), with a small amount of Fe(2+) in the structure, most probably a mixture of different nano-crystalline iron oxides and hydroxides, as in mono-metallic Fe-EPS. Palladium is found as Pd(0) in the form of metallic nanoparticles with face-centred cubic structure in both bi-metallic (FePd-EPS) and mono-metallic (Pd-EPS) species. In bi-metallic species, Pd and Fe nanoparticles agglomerate in larger clusters, but they remain spatially separated. The catalytic ability of bi-metallic species (FePd-EPS) in a hydrodechlorination reaction is improved in comparison with mono-metallic Pd-EPS.

Soil carbon storage in silvopasture and related land-use systems in the brazilian cerrado.

PubMed

Tonucci, Rafael G; Nair, P K Ramachandran; Nair, Vimala D; Garcia, Rasmo; Bernardino, Fernando S

2011-01-01

Silvopastoral management of fast-growing tree plantations is becoming popular in the Brazilian Cerrado (savanna). To understand the influence of such systems on soil carbon (C) storage, we studied C content in three aggregate size classes in six land-use systems (LUS) on Oxisols in Minas Gerais, Brazil. The systems were a native forest, a treeless pasture, 24- and 4-yr-old eucalyptus ( sp.) plantations, and 15- and 4-yr-old silvopastures of fodder grass plus animals under eucalyptus. From each system, replicated soil samples were collected from four depths (0-10, 10-20, 20-50, and 50-100 cm), fractionated into 2000- to 250-, 250- to 53-, and <53-μm size classes representing macroaggregates, microaggregates, and silt + clay, respectively, and their C contents determined. Macroaggregate was the predominant size fraction under all LUS, especially in the surface soil layers of tree-based systems. In general, C concentrations (g kg soil) in the different aggregate size fractions did not vary within the same depth. The soil organic carbon (SOC) stock (Mg C ha) to 1-m depth was highest under pasture compared with other LUS owing to its higher soil bulk density. The soils under all LUS had higher C stock compared with other reported values for managed tropical ecosystems: down to 1 m, total SOC stock values ranged from 461 Mg ha under pasture to 393 Mg ha under old eucalyptus. Considering the possibility for formation and retention of microaggregates within macroggregates in low management-intensive systems such as silvopasture, the macroaggregate dynamics in the soil seem to be a good indicator of its C storage potential. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

Effects of iron-aluminium oxides and organic carbon on aggregate stability of bauxite residues.

PubMed

Zhu, Feng; Li, Yubing; Xue, Shengguo; Hartley, William; Wu, Hao

2016-05-01

In order to successfully establish vegetation on bauxite residue, properties such as aggregate structure and stability require improvement. Spontaneous plant colonization on the deposits in Central China over the last 20 years has revealed that natural processes may improve the physical condition of bauxite residues. Samples from three different stacking ages were selected to determine aggregate formation and stability and its relationship with iron-aluminium oxides and organic carbon. The residue aggregate particles became coarser in both dry and wet sieving processes. The mean weight diameter (MWD) and geometry mean diameter (GMD) increased significantly, and the proportion of aggregate destruction (PAD) decreased. Natural stacking processes could increase aggregate stability and erosion resistant of bauxite residues. Free iron oxides and amorphous aluminium oxides were the major forms in bauxite residues, but there was no significant correlation between the iron-aluminium oxides and aggregate stability. Aromatic-C, alkanes-C, aliphatic-C and alkenes-C were the major functional groups present in the residues. With increasing stacking age, total organic carbon content and aggregate-associated organic carbon both increased. Alkanes-C, aliphatic-C and alkenes-C increased and were mainly distributed in macro-aggregates, whereas aromatic-C was mainly distributed in <0.05-mm aggregates. Organic carbon stability in micro-aggregates was higher than that in macro-aggregates and became more stable. Organic carbon contents in total residues, and within different aggregate sizes, were all negatively correlated with PAD. It indicated that organic materials had a more significant effect on macro-aggregate stability and the effects of iron-aluminium oxides maybe more important for stability of micro-aggregates.

Carbon Structural Investigations of Concentric Layers Within Macro-aggregates From Forest and Agricultural Soils

NASA Astrophysics Data System (ADS)

Dria, K. J.; Gamblin, D. E.; Smucker, A. J.; Park, E.; Filley, T. R.

2004-12-01

Much of the current research on the potential of agricultural and forest soils to act as sinks for greenhouse gases focuses on the capacity of the systems to form long-term stabilized fractions of soil organic matter (SOM). One proposed mechanism is that carbon is sequestered within soil aggregate interiors during the aggregation process. Repeated wetting-drying cycles change internal pore geometries and associated microhabitats and create more stable macro-aggregates. Research by Smucker and coworkers (EGU Abstracts, 2004) suggest that the exterior portions of aggregates contain greater concentrations of C and N than their interiors, establishing gradients of \\ä13C values across these aggregates. We present the results of a study to test if there exists molecular evidence of such gradients. Soil samples from forest, conventional tillage (CT) and no tillage (NT) agriculture ecosystems in Hoytville and Wooster LTER sites were gently sieved into various size fractions. Soil macro-aggregates (6.3-9.5mm) were peeled, by mechanical erosion chambers, into concentric layers and separated into exterior, transitional and interior regions. Alkaline CuO oxidation was used to determine the composition of lignin, suberin, and cutin biopolymers to determine changes in source and degradative states of SOM. Preliminary results indicate that both soils show similar relative yields of lignin and hydroxyl fatty acids with a greater abundance of lignin than cutin and suberin acids. Greater abundances (per 100mg organic carbon) of CuO products were observed in the native forest than in either agricultural system. The lignin in the NT agricultural soil was least oxidized, followed by the forest soils, then the CT agricultural soils. For both soils, slight trends in biopolymer concentrations were observed between the exterior, transitional and interior regions of the aggregates from the forest and CT or NT ecosystems.

Tailoring (bio)chemical activity of semiconducting nanoparticles: critical role of deposition and aggregation.

PubMed

Chernyshova, Irina V; Ponnurangam, Sathish; Somasundaran, Ponisseril

2011-06-22

The impact of deposition and aggregation on (bio)chemical properties of semiconducting nanoparticles (NPs) is perhaps among the least studied aspects of aquatic chemistry of solids. Employing a combination of in situ FTIR and ex situ X-ray photoelectron spectroscopy (XPS) and using the Mn(II) oxygenation on hematite (α-Fe(2)O(3)) and anatase (TiO(2)) NPs as a model catalytic reaction, we discovered that the catalytic and sorption performance of the semiconducting NPs in the dark can be manipulated by depositing them on different supports or mixing them with other NPs. We introduce the electrochemical concept of the catalytic redox activity to explain the findings and to predict the effects of (co)aggregation and deposition on the catalytic and corrosion properties of ferric (hydr)oxides. These results offer new possibilities for rationally tailoring the technological performance of semiconducting metal oxide NPs, provide a new framework for modeling their fate and transport in the environment and living organisms, and can be helpful in discriminating between weakly and strongly adsorbed species in spectra.

Identification of a green rust mineral in a reductomorphic soil by Mossbauer and Raman spectroscopies

NASA Astrophysics Data System (ADS)

Trolard, F.; Génin, J.-M. R.; Abdelmoula, M.; Bourrié, G.; Humbert, B.; Herbillon, A.

1997-03-01

Mössbauer and Raman spectroscopies are used to identify for the first time a green rust as a mineral in a reductomorphic soil from samples extracted in the forest of Fougères (Brittany-France). The Mossbauer spectrum displays two characteristic ferrous and ferric quadrupole doublets, the abundance ratio Fe(II)/Fe(Ill) of which is close to 1. Comparison with synthetic mixed valence Fe(II)Fe(HI) hydroxides supports the conclusion that the most probable formula is Fe2(OH)5, i.e., according to the pyroaurite-like crystal structure [Fe(n1Fe1III)(OH),]+o [OH] -. The microprobe Raman spectrum exhibits two bands at 518 and 427 cm-' as for synthetic green rusts. When exposed to the air, the new mineral goes rapidly from bluish-green to ochrous. The formula is compatible with the values of ionic activity products Q for equilibria between aqueous iron species and minerals obtained from soil waters, which suggests that this new mineral is likely to control the mobility of Fe in the environment.

Phosphorus removal from aquaculture effluents at the Northeast Fishery Center in Lamar, Pennsylvania using iron oxide sorption media

USGS Publications Warehouse

Sibrell, Philip; Kehler, Thomas

2016-01-01

Three different iron oxide-based sorption media samples were tested for removal of phosphorus (P) from fish hatchery effluents using fixed bed processing. Two of the media samples were derived from residuals produced by the treatment of acid mine drainage, which were then compared to granular ferric hydroxide (GFH), a commercially available sorption medium. All of the media types removed from 50 to 70% of the P from the incoming aquaculture wastewater over 70–175 days of operation without regeneration. In some of the sorption trials, the GFH media showed superior adsorption in the earlier stages of the trial, but the GFH appeared to reach saturation more quickly, so that media performance was similar – at about 60% removal of P – over a longer time period of 175 days. Media regeneration tests were also conducted for both the commercial and mine drainage media, and demonstrated longer term performance, with overall P removal of 50–55%, over 223 days of total operation, with the advantages of phosphorus recycle and media reuse.

Iron oxide shell coating on nano silicon prepared from the sand for lithium-ion battery application

NASA Astrophysics Data System (ADS)

Furquan, Mohammad; Vijayalakshmi, S.; Mitra, Sagar

2018-05-01

Elemental silicon, due to its high specific capacity (4200 mAh g-1) and non-toxicity is expected to be an attractive anode material for Li-ion battery. But its huge expansion volume (> 300 %) during charging of battery, leads to pulverization and cracking in the silicon particles and causes sudden failure of the Li-ion battery. In this work, we have designed yolk-shell type morphology of silicon, prepared from carbon coated silicon nanoparticles soaked in aqueous solution of ferric nitrate and potassium hydroxide. The soaked silicon particles were dried and finally calcined at 800 °C for 30 minutes. The product obtained is deprived of carbon and has a kind of yolk-shell morphology of nano silicon with iron oxide coating (Si@Iron oxide). This material has been tested for half-cell lithium-ion battery configuration. The discharge capacity is found to be ≈ 600 mAh g-1 at a current rate of 1.0 A g-1 for 200 cycles. It has shown a stable performance as anode for Li-ion battery application.

Application of support vector machines for copper potential mapping in Kerman region, Iran

NASA Astrophysics Data System (ADS)

Shabankareh, Mahdi; Hezarkhani, Ardeshir

2017-04-01

The first step in systematic exploration studies is mineral potential mapping, which involves classification of the study area to favorable and unfavorable parts. Support vector machines (SVM) are designed for supervised classification based on statistical learning theory. This method named support vector classification (SVC). This paper describes SVC model, which combine exploration data in the regional-scale for copper potential mapping in Kerman copper bearing belt in south of Iran. Data layers or evidential maps were in six datasets namely lithology, tectonic, airborne geophysics, ferric alteration, hydroxide alteration and geochemistry. The SVC modeling result selected 2220 pixels as favorable zones, approximately 25 percent of the study area. Besides, 66 out of 86 copper indices, approximately 78.6% of all, were located in favorable zones. Other main goal of this study was to determine how each input affects favorable output. For this purpose, the histogram of each normalized input data to its favorable output was drawn. The histograms of each input dataset for favorable output showed that each information layer had a certain pattern. These patterns of SVC results could be considered as regional copper exploration characteristics.

Synthesis and magnetic characterization of nickel ferrite nanoparticles prepared by co-precipitation route

NASA Astrophysics Data System (ADS)

Maaz, K.; Karim, S.; Mumtaz, A.; Hasanain, S. K.; Liu, J.; Duan, J. L.

2009-06-01

Magnetic nanoparticles of nickel ferrite (NiFe 2O 4) have been synthesized by co-precipitation route using stable ferric and nickel salts with sodium hydroxide as the precipitating agent and oleic acid as the surfactant. X-ray diffraction (XRD) and transmission electron microscope (TEM) analyses confirmed the formation of single-phase nickel ferrite nanoparticles in the range 8-28 nm depending upon the annealing temperature of the samples during the synthesis. The size of the particles ( d) was observed to be increasing linearly with annealing temperature of the sample while the coercivity with particle size goes through a maximum, peaking at ˜11 nm and then decreases for larger particles. Typical blocking effects were observed below ˜225 K for all the prepared samples. The superparamagnetic blocking temperature ( T B) was found to be increasing with increasing particle size that has been attributed to the increased effective anisotropy energy of the nanoparticles. The saturation moment of all the samples was found much below the bulk value of nickel ferrite that has been attributed to the disordered surface spins or dead/inert layer in these nanoparticles.

Air-stable nZVI formation mediated by glutamic acid: solid-state storable material exhibiting 2D chain morphology and high reactivity in aqueous environment

NASA Astrophysics Data System (ADS)

Siskova, Karolina; Tucek, Jiri; Machala, Libor; Otyepkova, Eva; Filip, Jan; Safarova, Klara; Pechousek, Jiri; Zboril, Radek

2012-03-01

We report a new chemical approach toward air-stable nanoscale zero-valent iron (nZVI). The uniformly sized (approx. 80 nm) particles, formed by the reduction of Fe(II) salt by borohydride in the presence of glutamic acid, are coated by a thin inner shell of amorphous ferric oxide/hydroxide and a secondary shell consisting of glutamic acid. The as-prepared nanoparticles stabilized by the inorganic-organic double shell create 2D chain morphologies. They are storable for several months under ambient atmosphere without the loss of Fe(0) relative content. They show one order of magnitude higher rate constant for trichlorethene decomposition compared with the pristine particles possessing only the inorganic shell as a protective layer. This is the first example of the inorganic-organic (consisting of low-molecular weight species) double-shell stabilized nanoscale zero-valent iron material being safely transportable in solid-state, storable on long-term basis under ambient conditions, environmentally acceptable for in situ applications, and extraordinarily reactive if contacted with reducible pollutants, all in one.

40 CFR 415.380 - Applicability; description of the ferric chloride production subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ferric chloride production subcategory. 415.380 Section 415.380 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Ferric Chloride Production Subcategory § 415.380 Applicability; description of the ferric chloride production subcategory. The provisions of this subpart are applicable to discharges and to the...

Reduction in soil aggregate size distribution due to wind erosion

NASA Astrophysics Data System (ADS)

Swet, Nitzan; Katra, Itzhak

2017-04-01

Soil erosion process by wind causes emission of fine soil particles, and thus alters the topsoil's properties, fertility, and erodibility. Topsoil resistance to erosion depends on its physicochemical properties, especially on the soil aggregation. Although the key role of aggregates in soil erodibility, quantitative information on the relations between soil aggregate size distribution (ASD) and erosion is still lucking. This study focuses on ASD analyses before and after soil erosion by wind. Wind tunnel experiments and soil analyses were conducted on semiarid loess topsoils with different initial conditions of aggregation. The results show that in all initial soil conditions saltation of sand particles caused the breakdown of macro-aggregates > 500 µm, resulting in increase of micro-aggregates (63-250 µm). The micro-aggregate production increases with the wind shear velocity (up to 0.61 m s-1) for soils with available macro-aggregates. The findings highlight dynamics in soil aggregation in response to erosion process, and therefore the significance of ASD in quantifying soil degradation and soil loss potential.

21 CFR 73.1298 - Ferric ammonium ferrocyanide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Ferric ammonium ferrocyanide. 73.1298 Section 73... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1298 Ferric ammonium ferrocyanide. (a) Identity. (1) The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing...

21 CFR 582.5306 - Ferric sodium pyrophosphate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Ferric sodium pyrophosphate. 582.5306 Section 582.5306 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Dietary Supplements 1 § 582.5306 Ferric sodium pyrophosphate. (a) Product. Ferric sodium pyrophosphate. (b...

C and N Content in Density Fractions of Whole Soil and Soil Size Fraction Under Cacao Agroforestry Systems and Natural Forest in Bahia, Brazil

NASA Astrophysics Data System (ADS)

Rita, Joice Cleide O.; Gama-Rodrigues, Emanuela Forestieri; Gama-Rodrigues, Antonio Carlos; Polidoro, Jose Carlos; Machado, Regina Cele R.; Baligar, Virupax C.

2011-07-01

Agroforestry systems (AFSs) have an important role in capturing above and below ground soil carbon and play a dominant role in mitigation of atmospheric CO2. Attempts has been made here to identify soil organic matter fractions in the cacao-AFSs that have different susceptibility to microbial decomposition and further represent the basis of understanding soil C dynamics. The objective of this study was to characterize the organic matter density fractions and soil size fractions in soils of two types of cacao agroforestry systems and to compare with an adjacent natural forest in Bahia, Brazil. The land-use systems studied were: (1) a 30-year-old stand of natural forest with cacao (cacao cabruca), (2) a 30-year-old stand of cacao with Erythrina glauca as shade trees (cacao + erythrina), and (3) an adjacent natural forest without cacao. Soil samples were collected from 0-10 cm depth layer in reddish-yellow Oxisols. Soil samples was separated by wet sieving into five fraction-size classes (>2000 μm, 1000-2000 μm, 250-1000 μm, 53-250 μm, and <53 μm). C and N accumulated in to the light (free- and intra-aggregate density fractions) and heavy fractions of whole soil and soil size fraction were determined. Soil size fraction obtained in cacao AFS soils consisted mainly (65 %) of mega-aggregates (>2000 μm) mixed with macroaggregates (32-34%), and microaggregates (1-1.3%). Soil organic carbon (SOC) and total N content increased with increasing soil size fraction in all land-use systems. Organic C-to-total N ratio was higher in the macroaggregate than in the microaggregate. In general, in natural forest and cacao cabruca the contribution of C and N in the light and heavy fractions was similar. However, in cacao + erythrina the heavy fraction was the most common and contributed 67% of C and 63% of N. Finding of this study shows that the majority of C and N in all three systems studied are found in macroaggregates, particularly in the 250-1000 μm size aggregate class. The heavy fraction was the most common organic matter fraction in these soils. Thus, in mature cacao AFS on highly weathered soils the main mechanisms of C stabilization could be the physical protection within macroaggregate structures thereby minimizing the impact of conversion of forest to cacao AFS.

C and N content in density fractions of whole soil and soil size fraction under cacao agroforestry systems and natural forest in Bahia, Brazil.

PubMed

Rita, Joice Cleide O; Gama-Rodrigues, Emanuela Forestieri; Gama-Rodrigues, Antonio Carlos; Polidoro, Jose Carlos; Machado, Regina Cele R; Baligar, Virupax C

2011-07-01

Agroforestry systems (AFSs) have an important role in capturing above and below ground soil carbon and play a dominant role in mitigation of atmospheric CO(2). Attempts has been made here to identify soil organic matter fractions in the cacao-AFSs that have different susceptibility to microbial decomposition and further represent the basis of understanding soil C dynamics. The objective of this study was to characterize the organic matter density fractions and soil size fractions in soils of two types of cacao agroforestry systems and to compare with an adjacent natural forest in Bahia, Brazil. The land-use systems studied were: (1) a 30-year-old stand of natural forest with cacao (cacao cabruca), (2) a 30-year-old stand of cacao with Erythrina glauca as shade trees (cacao + erythrina), and (3) an adjacent natural forest without cacao. Soil samples were collected from 0-10 cm depth layer in reddish-yellow Oxisols. Soil samples was separated by wet sieving into five fraction-size classes (>2000 μm, 1000-2000 μm, 250-1000 μm, 53-250 μm, and <53 μm). C and N accumulated in to the light (free- and intra-aggregate density fractions) and heavy fractions of whole soil and soil size fraction were determined. Soil size fraction obtained in cacao AFS soils consisted mainly (65 %) of mega-aggregates (>2000 μm) mixed with macroaggregates (32-34%), and microaggregates (1-1.3%). Soil organic carbon (SOC) and total N content increased with increasing soil size fraction in all land-use systems. Organic C-to-total N ratio was higher in the macroaggregate than in the microaggregate. In general, in natural forest and cacao cabruca the contribution of C and N in the light and heavy fractions was similar. However, in cacao + erythrina the heavy fraction was the most common and contributed 67% of C and 63% of N. Finding of this study shows that the majority of C and N in all three systems studied are found in macroaggregates, particularly in the 250-1000 μm size aggregate class. The heavy fraction was the most common organic matter fraction in these soils. Thus, in mature cacao AFS on highly weathered soils the main mechanisms of C stabilization could be the physical protection within macroaggregate structures thereby minimizing the impact of conversion of forest to cacao AFS.

FpvA-mediated ferric pyoverdine uptake in Pseudomonas aeruginosa: identification of aromatic residues in FpvA implicated in ferric pyoverdine binding and transport.

PubMed

Shen, Jiang-Sheng; Geoffroy, Valérie; Neshat, Shadi; Jia, Zongchao; Meldrum, Allison; Meyer, Jean-Marie; Poole, Keith

2005-12-01

A number of aromatic residues were seen to cluster in the upper portion of the three-dimensional structure of the FpvA ferric pyoverdine receptor of Pseudomonas aeruginosa, reminiscent of the aromatic binding pocket for ferrichrome in the FhuA receptor of Escherichia coli. Alanine substitutions in three of these, W362, W391, and F795, markedly compromised ferric pyoverdine binding and transport, consistent with a role of FpvA in ferric pyoverdine recognition.

21 CFR 184.1307 - Ferric sulfate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ferric sulfate. 184.1307 Section 184.1307 Food and... Substances Affirmed as GRAS § 184.1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS Reg. No. 10028-22-5) is a yellow substance that may be prepared by oxidizing iron (II) sulfate or by...

21 CFR 184.1307 - Ferric sulfate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ferric sulfate. 184.1307 Section 184.1307 Food and... Substances Affirmed as GRAS § 184.1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS Reg. No. 10028-22-5) is a yellow substance that may be prepared by oxidizing iron (II) sulfate or by...

21 CFR 184.1307 - Ferric sulfate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ferric sulfate. 184.1307 Section 184.1307 Food and... Substances Affirmed as GRAS § 184.1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS Reg. No. 10028-22-5) is a yellow substance that may be prepared by oxidizing iron (II) sulfate or by...

21 CFR 184.1307 - Ferric sulfate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ferric sulfate. 184.1307 Section 184.1307 Food and... Substances Affirmed as GRAS § 184.1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS Reg. No. 10028-22-5) is a yellow substance that may be prepared by oxidizing iron (II) sulfate or by...

Ferric reductase activity of low molecular weight human milk fraction is associated with enhanced iron solubility and uptake in Caco-2 cells.

PubMed

Pullakhandam, Raghu; Nair, Madhavan Krishnapillai; Kasula, Sunanda; Kilari, Sreenivasulu; Thippande, Tippeswamy Gowda

2008-09-19

It is known that the fractional absorption of extrinsic iron from human milk is higher in infants and adults. A low molecular weight milk fraction has been proposed to increase the bioavailability of iron from human milk. Nevertheless, the mechanisms remained elusive. Here in we demonstrate ferric reductase activity (Km7.73x10(-6)M) in low molecular weight human milk fraction (10kF, filtrate derived from ultra filtration of milk whey through 10kDa cutoff membrane), which increased ferric iron solubility and iron uptake in Caco-2 cells. The 10kF fraction was as effective as ascorbic acid (1:20 iron to ascorbic acid) in increasing the ferric iron solubility and uptake in Caco-2 cells. Further, gel filtration chromatography on peptide column led to co-elution of ferric reductase and iron solubilization activities at an apparent molecular mass of <1500Da. Interestingly, only these fractions containing ferric reductase activity also stimulated the uptake of iron in Caco-2 cells. Thus, it is concluded that human milk possesses ferric reductase activity and is associated with ferric iron solubilization and enhanced absorption.

21 CFR 582.5301 - Ferric phosphate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use. This...

21 CFR 582.5304 - Ferric pyrophosphate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5304 Ferric pyrophosphate. (a) Product. Ferric pyrophosphate. (b) Conditions of use. This...

21 CFR 582.5301 - Ferric phosphate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use. This...

21 CFR 582.5304 - Ferric pyrophosphate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5304 Ferric pyrophosphate. (a) Product. Ferric pyrophosphate. (b) Conditions of use. This...

21 CFR 582.5304 - Ferric pyrophosphate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5304 Ferric pyrophosphate. (a) Product. Ferric pyrophosphate. (b) Conditions of use. This...

21 CFR 582.5304 - Ferric pyrophosphate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5304 Ferric pyrophosphate. (a) Product. Ferric pyrophosphate. (b) Conditions of use. This...

21 CFR 582.5301 - Ferric phosphate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use. This...

21 CFR 582.5301 - Ferric phosphate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use. This...

21 CFR 582.5301 - Ferric phosphate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5301 Ferric phosphate. (a) Product. Ferric phosphate. (b) Conditions of use. This...

21 CFR 582.5304 - Ferric pyrophosphate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5304 Ferric pyrophosphate. (a) Product. Ferric pyrophosphate. (b) Conditions of use. This...

The Phosphate Binder Ferric Citrate and Mineral Metabolism and Inflammatory Markers in Maintenance Dialysis Patients: Results From Prespecified Analyses of a Randomized Clinical Trial

PubMed Central

Van Buren, Peter N.; Lewis, Julia B.; Dwyer, Jamie P.; Greene, Tom; Middleton, John; Sika, Mohammed; Umanath, Kausik; Abraham, Josephine D.; Arfeen, Shahabul S.; Bowline, Isai G.; Chernin, Gil; Fadem, Stephen Z.; Goral, Simin; Koury, Mark; Sinsakul, Marvin V.; Weiner, Daniel E.

2016-01-01

Background Phosphate binders are the cornerstone of hyperphosphatemia management in dialysis patients. Ferric citrate is an iron-based oral phosphate binder that effectively lowers serum phosphorus levels. Study Design 52-week, open-label, phase 3, randomized, controlled trial for safety-profile assessment. Setting & Participants Maintenance dialysis patients with serum phosphorus levels ≥6.0 mg/dL after washout of prior phosphate binders. Intervention 2:1 randomization to ferric citrate or active control (sevelamer carbonate and/or calcium acetate). Outcomes Changes in mineral bone disease, protein-energy wasting/inflammation, and occurrence of adverse events after 1 year. Measurements Serum calcium, intact parathyroid hormone, phosphorus, aluminum, white blood cell count, percentage of lymphocytes, serum urea nitrogen, and bicarbonate. Results There were 292 participants randomly assigned to ferric citrate, and 149, to active control. Groups were well matched. For mean changes from baseline, phosphorus levels decreased similarly in the ferric citrate and active control groups (−2.04 ± 1.99 [SD] vs −2.18 ± 2.25 mg/dL, respectively; P = 0.9); serum calcium levels increased similarly in the ferric citrate and active control groups (0.22 ± 0.90 vs 0.31 ± 0.95 mg/dL; P = 0.2). Hypercalcemia occurred in 4 participants receiving calcium acetate. Parathyroid hormone levels decreased similarly in the ferric citrate and active control groups (−167.1 ± 399.8 vs −152.7 ± 392.1 pg/mL; P = 0.8). Serum albumin, bicarbonate, serum urea nitrogen, white blood cell count and percentage of lymphocytes, and aluminum values were similar between ferric citrate and active control. Total and low-density lipoprotein cholesterol levels were lower in participants receiving sevelamer than those receiving ferric citrate and calcium acetate. Fewer participants randomly assigned to ferric citrate had serious adverse events compared with active control. Limitations Open-label study, few peritoneal dialysis patients. Conclusions Ferric citrate was associated with similar phosphorus control compared to active control, with similar effects on markers of bone and mineral metabolism in dialysis patients. There was no evidence of protein-energy wasting/inflammation or aluminum toxicity, and fewer participants randomly assigned to ferric citrate had serious adverse events. Ferric citrate is an effective phosphate binder with a safety profile comparable to sevelamer and calcium acetate. PMID:25958079

Sodium Ferric Gluconate Injection

MedlinePlus

Sodium ferric gluconate injection is used to treat iron-deficiency anemia (a lower than normal number of ... are also receiving the medication epoetin (Epogen, Procrit). Sodium ferric gluconate injection is in a class of ...

Ferric citrate hydrate for the treatment of hyperphosphatemia in nondialysis-dependent CKD.

PubMed

Yokoyama, Keitaro; Hirakata, Hideki; Akiba, Takashi; Fukagawa, Masafumi; Nakayama, Masaaki; Sawada, Kenichi; Kumagai, Yuji; Block, Geoffrey A

2014-03-01

Ferric citrate hydrate is a novel iron-based phosphate binder being developed for hyperphosphatemia in patients with CKD. A phase 3, multicenter, randomized, double blind, placebo-controlled study investigated the efficacy and safety of ferric citrate hydrate in nondialysis-dependent patients with CKD. Starting in April of 2011, 90 CKD patients (eGFR=9.21±5.72 ml/min per 1.73 m(2)) with a serum phosphate≥5.0 mg/dl were randomized 2:1 to ferric citrate hydrate or placebo for 12 weeks. The primary end point was change in serum phosphate from baseline to the end of treatment. Secondary end points included the percentage of patients achieving target serum phosphate levels (2.5-4.5 mg/dl) and change in fibroblast growth factor-23 at the end of treatment. The mean change in serum phosphate was -1.29 mg/dl (95% confidence interval, -1.63 to -0.96 mg/dl) in the ferric citrate hydrate group and 0.06 mg/dl (95% confidence interval, -0.20 to 0.31 mg/dl) in the placebo group (P<0.001 for difference between groups). The percentage of patients achieving target serum phosphate levels was 64.9% in the ferric citrate hydrate group and 6.9% in the placebo group (P<0.001). Fibroblast growth factor-23 concentrations were significantly lower in patients treated with ferric citrate hydrate versus placebo (change from baseline [median], -142.0 versus 67.0 pg/ml; P<0.001). Ferric citrate hydrate significantly increased serum iron, ferritin, and transferrin saturation compared with placebo (P=0.001 or P<0.001). Five patients discontinued active treatment because of treatment-emergent adverse events with ferric citrate hydrate treatment versus one patient with placebo. Overall, adverse drug reactions were similar in patients receiving ferric citrate hydrate or placebo, with gastrointestinal disorders occurring in 30.0% of ferric citrate hydrate patients and 26.7% of patients receiving placebo. In patients with nondialysis-dependent CKD, 12-week treatment with ferric citrate hydrate resulted in significant reductions in serum phosphate and fibroblast growth factor-23 while simultaneously increasing serum iron parameters.

Ferric Citrate Decreases Fibroblast Growth Factor 23 and Improves Erythropoietin Responsiveness in Hemodialysis Patients.

PubMed

Maruyama, Noriaki; Otsuki, Tomoyasu; Yoshida, Yoshinori; Nagura, Chinami; Kitai, Maki; Shibahara, Nami; Tomita, Hyoe; Maruyama, Takashi; Abe, Masanori

2018-06-06

Serum phosphate and vitamin D receptor activator regulate fibroblast growth factor 23 (FGF23), and iron may modulate FGF23 metabolism. The aim of the present study was to elucidate the effects of ferric citrate hydrate and lanthanum carbohydrate on serum FGF23 levels in hemodialysis patients. This prospective, open-label, multicenter study enrolled 60 patients on hemodialysis treated with lanthanum carbonate. Patients were randomly assigned to 2 groups: those switching from lanthanum carbonate to ferric citrate hydrate (ferric citrate group, n = 30) or those continuing lanthanum carbonate (control group, n = 30). Patients were monitored for 24 weeks. Endpoints included changes in FGF23, phosphate, and the dose of erythropoiesis stimulating agent (ESA), erythropoietin responsiveness index (ERI), and adverse events. FGF-23 levels were significantly lower in the ferric citrate group compared with the levels in the control group (change from baseline -6,160 vs. -1,118 pg/mL; p = 0.026). There were no significant changes in serum calcium, phosphate, and intact parathyroid hormone levels in either group. The ferric citrate group had significantly increased serum iron, ferritin, and transferrin saturation. Hemoglobin levels were significantly elevated, and the dose of ESA was significantly decreased in the ferric citrate group but not in the control group. ERI and the dose of intravenous saccharated ferric oxide were significantly lower in the ferric citrate group compared with those of the control group (p = 0.015 and p = 0.002). In patients on hemodialysis, 24-week treatment with ferric citrate hydrate resulted in significant reduction in FGF23 and ERI independently of serum phosphate level. © 2018 S. Karger AG, Basel.

Reduction of ferric iron by acidophilic heterotrophic bacteria: evidence for constitutive and inducible enzyme systems in Acidiphilium spp.

PubMed

Johnson, D B; Bridge, T A M

2002-01-01

To compare the abilities of two obligately acidophilic heterotrophic bacteria, Acidiphilium acidophilum and Acidiphilium SJH, to reduce ferric iron to ferrous when grown under different culture conditions. Bacteria were grown in batch culture, under different aeration status, and in the presence of either ferrous or ferric iron. The specific rates of ferric iron reduction by fermenter-grown Acidiphilium SJH were unaffected by dissolved oxygen (DO) concentrations, while iron reduction by A. acidophilum was highly dependent on DO concentrations in the growth media. The ionic form of iron present (ferrous or ferric) had a minimal effect on the abilities of harvested cells to reduce ferric iron. Whole cell protein profiles of Acidiphilium SJH were very similar, regardless of the DO status of the growth medium, while additional proteins were present in A. acidophilum grown microaerobically compared with aerobically-grown cells. The dissimilatory reduction of ferric iron is constitutive in Acidiphilium SJH while it is inducible in A. acidophilum. Ferric iron reduction by Acidiphilium spp. may occur in oxygen-containing as well as anoxic acidic environments. This will detract from the effectiveness of bioremediation systems where removal of iron from polluted waters is mediated via oxidation and precipitation of the metal.

Linking species richness, biodiversity and ecosystem function in soil system

Treesearch

David C. Coleman; William B. Whitman

2004-01-01

Soils are the central organizing entities in terrestrial ecosystem and possess extremely diverse prokaryotic and eukaryotic biota. They are physically and chemically complex, with micro- and macro-aggregates embedded within a solid, liquid and gaseous matrix that is continually changing in response to natural and human-induced perturbations. Recent advances in...

Roles of biology, chemistry, and physics in soil macroaggregate formation and stabilization

USDA-ARS?s Scientific Manuscript database

Soil functions or ecosystem services depend on the distribution of macro- (= 0.25 mm) and micro- (< 0.25 mm) aggregates and open space between aggregates. It is the arrangement of the aggregates and pore space which allows air and water movement in and out of soil; reduces compaction; and stimulates...

Influence of Soil Organic Matter Stabilization Mechanisms on Temperature Sensitivity of Soil Respiration

NASA Astrophysics Data System (ADS)

Gillabel, J.; de Gryze, S.; Six, J.; Merckx, R.

2007-12-01

Knowledge on the sensitivity of soil organic matter (SOM) respiration to changes in temperature is crucial for predicting future impacts of climate change on soil C stocks. Temperature sensitivity of respiration is determined by the chemical structure of the compound to be decomposed and by the availability of the organic matter for decomposers. Biochemically recalcitrant SOM has a higher temperature sensitivity than biochemically labile SOM. However, it is hypothesized that the stabilization of SOM by interaction with the soil matrix could be an important attenuating control on temperature sensitivity. We investigated the effect of different SOM stabilization mechanisms on temperature sensitivity of SOM respiration. Two main mechanisms were considered: chemical interactions of SOM with clay and silt particles, and physical protection inside aggregates. Soil samples from an agricultural silt loam soil were fractionated by wet-sieving into macroaggregates, microaggregates and silt+clay fractions. SOM stabilization in the silt+clay fraction occurs mainly chemically, whereas in aggregates physical protection of SOM is more important. Samples of each fraction and of bulk soil were incubated at two temperatures (20°C and 30°C) for one month. After 2% of total soil carbon was respired, temperature sensitivity was determined for respiration of the next 0.5% of total soil carbon. This was done by calculating a Q10 value as the ratio of the times needed at each temperature to respire that fraction of the soil C. This method allows determination of temperature sensitivity independent of C quality. Calculated Q10 values decreased in the order bulk soil > macroaggregates > microaggregates > silt+clay, with the difference between macroaggregate Q10 and silt+clay Q10 being the only significant difference. These results indicate that protection of SOM attenuates temperature sensitivity, with chemical protection (silt+clay) having a larger effect than physical protection (aggregates).

Reflectance spectroscopy of ferric sulfate-bearing montmorillonites as Mars soil analog materials

NASA Technical Reports Server (NTRS)

Bishop, J. L.; Pieters, C. M.; Burns, R. G.; Edwards, J. O.; Mancinelli, R. L.; Froschl, H.

1995-01-01

Spectroscopic analyses have shown that smectites enhanced in the laboratory with additional ferric species exhibit important similarities to those of the soils on Mars. Ferrihydrite in these chemically treated smectites has features in the visible to near-infrared region that resemble the energies and band strengths of features in reflectance spectra observed for several bright regions on Mars. New samples have been prepared with sulfate as well, because S was found by Viking to be a major component in the surface material on Mars. A suite of ferrihydrite-bearing and ferric sulfate-bearing montmorillonites, prepared with variable Fe3+ and S concentrations and variable pH conditions, has been analyzed using reflectance spectroscopy in the visible and infrared regions, Mossbauer spectroscopy at room temperature and 4 K, differential thermal analysis, and X-ray diffraction. These analyses support the formation of ferrihydrite of variable crystallinity in the ferrihydrite-bearing montmorillonites and a combination of schwertmannite and ferrihydrite in the ferric sulfate-bearing montmorillonites. Small quantities of poorly crystalline or nanophase forms of other ferric materials may also be present in these samples. The chemical formation conditions of the ferrihydrite-bearing and ferric sulfate-bearing montmorillonites influence the character of the low temperature Mossbauer sextets and the visible reflectance spectra. An absorption minimum is observed at 0.88-0.89 micrometers in spectra of the ferric sulfate-bearing samples, and at 0.89-0.92 micrometers in spectra of the ferrihydrate-bearing montmorillonites. Mossbauer spectra of the ferric sulfate-bearing montmorillonites indicate variable concentrations of ferrihydrite and schwertmannite in the interlaminar spaces and along grain surfaces. Dehydration under reduced atmospheric pressure conditions induces a greater effect on the adsorbed and interlayer water in ferrihydrite-bearing montmorillonite than on the water in ferric sulfate-bearing montmorillonite. Reflectance spectra of ferric sulfate-bearing montmorillonite include a strong 3-micrometers band that is more resistant to dry atmospheric conditions than the 3-micrometers band in spectra of similarly prepared ferrihydrite-bearing montmorillonites.

Ferric maltol therapy for iron deficiency anaemia in patients with inflammatory bowel disease: long-term extension data from a Phase 3 study.

PubMed

Schmidt, C; Ahmad, T; Tulassay, Z; Baumgart, D C; Bokemeyer, B; Howaldt, S; Stallmach, A; Büning, C

2016-08-01

Ferric maltol was effective and well-tolerated in iron deficiency anaemia patients with inflammatory bowel disease during a 12-week placebo-controlled trial. To perform a Phase 3 extension study evaluating long-term efficacy and safety with ferric maltol in inflammatory bowel disease patients in whom oral ferrous therapies had failed to correct iron deficiency anaemia. After 12 weeks of randomised, double-blind treatment, patients with iron deficiency anaemia and mild-to-moderate ulcerative colitis or Crohn's disease received open-label ferric maltol 30 mg b.d. for 52 weeks. 111 patients completed randomised treatment and 97 entered the open-label ferric maltol extension. In patients randomised to ferric maltol ('continued'; n = 50), mean ± s.d. haemoglobin increased by 3.07 ± 1.46 g/dL between baseline and Week 64. In patients randomised to placebo ('switch'; n = 47), haemoglobin increased by 2.19 ± 1.61 g/dL. Normal haemoglobin was achieved in high proportions of both continued and switch patients (89% and 83% at Week 64, respectively). Serum ferritin increased from 8.9 μg/L (baseline) to 26.0 μg/L (Week 12) in ferric maltol-treated patients, and to 57.4 μg/L amongst all patients at Week 64. In total, 80% of patients reported ≥1 adverse event by Week 64. Adverse events considered related to ferric maltol were recorded in 27/111 (24%) patients: 8/18 discontinuations due to adverse events were treatment-related. One patient was withdrawn due to increased ulcerative colitis activity. Normal haemoglobin was observed in ≥80% of patients from weeks 20-64 of long-term ferric maltol treatment, with concomitant increases in iron storage parameters. Ferric maltol was well-tolerated throughout this 64-week study. © 2016 The Authors. Alimentary Pharmacology & Therapeutics published by John Wiley & Sons Ltd.

Associations between iron concentration and productivity in montane streams of the Black Hills, South Dakota

USGS Publications Warehouse

Hayer, Cari Ann; Holcomb, Benjamin M.; Chipps, Steven R.

2013-01-01

Iron is an important micronutrient found in aquatic systems that can influence nutrient availability (e.g., phosphorus) and primary productivity. In streams, high iron concentrations often are associated with low pH as a result of acid mine drainage, which is known to affect fish and invertebrate communities. Streams in the Black Hills of South Dakota are generally circumneutral in pH, yet select streams exhibit high iron concentrations associated with natural iron deposits. In this study, we examined relationships among iron concentration, priphyton biomass, macroinvertebrate abundance, and fish assemblages in four Black Hills streams. The stream with the highest iron concentration (~5 mg Fe/L) had reduced periphyton biomass, invertebrate abundance, and fish biomass compared to the three streams with lower iron levels (0.1 to 0.6 mg Fe/L). Reduced stream productivity was attributed to indirect effects of ferric iron Fe+++), owing to iron-hydroxide precipitation that influenced habitat quality (i.e., substrate and turbidity) and food availability (periphyton and invertebrates) for higher trophic levels (e.g., fish). Additionally, reduced primary and secondary production was associated with reduced standing stocks of salmonid fishes. Our findings suggested that naturally occurring iron deposits may constrain macroinvertebrate and fish production.

Mobilization of natural colloids from an iron oxide-coated sand aquifer--Effect of pH and ionic strength

USGS Publications Warehouse

Bunn, Rebecca A.; Magelky, Robin D.; Ryan, Joseph N.; Elimelech, Menachem

2002-01-01

Field and laboratory column experiments were performed to assess the effect of elevated pH and reduced ionic strength on the mobilization of natural colloids in a ferric oxyhydroxide-coated aquifer sediment. The field experiments were conducted as natural gradient injections of groundwater amended by sodium hydroxide additions. The laboratory experiments were conducted in columns of undisturbed, oriented sediments and disturbed, disoriented sediments. In the field, the breakthrough of released colloids coincided with the pH pulse breakthrough and lagged the bromide tracer breakthrough. The breakthrough behavior suggested that the progress of the elevated pH front controlled the transport of the mobilized colloids. In the laboratory, about twice as much colloid release occurred in the disturbed sediments as in the undisturbed sediments. The field and laboratory experiments both showed that the total mass of colloid release increased with increasing pH until the concurrent increase in ionic strength limited release. A decrease in ionic strength did not mobilize significant amounts of colloids in the field. The amount of colloids released normalized to the mass of the sediments was similar for the field and the undisturbed laboratory experiments.

Interior microelectrolysis oxidation of polyester wastewater and its treatment technology.

PubMed

Yang, Xiaoyi

2009-09-30

This paper has investigated the effects of interior microelectrolysis pretreatment on polyester wastewater treatment and analyzed its mechanism on COD and surfactant removal. The efficiency of interior microelectrolysis is mainly influenced by solution pH, aeration and reaction time. Contaminants can be removed not only by redox reaction and flocculation in the result of ferrous and ferric hydroxides but also by electrophoresis under electric fields created by electron flow. pH confirms the chemical states of surfactants, Fe(II)/Fe(III) ratio and the redox potential, and thus influences the effects of electrophoresis, flocculation and redox action on contaminant removal. Anaerobic and aerobic batch tests were performed to study the degradation of polyester wastewater. The results imply that interior microelectrolysis and anaerobic pretreatment are lacking of effectiveness if applied individually in treating polyester wastewater in spite of their individual advantages. The interior microelectrolysis-anaerobic-aerobic process was investigated to treat polyester wastewater with comparison with interior microelectrolysis-aerobic process and anaerobic-aerobic process. High COD removal efficiencies have been gotten by the combination of interior microelectrolysis with anaerobic technology and aerobic technology. The results also imply that only biological treatment was less effective in polyester wastewater treatment.

Arsenic removal from water using lignocellulose adsorption medium (LAM).

PubMed

Kim, Juyoung; Mann, Justin D; Spencer, Jesse G

2006-01-01

Arsenate in water is readily adsorbed on lignocellulose adsorption medium (LAM) which is cotton-based and has been coated with iron(III) by soaking cotton pellets in ferric chloride solution. Capacities achieved with LAM average 32.8 mg As/g of medium at influent arsenic concentrations ranging from 20-30 mg As/L. Adsorption follows (R2 = 0.993) a Freundlich isotherm, (x/M) = 22.845 Ce0.25, where (x/M) is the ratio of milligrams of contaminant adsorbed per gram of adsorbent and Ce is the equilibrium concentration. As is often the case with adsorption from solution, the fit using a Langmuir isotherm was not as good (R2 = 0.8786). The adsorbent when saturated can be regenerated by treatment with dilute sodium hydroxide. After five regenerations, the capacity dropped by 11.5%. Arsenate washed off the adsorbent after regeneration, as well as that left on the medium, may be concentrated and disposed of properly or perhaps recycled. Consideration of costs shows that one ton of iron(III)-treated adsorbent can be used to remove arsenate at toxic levels from drinking water at a cost of about 3.20/ton US dollars plus the cost of media without regeneration.

U-EXTRACTION--IMPROVEMENTS IN ELIMINATION OF Mo BY USE OF FERRIC ION

DOEpatents

Clark, H.M.; Duffey, D.

1958-06-10

An improved solvent extraction process is described whereby U may be extracted by a water immiscible organic solvent from an aqueous solution of uranyl nitrate. It has been found that Mo in the presence of phosphate ions appears to form a complex with the phosphate which extracts along with the U. This extraction of Mo may be suppressed by providing ferric ion in the solution prior to the extraction step. The ferric ion is preferably provided in the form of ferric nitrate.

Adherence rates to ferric citrate as compared to active control in patients with end stage kidney disease on dialysis.

PubMed

Jalal, Diana; McFadden, Molly; Dwyer, Jamie P; Umanath, Kausik; Aguilar, Erwin; Yagil, Yoram; Greco, Barbara; Sika, Mohammed; Lewis, Julia B; Greene, Tom; Goral, Simin

2017-04-01

Oral phosphate binders are the main stay of treatment of hyperphosphatemia. Adherence rates to ferric citrate, a recently approved phosphate binder, are unknown. We conducted a post-hoc analysis to evaluate whether adherence rates were different for ferric citrate vs. active control in 412 subjects with end stage kidney disease (ESKD) who were randomized to ferric citrate vs. active control (sevelamer carbonate and/or calcium acetate). Adherence was defined as percent of actual number of pills taken to total number of pills prescribed. There were no significant differences in baseline characteristics including gender, race/ethnicity, and age between the ferric citrate and active control groups. Baseline phosphorus, calcium, and parathyroid hormone levels were similar. Mean (SD) adherence was 81.4% (17.4) and 81.7% (15.9) in the ferric citrate and active control groups, respectively (P = 0.88). Adherence remained similar between both groups after adjusting for gender, race/ethnicity, age, cardiovascular disease (CVD), and diabetic nephropathy (mean [95% CI]: 81.4% [78.2, 84.6] and 81.5% [77.7, 85.2] for ferric citrate and active control, respectively). Gender, race/ethnicity, age, and diagnosis of diabetic nephropathy did not influence adherence to the prescribed phosphate binder. Subjects with CVD had lower adherence rates to phosphate binder; this was significant only in the active control group. Adherence rates to the phosphate binder, ferric citrate, were similar to adherence rates to active control. Similar adherence rates to ferric citrate are notable since tolerance to active control was an entry criteria and the study was open label. Gender, race/ethnicity, nor age influenced adherence. © 2016 International Society for Hemodialysis.

Signal transfer through three compartments: transcription initiation of the Escherichia coli ferric citrate transport system from the cell surface.

PubMed

Härle, C; Kim, I; Angerer, A; Braun, V

1995-04-03

Transport of ferric citrate into cells of Escherichia coli K-12 involves two energy-coupled transport systems, one across the outer membrane and one across the cytoplasmic membrane. Previously, we have shown that ferric citrate does not have to enter the cytoplasm of E. coli K-12 to induce transcription of the fec ferric citrate transport genes. Here we demonstrate that ferric citrate uptake into the periplasmic space between the outer and the cytoplasmic membranes is not required for fec gene induction. Rather, FecA and the TonB, ExbB and ExbD proteins are involved in induction of the fec transport genes independent of their role in ferric citrate transport across the outer membrane. The uptake of ferric citrate into the periplasmic space of fecA and tonB mutants via diffusion through the porin channels did not induce transcription of fec transport genes. Point mutants in FecA displayed the constitutive expression of fec transport genes in the absence of ferric citrate but still required TonB, with the exception of one FecA mutant which showed a TonB-independent induction. The phenotype of the FecA mutants suggests a signal transduction mechanism across three compartments: the outer membrane, the periplasmic space and the cytoplasmic membrane. The signal is triggered upon the interaction of ferric citrate with FecA protein. It is postulated that FecA, TonB, ExbB and ExbD transfer the signal across the outer membrane, while the regulatory protein FecR transmits the signal across the cytoplasmic membrane to FecI in the cytoplasm. FecI serves as a sigma factor which facilitates binding of the RNA polymerase to the fec transport gene promoter upstream of fecA.(ABSTRACT TRUNCATED AT 250 WORDS)

Disinhibition of excessive volatile fatty acids to improve the efficiency of autothermal thermophilic aerobic sludge digestion by chemical approach.

PubMed

Jin, Ningben; Jin, Bo; Zhu, Nanwen; Yuan, Haiping; Ruan, Jianbo

2015-01-01

In this study, we explored a chemical approach to eliminate inhibition of excessive volatile fatty acids (VFAs) in autothermal thermophilic aerobic digestion (ATAD). Ferric nitrate, ferric chloride, potassium nitrate and potassium chloride were employed to demonstrate the combined action of ferric ion and nitrate ion. Supplementation of ferric nitrate in the sludge digestion system resulted in reducing the concentration of Total VFAs (TVFA) by round 5000mg/L and more than 2000mg/L of acetic acid at the end of digestion. Lower TVFA concentration contributed to faster sludge stabilization rate and the VS removal of ferric nitrate dosed digester achieved 38.18% after 12days digestion which was 9days in advance compared with the stabilization time of sludge in digester without chemicals addition. Lower concentrations of NH4(+)-N and SCOD in supernatant while higher content of TP in digestion sludge were obtained in digester with ferric nitrate added. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determination of the Molecular Structures of Ferric Enterobactin and Ferric Enantioenterobactin Using Racemic Crystallography.

PubMed

Johnstone, Timothy C; Nolan, Elizabeth M

2017-10-25

Enterobactin is a secondary metabolite produced by Enterobacteriaceae for acquiring iron, an essential metal nutrient. The biosynthesis and utilization of enterobactin permits many Gram-negative bacteria to thrive in environments where low soluble iron concentrations would otherwise preclude survival. Despite extensive work carried out on this celebrated molecule since its discovery over 40 years ago, the ferric enterobactin complex has eluded crystallographic structural characterization. We report the successful growth of single crystals containing ferric enterobactin using racemic crystallization, a method that involves cocrystallization of a chiral molecule with its mirror image. The structures of ferric enterobactin and ferric enantioenterobactin obtained in this work provide a definitive assignment of the stereochemistry at the metal center and reveal secondary coordination sphere interactions. The structures were employed in computational investigations of the interactions of these complexes with two enterobactin-binding proteins, which illuminate the influence of metal-centered chirality on these interactions. This work highlights the utility of small-molecule racemic crystallography for obtaining elusive structures of coordination complexes.

Transient species involved in catalytic dioxygen/peroxide activation by hemoproteins: possible involvement of protonated Compound I species.

PubMed

Silaghi-Dumitrescu, Radu; Cooper, Chris E

2005-11-07

Interaction of hemoproteins with peroxide leads in several cases to transient formation of ferric peroxo, ferric hydroperoxo, and "high-valent", formally Fev, oxo or hydroxo Compound species. Here, density functional calculations on ferric peroxo, ferric hydroperoxo, Compound and protonated Compound heme active site models are reported. The theoretical results, including calculated isotropic Fermi contact couplings and anisotropic spin dipole couplings, are found to generally correlate well with experimental EPR/ENDOR data. Hydrogen bonding and solvation affect the ferric-peroxo/ferrous-superoxo electromerism. The transition between the two electromers appears smooth, but neither hydrogen bonding to up to two water molecules, nor solvation appear able to dramatically alter the redox state of the superoxo ligand or of the iron. The presence of almost one full unpaired electron on the iron and of one full unpaired electron on the dioxygenic ligand in the "ferric-peroxo" state suggests a possible description of non-protonated "ferric-peroxo" as {ferric-superoxo+porphyrin radical}. Emerging from the DFT data is the possibility that a protonated Compound has already been detected in ENDOR experiments on cytochrome P450. The general feasibility of a protonated Compound in P450 monooxygenases is probed in light of these findings. To encompass the multiple mechanisms available in P450 for substrate oxidation, we define "mechanistic promiscuity" as the feature allowing an enzyme to perform the same reaction, with the same product, using more than one mechanism.

21 CFR 73.1298 - Ferric ammonium ferrocyanide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Ferric ammonium ferrocyanide. 73.1298 Section 73.1298 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1298 Ferric ammonium ferrocyanide. (a...

21 CFR 73.1025 - Ferric ammonium citrate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Ferric ammonium citrate. 73.1025 Section 73.1025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1025 Ferric ammonium citrate. (a) Identity. The...

21 CFR 73.1298 - Ferric ammonium ferrocyanide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Ferric ammonium ferrocyanide. 73.1298 Section 73.1298 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1298 Ferric ammonium ferrocyanide. (a...

21 CFR 73.1299 - Ferric ferrocyanide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ferric ferrocyanide. 73.1299 Section 73.1299 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1299 Ferric ferrocyanide. (a) Identity. (1) The...

21 CFR 73.1299 - Ferric ferrocyanide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Ferric ferrocyanide. 73.1299 Section 73.1299 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1299 Ferric ferrocyanide. (a) Identity. (1) The...

21 CFR 73.1025 - Ferric ammonium citrate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Ferric ammonium citrate. 73.1025 Section 73.1025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1025 Ferric ammonium citrate. (a) Identity. The...

21 CFR 73.1025 - Ferric ammonium citrate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Ferric ammonium citrate. 73.1025 Section 73.1025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1025 Ferric ammonium citrate. (a) Identity. The...

21 CFR 73.1298 - Ferric ammonium ferrocyanide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ferric ammonium ferrocyanide. 73.1298 Section 73.1298 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1298 Ferric ammonium ferrocyanide. (a...

21 CFR 73.1298 - Ferric ammonium ferrocyanide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Ferric ammonium ferrocyanide. 73.1298 Section 73.1298 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1298 Ferric ammonium ferrocyanide. (a...

21 CFR 73.1299 - Ferric ferrocyanide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Ferric ferrocyanide. 73.1299 Section 73.1299 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1299 Ferric ferrocyanide. (a) Identity. (1) The...

21 CFR 73.1299 - Ferric ferrocyanide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Ferric ferrocyanide. 73.1299 Section 73.1299 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1299 Ferric ferrocyanide. (a) Identity. (1) The...

46 CFR 151.50-75 - Ferric chloride solution.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Ferric chloride solution. 151.50-75 Section 151.50-75 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-75 Ferric chloride solution...

21 CFR 73.1025 - Ferric ammonium citrate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Ferric ammonium citrate. 73.1025 Section 73.1025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1025 Ferric ammonium citrate. (a) Identity. The...

21 CFR 73.1025 - Ferric ammonium citrate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ferric ammonium citrate. 73.1025 Section 73.1025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1025 Ferric ammonium citrate. (a) Identity. The...

QTL analysis of ferric reductase activity in the model legume lotus japonicus

USDA-ARS?s Scientific Manuscript database

Physiological and molecular studies have demonstrated that iron accumulation from the soil into Strategy I plants can be limited by ferric reductase activity. An initial study of Lotus japonicus ecotypes Miyakojima MG-20 and Gifu B-129 identified significant leaf chlorosis and ferric reductase activ...

Mid-infrared transmission spectra of crystalline and nanophase iron oxides/oxyhydroxides and implications for remote sensing of Mars

NASA Technical Reports Server (NTRS)

Bell, James F., III; Roush, Ted L.; Morris, Richard V.

1995-01-01

Ferric-iron-bearing materials play an important role in the interpretation of visible to near-IR Mars spectra, and they may play a similarly important role in the analysis of new mid-IR spacecraft spectral observations to be obtained over the next decade. We review existing data on mid-IR transmission spectra of ferric oxides/oxyhydroxides and present new transmission spectra for ferric-bearing materials spanning a wide range of mineralogy and crystallinity. These materials include 11 samples of well-crystallized ferric oxides (hematite, maghemite, and magnetite) and ferric oxyhydroxides (goethite, lepidocrocite). We also report the first transmission spectra for purely nanophase ferric oxide samples that have been shown to exhibit spectral similarities to Mars in the visible to near-IR and we compare these data to previous and new transmission spectra of terrestrial palagonites. Most of these samples show numerous, diagnostic absorption features in the mid-IR due to Fe(3+)-O(2-) vibrational transitions, structural and/or bound OH, and/or silicates. These data indicate that high spatial resolution, moderate spectral resolution mid-IR ground-based and spacecraft observations of Mars may be able to detect and uniquely discriminate among different ferric-iron-bearing phases on the Martian surface or in the airborne dust.

Mid-infrared transmission spectra of crystalline and nanophase iron oxides/oxyhydroxides and implications for remote sensing of Mars

NASA Technical Reports Server (NTRS)

Bell, James F., III; Roush, Ted L.; Morris, Richard V.

1995-01-01

Ferric-iron-bearing materials play an important role in the interpretation of visible to near-IR Mars spectra, and they may play a similarly important role in the analysis of new mid-IR spacecraft spectral observations to be obtained over the next decade. We review exisiting data on mid-IR transmission spectra of ferric oxides/oxyhydroxides and present new transmission spectra for ferric-bearing materials spanning a wide range of mineralogy and crystallinity. These materials include 11 samples of well-crystallized ferric oxides (hematite, maghemite, and magnetite) and ferric oxyhydroxides (goethite, lepidocrocite). We also report the first transmission spectra for purely nanophase ferric oxide samples that have been shown to exhibit spectral similarities to Mars in the visible to near-IR and we compare these data to previous and new transmission spectra of terrestial palagonites. Most of these samples show numerous, diagnostic absorption features in the mid-IR due to Fe(3+) - 0(2-) vibrational transitions, structural and/or bound OH, and/or silicates. These data indicate that high spatial resolution, moderate spectral resolution mid-IR ground-based and spacecraft observations of Mars may be able to detect and uniquely discriminate among different ferric-iron-bearing phases on the Martian surface or in the airborne dust.

A mass balance approach to investigate arsenic cycling in a petroleum plume.

PubMed

Ziegler, Brady A; Schreiber, Madeline E; Cozzarelli, Isabelle M; Crystal Ng, G-H

2017-12-01

Natural attenuation of organic contaminants in groundwater can give rise to a series of complex biogeochemical reactions that release secondary contaminants to groundwater. In a crude oil contaminated aquifer, biodegradation of petroleum hydrocarbons is coupled with the reduction of ferric iron (Fe(III)) hydroxides in aquifer sediments. As a result, naturally occurring arsenic (As) adsorbed to Fe(III) hydroxides in the aquifer sediment is mobilized from sediment into groundwater. However, Fe(III) in sediment of other zones of the aquifer has the capacity to attenuate dissolved As via resorption. In order to better evaluate how long-term biodegradation coupled with Fe-reduction and As mobilization can redistribute As mass in contaminated aquifer, we quantified mass partitioning of Fe and As in the aquifer based on field observation data. Results show that Fe and As are spatially correlated in both groundwater and aquifer sediments. Mass partitioning calculations demonstrate that 99.9% of Fe and 99.5% of As are associated with aquifer sediment. The sediments act as both sources and sinks for As, depending on the redox conditions in the aquifer. Calculations reveal that at least 78% of the original As in sediment near the oil has been mobilized into groundwater over the 35-year lifespan of the plume. However, the calculations also show that only a small percentage of As (∼0.5%) remains in groundwater, due to resorption onto sediment. At the leading edge of the plume, where groundwater is suboxic, sediments sequester Fe and As, causing As to accumulate to concentrations 5.6 times greater than background concentrations. Current As sinks can serve as future sources of As as the plume evolves over time. The mass balance approach used in this study can be applied to As cycling in other aquifers where groundwater As results from biodegradation of an organic carbon point source coupled with Fe reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

A mass balance approach to investigate arsenic cycling in a petroleum plume

USGS Publications Warehouse

Ziegler, Brady A.; Schreiber, Madeline E.; Cozzarelli, Isabelle M.; Ng. G.-H. Crystal,

2017-01-01

Natural attenuation of organic contaminants in groundwater can give rise to a series of complex biogeochemical reactions that release secondary contaminants to groundwater. In a crude oil contaminated aquifer, biodegradation of petroleum hydrocarbons is coupled with the reduction of ferric iron (Fe(III)) hydroxides in aquifer sediments. As a result, naturally occurring arsenic (As) adsorbed to Fe(III) hydroxides in the aquifer sediment is mobilized from sediment into groundwater. However, Fe(III) in sediment of other zones of the aquifer has the capacity to attenuate dissolved As via resorption. In order to better evaluate how long-term biodegradation coupled with Fe-reduction and As mobilization can redistribute As mass in contaminated aquifer, we quantified mass partitioning of Fe and As in the aquifer based on field observation data. Results show that Fe and As are spatially correlated in both groundwater and aquifer sediments. Mass partitioning calculations demonstrate that 99.9% of Fe and 99.5% of As are associated with aquifer sediment. The sediments act as both sources and sinks for As, depending on the redox conditions in the aquifer. Calculations reveal that at least 78% of the original As in sediment near the oil has been mobilized into groundwater over the 35-year lifespan of the plume. However, the calculations also show that only a small percentage of As (∼0.5%) remains in groundwater, due to resorption onto sediment. At the leading edge of the plume, where groundwater is suboxic, sediments sequester Fe and As, causing As to accumulate to concentrations 5.6 times greater than background concentrations. Current As sinks can serve as future sources of As as the plume evolves over time. The mass balance approach used in this study can be applied to As cycling in other aquifers where groundwater As results from biodegradation of an organic carbon point source coupled with Fe reduction.

76 FR 17556 - Sodium Ferric Ethylenediaminetetraacetate; Exemption From the Requirement of a Tolerance

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-30

... Document provided as references in Unit IX. (Refs. 5 and 6). B. Biochemical Pesticide Human Health... snails. EPA assessed the risks to human health and concluded that, when sodium ferric EDTA was used in... human health from residues of sodium ferric EDTA in food crops. Furthermore, residues from the...

High Resolution Transmission Electron Microscopy (HRTEM) of nanophase ferric oxides

NASA Technical Reports Server (NTRS)

Golden, D. C.; Morris, R. V.; Ming, D. W.; Lauer, H. V., Jr.

1994-01-01

Iron oxide minerals are the prime candidates for Fe(III) signatures in remotely sensed Martian surface spectra. Magnetic, Mossbauer, and reflectance spectroscopy have been carried out in the laboratory in order to understand the mineralogical nature of Martian analog ferric oxide minerals of submicron or nanometer size range. Out of the iron oxide minerals studied, nanometer sized ferric oxides are promising candidates for possible Martian spectral analogs. 'Nanophase ferric oxide (np-Ox)' is a generic term for ferric oxide/oxihydroxide particles having nanoscale (less than 10 nm) particle dimensions. Ferrihydrite, superparamagnetic particles of hematite, maghemite and goethite, and nanometer sized particles of inherently paramagnetic lepidocrocite are all examples of nanophase ferric oxides. np-Ox particles in general do not give X-ray diffraction (XRD) patterns with well defined peaks and would often be classified as X-ray amorphous. Therefore, different np-Oxs preparations should be characterized using a more sensitive technique e.g., high resolution transmission electron microscopy (HRTEM). The purpose of this study is to report the particle size, morphology and crystalline order, of five np-Ox samples by HRTEM imaging and electron diffraction (ED).

A case of osteomalacia due to deranged mineral balance caused by saccharated ferric oxide and short-bowel syndrome: A case report.

PubMed

Nomoto, Hiroshi; Miyoshi, Hideaki; Nakamura, Akinobu; Nagai, So; Kitao, Naoyuki; Shimizu, Chikara; Atsumi, Tatsuya

2017-09-01

Saccharated ferric oxide has been shown to lead to elevation of fibroblast growth factor 23, hypophosphatemia, and, consequently, osteomalacia. Moreover, mineral imbalance is often observed in patients with short-bowel syndrome to some degree. A 62-year-old woman with short-bowel syndrome related with multiple resections of small intestines due to Crohn disease received regular intravenous administration of saccharated ferric oxide. Over the course of treatment, she was diagnosed with tetany, which was attributed to hypocalcemia. Additional assessments of the patient revealed not only hypocalcemia, but also hypophosphatemia, hypomagnesemia, osteomalacia, and a high concentration of fibroblast growth factor 23 (314 pg/mL). We diagnosed her with mineral imbalance-induced osteomalacia due to saccharated ferric oxide and short-bowel syndrome. Magnesium replacement therapy and discontinuation of saccharated ferric oxide alone. These treatments were able to normalize her serum mineral levels and increase her bone mineral density. This case suggests that adequate evaluation of serum minerals, including phosphate and magnesium, during saccharated ferric oxide administration may be necessary, especially in patients with short-bowel syndrome.

Experimental determination of the phase boundary between kornelite and pentahydrated ferric sulfate at 0.1MPa

USGS Publications Warehouse

Kong, W.G.; Wang, A.; Chou, I.-Ming

2011-01-01

Recent findings of various ferric sulfates on Mars emphasize the importance of understanding the fundamental properties of ferric sulfates at temperatures relevant to that of Martian surface. In this study, the phase boundary between kornelite (Fe2(SO4)3.7H2O) and pentahydrated ferric sulfate (Fe2(SO4)3.5H2O) was experimentally determined using the humidity-buffer technique together with gravimetric measurements and Raman spectroscopy at 0.1MPa in the 36-56??C temperature range. Through the thermodynamic analysis of our experimental data, the enthalpy change (-290.8??0.3kJ/mol) and the Gibbs free energy change (-238.82??0.02kJ/mol) for each water molecule of crystallization in the rehydration of pentahydrated ferric sulfate to kornelite were obtained. ?? 2011 Elsevier B.V.

Granulation and ferric oxides loading enable biochar derived from cotton stalk to remove phosphate from water.

PubMed

Ren, Jing; Li, Nan; Li, Lei; An, Jing-Kun; Zhao, Lin; Ren, Nan-Qi

2015-02-01

Granulation of biochar powder followed by immobilization of ferric oxides on the macroporous granular biochar (Bg-FO-1) substantially enhanced phosphate removal from water. BET analysis confirmed that both granulation and ferric oxides loading can increase the surface areas and pore volumes effectively. Bg-FO-1 was proven to be a favorable adsorbent for phosphate. The phosphate adsorption capacity was substantially increased from 0 mg/g of raw biochar powder to 0.963 mg/g (Bg-FO-1). When the ferric oxides loading was prior to granulation, the adsorption capacity was decreased by 59-0.399 mg/g, possibly due to the decrease of micropore and mesopore area as well as the overlaying of binders to the activated sites produced by ferric oxides. Copyright © 2014 Elsevier Ltd. All rights reserved.

Radioactive excretion in human milk following administration of /sup 99m/Tc macroaggregated albumin

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

Pittard, W.B.; Merkatz, R.; Fletcher, B.D.

Albumin-tagged sodium pertechnetate (technetium) is routinely used in nuclear medicine for scanning procedures of the lung. The rate of excretion of this radionuclide into breast milk and the resultant potential radiation hazard to the nursing infant have received little attention. Therefore the milk from a nursing mother who required a lung scan because of suspected pulmonary emboli using an intravenous injection of 4 mCi of /sup 99m/Tc macroaggregated human serum albumin was monitored. Albumin tagging severely limited the entrance of technetium into her milk and the radioactivity of the milk returned to base line by 24 hours. A total ofmore » 2.02 muCi of technetium was measured in the 24-hour milk collection after technetium injection and 94% of this amount was excreted by 15.5 hours. This amount of technetium administered orally to a newborn would deliver a total body radiation dose of .3 mrad. Therefore, an infant would receive trivial doses of radiation if breast-feeding were resumed 15.5 hours after administration of the radionuclide to the mother and nursing can clearly be resumed safely 24 hours after injection.« less

Ferric maltol is effective in correcting iron deficiency anemia in patients with inflammatory bowel disease: results from a phase-3 clinical trial program.

PubMed

Gasche, Christoph; Ahmad, Tariq; Tulassay, Zsolt; Baumgart, Daniel C; Bokemeyer, Bernd; Büning, Carsten; Howaldt, Stefanie; Stallmach, Andreas

2015-03-01

Iron deficiency anemia (IDA) is frequently seen in inflammatory bowel disease. Traditionally, oral iron supplementation is linked to extensive gastrointestinal side effects and possible disease exacerbation. This multicenter phase-3 study tested the efficacy and safety of ferric maltol, a complex of ferric (Fe) iron with maltol (3-hydroxy-2-methyl-4-pyrone), as a novel oral iron therapy for IDA. Adult patients with quiescent or mild-to-moderate ulcerative colitis or Crohn's disease, mild-to-moderate IDA (9.5-12.0 g/dL and 9.5-13.0 g/dL in females and males, respectively), and documented failure on previous oral ferrous products received oral ferric maltol capsules (30 mg twice a day) or identical placebo for 12 weeks according to a randomized, double-blind, placebo-controlled study design. The primary efficacy endpoint was change in hemoglobin (Hb) from baseline to week 12. Safety and tolerability were assessed. Of 329 patients screened, 128 received randomized therapy (64 ferric maltol-treated and 64 placebo-treated patients) and comprised the intent-to-treat efficacy analysis: 55 ferric maltol patients (86%) and 53 placebo patients (83%) completed the trial. Significant improvements in Hb were observed with ferric maltol versus placebo at weeks 4, 8, and 12: mean (SE) 1.04 (0.11) g/dL, 1.76 (0.15) g/dL, and 2.25 (0.19) g/dL, respectively (P < 0.0001 at all time-points; analysis of covariance). Hb was normalized in two-thirds of patients by week 12. The safety profile of ferric maltol was comparable with placebo, with no impact on inflammatory bowel disease severity. Ferric maltol provided rapid clinically meaningful improvements in Hb and showed a favorable safety profile, suggesting its possible use as an alternative to intravenous iron in IDA inflammatory bowel disease.

Evidence of the direct involvement of the substrate TCP radical in functional switching from oxyferrous O2 carrier to ferric peroxidase in the dual-function hemoglobin/dehaloperoxidase from Amphitrite ornata.

PubMed

Sun, Shengfang; Sono, Masanori; Du, Jing; Dawson, John H

2014-08-05

The coelomic O2-binding hemoglobin dehaloperoxidase (DHP) from the sea worm Amphitrite ornata is a dual-function heme protein that also possesses a peroxidase activity. Two different starting oxidation states are required for reversible O2 binding (ferrous) and peroxidase (ferric) activity, bringing into question how DHP manages the two functions. In our previous study, the copresence of substrate 2,4,6-trichlorophenol (TCP) and H2O2 was found to be essential for the conversion of oxy-DHP to enzymatically active ferric DHP. On the basis of that study, a functional switching mechanism involving substrate radicals (TCP(•)) was proposed. To further support this mechanism, herein we report details of our investigations into the H2O2-mediated conversion of oxy-DHP to the ferric or ferryl ([TCP] < [H2O2]) state triggered by both biologically relevant [TCP and 4-bromophenol (4-BP)] and nonrelevant (ferrocyanide) compounds. At <50 μM H2O2, all of these conversion reactions are completely inhibited by ferric heme ligands (KCN and imidazole), indicating the involvement of ferric DHP. Furthermore, the spin-trapping reagent 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) effectively inhibits the TCP/4-BP (but not ferrocyanide)-triggered conversion of oxy-DHP to ferric DHP. These results and O2 concentration-dependent conversion rates observed in this study demonstrate that substrate TCP triggers the conversion of oxy-DHP to a peroxidase by TCP(•) oxidation of the deoxyferrous state. TCP(•) is progressively generated, by increasingly produced amounts of ferric DHP, upon H2O2 oxidation of TCP catalyzed initially by trace amounts of ferric enzyme present in the oxy-DHP sample. The data presented herein further address the mechanism of how the halophenolic substrate triggers the conversion of hemoglobin DHP into a peroxidase.

Mössbauer and infrared spectroscopy as a diagnostic tool for the characterization of ferric tannates

NASA Astrophysics Data System (ADS)

Jaén, Juan A.; Navarro, César

2009-07-01

Fourier transform infrared spectroscopy and Mössbauer spectroscopy are use for the characterization and qualitative analysis of hydrolysable and condensed tannates. The two classes of tannates may be differentiated from the characteristic IR pattern. Mössbauer proof that a mixture of mono- and bis-type ferric tannate complexes, and an iron(II)-tannin complex are obtained from the interaction of hydrolysable tannins (tannic acid and chestnut tannin) and condensed tannins (mimosa and quebracho) with a ferric nitrate solution. At pH 7, a partially hydrolyzed ferric tannate complex was also obtained.

Aluminum Hydroxide and Magnesium Hydroxide

MedlinePlus

Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They ... They combine with stomach acid and neutralize it. Aluminum Hydroxide, Magnesium Hydroxide are available without a prescription. ...

Formation of ferric oxides from aqueous solutions: A polyhedral approach by X-ray absorption spectroscopy. I. Hydrolysis and formation of ferric gels

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

Combes, J.M.; Manceau, A.; Calas, G.

1989-03-01

X-ray absorption spectroscopy (XAS) was used to follow the evolution of local structural environments around ferric ions during the formation of ferric hydrous oxide gels from 1 M chloride and 0.1 M nitrate solutions. Fe K-XANES and EXAFS confirm that ferric ions remain 6-fold coordinated during this evolution. With increasing OH availability in the solution, Cl{sup {minus}} anions tend gradually to be exchanged for (O, OH, OH{sub 2}) ligands. Below OH/Fe = 1, no structural order is detected beyond the first coordination sphere. Above this ratio, two Fe-Fe distances at 3.05 {angstrom} and 3.44 {angstrom} are observed and correspond tomore » the presence of edge- and vertex-sharing Fe-octahedra. XAS results show that ferric gels and highly polymerized aqueous species are short-range ordered. The main contribution to disorder in the gels arises from the small size of coherently scattering domains also responsible for their X-ray amorphous character. From the initial to the final stage of hydrolysis, particles possess a nearly spherical shape with a minimum average diameter ranging from 10-30 {angstrom} for polymers formed from chloride and nitrate solutions. As polymerization proceeds, the local order extends to several tens of angstroms and the particle structures becomes progressively closer to that of akaganeite ({beta}-FeOOH) or goethite ({alpha}-FeOOH). This local structure is distinct from that of the lepidocrocite ({gamma}-FeOOH)-like structure of ferric gels precipitated after oxidation of divalent Fe solutions. The growth of the crystalline Fe-oxyhydroxides from gels takes place by the progressive long-range ordering in the ferric polymers without modifying the short-range order around Fe.« less

A Cost-effectiveness Analysis of Ferric Carboxymaltose in Patients With Iron Deficiency and Chronic Heart Failure in Spain.

PubMed

Comín-Colet, Josep; Rubio-Rodríguez, Darío; Rubio-Terrés, Carlos; Enjuanes-Grau, Cristina; Gutzwiller, Florian S; Anker, Stefan D; Ponikowski, Piotr

2015-10-01

Treatment with ferric carboxymaltose improves symptoms, functional capacity, and quality of life in patients with chronic heart failure and iron deficiency. The aim of this study was to assess the cost-effectiveness of ferric carboxymaltose treatment vs no treatment in these patients. We used an economic model based on the Spanish National Health System, with a time horizon of 24 weeks. Patient characteristics and ferric carboxymaltose effectiveness (quality-adjusted life years) were taken from the Ferinject® Assessment in patients with IRon deficiency and chronic Heart Failure trial. Health care resource use and unit costs were taken either from Spanish sources, or from the above mentioned trial. In the base case analysis, patients treated with and without ferric carboxymaltose treatment acquired 0.335 and 0.298 quality-adjusted life years, respectively, representing a gain of 0.037 quality-adjusted life years for each treated patient. The cost per patient was €824.17 and €597.59, respectively, resulting in an additional cost of €226.58 for each treated patient. The cost of gaining 1 quality adjusted life year with ferric carboxymaltose was €6123.78. Sensitivity analyses confirmed the robustness of the model. The probability of ferric carboxymaltose being cost-effective (< €30 000 per quality-adjusted life year) and dominant (more effective and lower cost than no treatment) was 93.0% and 6.6%, respectively. Treatment with ferric carboxymaltose in patients with chronic heart failure and iron deficiency, with or without anemia, is cost-effective in Spain. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

The reactivity of Fe(II) associated with goethite formed during short redox cycles toward Cr(VI) reduction under oxic conditions

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

Tomaszewski, Elizabeth J.; Lee, Seungyeol; Rudolph, Jared

Chromium (Cr) is a toxic metal that causes a myriad of health problems and enters the environment as a result of anthropogenic activities and/or natural processes. The toxicity and solubility of chromium is linked to its oxidation state; Cr(III) is poorly soluble and relatively nontoxic, while Cr(VI) is soluble and a known carcinogen. Solid Fe(II) in iron-bearing minerals, such as pyrite, magnetite, and green rusts, reduce the oxidation state of chromium, reducing its toxicity and mobility. However, these minerals are not the only potential sources of solid-associated Fe(II) available for Cr(VI) reduction. For example, ferric (Fe(III)) (hydr)oxides, such as goethitemore » or hematite, can have Fe(II) in the solid without phase transformation; however, the reactivity of Fe(II) within Fe(III) (hydr)oxides with contaminants, has not been previously investigated. Here, we cyclically react goethite with dissolved Fe(II) followed by dissolved O2, leading to the formation of reactive Fe(II) associated with goethite. In separate reactors, the reactivity of this Fe(II) is probed under oxic conditions, by exposure to chromate (CrO42 -) after either one, two, three or four redox cycles. Cr is not present during redox cycling; rather, it is introduced to a subset of the solid after each oxidation half-cycle. Analysis of X-ray absorption near edge structure (XANES) spectra reveals that the extent of Cr(VI) reduction to Cr(III) depends not only on solid Fe(II) content but also surface area and mean size of ordered crystalline domains, determined by BET surface area analysis and X-ray diffraction (XRD), respectively. Shell-by-shell fitting of the extended X-ray absorption fine structure (EXAFS) spectra demonstrates chromium forms both single and double corner sharing complexes on the surface of goethite, in addition to sorbed Cr(III) species. Finally, transmission electron microscope (TEM) imaging and X-ray energy-dispersive spectroscopy (EDS) illustrate that Cr preferentially localizes on the (100) face of goethite, independent of the number of redox cycles goethite undergoes. This work demonstrates that under oxic conditions, solid Fe(II) associated with goethite resulting from rapid redox cycling is reactive and available for electron transfer to Cr(VI), suggesting Fe(III) (hydr)oxides may act as reservoirs of reactive electron density, even in oxygen saturated environments.« less

The use of waterworks sludge for the treatment of vegetable oil refinery industry wastewater.

PubMed

Basibuyuk, M; Kalat, D G

2004-03-01

Water treatment works using coagulation/flocculation in the process stream will generate a waste sludge. This sludge is termed as ferric, alum, or lime sludge based on which coagulant was primarily used. The works in Adana, Turkey uses ferric chloride. The potential for using this sludge for the treatment of vegetable oil refinery industry wastewater by coagulation has been investigated. The sludge acted as a coagulant and excellent oil and grease, COD and TSS removal efficiencies were obtained. The optimum conditions were a pH of 6 and a sludge dose of 1100 mg SS l(-1). The efficiency of sludge was also compared with alum and ferric chloride for the vegetable oil refinery wastewater. At doses of 1300-1900 mg SS l(-1), the sludge was as effective as ferric chloride and alum at removing oil and grease, COD, and TSS. In addition, various combinations of ferric chloride and waterworks sludge were also examined. Under the condition of 12.5 mg l(-1) fresh ferric chloride and 1000 mg SS l(-1) sludge dose, 99% oil and grease 99% TSS and 83% COD removal efficiencies were obtained.

A case of osteomalacia due to deranged mineral balance caused by saccharated ferric oxide and short-bowel syndrome

PubMed Central

Nomoto, Hiroshi; Miyoshi, Hideaki; Nakamura, Akinobu; Nagai, So; Kitao, Naoyuki; Shimizu, Chikara; Atsumi, Tatsuya

2017-01-01

Abstract Rationale: Saccharated ferric oxide has been shown to lead to elevation of fibroblast growth factor 23, hypophosphatemia, and, consequently, osteomalacia. Moreover, mineral imbalance is often observed in patients with short-bowel syndrome to some degree. Patient concerns: A 62-year-old woman with short-bowel syndrome related with multiple resections of small intestines due to Crohn disease received regular intravenous administration of saccharated ferric oxide. Over the course of treatment, she was diagnosed with tetany, which was attributed to hypocalcemia. Additional assessments of the patient revealed not only hypocalcemia, but also hypophosphatemia, hypomagnesemia, osteomalacia, and a high concentration of fibroblast growth factor 23 (314 pg/mL). Diagnoses: We diagnosed her with mineral imbalance-induced osteomalacia due to saccharated ferric oxide and short-bowel syndrome. Interventions: Magnesium replacement therapy and discontinuation of saccharated ferric oxide alone. Outcomes: These treatments were able to normalize her serum mineral levels and increase her bone mineral density. Lessons: This case suggests that adequate evaluation of serum minerals, including phosphate and magnesium, during saccharated ferric oxide administration may be necessary, especially in patients with short-bowel syndrome. PMID:28953654

Effects of chlorpyrifos on soil carboxylesterase activity at an aggregate-size scale.

PubMed

Sanchez-Hernandez, Juan C; Sandoval, Marco

2017-08-01

The impact of pesticides on extracellular enzyme activity has been mostly studied on the bulk soil scale, and our understanding of the impact on an aggregate-size scale remains limited. Because microbial processes, and their extracellular enzyme production, are dependent on the size of soil aggregates, we hypothesized that the effect of pesticides on enzyme activities is aggregate-size specific. We performed three experiments using an Andisol to test the interaction between carboxylesterase (CbE) activity and the organophosphorus (OP) chlorpyrifos. First, we compared esterase activity among aggregates of different size spiked with chlorpyrifos (10mgkg -1 wet soil). Next, we examined the inhibition of CbE activity by chlorpyrifos and its metabolite chlorpyrifos-oxon in vitro to explore the aggregate size-dependent affinity of the pesticides for the active site of the enzyme. Lastly, we assessed the capability of CbEs to alleviate chlorpyrifos toxicity upon soil microorganisms. Our principal findings were: 1) CbE activity was significantly inhibited (30-67% of controls) in the microaggregates (<0.25mm size) and smallest macroaggregates (<1.0 - 0.25mm), but did not change in the largest macroaggregates (>1.0mm) compared with the corresponding controls (i.e., pesticide-free aggregates), 2) chlorpyrifos-oxon was a more potent CbE inhibitor than chlorpyrifos; however, no significant differences in the CbE inhibition were found between micro- and macroaggregates, and 3) dose-response relationships between CbE activity and chlorpyrifos concentrations revealed the capability of the enzyme to bind chlorpyrifos-oxon, which was dependent on the time of exposure. This chemical interaction resulted in a safeguarding mechanism against chlorpyrifos-oxon toxicity on soil microbial activity, as evidenced by the unchanged activity of dehydrogenase and related extracellular enzymes in the pesticide-treated aggregates. Taken together, these results suggest that environmental risk assessments of OP-polluted soils should consider the fractionation of soil in aggregates of different size to measure the CbE activity, and other potential soil enzyme activities. Copyright © 2017 Elsevier Inc. All rights reserved.

Macro-aggregates (MAA) of albumin for lung imaging. Studies on better tissue to background ratio, on MAA stability and reuse after its first preparation.

PubMed

Malhotra, Anshoo; Kumar, Pardeep; Sharma, Sarika; Dhawan, Davinder K

2010-01-01

The present study was designed to develop stable and economically competitive radioactive technetium-99m macro-aggregates of albumin ((99m)Tc-MAA) which could be used for imaging of lungs. Macro-aggregates were freshly prepared and labeled with (99m)Tc pertechnetate by following the standard protocol which included incubation of formulation at 80(o) C for 10 min. We studied 7 rats in every experiment. The rats were injected intravenously with (99m)Tc MAA and were sacrificed after 10 min to study its distribution in the lungs and other non target tissues using gamma ray spectrometer. This standard protocol was further experimented upon in order to achieve high target to non target ratio. Different formulations were prepared by incubating them at 80 degrees for different incubation times of 5, 10, 15, 20, 25 and 30 min. Formulation of MAA prepared by incubating at 80 degrees for 20 min labeled with (99m)Tc showed the highest target to non target ratio. Another group of rats that received the above formulation were sacrificed after two additional time intervals of 5 and 15 min. The target to non target ratio was high in animals sacrificed after 5 min of injecting them with (99m)Tc the MAA formulation prepared by heating at 80 degrees for 20 min as compared to animals sacrificed after 10 and 15 min. Formulations of MAA following storage at room temperatures which varied from 5(o)C to 18(o)C, for different time durations 1, 2 and 9 days were also evaluated for their ability to be reused after reheating and labeling with (99m)Tc. The formulation of MAA kept for 9 days showed the best target to non-target ratio. The present study suggests that MAA once prepared can be reused following labeling with (99m)Tc even after 9 days of storage with better target to non target ratio as compared to storage timer period of 1 and 2 days.

Sodium Hydroxide and Calcium Hydroxide Hybrid Oxygen Bleaching with System

NASA Astrophysics Data System (ADS)

Doelle, K.; Bajrami, B.

2018-01-01

This study investigates the replacement of sodium hydroxide in the oxygen bleaching stage using a hybrid system consisting of sodium hydroxide calcium hydroxide. Commercial Kraft pulping was studied using yellow pine Kraft pulp obtained from a company in the US. The impact of sodium hydroxide, calcium hydroxide hybrid system in regard to concentration, reaction time and temperature for Kraft pulp was evaluated. The sodium hydroxide and calcium hydroxide dosage was varied between 0% and 15% based on oven dry fiber content. The bleaching reaction time was varied between 0 and 180 minutes whereas the bleaching temperature ranged between 70 °C and 110 °C. The ability to bleach pulp was measured by determining the Kappa number. Optimum bleaching results for the hybrid system were achieved with 4% sodium hydroxide and 2% calcium hydroxide content. Beyond this, the ability to bleach pulp decreased.

Contribution to the knowledge of nickel hydroxide electrodes. 5. Analysis and electrochemical behavior of cadmium nickel hydroxides

NASA Technical Reports Server (NTRS)

Bode, H.; Dennstedt, W.

1981-01-01

Electrochemical experiments performed at sintered and bulk electrodes show that beta nickel hydroxide contains an electrochemically inactive proportion of cadmium hydroxide of up to 10%. The electrochemically ineffective cadmium hydroxide is homogeneously dissolved in beta nickel hydroxide.

40 CFR 117.3 - Determination of reportable quantities.

Code of Federal Regulations, 2010 CFR

2010-07-01

... fluoride X 1 (0.454) Beryllium nitrate X 1 (0.454) Butyl acetate D 5,000 (2,270) Butylamine C 1,000 (454) n... B 100 (45.4) Cupric acetoarsenite X 1 (0.454) Cupric chloride A 10 (4.54) Cupric nitrate B 100 (45.4... 1,000 (454) Ferric chloride C 1,000 (454) Ferric fluoride B 100 (45.4) Ferric nitrate C 1,000 (454...

40 CFR 117.3 - Determination of reportable quantities.

Code of Federal Regulations, 2011 CFR

2011-07-01

... fluoride X 1 (0.454) Beryllium nitrate X 1 (0.454) Butyl acetate D 5,000 (2,270) Butylamine C 1,000 (454) n... B 100 (45.4) Cupric acetoarsenite X 1 (0.454) Cupric chloride A 10 (4.54) Cupric nitrate B 100 (45.4... 1,000 (454) Ferric chloride C 1,000 (454) Ferric fluoride B 100 (45.4) Ferric nitrate C 1,000 (454...

SEPARATION OF PLUTONIUM HYDROXIDE FROM BISMUTH HYDROXIDE

DOEpatents

Watt, G.W.

1958-08-19

An tmproved method is described for separating plutonium hydroxide from bismuth hydroxide. The end product of the bismuth phosphate processes for the separation amd concentration of plutonium is a inixture of bismuth hydroxide amd plutonium hydroxide. It has been found that these compounds can be advantageously separated by treatment with a reducing agent having a potential sufficient to reduce bismuth hydroxide to metalltc bisinuth but not sufficient to reduce the plutonium present. The resulting mixture of metallic bismuth and plutonium hydroxide can then be separated by treatment with a material which will dissolve plutonium hydroxide but not metallic bismuth. Sodiunn stannite is mentioned as a preferred reducing agent, and dilute nitric acid may be used as the separatory solvent.

Demonstration of the efficiency and robustness of an acid leaching process to remove metals from various CCA-treated wood samples.

PubMed

Coudert, Lucie; Blais, Jean-François; Mercier, Guy; Cooper, Paul; Janin, Amélie; Gastonguay, Louis

2014-01-01

In recent years, an efficient and economically attractive leaching process has been developed to remove metals from copper-based treated wood wastes. This study explored the applicability of this leaching process using chromated copper arsenate (CCA) treated wood samples with different initial metal loading and elapsed time between wood preservation treatment and remediation. The sulfuric acid leaching process resulted in the solubilization of more than 87% of the As, 70% of the Cr, and 76% of the Cu from CCA-chips and in the solubilization of more than 96% of the As, 78% of the Cr and 91% of the Cu from CCA-sawdust. The results showed that the performance of this leaching process might be influenced by the initial metal loading of the treated wood wastes and the elapsed time between preservation treatment and remediation. The effluents generated during the leaching steps were treated by precipitation-coagulation to satisfy the regulations for effluent discharge in municipal sewers. Precipitation using ferric chloride and sodium hydroxide was highly efficient, removing more than 99% of the As, Cr, and Cu. It appears that this leaching process can be successfully applied to remove metals from different CCA-treated wood samples and then from the effluents. Copyright © 2013 Elsevier Ltd. All rights reserved.

Re-aluminising the primary mirror of the South African Astronomical Observatory's 74-inch telescope

NASA Astrophysics Data System (ADS)

Crause, Lisa A.; Stoffels, John; Koorts, Willie; Christian, Brendt; de Water, Wilhelmina; Fransman, Timothy; Gibbons, Denville; Machete, Nelson; Sefako, Ramotholo R.; Taaibos, Sinethemba

2016-07-01

Telescope mirrors reside in harsh environments and thus require periodic re-aluminisation to maintain their reflectivity. The SAAO's Sutherland field station suffers from dust and frequent bouts of high humidity. Dust settling on the mirrors adheres to the upward-facing optical surfaces and is not removed by CO2 cleaning. The 74-inch primary mirror was unsuccessfully re-aluminised in April 2015. Parts of the mirror proved difficult to clean and the resulting coating included hazy, white patches in those problem areas. Cotton wool soaked with ferric chloride was used to strip small patches of coating, confirming that no optical surface damage had occurred. The 55 year-old aluminising equipment for the 74-inch required an extensive overhaul and the spruced up system was then used to re-coat the primary mirror in November 2015. We used the same de-ionised water, potassium hydroxide, sodium lauryl sulphate, cotton wool, safety gear and cleaning techniques employed by the mirror coating team at the neighbouring Southern African Large Telescope, as well as their Ocean Optics reflectometer to quantify the improvement in reflectivity. Measurements at 320 nm on different parts of the dirty primary ranged between 10 % and 70 %, while the new coating exceeded 95 % over the entire surface.

Haemoglobin Levels in Normal Infants Aged 3 to 24 Months, and the Effect of Iron

PubMed Central

Burman, David

1972-01-01

From the age of 3 to 24 months, capillary Hb levels were measured on normal term infants who received no medicinal iron from any source. The mean and standard deviations are recorded at 3-monthly intervals. Females had a higher Hb than males when considered as an overall trend throughout the period. There was no effect of social class or weight gain from birth in either sex. Birthweight was significantly related to Hb at 3 months in males only and at no other age. There was no relation between illness and Hb. Compared with earlier series in England, the level of Hb in infants is generally higher now than previously, particularly in the second year of life. Infants were given either 10 mg iron in the form of colloidal ferric hydroxide daily, or a placebo. Iron raised the Hb in males of social classes I and II, those with a birthweight below 3·18 kg, and those who gained most weight. Iron made no difference to the incidence of infection. In the absence of a proven relation between a low Hb and morbidity in an affluent community, the routine administration of iron or other haematinics to normal term infants cannot be justified. PMID:5023475

Mobility and chemical fate of arsenic and antimony in water and sediments of Sarouq River catchment, Takab geothermal field, northwest Iran.

PubMed

Sharifi, Reza; Moore, Farid; Keshavarzi, Behnam

2016-04-01

Arsenic (As) and antimony (Sb) concentrations in water and sediments were determined along flow paths in the Sarouq River, Zarshuran and Agh Darreh streams. The results indicate high As and Sb concentrations in water and sediment samples. Raman spectroscopy shows hematite (α-Fe2O3), goethite [α-FeO(OH)] and lepidocrocite [γ-FeO(OH)] in sediment samples. Calculated saturation indices (SI) indicate oversaturation with respect to amorphous Fe(OH)3 for all samples, but undersaturation with respect to Al and Mn mineral and amorphous phases. Therefore, ferric oxides and hydroxides are assumed to be principal mineral phases for arsenic and antimony attenuation by adsorption/co-precipitation processes. The considerable difference between As and Sb concentration in sediment is due to strong adsorption of As(V) into the solid phase. Also, lower affinity of Sb(V) for mineral surfaces suggests a greater potential for aqueous transport. The adsorption of arsenic and antimony was examined using the Freundlich adsorption isotherm to determine their distribution model in water-sediment system and its compatibility with the existing theoretical model. The results showed that the adsorption behavior of both elements complies with the Freundlich adsorption isotherm. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of total cyanide in coking wastewater during a coagulation process: significance of organic polymers.

PubMed

Shen, Jian; Zhao, He; Cao, Hongbin; Zhang, Yi; Chen, Yongsheng

2014-02-01

Whether a cationic organic polymer can remove more total cyanide (TCN) than a non-ionic organic polymer during the same flocculation system has not been reported previously. In this study, the effects of organic polymers with different charge density on the removal mechanisms of TCN in coking wastewater are investigated by polyferric sulfate (PFS) with a cationic organic polymer (PFS-C) or a non-ionic polymer (PFS-N). The coagulation experiments results show that residual concentrations of TCN (Fe(CN)6(3-)) after PFS-C flocculation (TCN < 0.2 mg/L) are much lower than that after PFS-N precipitation. This can be attributed to the different TCN removal mechanisms of the individual organic polymers. To investigate the roles of organic polymers, physical and structural characteristics of the flocs are analyzed by FT-IR, XPS, TEM and XRD. Owing to the presence of N+ in PFS-C, Fe(CN)6(3-) and negative flocs (Fe(CN)6(3-) adsorbed on ferric hydroxides) can be removed via charge neutralization and electrostatic patch flocculation by the cationic organic polymer. However, non-ionic N in PFS-N barely reacts with cyanides through sweeping or bridging, which indicates that the non-ionic polymer has little influence on TCN removal.

Valence tautomerism in synthetic models of cytochrome P450

PubMed Central

Das, Pradip Kumar; Samanta, Subhra; McQuarters, Ashley B.; Lehnert, Nicolai

2016-01-01

CytP450s have a cysteine-bound heme cofactor that, in its as-isolated resting (oxidized) form, can be conclusively described as a ferric thiolate species. Unlike the native enzyme, most synthetic thiolate-bound ferric porphyrins are unstable in air unless the axial thiolate ligand is sterically protected. Spectroscopic investigations on a series of synthetic mimics of cytP450 indicate that a thiolate-bound ferric porphyrin coexists in organic solutions at room temperature (RT) with a thiyl-radical bound ferrous porphyrin, i.e., its valence tautomer. The ferric thiolate state is favored by greater enthalpy and is air stable. The ferrous thiyl state is favored by entropy, populates at RT, and degrades in air. These ground states can be reversibly interchanged at RT by the addition or removal of water to the apolar medium. It is concluded that hydrogen bonding and local electrostatics protect the resting oxidized cytP450 active site from degradation in air by stabilizing the ferric thiolate ground state in contrast to its synthetic analogs. PMID:27302948

Monoclonal Antibodies to Ferric Pseudobactin, the Siderophore of Plant Growth-Promoting Pseudomonas putida B10

PubMed Central

Buyer, Jeffrey S.; Sikora, Lawrence J.; Kratzke, Marian G.

1990-01-01

Monoclonal antibodies to ferric pseudobactin, the siderophore (microbial iron transport agent) of plant growth-promoting Pseudomonas putida B10, have been developed. Three immunoglobulin G subclass 1-type monoclonal antibodies have been characterized. Each antibody appears to be unique on the basis of their reactions with ferric pseudobactin and with culture supernatants from other pseudomonads. None of the three cross-reacts with ferric pseudobactin-type siderophores produced by seven other pseudomonads. However, P. aeruginosa ATCC 15692 and P. fluorescens ATCC 17400 produced relatively high-molecular-mass compounds (mass greater than approximately 30,000 daltons) that did react with the antibodies. The compound from P. aeruginosa was not iron regulated, while the compound from P. fluorescens was produced only under iron-limiting conditions. A competitive assay using these antibodies has a detection limit of 5 × 10−12 mol of ferric pseudobactin. This is, to our knowledge, the first report of monoclonal antibodies reactive with siderophores. PMID:16348116

Managing hyperphosphatemia in patients with chronic kidney disease on dialysis with ferric citrate: latest evidence and clinical usefulness

PubMed Central

Fadem, Stephen Z.; Kant, Kotagal S.; Bhatt, Udayan; Sika, Mohammed; Lewis, Julia B.; Negoi, Dana

2015-01-01

Ferric citrate is a novel phosphate binder that allows the simultaneous treatment of hyperphosphatemia and iron deficiency in patients being treated for end-stage renal disease with hemodialysis (HD). Multiple clinical trials in HD patients have uniformly and consistently demonstrated the efficacy of the drug in controlling hyperphosphatemia with a good safety profile, leading the US Food and Drug Administration in 2014 to approve its use for that indication. A concurrent beneficial effect, while using ferric citrate as a phosphate binder, is its salutary effect in HD patients with iron deficiency being treated with an erythropoietin-stimulating agent (ESA) in restoring iron that becomes available for reversing chronic kidney disease (CKD)-related anemia. Ferric citrate has also been shown in several studies to diminish the need for intravenous iron treatment and to reduce the requirement for ESA. Ferric citrate is thus a preferred phosphate binder that helps resolve CKD-related mineral bone disease and iron-deficiency anemia. PMID:26336594

Influence of organic matter on the transport of Cryptosporidium parvum oocysts in a ferric oxyhydroxide-coated quartz sand saturated porous medium

USGS Publications Warehouse

Abudalo, R.A.; Ryan, J.N.; Harvey, R.W.; Metge, D.W.; Landkamer, Lee L.

2010-01-01

To assess the effect of organic matter on the transport of Cryptosporidium parvum oocysts in a geochemically heterogeneous saturated porous medium, we measured the breakthrough and collision efficiencies of oocysts as a function of dissolved organic matter concentration in a flow-through column containing ferric oxyhydroxide-coated sand. We characterized the surface properties of the oocysts and ferric oxyhydroxide-coated sand using microelectrophoresis and streaming potential, respectively, and the amount of organic matter adsorbed on the ferric oxyhydroxide-coated sand as a function of the concentration of dissolved organic matter (a fulvic acid isolated from Florida Everglades water). The dissolved organic matter had no significant effect on the zeta potential of the oocysts. Low concentrations of dissolved organic matter were responsible for reversing the charge of the ferric oxyhydroxide-coated sand surface from positive to negative. The charge reversal and accumulation of negative charge on the ferric oxyhydroxide-coated sand led to increases in oocyst breakthrough and decreases in oocyst collision efficiency with increasing dissolved organic matter concentration. The increase in dissolved organic matter concentration from 0 to 20 mg L-1 resulted in a two-fold decrease in the collision efficiency. ?? 2009 Elsevier Ltd.

Folding process of silk fibroin induced by ferric and ferrous ions

NASA Astrophysics Data System (ADS)

Ji, Dan; Deng, Yi-Bin; Zhou, Ping

2009-12-01

Bombyx mori silk fiber has useful mechanical properties largely due to a high content of ordered β-sheet crystallites separated by non-crystalline spacers. Metallic ions present in the silk dope in nature could affect the β-sheet content. In this work, we used solid-state 13C NMR, EPR and Raman spectroscopy to investigate how the ferric/ferrous ions affect the folding process of the silk fibroin. NMR and Raman results indicate that ferric and ferrous ions have different effects on the secondary structure of silk fibroin. Ferric ions can induce a conformation change from helix to β-sheet form in silk fibroin when their concentration exceeds a critical value, while ferrous ions cannot. EPR results indicate that the ferric ions bound with silk fibroin have a high-spin state ( S = 5/2) with g-value of g1 = 1.950, g2 = 1.990 and g3 = 1.995, zero-field splitting interaction D of 1.2-2 cm -1, and symmetric character of E/ D = 1/3, resulting in an effective g-value of g' = 4.25. The hydrophilic spacer GTGSSGFGPYVAN(H)GGYSGYEYAWSSESDFGT in the heavy chain of silk fibroin is likely to be involved in the binding of ferric ions, and His, Asn and Tyr residues are considered as the potential binding sites.

Scientific results and lessons learned from an integrated crewed Mars exploration simulation at the Rio Tinto Mars analogue site

NASA Astrophysics Data System (ADS)

Orgel, Csilla; Kereszturi, Ákos; Váczi, Tamás; Groemer, Gernot; Sattler, Birgit

2014-02-01

Between 15 and 25 April 2011 in the framework of the PolAres programme of the Austrian Space Forum, a five-day field test of the Aouda.X spacesuit simulator was conducted at the Rio Tinto Mars-analogue site in southern Spain. The field crew was supported by a full-scale Mission Control Center (MCC) in Innsbruck, Austria. The field telemetry data were relayed to the MCC, enabling a Remote Science Support (RSS) team to study field data in near-real-time and adjust the flight planning in a flexible manner. We report on the experiences in the field of robotics, geophysics (Ground Penetrating Radar) and geology as well as life sciences in a simulated spaceflight operational environment. Extravehicular Activity (EVA) maps had been prepared using Google Earth and aerial images. The Rio Tinto mining area offers an excellent location for Mars analogue simulations. It is recognised as a terrestrial Mars analogue site because of the presence of jarosite and related sulphates, which have been identified by the NASA Mars Exploration Rover "Opportunity" in the El Capitan region of Meridiani Planum on Mars. The acidic, high ferric-sulphate content water of Rio Tinto is also considered as a possible analogue in astrobiology regarding the analysis of ferric sulphate related biochemical pathways and produced biomarkers. During our Mars simulation, 18 different types of soil and rock samples were collected by the spacesuit tester. The Raman results confirm the presence of minerals expected, such as jarosite, different Fe oxides and oxi-hydroxides, pyrite and complex Mg and Ca sulphates. Eight science experiments were conducted in the field. In this contribution first we list the important findings during the management and realisation of tests, and also a first summary of the scientific results. Based on these experiences suggestions for future analogue work are also summarised. We finish with recommendations for future field missions, including the preparation of the experiments, communication and data transfer - as an aid to the planning of future simulations.

Iron Oxidation Processes During Asteroidal Fluid-Rock Interactions: a Nanoscale Study of Serpentine-bearing Alteration Assemblages in the Murray Meteorite

NASA Astrophysics Data System (ADS)

Elmaleh, A.; Bourdelle, F.; Benzerara, K.; Caste, F.; Leroux, H.; Devouard, B.

2014-12-01

Carbonaceous chondrites of the CM and CI groups contain large amounts of water bound in minerals, attesting to early water-rock interactions on their parent bodies. In CM2 chondrites such as the Murray meteorite the alteration assemblages mostly consist of serpentines with variable chemical compositions. Even though chondritic serpentines formed from anoxic fluids, they contain significant amounts of ferric iron. In order to evaluate mass transfers and redox processes during alteration, we performed a study of a heavily altered calcium-aluminium-rich inclusion (CAI), at the nanometer scale (Transmission Electron Microscopy and Soft x-Ray Scanning Transmission Spectro-Microscopy, on ultra-thin sections prepared by Focused Ion Beam - FIB - milling). Using x-ray absorption spectroscopy at the Fe L2,3-edges, and based on literature references and on measurements of crystallographically oriented FIB foils of cronstedtite (the mixed-valence Fe endmember of serpentine) we estimated over 50% Fe3+ in alteration assemblages. We measured higher ferric iron proportions in mixed Fe,Mg,Al-serpentine/hydroxide disordered phases than in well-crystallized Al,Mg-bearing cronstedtite. We suggest that aqueous Fe2+ was transported to the initially Fe-depleted CAI. There, local changes in pH conditions and / or mineral catalysis would have promoted the partial oxidation of Fe. Later input of Al- and Mg-rich solutions might then have destabilized the initial serpentine, yielding assemblages un-equilibrated from the structural, chemical and redox point of views, similar to the polysomatic assemblages observed in terrestrial hydrothermal systems. Here, we illustrate the usefulness of such a combined study for better understanding the processes of hydration on the parent body of carbonaceous chondrites. Interestingly, as the reactions proposed for the oxidation of Fe generate hydrogen, reduction reactions - involving carbon species, for instance - are expected to follow the ones described here. Alternatively, given the high rate of diffusion of hydrogen some degree of H2 escape may be expected too, which would have induced increasingly oxidizing conditions during aqueous alteration.

Transformation of organo-ferric peat colloids by a heterotrophic bacterium

NASA Astrophysics Data System (ADS)

Oleinikova, Olga V.; Shirokova, Liudmila S.; Gérard, Emmanuele; Drozdova, Olga Yu.; Lapitskiy, Sergey A.; Bychkov, Andrey Yu.; Pokrovsky, Oleg S.

2017-05-01

Bacterial mineralization of allochthonous (soil) dissolved organic matter (DOM) in boreal waters governs the CO2 flux from the lakes and rivers to the atmosphere, which is one of the main factor of carbon balance in high latitudes. However, the fate of colloidal trace element (TE) during bacterial processing of DOM remains poorly constrained. We separated monoculture of Pseudomonas saponiphila from a boreal creek and allowed it to react with boreal Fe-rich peat leachate of approximate colloidal (3 kDa-0.45 μm) composition C1000Fe12Al3.3Mg2Ca3.7P1.2Mn0.1Ba0.5 in nutrient-free media. The total net decrease of Dissolved Organic Carbon (DOC) concentration over 4 day of exposure was within 5% of the initial value, whereas the low molecular weight fraction of Corg (LMW<3 kDa) yielded a 16%-decrease due to long-term bio-uptake or coagulation. There was a relative depletion in Fe over Corg of 0.45 μm, colloidal and LMW fraction in the course of peat leachate interaction with P. saponiphila. Al, Mn, Ni, Cu, Ga, REEs, Y, U were mostly affected by bacterial presence and exhibited essentially the adsorption at the cell surface over first hours of reaction, in contrast to Fe, Ti, Zr, and Nb that showed both short-term adsorption and long-term removal by physical coagulation/coprecipitation with Fe hydroxide. The low molecular weight fraction (LMW<3 kDa) of most TE was a factor of 2-5 less affected by microbial presence via adsorption or removal than the high molecular weight (HMW) colloidal fractions (<0.45 μm and <50 kDa). The climate change-induced acceleration of heterotrophic bacterial activity in boreal and subarctic waters may lead to preferential removal of Fe over DOC from conventionally dissolved fraction and the decrease of the proportion of LMW < 3 kDa fraction and the increase of HMW colloids. Enhanced heterotrophic mineralization of organo-ferric colloids under climate warming scenario may compensate for on-going "browning" of surface waters.

Colour and stability assessment of blue ferric anthocyanin chelates in liquid pectin-stabilised model systems.

PubMed

Buchweitz, M; Brauch, J; Carle, R; Kammerer, D R

2013-06-01

The formation of blue coloured ferric anthocyanin chelates and their colour stability during storage and thermal treatment were monitored in a pH range relevant to food (3.6-5.0). Liquid model systems were composed of different types of Citrus pectins, juices (J) and the respective phenolic extracts (E) from elderberry (EB), black currant (BC), red cabbage (RC) and purple carrot (PC) in the presence of ferric ions. For EB, BC and PC, pure blue colours devoid of a violet tint were exclusively observed for the phenolic extracts and at pH values ≥ 4.5 in model systems containing high methoxylated and amidated pectins, respectively. Colour and its stability strongly depended on the amount of ferric ions and the plant source; however, colour decay could generally be described as a pseudo-first-order kinetics. Despite optimal colour hues for RC-E and RC-J, storage and heat stabilities were poor. Highest colour intensities and best stabilities were observed for model systems containing PC-E at a molar anthocyanin:ferric ion ratio of 1:2. Ascorbic and lactic acids interfered with ferric ions, thus significantly affecting blue colour evolution and stability. Colour loss strongly depended on heat exposure with activation energies ranging between 60.5 and 78.4 kJ/mol. The comprehensive evaluation of the interrelationship of pigment source, pH conditions and pectin type on chelate formation and stability demonstrated that ferric anthocyanin chelates are promising natural blue food colourants. Copyright © 2012 Elsevier Ltd. All rights reserved.

Multiconfigurational and DFT analyses of the electromeric formulation and UV-vis absorption spectra of the superoxide adduct of ferrous superoxide reductase.

PubMed

Attia, Amr A A; Cioloboc, Daniela; Lupan, Alexandru; Silaghi-Dumitrescu, Radu

2016-12-01

The putative initial adduct of ferrous superoxide reductase (SOR) with superoxide has been alternatively formulated as ferric-peroxo or ferrous-superoxo. The ~600-nm UV-vis absorption band proposed to be assigned to this adduct (either as sole intermediate in the SOR catalytic cycle, or as one of the two intermediates) has recently been interpreted as due to a ligand-to-metal charge transfer, involving thiolate and superoxide in a ferrous complex, contrary to an alternative assignment as a predominantly cysteine thiolate-to-ferric charge transfer in a ferric-peroxo electromer. In an attempt to clarify the electromeric formulation of this adduct, we report a computational study using a multiconfigurational complete active space self-consistent field (MC-CASSCF) wave function approach as well as modelling the UV-vis absorption spectra with time-dependent density functional theory (TD-DFT). The MC-CASSCF calculations disclose a weak interaction between iron and the dioxygenic ligand and a dominant configuration with an essentially ferrous-superoxo character. The computed UV-vis absorption spectra reveal a marked dependence on the choice of density functional - both in terms of location of bands and in terms of orbital contributors. For the main band in the visible region, besides the recently reported thiolate-to-superoxide charge transfer, a more salient, and less functional-dependent, feature is a thiolate-to-ferric iron charge transfer, consistent with a ferric-peroxo electromer. By contrast, the computed UV-vis spectra of a ferric-hydroperoxo SOR model match distinctly better (and with no qualitative dependence on the DFT methodology) the 600-nm band as due to a mainly thiolate-to-ferric character - supporting the assignment of the SOR "600-nm intermediate" as a S=5/2 ferric-hydroperoxo species. Copyright © 2016 Elsevier Inc. All rights reserved.

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.

Ferric sulfates on Mars: Surface Explorations and Laboratory Experiments

NASA Astrophysics Data System (ADS)

Wang, A.; Ling, Z.; Freeman, J. J.

2008-12-01

Recent results from missions to Mars have reinforced the importance of sulfates for Mars science. They are the hosts of water, the sinks of acidity, and maybe the most active species in the past and current surface/near-surface processes on Mars. Fe-sulfate was found frequently by Spirit and Opportunity rovers: jarosite in Meridiani Planum outcrops and a less specific "ferric sulfate" in the salty soils excavated by Spirit at Gusev Crater. Pancam spectral analysis suggests a variety of ferric sulfates in these soils, i.e. ferricopiapite, jarosite, fibroferrite, and rhomboclase. A change in the Pancam spectral features occurred in Tyrone soils after ~ 190 sols of exposure to surface conditions. Dehydration of ferric sulfate is a possible cause. We synthesized eight ferric sulfates and conducted a series of hydration/dehydration experiments. Our goal was to establish the stability fields and phase transition pathways of these ferric sulfates. In our experiments, water activity, temperature, and starting structure are the variables. No redox state change was observed. Acidic, neutral, and basic salts were used. Ferric sulfate sample containers were placed into relative humidity buffer solutions that maintain static relative humidity levels at three temperatures. The five starting phases were ferricopiapite (Fe4.67(SO4)6(OH)2.20H2O), kornelite (Fe2(SO4)3.7H2O), rhomboclase (FeH(SO4)2.4H2O), pentahydrite (Fe2(SO4)3.5H2O), and an amorphous phase (Fe2(SO4)3.5H2O). A total of one hundred fifty experiments have been running for nearly ten months. Thousands of coupled Raman and gravimetric measurements were made at intermediate steps to monitor the phase transitions. The first order discovery from these experiments is the extremely large stability field of ferricopiapite. Ferricopiapite is the major ferric sulfate to precipitate from a Fe3+-S-rich aqueous solution at mid-low temperature, and it has the highest H2O/Fe ratio (~ 4.3). However, unlike the Mg-sulfate with highest hydration state (epsomite, at mid-low temperature), which would dehydrate readily at low relative humidity, ferricopiapite remains unchanged over ten months under extremely dry conditions. On the other hand, amorphous ferric sulfate which forms easily from solutions at dry conditions, is similar to the amorphous magnesium sulfate in stability field, thus can potentially be a very important phase in the phase transition pathways of ferric sulfates on Mars.

Reduction in soil aggregation in response to dust emission processes

NASA Astrophysics Data System (ADS)

Swet, Nitzan; Katra, Itzhak

2016-09-01

Dust emission by aeolian (wind) soil erosion depends on the topsoil properties of the source area, especially on the nature of the aggregates where most dust particles are held. Although the key role of soil aggregates in dust emission, the response of soil aggregation to aeolian processes and its implications for dust emission remain unknown. This study focuses on aggregate size distribution (ASD) analyses before and after in-situ aeolian experiments in semiarid loess soils that are associated with dust emission. Wind tunnel simulations show that particulate matter (PM) emission and saltation rates depend on the initial ASD and shear velocity. Under all initial ASD conditions, the content of saltator-sized aggregates (63-250 μm) increased by 10-34% due to erosion of macro-aggregates (> 500 μm), resulting in a higher size ratio (SR) between the saltators and macro-aggregates following the aeolian erosion. The results revealed that the saltator production increases significantly for soils that are subjected to short-term (anthropogenic) disturbance of the topsoil. The findings highlight a decrease in soil aggregation for all initial ASD's in response to aeolian erosion, and consequently its influence on the dust emission potential. Changes in ASD should be considered as a key parameter in dust emission models of complex surfaces.

Soil aggregation and aggregating agents as affected by long term contrasting management of an Anthrosol

NASA Astrophysics Data System (ADS)

Zhang, Shulan; Wang, Renjie; Yang, Xueyun; Sun, Benhua; Li, Qinghui

2016-12-01

Soil aggregation was studied in a 21-year experiment conducted on an Anthrosol. The soil management regimes consisted of cropland abandonment, bare fallow without vegetation and cropping system. The cropping system was combined with the following nutrient management treatments: control (CONTROL, no nutrient input); nitrogen, phosphorus and potassium (NPK); straw plus NPK (SNPK); and manure (M) plus NPK (MNPK). Compared with the CONTROL treatment, the abandonment treatment significantly increased the formation of large soil macroaggregates (>2 mm) and consequently improved the stability of aggregates in the surface soil layer due to enhancement of hyphal length and of soil organic matter content. However, in response to long-term bare fallow treatment aggregate stability was low, as were the levels of aggregating agents. Long term fertilization significantly redistributed macroaggregates; this could be mainly ascribed to soil organic matter contributing to the formation of 0.5-2 mm classes of aggregates and a decrease in the formation of the >2 mm class of aggregates, especially in the MNPK treatment. Overall, hyphae represented a major aggregating agent in both of the systems tested, while soil organic compounds played significantly different roles in stabilizing aggregates in Anthrosol when the cropping system and the soil management regimes were compared.

Preparation of Tc-99m-macroaggregated albumin from recombinant human albumin for lung perfusion imaging.

PubMed

Hunt, A P; Frier, M; Johnson, R A; Berezenko, S; Perkins, A C

2006-01-01

Human serum albumin (HSA) extracted from pooled blood taken from human donors is used in the production of (99m)Tc-labelled macroaggregated albumin (MAA) for lung perfusion imaging. However, concerns for the safety of blood-derived products due to potential contamination by infective agents (e.g. new variant CJD), make alternative production methods necessary. Recombinant DNA technology is a promising method of albumin production avoiding problems associated with human-derived HSA. This paper presents results comparing MAA prepared from recombinant human albumin (rHA, Recombumin) (rMAA) with in-house produced HSA MAA (hMAA) and commercially available MAA (cMAA). (99m)Tc-MAA was prepared using previously published production methods by heating a mixture of albumin and stannous chloride in acetate buffer (pH 5.4) at 70 degrees C for 20 min. Parameters investigated include aggregate size, radiolabelling efficiency, radiochemical and aggregate stability at 4 degrees C and in vitro (in whole human blood) at 37 degrees C and biodistribution studies. Results showed that rMAA could be produced with similar morphology, labelling efficiency and stability to hMAA and cMAA. Our findings confirm that rHA shows significant potential as a direct replacement for HSA in commercially available MAA.

Effects of reclamation years on composition and diversity of soil bacterial communities in Northwest China.

PubMed

Cheng, Zhibo; Zhang, Fenghua; Gale, William Jeffrey; Wang, Weichao; Sang, Wen; Yang, Haichang

2018-01-01

The objective of this study was to evaluate bacterial community structure and diversity in soil aggregate fractions when salinized farmland was reclaimed after >27 years of abandonment and then farmed again for 1, 5, 10, and 15 years. Illumina MiSeq high-throughput sequencing was performed to characterize the soil bacterial communities in 5 aggregate size classes in each treatment. The results indicated that reclamation significantly increased macro-aggregation (>0.25 mm), as well as soil organic C, available N, and available P. The 10-year field had the largest proportion (93.9%) of soil in the macro-aggregate size classes (i.e., >0.25 mm) and the highest soil electrical conductivity. The 5 most dominant phyla in the soil samples were Proteobacteria, Actinobacteria, Gemmatimonadetes, Acidobacteria, and Bacteroidetes. The phylogenetic diversity, Chao1, and Shannon indices increased after the abandoned land was reclaimed for farming, reaching maximums in the 15-year field. Among aggregate size classes, the 1-0.25 mm aggregates generally had the highest phylogenetic diversity, Chao1, and Shannon indices. Soil organic C and soil electrical conductivity were the main environmental factors affecting the soil bacterial communities. The composition and structure of the bacterial communities also varied significantly depending on soil aggregate size and time since reclamation.

Soil aggregation and aggregating agents as affected by long term contrasting management of an Anthrosol

PubMed Central

Zhang, Shulan; Wang, Renjie; Yang, Xueyun; Sun, Benhua; Li, Qinghui

2016-01-01

Soil aggregation was studied in a 21-year experiment conducted on an Anthrosol. The soil management regimes consisted of cropland abandonment, bare fallow without vegetation and cropping system. The cropping system was combined with the following nutrient management treatments: control (CONTROL, no nutrient input); nitrogen, phosphorus and potassium (NPK); straw plus NPK (SNPK); and manure (M) plus NPK (MNPK). Compared with the CONTROL treatment, the abandonment treatment significantly increased the formation of large soil macroaggregates (>2 mm) and consequently improved the stability of aggregates in the surface soil layer due to enhancement of hyphal length and of soil organic matter content. However, in response to long-term bare fallow treatment aggregate stability was low, as were the levels of aggregating agents. Long term fertilization significantly redistributed macroaggregates; this could be mainly ascribed to soil organic matter contributing to the formation of 0.5–2 mm classes of aggregates and a decrease in the formation of the >2 mm class of aggregates, especially in the MNPK treatment. Overall, hyphae represented a major aggregating agent in both of the systems tested, while soil organic compounds played significantly different roles in stabilizing aggregates in Anthrosol when the cropping system and the soil management regimes were compared. PMID:27958366

Ferrite with extraordinary electric and dielectric properties prepared from self-combustion technique

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

Chen Qian; Du Piyi; Huang Wenyan

2007-03-26

Nickel-zinc ferrites (Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4}) with extraordinary electric and dielectric properties were prepared by self-combustion technique. The resistivity of ferrite in the ferric citrate system is on the order of 10{sup 10} {omega} cm, which is about four orders higher than that of ferrite in the ferric nitrate system as well as that of ferrite prepared by the conventional method. The dielectric loss of sample in the ferric citrate system is only 0.008. The amorphous phase and its encapsulation well around the grains have played most important roles in both high resistivity and low dielectric loss of ferritemore » in the ferric citrate system.« less

Effects of adhesions of amorphous Fe and Al hydroxides on surface charge and adsorption of K+ and Cd2+ on rice roots.

PubMed

Liu, Zhao-Dong; Wang, Hai-Cui; Zhou, Qin; Xu, Ren-Kou

2017-11-01

Iron (Fe) and aluminum (Al) hydroxides in variable charge soils attached to rice roots may affect surface-charge properties and subsequently the adsorption and uptake of nutrients and toxic metals by the roots. Adhesion of amorphous Fe and Al hydroxides onto rice roots and their effects on zeta potential of roots and adsorption of potassium (K + ) and cadmium (Cd 2+ ) by roots were investigated. Rice roots adsorbed more Al hydroxide than Fe hydroxide because of the greater positive charge on Al hydroxide. Adhesion of Fe and Al hydroxides decreased the negative charge on rice roots, and a greater effect of the Al hydroxide. Consequently, adhesion of Fe and Al hydroxides reduced the K + and Cd 2+ adsorption by rice roots. The results of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and desorption of K + and Cd 2+ from rice roots indicated that physical masking by Fe and Al hydroxides and diffuse-layer overlapping between the positively-charged hydroxides and negatively-charged roots were responsible for the reduction of negative charge on roots induced by adhesion of the hydroxides. Therefore, the interaction between Fe and Al hydroxides and rice roots reduced negative charge on roots and thus inhibited their adsorption of nutrient and toxic cations. Copyright © 2017 Elsevier Inc. All rights reserved.

Nickel hydroxide electrode. 3: Thermogravimetric investigations of nickel (II) hydroxides

NASA Technical Reports Server (NTRS)

Dennstedt, W.; Loeser, W.

1982-01-01

Water contained in Ni hydroxide influences its electrochemical reactivity. The water content of alpha and beta Ni hydroxides is different with respect to the amount and bond strength. Thermogravimetric experiments show that the water of the beta Ni hydroxides exceeding the stoichiometric composition is completely removed at 160 deg. The water contained in the interlayers of the beta hydroxide, however, is removed only at higher temperatures, together with the water originating from the decomposition of the hydroxide. These differences are attributed to the formation of II bonds within the interlayers and between interlayers and adjacent main layers. An attempt is made to explain the relations between water content and the oxidizability of the Ni hydroxides.

Dissociation of a ferric maltol complex and its subsequent metabolism during absorption across the small intestine of the rat.

PubMed Central

Barrand, M. A.; Callingham, B. A.; Dobbin, P.; Hider, R. C.

1991-01-01

1. The fate and disposition of [59Fe]-ferric [3H]-maltol after intravenous administration were investigated in anaesthetized rats. Immediate dissociation of ferric iron from maltol took place in the circulation even with high doses of ferric maltol (containing 1 mg elemental iron). In plasma samples withdrawn within 1 min of injection and subjected to gel filtration, 59Fe eluted with the high molecular weight proteins whilst the tritium was associated with low molecular weight material. 2. The rates of elimination of 59Fe and of tritium from the plasma and their ultimate fate were very different. The half life for 59Fe in the plasma was around 70 min and 59Fe appeared mainly in the bone marrow and liver. There was an initial rapid exit of tritium from the plasma with a half life of around 12 min. This was followed either by a plateau or by a rise in tritium levels, involving entry of maltol metabolites into the circulation. These metabolites could be recovered in the urine. 3. Entry of 59Fe and of tritium into the blood plasma after intraduodenal administration of [59Fe]-ferric [3H]-maltol was also very different. At low doses of ferric maltol (containing 100 micrograms elemental iron), the tritium appeared in the plasma in highest amounts within seconds and then decreased whilst there was a slow rise in 59Fe levels. At higher doses of ferric maltol (containing 7 mg elemental iron), levels of 59Fe in the plasma were highest at 5 min and then fell whereas tritium levels rose steadily. Mucosal processing of 59Fe prevented further entry of iron at high dose into the circulation.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1364845

Evaluation of Ferric and Ferrous Iron Therapies in Women with Iron Deficiency Anaemia

PubMed Central

Berber, Ilhami; Erkurt, Mehmet Ali; Aydogdu, Ismet; Kuku, Irfan

2014-01-01

Introduction. Different ferric and ferrous iron preparations can be used as oral iron supplements. Our aim was to compare the effects of oral ferric and ferrous iron therapies in women with iron deficiency anaemia. Methods. The present study included 104 women diagnosed with iron deficiency anaemia after evaluation. In the evaluations performed to detect the aetiology underlying the iron deficiency anaemia, it was found and treated. After the detection of the iron deficiency anaemia aetiology and treatment of the underlying aetiology, the ferric group consisted of 30 patients treated with oral ferric protein succinylate tablets (2 × 40 mg elemental iron/day), and the second group consisted of 34 patients treated with oral ferrous glycine sulphate tablets (2 × 40 mg elemental iron/day) for three months. In all patients, the following laboratory evaluations were performed before beginning treatment and after treatment. Results. The mean haemoglobin and haematocrit increases were 0.95 g/dL and 2.62% in the ferric group, while they were 2.25 g/dL and 5.91% in the ferrous group, respectively. A significant difference was found between the groups regarding the increase in haemoglobin and haematocrit values (P < 0.05). Conclusion. Data are submitted on the good tolerability, higher efficacy, and lower cost of the ferrous preparation used in our study. PMID:25006339

21 CFR 184.1631 - Potassium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... Listing of Specific Substances Affirmed as GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide..., including pellets, flakes, sticks, lumps, and powders. Potassium hydroxide is obtained commercially from the...

21 CFR 184.1631 - Potassium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... Listing of Specific Substances Affirmed as GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide..., including pellets, flakes, sticks, lumps, and powders. Potassium hydroxide is obtained commercially from the...

21 CFR 73.2299 - Ferric ferrocyanide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2299 Ferric ferrocyanide. (a) Identity and... coloring externally applied cosmetics, including cosmetics applied to the area of the eye, in amounts...

21 CFR 73.2299 - Ferric ferrocyanide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2299 Ferric ferrocyanide. (a) Identity and... coloring externally applied cosmetics, including cosmetics applied to the area of the eye, in amounts...

21 CFR 73.2299 - Ferric ferrocyanide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2299 Ferric ferrocyanide. (a) Identity and... coloring externally applied cosmetics, including cosmetics applied to the area of the eye, in amounts...

21 CFR 184.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... is prepared as a white precipitate by the addition of sodium hydroxide to a water soluble magnesium... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... Listing of Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide...

21 CFR 184.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... is prepared as a white precipitate by the addition of sodium hydroxide to a water soluble magnesium... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... Listing of Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide...

21 CFR 184.1631 - Potassium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide (KOH, CAS Reg. No. 1310-58-3) is also... powders. Potassium hydroxide is obtained commercially from the electrolysis of potassium chloride solution...

Direct Method for Continuous Determination of Iron Oxidation by Autotrophic Bacteria

PubMed Central

Steiner, Michael; Lazaroff, Norman

1974-01-01

A method for direct, continuous determination of ferric ions produced in autotrophic iron oxidation, which depends upon the measurement of ferric ion absorbance at 304 nm, is described. The use of initial rates is shown to compensate for such changes in extinction during oxidation, which are due to dependence of the extinction coefficient on the ratio of complexing anions to ferric ions. A graphical method and a computer method are given for determination of absolute ferric ion concentration, at any time interval, in reaction mixtures containing Thiobacillus ferrooxidans and ferrous ions at known levels of SO42+ and hydrogen ion concentrations. Some examples are discussed of the applicability of these methods to study of the rates of ferrous ion oxidation related to sulfate concentration. PMID:4441066

Thermochemical Concrete Pavement Scaling Mechanism: Navy F/A-18 Jet Aircraft Parking Apron Problem

DTIC Science & Technology

1998-06-01

boiling and recondensation) in hot, concentrated potassium hydroxide (E): Eqn 11 Alkaline Hydrolysis of Esters with Potassium Hydroxide KOH...RC02R’ -> KC02R + R’OH potassium alkyl ester (B) potassium ethanol(L) hydroxide (E) carboxylate (F) The overall reaction appears to make sense...carbonate (H) water 2. The parallel between calcium hydroxide and potassium hydroxide is not very accurate. Potassium hydroxide is a much stronger alkali

21 CFR 184.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... addition of sodium hydroxide to a water soluble magnesium salt or by hydration of reactive grades of... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2, CAS Reg. No. 1309-42-8) occurs...

21 CFR 73.2298 - Ferric ammonium ferrocyanide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2298 Ferric ammonium ferrocyanide. (a... ferrocyanide is safe for use in coloring externally applied cosmetics, including cosmetics applied to the area...

21 CFR 73.2298 - Ferric ammonium ferrocyanide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2298 Ferric ammonium ferrocyanide. (a... ferrocyanide is safe for use in coloring externally applied cosmetics, including cosmetics applied to the area...

21 CFR 73.2298 - Ferric ammonium ferrocyanide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2298 Ferric ammonium ferrocyanide. (a... ferrocyanide is safe for use in coloring externally applied cosmetics, including cosmetics applied to the area...

Stimulation of NADH-dependent microsomal DNA strand cleavage by rifamycin SV.

PubMed

Kukiełka, E; Cederbaum, A I

1995-04-15

Rifamycin SV is an antibiotic anti-bacterial agent used in the treatment of tuberculosis. This drug can autoxidize, especially in the presence of metals, and generate reactive oxygen species. A previous study indicated that rifamycin SV can increase NADH-dependent microsomal production of reactive oxygen species. The current study evaluated the ability of rifamycin SV to interact with iron and increase microsomal production of hydroxyl radical, as detected by conversion of supercoiled plasmid DNA into the relaxed open circular state. The plasmid used was pBluescript II KS(-), and the forms of DNA were separated by agarose-gel electrophoresis. Incubation of rat liver microsomes with plasmid plus NADH plus ferric-ATP caused DNA strand cleavage. The addition of rifamycin SV produced a time- and concentration-dependent increase in DNA-strand cleavage. No stimulation by rifamycin SV occurred in the absence of microsomes, NADH or ferric-ATP. Stimulation occurred with other ferric complexes besides ferric-ATP, e.g. ferric-histidine, ferric-citrate, ferric-EDTA, and ferric-(NH4)2SO4. Rifamycin SV did not significantly increase the high rates of DNA strand cleavage found with NADPH as the microsomal reductant. The stimulation of NADH-dependent microsomal DNA strand cleavage was completely blocked by catalase, superoxide dismutase, GSH and a variety of hydroxyl-radical-scavenging agents, but not by anti-oxidants that prevent microsomal lipid peroxidation. Redox cycling agents, such as menadione and paraquat, in contrast with rifamycin SV, stimulated the NADPH-dependent reaction; menadione and rifamycin SV were superior to paraquat in stimulating the NADH-dependent reaction. These results indicate that rifamycin SV can, in the presence of an iron catalyst, increase microsomal production of reactive oxygen species which can cause DNA-strand cleavage. In contrast with other redox cycling agents, the stimulation by rifamycin SV is more pronounced with NADH than with NADPH as the microsomal reductant. Interactions between rifamycin SV, iron and NADH generating hydroxyl-radical-like species may play a role in some of the hepatotoxic effects associated with the use of this antibacterial antibiotic.

Dissolution mechanism of aluminum hydroxides in acid media

NASA Astrophysics Data System (ADS)

Lainer, Yu. A.; Gorichev, I. G.; Tuzhilin, A. S.; Gololobova, E. G.

2008-08-01

The effects of the concentration, temperature, and potential at the hydroxide/electrolyte interface on the aluminum hydroxide dissolution in sulfuric, hydrochloric, and perchloric acids are studied. The limiting stage of the aluminum hydroxide dissolution in the acids is found to be the transition of the complexes that form on the aluminum hydroxide surface from the solid phase into the solution. The results of the calculation of the acid-base equilibrium constants at the oxide (hydroxide)/solution interface using the experimental data on the potentiometric titration of Al2O3 and AlOOH suspensions are analyzed. A mechanism is proposed for the dissolution of aluminum hydroxides in acid media.

Synthesis of high capacity cathodes for lithium-ion batteries by morphology-tailored hydroxide co-precipitation

NASA Astrophysics Data System (ADS)

Wang, Dapeng; Belharouak, Ilias; Ortega, Luis H.; Zhang, Xiaofeng; Xu, Rui; Zhou, Dehua; Zhou, Guangwen; Amine, Khalil

2015-01-01

Nickel manganese hydroxide co-precipitation inside a continuous stirred tank reactor was studied with sodium hydroxide and ammonium hydroxide as the precipitation agents. The ammonium hydroxide concentration had an effect on the primary and secondary particle evolution. The two-step precipitation mechanism proposed earlier was experimentally confirmed. In cell tests, Li- and Mn-rich composite cathode materials based on the hydroxide precursors demonstrated good electrochemical performance in terms of cycle life over a wide range of lithium content.

Electrical conduction studies in ferric-doped KHSO 4 single crystals

NASA Astrophysics Data System (ADS)

Sharon, M.; Kalia, A. K.

1980-03-01

Direct-current conductivity of ferric-doped (138, 267, and 490 ppm) single crystals of KHSO 4 has been studied. The mechanism for the dc conduction process is discussed. It is observed that the ferric ion forms a (Fe 3+-two vacancies) complex and the enthaply for its formation is 0.09 ± 0.01 eV. It is proposed that each ferric ion removes two protons from each HSO 4 dimer. The conductivity plot shows the presence of intrinsic and extrinsic regions. It is proposed that in the intrinsic region the dimer of HSO -4 breaks reversibly to form a long-chain monomer-type structure. The conductivity in the KHSO 4 crystal is proposed to be controlled by the rotation of HSO -4 tetrahedra along the axis which contains no hydrogen atom. Isotherm calculation for the trivalent-doped system is applied to this crystal and the results are compared with Co 2+-doped KHSO 4 crystal. The distribution coefficient of ferric ion in the KHSO 4 single crystal is calculated to be 4.5 × 10 -1. Ferric ion causes tapering in the crystal growth habit of KHSO 4 and it is believed to be due to the presence of (Fe 3+-two vacancies) complex. The enthalpy values for the various other processes are as follows: enthalpy for the breakage of HSO -4 dimer ( Hi) = 1.28 ± 0.01 eV; enthalpy for the rotation of HSO -4 tetrahedron ( Hm) = 0.58 ± 0.01 eV.

Effect of ferric oxyhydroxide grain coatings on the transport of bacteriophage PRD1 and Cryptosporidium parvum oocysts in saturated porous media

USGS Publications Warehouse

Abudalo, R.A.; Bogatsu, Y.G.; Ryan, J.N.; Harvey, R.W.; Metge, D.W.; Elimelech, M.

2005-01-01

To test the effect of geochemical heterogeneity on microorganism transport in saturated porous media, we measured the removal of two microorganisms, the bacteriophage PRD1 and oocysts of the protozoan parasite Cryptosporidium parvum, in flow-through columns of quartz sand coated by different amounts of a ferric oxyhydroxide. The experiments were conducted over ranges of ferric oxyhydroxide coating fraction of ?? = 0-0.12 for PRD1 and from ?? = 0-0.32 for the oocysts at pH 5.6-5.8 and 10-4 M ionic strength. To determine the effect of pH on the transport of the oocysts, experiments were also conducted over a pH range of 5.7-10.0 at a coating fraction of ?? = 0.04. Collision (attachment) efficiencies increased as the fraction of ferric oxyhydroxide coated quartz sand increased, from ?? = 0.0071 to 0.13 over ?? = 0-0.12 for PRD1 and from ?? = 0.059 to 0.75 over ?? = 0-0.32 for the oocysts. Increasing the pH from 5.7 to 10.0 resulted in a decrease in the oocyst collision efficiency as the pH exceeded the expected point of zero charge of the ferric oxyhydroxide coatings. The collision efficiencies correlated very well with the fraction of quartz sand coated by the ferric oxyhydroxide for PRD1 but not as well for the oocysts. ?? 2005 American Chemical Society.

A novel role of the ferric reductase Cfl1 in cell wall integrity, mitochondrial function, and invasion to host cells in Candida albicans.

PubMed

Yu, Qilin; Dong, Yijie; Xu, Ning; Qian, Kefan; Chen, Yulu; Zhang, Biao; Xing, Laijun; Li, Mingchun

2014-11-01

Candida albicans is an important opportunistic pathogen, causing both superficial mucosal infections and life-threatening systemic diseases. Iron acquisition is an important factor for pathogen-host interaction and also a significant element for the pathogenicity of this organism. Ferric reductases, which convert ferric iron into ferrous iron, are important components of the high-affinity iron uptake system. Sequence analyses have identified at least 17 putative ferric reductase genes in C. albicans genome. CFL1 was the first ferric reductase identified in C. albicans. However, little is known about its roles in C. albicans physiology and pathogenicity. In this study, we found that disruption of CFL1 led to hypersensitivity to chemical and physical cell wall stresses, activation of the cell wall integrity (CWI) pathway, abnormal cell wall composition, and enhanced secretion, indicating a defect in CWI in this mutant. Moreover, this mutant showed abnormal mitochondrial activity and morphology, suggesting a link between ferric reductases and mitochondrial function. In addition, this mutant displayed decreased ability of adhesion to both the polystyrene microplates and buccal epithelial cells and invasion of host epithelial cells. These findings revealed a novel role of C. albicans Cfl1 in maintenance of CWI, mitochondrial function, and interaction between this pathogen and the host. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Role of Intravenous Ferric Carboxy-maltose in Pregnant Women with Iron Deficiency Anaemia.

PubMed

Mishra, Vineet; Gandhi, Khusaili; Roy, Priyankur; Hokabaj, Shaheen; Shah, Kunur N

2017-09-08

Iron deficiency is a common nutritional deficiency amongst women of childbearing age. Peri-partum iron deficiency anaemia is associated with significant maternal, foetal and infant morbidity. Current options for treatment include oral iron, which can be ineffective and poorly tolerated, and red blood cell transfusions, which carry an inherent risk and should be avoided. Ferric carboxymaltose is a modern treatment option. The study was designed to assess the safety and efficacy of intravenous ferric carboxymaltose for correction of iron deficiency anaemia in pregnant women. A prospective study was conducted at Institute of Kidney Disease and Research Centre, Ahmedabad from January 2014 to December 2016. Antenatal women (108) with iron deficiency anaemia were the study subjects. Socio-demographic profile was recorded and anaemia was assessed based on recent haemoglobin reports. Iron deficiency was diagnosed on basis of serum ferritin value. Intravenous ferric carboxymaltose as per total correction dose (maximum 1500mg) was administered to all women; the improvement in haemoglobin levels were assessed after 3 weeks of total dose infusion. Most of the women(n= 45, 41.7%), were in the age group of 27-30 years. Most of the women (n = 64, 59.3%) had moderate anaemia as per WHO guidelines. Mean haemoglobin levels significantly increased over a period of 3 weeks after Ferric carboxymaltose administrationand no serious life threatening adverse events were observed. Intravenous ferric carboxymaltose was safe and effective in pregnent women with iron deficiency anaemia.

Using 13C labeled glucose to determine soil microbial and physical controls of new C incorporation under drying-rewetting cycles and conservation agricultural management

NASA Astrophysics Data System (ADS)

Li, L.; Schaeffer, S. M.

2017-12-01

Drying-rewetting cycles can induce carbon (C) depletion in soil, while conservation agricultural management aims at soil C sequestration. Understanding the combined effect of drying-rewetting cycles and conservation management is critical for sustaining agricultural soil under climate change. Soil organic C can be stored in a relatively rapidly cycling active pool, or a more slowly cycling passive pool. We conducted a 24-days mesocosm incubation using an agricultural soil from western Tennessee under 35-years of conservation management. Different lengths of drought period before rewetting of 0, 3, 6, and 24 days were applied on the mesocosms. To trace the fate of newly added C, 13C labeled glucose was added to the mesocosms at the beginning of the incubation. After 24 days, dissolvable organic C, microbial biomass C, accumulative microbial respiration, and extracellular enzyme activity were analyzed to evaluate the active C pool; hydrogen peroxide oxidation and aggregate size fractionation were used to examine the passive C pool. The highest cumulative microbial respiration was found in the 6-days treatment combining a N-fixing cover crop with no-tillage, and the lowest in the 24-day treatment with a wheat cover crop combined with conventional-tillage (1000.0±20.5 and 106.8±17.5 µg C-CO2 g-1 dry soil, respectively). The 6-days treatment induced 0.5-4.3 times higher cumulative C-CO2 emission than the 3-days treatment. The proportion of macroaggregates in bulk soil varied between 97.2% and 76.7%, and it was negatively correlated with drying-rewetting frequency. The proportion of microaggregates in bulk soil varied between 21.9% and 2.1%, and it was positively correlated with drying-rewetting frequency. 13C recovery rate in bulk soil varied between 11-53%. The vetch-cover-crop-with-no-tillage treatment facilitated 13C accumulation the most. Our results show that the N fixing cover crops combined with no-tillage treatment induced the highest C accumulation in bulk soil, while the no cover crop combined with conventional tillage induced the lowest C concentration. Our results show that frequent drying-rewetting cycles disrupt macroaggregates and release the microaggregates within macroaggregates, and favor greater C loss combined with greater C storage in less stable aggregate fractions.

[Filamentous and phosphate solubilizing fungi relationships with some edaphic parameters and coffee plantations management].

PubMed

Posada, Raúl Hernando; Sánchez de Prager, Marina; Sieverding, Ewald; Aguilar Dorantes, Karla; Heredia-Abarca, Gabriela Patricia

2012-09-01

Soil properties and the environment have multiple outcomes on fungal communities. Although, the interaction effects between management intensity, pH, available phosphorus, organic carbon, soil texture and different fractions of water stable macro-aggregates on the communities of microscopic filamentous fungi (MFF), iron phosphate solubilizing fungi (PSF-Fe), and iron and calcium phosphate solubilizing fungi (PSF-(Fe+Ca)), have been previously evaluated in field conditions, this has never been performed in terms of their combined effects, neither with phosphate solubilizing fungi. To assess this, we collected 40 composite soil samples from eight Mexican and Colombian coffee plantations, with different management intensities and physico-chemical edaphic parameters, during 2008-2009. We isolated different communities of MFF, PSF-Fe and PSF-(Fe+Ca), by wet sieving and soil particles culture in Potato-Dextrose-Agar from soil samples, and we classified isolates in terms of their phosphate solubilizing ability. Following the principal component analysis results, we decided to analyze fungal communities and abiotic factors interactions for each country separately. Structural Equation Models revealed that organic carbon was positively associated to MFF richness and number of isolates (lambda>0.58), but its relationship with PSF-Fe and PSF-(Fe+Ca) were variable; while the available phosphorus, pH and water stable macro-aggregate fractions did not show a clear pattern. Management intensity was negatively related to PSF-Fe (lambda < or = -0.21) morphotype richness and the number of isolates in Colombian coffee plantations. We found that the relationships of clay and organic carbon content, and available phosphorus and soil pH, with the species richness and number of isolates of MFF, PSF-Fe and PSF-(Fe+Ca) were highly variable; this made impossible to generalize the responses between saprotrophic fungal groups and geographic zones. The management intensity was not related to species richness and number of isolates of MFF in any coffee areas, while for PSF the relationship could not be defined. The different water stable macro-aggregates fractions did not show a defined pattern in relation to the species richness and the number of isolates of saprophytic and phosphate solubilizing fungi (PSF). This study highlights the need to take into account edaphic and geographic context in order to reach a better understanding of the intensity management effects on MFF and PSF function in agroecosystems.

Effects of straw and biochar amendments on aggregate stability, soil organic carbon, and enzyme activities in the Loess Plateau, China.

PubMed

Zhang, Man; Cheng, Gong; Feng, Hao; Sun, Benhua; Zhao, Ying; Chen, Haixin; Chen, Jing; Dyck, Miles; Wang, Xudong; Zhang, Jianguo; Zhang, Afeng

2017-04-01

Soil from the Loess Plateau of China is typically low in organic carbon and generally has poor aggregate stability. Application of organic amendments to these soils could help to increase and sustain soil organic matter levels and thus to enhance soil aggregate stability. A field experiment was carried out to evaluate the effect of the application of wheat straw and wheat straw-derived biochar (pyrolyzed at 350-550 °C) amendments on soil aggregate stability, soil organic carbon (SOC), and enzyme activities in a representative Chinese Loess soil during summer maize and winter wheat growing season from 2013 to 2015. Five treatments were set up as follows: no fertilization (CK), application of inorganic fertilizer (N), wheat straw applied at 8 t ha -1 with inorganic fertilizer (S8), and wheat straw-derived biochar applied at 8 t ha -1 (B8) and 16 t ha -1 (B16) with inorganic fertilizer, respectively. Compared to the N treatment, straw and straw-derived biochar amendments significantly increased SOC (by 33.7-79.6%), microbial biomass carbon (by 18.9-46.5%), and microbial biomass nitrogen (by 8.3-38.2%), while total nitrogen (TN) only increased significantly in the B16 plot (by 24.1%). The 8 t ha -1 straw and biochar applications had no significant effects on soil aggregation, but a significant increase in soil macro-aggregates (>2 mm) (by 105.8%) was observed in the B16 treatment. The concentrations of aggregate-associated SOC increased by 40.4-105.8% in macro-aggregates (>2 mm) under straw and biochar amendments relative to the N treatment. No significant differences in invertase and alkaline phosphatase activity were detected among different treatments. However, urease activity was greater in the biochar treatment than the straw treatment, indicating that biochar amendment improved the transformation of nitrogen in the soil. The carbon pool index and carbon management index were increased with straw and biochar amendments, especially in the B16 treatment. In conclusion, application of carbonized crop residue as biochar, especially at a rate of 16 t ha -1 , could be a potential solution to recover the depleted SOC and enhance the formation of macro-aggregates in Loess Plateau soils of China.

Iron oxide minerals in dust-source sediments from the Bodélé Depression, Chad: Implications for radiative properties and Fe bioavailability of dust plumes from the Sahara

USGS Publications Warehouse

Moskowitz, Bruce M; Reynolds, Richard L.; Goldstein, Harland L.; Beroquo, Thelma; Kokaly, Raymond F.; Bristow, Charlie S

2016-01-01

Atmospheric mineral dust can influence climate and biogeochemical cycles. An important component of mineral dust is ferric oxide minerals (hematite and goethite) which have been shown to influence strongly the optical properties of dust plumes and thus affect the radiative forcing of global dust. Here we report on the iron mineralogy of dust-source samples from the Bodélé Depression (Chad, north-central Africa), which is estimated to be Earth’s most prolific dust producer and may be a key contributor to the global radiative budget of the atmosphere as well as to long-range nutrient transport to the Amazon Basin. By using a combination of magnetic property measurements, Mössbauer spectroscopy, reflectance spectroscopy, chemical analysis, and scanning electron microscopy, we document the abundance and relative amounts of goethite, hematite, and magnetite in dust-source samples from the Bodélé Depression. The partition between hematite and goethite is important to know to improve models for the radiative effects of ferric oxide minerals in mineral dust aerosols. The combination of methods shows (1) the dominance of goethite over hematite in the source sediments, (2) the abundance and occurrences of their nanosize components, and (3) the ubiquity of magnetite, albeit in small amounts. Dominant goethite and subordinate hematite together compose about 2% of yellow-reddish dust-source sediments from the Bodélé Depression and contribute strongly to diminution of reflectance in bulk samples. These observations imply that dust plumes from the Bodélé Depression that are derived from goethite-dominated sediments strongly absorb solar radiation. The presence of ubiquitous magnetite (0.002–0.57 wt%) is also noteworthy for its potentially higher solubility relative to ferric oxide and for its small sizes, including PM < 0.1 μm. For all examined samples, the average iron apportionment is estimated at about 33% in ferric oxide minerals, 1.4% in magnetite, and 65% in ferric silicates. Structural iron in clay minerals may account for much of the iron in the ferric silicates. We estimate that the mean ferric oxides flux exported from the Bodélé Depression is 0.9 Tg/yr with greater than 50% exported as ferric oxide nanoparticles (<0.1 μm). The high surface-to-volume ratios of ferric oxide nanoparticles once entrained into dust plumes may facilitate increased atmospheric chemical and physical processing and affect iron solubility and bioavailability to marine and terrestrial ecosystems.

Advances in aluminum hydroxide-based adjuvant research and its mechanism.

PubMed

He, Peng; Zou, Yening; Hu, Zhongyu

2015-01-01

In the past few decades, hundreds of materials have been tried as adjuvant; however, only aluminum-based adjuvants continue to be used widely in the world. Aluminum hydroxide, aluminum phosphate and alum constitute the main forms of aluminum used as adjuvants. Among these, aluminum hydroxide is the most commonly used chemical as adjuvant. In spite of its wide spread use, surprisingly, the mechanism of how aluminum hydroxide-based adjuvants exert their beneficial effects is still not fully understood. Current explanations for the mode of action of aluminum hydroxide-based adjuvants include, among others, the repository effect, pro-phagocytic effect, and activation of the pro-inflammatory NLRP3 pathway. These collectively galvanize innate as well as acquired immune responses and activate the complement system. Factors that have a profound influence on responses evoked by aluminum hydroxide-based adjuvant applications include adsorption rate, strength of the adsorption, size and uniformity of aluminum hydroxide particles, dosage of adjuvant, and the nature of antigens. Although vaccines containing aluminum hydroxide-based adjuvants are beneficial, sometimes they cause adverse reactions. Further, these vaccines cannot be stored frozen. Until recently, aluminum hydroxide-based adjuvants were known to preferentially prime Th2-type immune responses. However, results of more recent studies show that depending on the vaccination route, aluminum hydroxide-based adjuvants can enhance both Th1 as well as Th2 cellular responses. Advances in systems biology have opened up new avenues for studying mechanisms of aluminum hydroxide-based adjuvants. These will assist in scaling new frontiers in aluminum hydroxide-based adjuvant research that include improvement of formulations, use of nanoparticles of aluminum hydroxide and development of composite adjuvants.

Advances in aluminum hydroxide-based adjuvant research and its mechanism

PubMed Central

He, Peng; Zou, Yening; Hu, Zhongyu

2015-01-01

In the past few decades, hundreds of materials have been tried as adjuvant; however, only aluminum-based adjuvants continue to be used widely in the world. Aluminum hydroxide, aluminum phosphate and alum constitute the main forms of aluminum used as adjuvants. Among these, aluminum hydroxide is the most commonly used chemical as adjuvant. In spite of its wide spread use, surprisingly, the mechanism of how aluminum hydroxide-based adjuvants exert their beneficial effects is still not fully understood. Current explanations for the mode of action of aluminum hydroxide-based adjuvants include, among others, the repository effect, pro-phagocytic effect, and activation of the pro-inflammatory NLRP3 pathway. These collectively galvanize innate as well as acquired immune responses and activate the complement system. Factors that have a profound influence on responses evoked by aluminum hydroxide-based adjuvant applications include adsorption rate, strength of the adsorption, size and uniformity of aluminum hydroxide particles, dosage of adjuvant, and the nature of antigens. Although vaccines containing aluminum hydroxide-based adjuvants are beneficial, sometimes they cause adverse reactions. Further, these vaccines cannot be stored frozen. Until recently, aluminum hydroxide-based adjuvants were known to preferentially prime Th2-type immune responses. However, results of more recent studies show that depending on the vaccination route, aluminum hydroxide-based adjuvants can enhance both Th1 as well as Th2 cellular responses. Advances in systems biology have opened up new avenues for studying mechanisms of aluminum hydroxide-based adjuvants. These will assist in scaling new frontiers in aluminum hydroxide-based adjuvant research that include improvement of formulations, use of nanoparticles of aluminum hydroxide and development of composite adjuvants. PMID:25692535

Iron uptake in Mycelia sterilia EP-76.

PubMed Central

Adjimani, J P; Emery, T

1987-01-01

The cyclic trihydroxamic acid, N,N',N''-triacetylfusarinine C, produced by Mycelia sterilia EP-76, was shown to be a ferric ionophore for this organism. The logarithm of the association constant k for the ferric triacetylfusarinine C chelate was determined to be 31.8. Other iron-chelating agents, such as rhodotorulic acid, citric acid, and the monomeric subunit of triacetylfusarinine C, N-acetylfusarinine, delivered iron to the cells by an indirect mechanism involving iron exchange into triacetylfusarinine C. In vitro ferric ion exchange was found to be rapid with triacetylfusarinine C. Gallium uptake rates comparable to those of iron were observed with the chelating agents that transport iron into the cell. Ferrichrome, but not ferrichrome A, was also capable of delivering iron and gallium to this organism, but not by an exchange mechanism. Unlike triacetylfusarinine C, the 14C-ligand of ferrichrome was retained by the cell. A midpoint potential of -690 mV with respect to the saturated silver chloride electrode was obtained for the ferric triacetylfusarinine C complex, indicating that an unfavorable reduction potential was not the reason for the use of a hydrolytic mechanism of intracellular iron release from the ferric triacetylfusarinine C chelate. PMID:3611025

Fibrous materials on polyhydroxybutyrate and ferric iron (III)-based porphyrins basis: physical-chemical and antibacterial properties

NASA Astrophysics Data System (ADS)

Olkhov, A.; Lobanov, A.; Staroverova, O.; Tyubaeva, P.; Zykova, A.; Pantyukhov, P.; Popov, A.; Iordanskii, A.

2017-02-01

Ferric iron (III)-based complexes with porphyrins are the homogenous catalysts of auto-oxidation of several biogenic substances. The most perspective carrier for functional low-molecular substances is the polymer fibers with nano-dimensional parameters. Application of natural polymers, poly-(3-hydroxybutyrate) or polylactic acid for instance, makes possible to develop fiber and matrice systems to solve ecological problem in biomedicine The aim of the article is to obtain fibrous material on poly-(3-hydroxybutyrate) and ferric iron (III)-based porphyrins basis and to examine its physical-chemical and antibacterial properties. The work is focused on possibility to apply such material to biomedical purposes. Microphotographs of obtained material showed that addition of 1% wt. ferric iron (III)-based porphyrins to PHB led to increased average diameter and disappeared spindly structures in comparison with initial PHB. Biological tests of nonwoven fabrics showed that fibers, containing ferric iron (III)-based tetraphenylporphyrins, were active in relation to bacterial test-cultures. It was found that materials on polymer and metal complexes with porphyrins basis can be applied to production of decontamination equipment in relation to pathogenic and opportunistic microorganisms.

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

Sullivan, M.F.; Ruemmler, P.S.; Ryan, J.L.

Neptunium-237(V) nitrate was administered by gavage to groups of fed or fasted adult and 5-day-old rats. Some groups also received the oxidants quinhydrone or ferric iron and others received the reducing agent ferrous iron. Adult mice received ferric or ferrous iron and /sup 235/Np. When the adult rats were killed at 7 days after gavage, measurements showed that, compared with rats that were fed, a 24-hr fast caused a fivefold increase in /sup 237/Np absorption and retention. Both quinhydrone and ferric iron caused an even greater increase in absorption in both fed and fasted rats. Ferrous iron, on the othermore » hand, decreased absorption in fasted rats to values lower than those obtained in fed rats. Similar results were obtained in mice treated with /sup 235/Np and either ferric or ferrous iron. The effects of ferric and ferrous iron on neptunium absorption by neonatal rats were similar to their effects on adult animals but of lesser magnitude. These results are consistent with the hypothesis that Np(V), when given in small mass quantities to fed animals, is reduced in the gastrointestinal tract to Np(IV), which is less well absorbed than Np(V).« less

Antibacterial action of calcium hydroxide vehicles and calcium hydroxide pastes.

PubMed

Pacios, María Gabriela; Silva, Clara; López, María Elena; Cecilia, Marta

2012-11-01

To evaluate the in vitro action of vehicles alone and with calcium hydroxide against different bacterial species. Agar plates were inoculated with the microbial suspensions, and wells were made and filled with the calcium hydroxide pastes and the vehicles used to prepare the pastes. The zones of inhibited bacterial growth were recorded, and the resulting measurements were statistically analyzed. Enterococcus faecalis was the most resistant microorganism to all medicaments. Calcium hydroxide + p-monochlorophenol; calcium hydroxide + p-monochlorophenol-propylene glycol pastes; and p-monochlorophenol, p-monochlorophenol-propylene glycol, and chlorhexidine gluconate gel alone showed the largest zones of inhibition against all the tested microorganisms. The vehicle used to prepare the calcium hydroxide paste might contribute to its antibacterial action. Chlorhexidine gluconate gel used alone, and camphorated p-monochlorophenol and camphorated p-monochlorophenol-propylene glycol as vehicles of calcium hydroxide, could be recommended, in an antimicrobial sense. © 2012 Wiley Publishing Asia Pty Ltd.

Influence of tillage practices and straw incorporation on soil aggregates, organic carbon, and crop yields in a rice-wheat rotation system

PubMed Central

Song, Ke; Yang, Jianjun; Xue, Yong; Lv, Weiguang; Zheng, Xianqing; Pan, Jianjun

2016-01-01

In this study, a fixed-site field experiment was conducted to study the influence of different combinations of tillage and straw incorporation management on carbon storage in different-sized soil aggregates and on crop yield after three years of rice-wheat rotation. Compared to conventional tillage, the percentages of >2 mm macroaggregates and water-stable macroaggregates in rice-wheat double-conservation tillage (zero-tillage and straw incorporation) were increased 17.22% and 36.38% in the 0–15 cm soil layer and 28.93% and 66.34% in the 15–30 cm soil layer, respectively. Zero tillage and straw incorporation also increased the mean weight diameter and stability of the soil aggregates. In surface soil (0–15 cm), the maximum proportion of total aggregated carbon was retained with 0.25–0.106 mm aggregates, and rice-wheat double-conservation tillage had the greatest ability to hold the organic carbon (33.64 g kg−1). However, different forms occurred at higher levels in the 15–30 cm soil layer under the conventional tillage. In terms of crop yield, the rice grown under conventional tillage and the wheat under zero tillage showed improved equivalent rice yields of 8.77% and 6.17% compared to rice-wheat double-cropping under zero tillage or conventional tillage, respectively. PMID:27812038

Cu2+ ions as a paramagnetic probe to study the surface chemical modification process of layered double hydroxides and hydroxide salts with nitrate and carboxylate anions.

PubMed

Arizaga, Gregorio Guadalupe Carbajal; Mangrich, Antonio Salvio; Wypych, Fernando

2008-04-01

A layered zinc hydroxide nitrate (Zn5(OH)8(NO3)2.2H2O) and a layered double hydroxide (Zn/Al-NO3) were synthesized by coprecipitation and doped with different amounts of Cu2+ (0.2, 1, and 10 mol%), as paramagnetic probe. Although the literature reports that the nitrate ion is free (with D3h symmetry) between the layers of these two structures, the FTIR spectra of two zinc hydroxide nitrate samples show the C2v symmetry for the nitrate ion, whereas the g ||/A || value in the EPR spectra of Cu2+ is high. This fact suggests bonding of some nitrate ions to the layers of the zinc hydroxide nitrate. The zinc hydroxide nitrate was used as matrix in the intercalation reaction with benzoate, o-chlorobenzoate, and o-iodobenzoate ions. FTIR spectra confirm the ionic exchange reaction and the EPR spectroscopy reveals bonding of the organic ions to the inorganic layers of the zinc hydroxide nitrate, while the layered double hydroxides show only exchange reactions.

The fate of iron on Mars: Mechanism of oxidation of basaltic minerals to ferric-bearing assemblages

NASA Technical Reports Server (NTRS)

Burns, Roger G.

1992-01-01

Perhaps the most conspicuous indication that chemical weathering has occurred on the surface of Mars is the overall color of the red planet and the spectroscopic features that identify ferric-bearing assemblages in the martian regolith. Apparently, Fe(2+) ions in primary minerals in parent igneous rocks on the martian surface have been oxidized to ferric iron, which occurs in degradation products that now constitute the regolith. The mineralogy of the unweathered igneous rocks prior to weathering on the martian surface is reasonably well constrained, mainly as a result of petrographic studies of the SNC meteorites. However, the alteration products resulting from oxidative weathering of these rocks are less well-constrained. The topics covered include the following: primary rocks subjected to chemical weathering; dissolution processes; oxidation of dissolved Fe(2+); mechanism of polymerization of hydrous ferric oxides; terrestrial occurrences of ferromagnesian smectites; and dehydroxylated Mg-Fe smectites on Mars.

The continuum slope of Mars - Bidirectional reflectance investigations and applications to Olympus Mons

NASA Astrophysics Data System (ADS)

Fischer, E. M.; Pieters, C. M.

1993-04-01

Two primary causes of near-IR continuum slope variations have been observed in an investigation of the bidirectional reflectance characteristics of ferric coatings on the continuum slope of Mars. First, the presence of a thin ferric coating on a dark substrate produces a negative continuum slope due to the wavelength-dependent transparency of the ferric coating. Second, wavelength-dependent directional reflectance occurs when the surface particles are tightly packed, particle sizes are on the order of or smaller than the wavelength of light, or the surface is otherwise smooth on the order of the wavelength of light. Based on these results, the annuli on the flanks of Olympus Mons which are defined by reflectance and continuum slope are consistent with spatial variations in surface texture and possibly with spatial variations in the thickness of a ferric dust coating or rind.

Method and system for producing hydrogen using sodium ion separation membranes

DOEpatents

Bingham, Dennis N; Klingler, Kerry M; Turner, Terry D; Wilding, Bruce M; Frost, Lyman

2013-05-21

A method of producing hydrogen from sodium hydroxide and water is disclosed. The method comprises separating sodium from a first aqueous sodium hydroxide stream in a sodium ion separator, feeding the sodium produced in the sodium ion separator to a sodium reactor, reacting the sodium in the sodium reactor with water, and producing a second aqueous sodium hydroxide stream and hydrogen. The method may also comprise reusing the second aqueous sodium hydroxide stream by combining the second aqueous sodium hydroxide stream with the first aqueous sodium hydroxide stream. A system of producing hydrogen is also disclosed.

The effect of polymers onto the size of zinc layered hydroxide salt and its calcined product

NASA Astrophysics Data System (ADS)

Hussein, Mohd Zobir bin; Ghotbi, Mohammad Yeganeh; Yahaya, Asmah Hj; Abd Rahman, Mohd Zaki

2009-02-01

Zinc hydroxide nitrate, a brucite-like layered material was synthesized using pH control method. Poly(vinyl alcohol) and poly(ethylene glycol) were used at various percentages as size decreasing agents during the synthesis of zinc hydroxide nitrate. SEM and PXRD showed the decrease of size and thickness of the resultant zinc hydroxide nitrates. TG and surface area data confirmed the decrease of the particle sizes, too. When zinc hydroxide nitrates were heat treated at 500 °C, the physical properties of nano zinc oxides obtained depended on the parent material, zinc hydroxide nitrate.

Stabilization of the As-contaminated soil from the metal mining areas in Korea.

PubMed

Ko, Myoung-Soo; Kim, Ju-Yong; Bang, Sunbeak; Lee, Jin-Soo; Ko, Ju-In; Kim, Kyoung-Woong

2012-01-01

The stabilization efficiencies of arsenic (As) in contaminated soil were evaluated using various additives such as limestone, steel mill slag, granular ferric hydroxide (GFH), and mine sludge collected from an acid mine drainage treatment system. The soil samples were collected from the Chungyang area, where abandoned Au-Ag mines are located. Toxicity characteristic leaching procedure, synthetic precipitation leaching procedure, sequential extraction analysis, aqua regia digestion, cation exchange capacity, loss on ignition, and particle size distribution were conducted to assess the physical and chemical characteristics of highly arsenic-contaminated soils. The total concentrations of arsenic in the Chungyang area soil ranged up to 145 mg/kg. After the stabilization tests, the removal percentages of dissolved As(III) and As(V) were found to differ from the additives employed. Approximately 80 and 40% of the As(V) and As(III), respectively, were removed with the use of steel mill slag. The addition of limestone had a lesser effect on the removal of arsenic from solution. However, more than 99% of arsenic was removed from solution within 24 h when using GFH and mine sludge, with similar results observed when the contaminated soils were stabilized using GFH and mine sludge. These results suggested that GFH and mine sludge may play a significant role on the arsenic stabilization. Moreover, this result showed that mine sludge can be used as a suitable additive for the stabilization of arsenic.

Fe(II) oxidation during acid mine drainage neutralization in a pilot-scale Sequencing Batch Reactor.

PubMed

Zvimba, J N; Mathye, M; Vadapalli, V R K; Swanepoel, H; Bologo, L

2013-01-01

This study investigated Fe(II) oxidation during acid mine drainage (AMD) neutralization using CaCO3 in a pilot-scale Sequencing Batch Reactor (SBR) of hydraulic retention time (HRT) of 90 min and sludge retention time (SRT) of 360 min in the presence of air. The removal kinetics of Fe(II), of initial concentration 1,033 ± 0 mg/L, from AMD through oxidation to Fe(III) was observed to depend on both pH and suspended solids, resulting in Fe(II) levels of 679 ± 32, 242 ± 64, 46 ± 16 and 28 ± 0 mg/L recorded after cycles 1, 2, 3 and 4 respectively, with complete Fe(II) oxidation only achieved after complete neutralization of AMD. Generally, it takes 30 min to completely oxidize Fe(II) during cycle 4, suggesting that further optimization of SBR operation based on both pH and suspended solids manipulation can result in significant reduction of the number of cycles required to achieve acceptable Fe(II) oxidation for removal as ferric hydroxide. Overall, complete removal of Fe(II) during AMD neutralization is attractive as it promotes recovery of better quality waste gypsum, key to downstream gypsum beneficiation for recovery of valuables, thereby enabling some treatment-cost recovery and prevention of environmental pollution from dumping of sludge into landfills.

40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

Ferric Iron Production in Magma Oceans and Evolution of Mantle Oxidation State

NASA Astrophysics Data System (ADS)

Schaefer, L.; Elkins-Tanton, L. T.; Pahlevan, K.

2018-05-01

Self-oxidation of the magma ocean by ferric iron production at high pressure may explain the mantle oxidation state of the Earth. Partitioning during fractional crystallization can further increase the mantle oxygen fugacity during solidification.

21 CFR 582.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

40 CFR 721.10504 - Surface modified magnesium hydroxide (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Surface modified magnesium hydroxide... Specific Chemical Substances § 721.10504 Surface modified magnesium hydroxide (generic). (a) Chemical... as surface modified magnesium hydroxide (PMN P-06-682) is subject to reporting under this section for...

21 CFR 582.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

21 CFR 582.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

40 CFR 721.10573 - Magnesium hydroxide surface treated with substituted alkoxysilanes (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Magnesium hydroxide surface treated... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10573 Magnesium hydroxide surface... to reporting. (1) The chemical substance identified generically as magnesium hydroxide surface...

21 CFR 582.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

40 CFR 721.10504 - Surface modified magnesium hydroxide (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Surface modified magnesium hydroxide... Specific Chemical Substances § 721.10504 Surface modified magnesium hydroxide (generic). (a) Chemical... as surface modified magnesium hydroxide (PMN P-06-682) is subject to reporting under this section for...

40 CFR 721.10573 - Magnesium hydroxide surface treated with substituted alkoxysilanes (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Magnesium hydroxide surface treated... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10573 Magnesium hydroxide surface... to reporting. (1) The chemical substance identified generically as magnesium hydroxide surface...

21 CFR 582.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

21 CFR 582.1205 - Calcium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This...

21 CFR 582.1631 - Potassium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

21 CFR 582.1631 - Potassium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

21 CFR 582.1631 - Potassium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

21 CFR 582.1631 - Potassium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

21 CFR 582.1631 - Potassium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

DEMONSTRATION OF A BIOAVAILABLE FERRIC IRON TEST KIT

EPA Science Inventory

Bioavailable ferric iron (BAFeIII) is used by iron-reducing bacteria as an electron acceptor during the oxidation of various organic contaminants such as vinyl chloride and benzene. Quantification of BAFeIII is important with respect to characterizing candidate natural attenuati...

Ferric Hydrogensulfate [Fe(HSO4)3] As a Reusable Heterogeneous Catalyst for the Synthesis of 5-Substituted-1H-Tetrazoles and Amides

PubMed Central

Eshghi, Hossein; Seyedi, Seyed Mohammad; Zarei, Elaheh Rahimi

2011-01-01

Ferric hydrogensulfate catalyzed the synthesis of 5-substituted 1H-tetrazoles via [2 + 3] cycloaddition of nitriles and sodium azide. This method has the advantages of high yields, simple methodology, and easy workup. The catalyst can be recovered by simple filtration and reused delivering good yields. Also, ferric hydrogensulfate catalyzed the hydrolysis of nitriles to primary amides under aqueous conditions. Various aliphatic and aromatic nitriles converted to the corresponding amides in good yields without any contamination with carboxylic acids. PMID:24052817

Kinetics of the Reaction Between Alcohols and Isocyanates Catalyzed by Ferric Acetylacetonate

NASA Technical Reports Server (NTRS)

Schieler, Leroy

1961-01-01

The rate and temperature dependence of reaction for the ferric acetylacetonate catalyzed reaction between a-naphthyl, ortho-tolyl, and para-tolyl isocyanates and n-butyl alcohol are investigated. The effect of substituents on the reactivity of isocyanate and hydroxyl group are reported and for substituted isocyanates are correlated by means of the Hammett equation. Several metal chelates were studied and their catalytic activity was compared to that of ferric acetylacetonate. All rate data are interpreted in terms of a mechanism involving simultaneous second-order uncatalyzed and catalyzed reactions between alcohol and isocyanate.

Ferric reductase genes involved in high-affinity iron uptake are differentially regulated in yeast and hyphae of Candida albicans.

PubMed

Jeeves, Rose E; Mason, Robert P; Woodacre, Alexandra; Cashmore, Annette M

2011-09-01

The pathogenic yeast Candida albicans possesses a reductive iron uptake system which is active in iron-restricted conditions. The sequestration of iron by this mechanism initially requires the reduction of free iron to the soluble ferrous form, which is catalysed by ferric reductase proteins. Reduced iron is then taken up into the cell by a complex of a multicopper oxidase protein and an iron transport protein. Multicopper oxidase proteins require copper to function and so reductive iron and copper uptake are inextricably linked. It has previously been established that Fre10 is the major cell surface ferric reductase in C. albicans and that transcription of FRE10 is regulated in response to iron levels. We demonstrate here that Fre10 is also a cupric reductase and that Fre7 also makes a significant contribution to cell surface ferric and cupric reductase activity. It is also shown, for the first time, that transcription of FRE10 and FRE7 is lower in hyphae compared to yeast and that this leads to a corresponding decrease in cell surface ferric, but not cupric, reductase activity. This demonstrates that the regulation of two virulence determinants, the reductive iron uptake system and the morphological form of C. albicans, are linked. Copyright © 2011 John Wiley & Sons, Ltd.

A novel, kinetically stable, catalytically active, all-ferric, nitrite-bound complex of Paracoccus pantotrophus cytochrome cd1.

PubMed Central

Allen, James W A; Higham, Christopher W; Zajicek, Richard S; Watmough, Nicholas J; Ferguson, Stuart J

2002-01-01

The oxidized form of Paracoccus pantotrophus cytochrome cd(1) nitrite reductase, as isolated, has bis-histidinyl co-ordination of the c haem and His/Tyr co-ordination of the d(1) haem. On reduction, the haem co-ordinations change to His/Met and His/vacant respectively. If the latter form of the enzyme is reoxidized, a conformer is generated in which the ferric c haem is His/Met co-ordinated; this can revert to the 'as isolated' state of the enzyme over approx. 20 min at room temperature. However, addition of nitrite to the enzyme after a cycle of reduction and reoxidation produces a kinetically stable, all-ferric complex with nitrite bound to the d(1) haem and His/Met co-ordination of the c haem. This complex is catalytically active with the physiological electron donor protein pseudoazurin. The effective dissociation constant for nitrite is 2 mM. Evidence is presented that d(1) haem is optimized to bind nitrite, as opposed to other anions that are commonly good ligands to ferric haem. The all-ferric nitrite bound state of the enzyme could not be generated stoichiometrically by mixing nitrite with the 'as isolated' conformer of cytochrome cd(1) without redox cycling. PMID:12086580

Mapping hydrothermal alteration using aircraft VNIR scanners at the Rosemont porphyry copper deposit. [Visible-Near Infrared

NASA Technical Reports Server (NTRS)

Sadowski, R. M.; Abrams, M. J.

1983-01-01

Two Visible-Near Infrared (VNIR) scanners, the NS-001 and the M2S, were flown over the Rosemont porphyry copper deposit as part of the NASA/JPL/GEOSAT test site program. This program was established to determine the feasibility and limitations of mapping hydrothermal alteration with multispectral scanners. Data from the NS-001 at 0.83 and 2.2 microns were used to identify Fe(3+) and OH enriched outcrops. These areas were then correlated with three alteration assemblages. The first correlation, hematite-epidote, was the most obvious and appeared as a strong ferric iron signature associated with hematite stained Cretaceous arkoses and andesites. The second correlation, qtz-sericite, showed a combined ferric-hydroxyl signature for a phyllicly altered quartz monzonite. The third correlation, skarn, was identified only after a review of calc-silicate mineral VNIR spectra. Altered limestones that outcrop west of the deposit have a similar ferric iron-hydroxyl signature as the quartz-sericite altered quartz monzonite. This skarn signature has been interpreted to indicate the presence of andradite, hydro-grossularite and idocrase. Data from the second scanner, M2S, was used to search for variation in ferric iron mineral type. Resulting imagery data indicated that hematite was the dominant ferric iron mineral present in the Rosemont area.

Purification and characterization of an iron-induced ferritin from soybean (Glycine max) cell suspensions.

PubMed Central

Lescure, A M; Massenet, O; Briat, J F

1990-01-01

Ferric citrate induces ferritin synthesis and accumulation in soybean (Glycine max) cell suspension cultures [Proudhon, Briat & Lescure (1989) Plant Physiol. 90, 586-590]. This iron-induced ferritin has been purified from cells grown for 72 h in the presence of either 100 microM- or 500 microM-ferric citrate. It has a molecular mass of about 600 kDa and is built up from a 28 kDa subunit which is recognized by antibodies raised against pea (Pisum sativum) seed ferritin and it has the same N-terminal sequence as this latter, except for residue number 3, which is alanine in pea seed ferritin instead of valine in iron-induced soybean cell ferritin. It contains an average of 1800 atoms of iron per molecule whatever the ferric citrate concentration used to induce its synthesis. It is shown that the presence of 100 microM- or 500 microM-ferric citrate in the culture medium leads respectively to an 11- and 28-fold increase in the total intracellular iron concentration and to a 30- and 60-fold increase in the ferritin concentration. However, the percentage of iron stored in the mineral core of ferritin remains constant whatever the ferric citrate concentration used and represents only 5-6% of cellular iron. Images Fig. 2. Fig. 3. PMID:2264818

Purification and characterization of an iron-induced ferritin from soybean (Glycine max) cell suspensions.

PubMed

Lescure, A M; Massenet, O; Briat, J F

1990-11-15

Ferric citrate induces ferritin synthesis and accumulation in soybean (Glycine max) cell suspension cultures [Proudhon, Briat & Lescure (1989) Plant Physiol. 90, 586-590]. This iron-induced ferritin has been purified from cells grown for 72 h in the presence of either 100 microM- or 500 microM-ferric citrate. It has a molecular mass of about 600 kDa and is built up from a 28 kDa subunit which is recognized by antibodies raised against pea (Pisum sativum) seed ferritin and it has the same N-terminal sequence as this latter, except for residue number 3, which is alanine in pea seed ferritin instead of valine in iron-induced soybean cell ferritin. It contains an average of 1800 atoms of iron per molecule whatever the ferric citrate concentration used to induce its synthesis. It is shown that the presence of 100 microM- or 500 microM-ferric citrate in the culture medium leads respectively to an 11- and 28-fold increase in the total intracellular iron concentration and to a 30- and 60-fold increase in the ferritin concentration. However, the percentage of iron stored in the mineral core of ferritin remains constant whatever the ferric citrate concentration used and represents only 5-6% of cellular iron.

Effects of natural zeolite and ferric oxide to electromagnetic and reflection loss properties of polyurethane nanocomposite

NASA Astrophysics Data System (ADS)

Gultom, G.; Wirjosentono, B.; Ginting, M.; Sebayang, K.

2017-07-01

Microwave-absorptive polymeric composite materials are becoming important to protect interference of any communication systems due to increasing use of microwave-inducing devices. In this work, the microwave-absorptive polyurethane nanocomposites were prepared using natural zeolites of Sarulla North Sumatra and commercial ferric oxide as fillers. Weight ratios of the polyurethane to natural zeolite and ferric oxide were varied (90%:6%:4%; 80%:12%:8%; 70%:24%:6%) by weight. The fillers were prepared using ball milling technique and characterized for their particle size distributions using Particle Size Analyzer. The nanocomposites, prepared using in-situ reaction of polyethylene glycol, toluene diisocyanate and fillers. The complex permittivity (ε’and ε”) and complex permeability (μ’ and μ”) as electromagnetic properties were calculated using NRW method after collecting real and imaginary S parameter using Vector Network Analyzer measurement at X band frequency. Results show ratio of the fillers will affect the permeability, permittivity and reflection loss of the materials. The best reflection loss was shown -40.588 dB (>99 % absorption) at ratio for polyurethane : nanozeolite : ferric oxide (80%:12%:8%) by weight observed at 10.92 GHz. According to the measurement and calculation was shown the polyurethane filled with natural nanozeolite and ferric oxide is a good electromagnetic wave attenuation material.

Evaluation of different iron compounds in chlorotic Italian lemon trees (Citrus lemon).

PubMed

Ortiz, Patricio Rivera; Castro Meza, Blanca I; de la Garza Requena, Francisco R; Flores, Guillermo Mendoza; Etchevers Barra, Jorge D

2007-05-01

The severe deficiency of iron or ferric chlorosis is a serious problem of most citrus trees established in calcareous soils, as a result of the low availability of iron in these soils and the poor uptake and limited transport of this nutrient in trees. The objective of this study was to evaluate the response of chlorotic Italian lemon trees (Citrus lemon) to the application of iron compounds to roots and stems. On comparing the effects of aqueous solutions of ferric citrate, ferrous sulphate and FeEDDHA chelate, applied to 20% of the roots grown in soil and sand, of trees that were planted in pots containing calcareous soil, it was observed that the chelate fully corrected ferric chlorosis, while citrate and sulphate did not solve the problem. EDDHA induced the root uptake of iron as well as the movement of the nutrient up to the leaves. With the use of injections of ferric solutions into the secondary stem of adult trees, ferric citrate corrected chlorosis but ferrous sulphate did not. The citrate ion expanded the mobility of iron within the plant, from the injection points up to the leaves, whereas the sulphate ion did not sufficiently improve the movement of iron towards the leaf mesophyll.

Oxidation and coagulation of humic substances by potassium ferrate.

PubMed

Graham, N J D; Khoi, T T; Jiang, J-Q

2010-01-01

Ferrate (FeO₄²⁻) is believed to have a dual role in water treatment, both as oxidant and coagulant. Few studies have considered the coagulation effect in detail, mainly because of the difficulty of separating the oxidation and coagulation effects. This paper summarises some preliminary results from laboratory-based experiments that are investigating the coagulation reaction dynamically via a PDA instrument, between ferrate and humic acid (HA) at different doses and pH values, and comparing the observations with the use of ferric chloride. The PDA output gives a comparative measure of the rate of floc growth and the magnitude of floc formation. The results of the tests show some significant differences in the pattern of behaviour between ferrate and ferric chloride. At pH 5 the chemical dose range (as Fe) corresponding to HA coagulation was much broader for ferrate than ferric chloride, and the optimal Fe dose was greater. Ferrate oxidation appears to increase the hydrophilic and electronegative nature of the HA leading to an extended region of charge neutralisation. A consequence of the ferrate oxidation is that the extent of HA removal was slightly lower ( approximately 5%) than with ferric chloride. At pH 7, in the sweep flocculation domain, ferrate achieved much greater floc formation than ferric chloride, but a substantially lower degree of HA removal.

Process for changing caking coals to noncaking coals

DOEpatents

Beeson, Justin L.

1980-01-01

Caking coals are treated in a slurry including alkaline earth metal hydroxides at moderate pressures and temperatures in air to form noncaking carbonaceous material. Hydroxides such as calcium hydroxide, magnesium hydroxide or barium hydroxide are contemplated for slurrying with the coal to interact with the agglomerating constituents. The slurry is subsequently dewatered and dried in air at atmospheric pressure to produce a nonagglomerating carbonaceous material that can be conveniently handled in various coal conversion and combustion processes.

Controllable synthesis of layered Co-Ni hydroxide hierarchical structures for high-performance hybrid supercapacitors

NASA Astrophysics Data System (ADS)

Yuan, Peng; Zhang, Ning; Zhang, Dan; Liu, Tao; Chen, Limiao; Ma, Renzhi; Qiu, Guanzhou; Liu, Xiaohe

2016-01-01

A facile solvothermal method is developed for synthesizing layered Co-Ni hydroxide hierarchical structures by using hexamethylenetetramine (HMT) as alkaline reagent. The electrochemical measurements reveal that the specific capacitances of layered bimetallic (Co-Ni) hydroxides are generally superior to those of layered monometallic (Co, Ni) hydroxides. The as-prepared Co0.5Ni0.5 hydroxide hierarchical structures possesses the highest specific capacitance of 1767 F g-1 at a galvanic current density of 1 A g-1 and an outstanding specific capacitance retention of 87% after 1000 cycles. In comparison with the dispersed nanosheets of Co-Ni hydroxide, layered hydroxide hierarchical structures show much superior electrochemical performance. This study provides a promising method to construct hierarchical structures with controllable transition-metal compositions for enhancing the electrochemical performance in hybrid supercapacitors.

40 CFR 721.4600 - Recovered metal hydroxide.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Recovered metal hydroxide. 721.4600... Substances § 721.4600 Recovered metal hydroxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a recovered metal hydroxide (PMN P-91-809...

Polysulfide intercalated layered double hydroxides for metal capture applications

DOEpatents

Kanatzidis, Mercouri G.; Ma, Shulan

2017-04-04

Polysulfide intercalated layered double hydroxides and methods for their use in vapor and liquid-phase metal capture applications are provided. The layered double hydroxides comprise a plurality of positively charged host layers of mixed metal hydroxides separated by interlayer spaces. Polysulfide anions are intercalated in the interlayer spaces.

21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

Code of Federal Regulations, 2010 CFR

2010-04-01

... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white, odorless, tasteless, amorphous powder consisting essentially of aluminum hydroxide (Al2 O3· XH2 O). (2) Color additive...

21 CFR 73.1326 - Chromium hydroxide green.

Code of Federal Regulations, 2010 CFR

2010-04-01

... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide (Cr2O3·XH2O). (2) Color additive mixtures for drug use made with chromium hydroxide green may contain only those...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

21 CFR 184.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... salt or by hydration of reactive grades of magnesium oxide. (b) The ingredient meets the specifications... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... Listing of Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide...

21 CFR 184.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... hydration of reactive grades of magnesium oxide. (b) The ingredient meets the specifications of the Food... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium hydroxide. 184.1428 Section 184.1428 Food... Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2, CAS...

21 CFR 582.1763 - Sodium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

21 CFR 582.1763 - Sodium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

21 CFR 582.1763 - Sodium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

21 CFR 582.1763 - Sodium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

21 CFR 582.1763 - Sodium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

ESTCP DEMONSTRATION OF A BIOAVAILABLE FERRIC IRON TEST KIT

EPA Science Inventory

Bioavailable ferric iron (BAFeIII) is used by iron-reducing bacteria as an electron acceptor during the oxidation of various organic contaminants such as vinyl chloride and benzene. Quantification of BAFeIII is important with respect to characterizing candidate natural attenuati...

Systematic review with network meta-analysis: comparative efficacy and tolerability of different intravenous iron formulations for the treatment of iron deficiency anaemia in patients with inflammatory bowel disease.

PubMed

Aksan, A; Işık, H; Radeke, H H; Dignass, A; Stein, J

2017-05-01

Iron deficiency anaemia (IDA) is a common complication of inflammatory bowel disease (IBD) associated with reduced quality of life and increased hospitalisation rates. While the best way of treating IDA in IBD patients is not clearly established, current European guidelines recommend intravenous iron therapy in IBD patients with severe anaemia or intolerance to oral iron compounds. To compare the efficacy and tolerability of different intravenous iron formulations used to treat IDA in IBD patients in a systematic review and Bayesian network meta-analysis (NMA), PROSPERO registration number: 42016046565. In June 2016, we systematically searched for studies analysing efficacy and safety of intravenous iron for IDA therapy in IBD. Primary outcome was therapy response, defined as Hb normalisation or increase ≥2 g/dL. Five randomised, controlled trials (n = 1143 patients) were included in a network meta-analysis. Only ferric carboxymaltose was significantly more effective than oral iron [OR=1.9, 95% CrI: (1.1;3.2)]. Rank probabilities showed ferric carboxymaltose to be most effective, followed by iron sucrose, iron isomaltose and oral iron. Pooled data from the systematic review (n = 1746 patients) revealed adverse event rates of 12.0%, 15.3%, 12.0%, 17.0% for ferric carboxymaltose, iron sucrose, iron dextran and iron isomaltose respectively. One drug-related serious adverse event (SAE) each was reported for ferric carboxymaltose and iron isomaltoside, and one possibly drug-related SAE for iron sucrose. Ferric carboxymaltose was the most effective intravenous iron formulation, followed by iron sucrose. In addition, ferric carboxymaltose tended to be better tolerated. Thus, nanocolloidal IV iron products exhibit differing therapeutic and safety characteristics and are not interchangeable. © 2017 John Wiley & Sons Ltd.

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

Kleinlein, Claudia; Zheng, Shao-Liang; Betley, Theodore A.

Three ferric dipyrromethene complexes featuring different ancillary ligands were synthesized by one electron oxidation of ferrous precursors. Four-coordinate iron complexes of the type ( ArL)FeX 2 [ ArL = 1,9-(2,4,6-Ph 3C 6H 2) 2-5-mesityldipyrromethene] with X = Cl or tBuO were prepared and found to be high-spin (S = 5/2), as determined by superconducting quantum interference device magnetometry, electron paramagnetic resonance, and 57Fe Mössbauer spectroscopy. The ancillary ligand substitution was found to affect both ground state and excited properties of the ferric complexes examined. While each ferric complex displays reversible reduction and oxidation events, each alkoxide for chloride substitution resultsmore » in a nearly 600 mV cathodic shift of the Fe III/II couple. The oxidation event remains largely unaffected by the ancillary ligand substitution and is likely dipyrrin-centered. While the alkoxide substituted ferric species largely retain the color of their ferrous precursors, characteristic of dipyrrin-based ligand-to-ligand charge transfer (LLCT), the dichloride ferric complex loses the prominent dipyrrin chromophore, taking on a deep green color. Time-dependent density functional theory analyses indicate the weaker-field chloride ligands allow substantial configuration mixing of ligand-to-metal charge transfer into the LLCT bands, giving rise to the color changes observed. Furthermore, the higher degree of covalency between the alkoxide ferric centers is manifest in the observed reactivity. Delocalization of spin density onto the tert-butoxide ligand in ( ArL)FeCl(O tBu) is evidenced by hydrogen atom abstraction to yield ( ArL)FeCl and HOtBu in the presence of substrates containing weak C–H bonds, whereas the chloride ( ArL)FeCl 2 analogue does not react under these conditions.« less

Ferric carboxymaltose with or without erythropoietin for the prevention of red-cell transfusions in the perioperative period of osteoporotic hip fractures: a randomized contolled trial. The PAHFRAC-01 project.

PubMed

Bernabeu-Wittel, Máximo; Aparicio, Reyes; Romero, Manuel; Murcia-Zaragoza, José; Monte-Secades, Rafael; Rosso, Clara; Montero, Abelardo; Ruiz-Cantero, Alberto; Melero-Bascones, María

2012-02-21

Around one third to one half of patients with hip fractures require red-cell pack transfusion. The increasing incidence of hip fracture has also raised the need for this scarce resource. Additionally, red-cell pack transfusions are not without complications which may involve excessive morbidity and mortality. This makes it necessary to develop blood-saving strategies. Our objective was to assess safety, efficacy, and cost-effictveness of combined treatment of i.v. ferric carboxymaltose and erythropoietin (EPOFE arm) versus i.v. ferric carboxymaltose (FE arm) versus a placebo (PLACEBO arm) in reducing the percentage of patients who receive blood transfusions, as well as mortality in the perioperative period of hip fracture intervention. Multicentric, phase III, randomized, controlled, double blinded, parallel groups clinical trial. Patients > 65 years admitted to hospital with a hip fracture will be eligible to participate. Patients will be treated with either a single dosage of i.v. ferric carboxymaltose of 1 g and subcutaneous erythropoietin (40.000 IU), or i.v. ferric carboxymaltose and subcutaneous placebo, or i.v. placebo and subcutaneous placebo. Follow-up will be performed until 60 days after discharge, assessing transfusion needs, morbidity, mortality, safety, costs, and health-related quality of life. Intention to treat, as well as per protocol, and incremental cost-effectiveness analysis will be performed. The number of recruited patients per arm is set at 102, a total of 306 patients. We think that this trial will contribute to the knowledge about the safety and efficacy of ferric carboxymaltose with/without erythropoietin in preventing red-cell pack transfusions in patients with hip fracture. CLINICALTRIALS.GOV IDENTIFIER: NCT01154491.

Visible Wavelength Spectroscopy of Ferric Minerals: A Key Tool for Identification of Ancient Martian Aqueous Environments

NASA Technical Reports Server (NTRS)

Murchie, Scott L.; Bell, J. F., III; Morris, Richard V.

2000-01-01

The mineralogic signatures of past aqueous alteration of a basaltic Martian crust may include iron oxides and oxyhydroxides, zeolites, carbonates, phyllosilicates, and silica. The identities, relative abundances, and crystallinities of the phases formed in a particular environment depend on physicochemical conditions. At one extreme, hot spring environments may be characterized by smectite-chlorite to talc-kaolinite silicate assemblages, plus crystalline ferric oxides dominated by hematite. However, most environments, including cold springs, pedogenic layers, and ponded surface water, are expected to deposit iron oxides and oxyhydroxides, carbonates, and smectite-dominated phyllosilicates. A substantial fraction of the ferric iron is expected to occur in nanophase form, with the exact mineralogy strongly influenced by Eh-pH conditions. Detection of these phases has been an objective of a large body of terrestrial telescopic, Mars orbital, and landed spectral investigations and in situ compositional measurements. However, clear identifications of many of these phases is lacking. Neither carbonate nor silica has been unequivocally detected by any method. Although phyllosilicates may occur near the limit of detection by remote sensing, in general they appear to occur in only poorly crystalline form. In contrast, compelling evidence for ferric iron minerals has been gathered by recent telescopic investigations, the Imager for Mars Pathfinder (IMP), and the Thermal Emission Spectrometer (TES) on the Mars Global Surveyor (MGS). These data yield two crucial findings: (1) In the global, high spatial resolution TES data set, highly crystalline ferric iron (as coarse-grained 'gray' hematite) has been recognized but with only very limited spatial occurrence and (2) Low-resolution telescopic reflectance spectroscopy, very limited orbital reflectance spectroscopy, and landed multispectral imaging provide strong indications that at least two broad classes of ferric iron minerals are commonplace in non-dust covered regions.

Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review

PubMed Central

Shalavi, S; Yazdizadeh, M

2012-01-01

The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. Calcium hydroxide has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also a valuable anti-endotoxin agent. However, its effect on microbial biofilms is controversial. PMID:23323217

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 184.1763 - Sodium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

21 CFR 184.1763 - Sodium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

21 CFR 184.1763 - Sodium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

21 CFR 184.1763 - Sodium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 73.1326 - Chromium hydroxide green.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide (Cr2O3·XH2O...

Ytterbium coating of spherical Ni(OH) 2 cathode materials for Ni-MH batteries at elevated temperature

NASA Astrophysics Data System (ADS)

He, Xiangming; Wang, Li; Li, Wen; Jiang, Changyin; Wan, Chunrong

The Yb/Co coated nickel hydroxides were prepared by precipitation of Yb(OH) 3 on the surface of spherical nickel hydroxide, followed by precipitation of Co(OH) 2 on its surface. The optimum coating content of ytterbium was around 2% (atomic concentration) to obtain high discharge capacity at 60 °C. It was shown that the discharge capacity of nickel hydroxide at high temperatures was improved by coating of ytterbium and cobalt hydroxide. The high temperature performances of the sealed AAA-sized Ni-MH batteries using Yb/Co coated nickel hydroxide as positive electrodes were carried out, showing much better than those using the un-coated and only Co(OH) 2 coated nickel hydroxide electrodes. The charge acceptance of the battery using 2% Yb and 2% Co coated nickel hydroxide reached 92% at 60 °C, where the charge acceptances for the un-coated and only cobalt coated ones were only 42 and 46%, respectively. It has shown that the Yb/Co coating is an effective way to improve the high temperature performance of nickel hydroxide for nickel-metal hydride batteries.

Comparison of phenol and sodium hydroxide chemical matricectomies for the treatment of ingrowing toenails.

PubMed

Bostanci, Seher; Kocyigit, Pelin; Gürgey, Erbak

2007-06-01

Chemical matricectomy is performed mainly by two agents: phenol and sodium hydroxide. Both agents have excellent cure rates, but there are no data about the comparison of postoperative healing periods. This study was designed to compare the postoperative morbidity rates of sodium hydroxide and phenol matricectomies. Forty-six patients with 154 ingrowing nail sides were treated with either sodium hydroxide or phenol matricectomy. In the postoperative period, the patients were evaluated for the duration and severity of pain, drainage, and peripheral tissue destruction; complete healing periods; and overall success rates. The incidence of pain was higher in the sodium hydroxide group on the first visit, on the second day, but all patients became pain-free after that. The incidence and duration of drainage and peripheral tissue destruction was significantly higher in the phenol group. The mean period for complete recovery was 10.8 days in the sodium hydroxide group, whereas it was 18.02 days in the phenol group. The overall success rates in the sodium hydroxide and phenol groups were found to be 95.1 and 95.8%, respectively. Both sodium hydroxide and phenol are effective agents giving high success rates, but sodium hydroxide causes less postoperative morbidity and provides faster recovery.

Antimicrobial activity of calcium hydroxide and chlorhexidine on intratubular Candida albicans

PubMed Central

Jacques Rezende Delgado, Ronan; Helena Gasparoto, Thaís; Renata Sipert, Carla; Ramos Pinheiro, Claudia; Gomes de Moraes, Ivaldo; Brandão Garcia, Roberto; Antônio Hungaro Duarte, Marco; Monteiro Bramante, Clóvis; Aparecido Torres, Sérgio; Pompermaier Garlet, Gustavo; Paula Campanelli, Ana; Bernardineli, Norberti

2013-01-01

This study investigated the efficacy of calcium hydroxide and chlorhexidine gel for the elimination of intratubular Candida albicans (C. albicans). Human single-rooted teeth contaminated with C. albicans were treated with calcium hydroxide, 2% chlorhexidine gel, calcium hydroxide plus 2% chlorhexidine gel, or saline (0.9% sodium chloride) as a positive control. The samples obtained at depths of 0–100 and 100–200 µm from the root canal system were analyzed for C. albicans load by counting the number of colony forming units and for the percentage of viable C. albicans using fluorescence microscopy. First, the antimicrobial activity of calcium hydroxide and the 2% chlorhexidine gel was evaluated by counting the number of colony forming units. After 14 days of intracanal medication, there was a significant decrease in the number of C. albicans colony forming units at a depth of 0–100 µm with chlorhexidine treatment either with or without calcium hydroxide compared with the calcium hydroxide only treatment. However, there were no differences in the number of colony forming units at the 100–200 µm depth for any of the medications investigated. C. albicans viability was also evaluated by vital staining techniques and fluorescence microscopy analysis. Antifungal activity against C. albicans significantly increased at both depths in the chlorhexidine groups with and without calcium hydroxide compared with the groups treated with calcium hydroxide only. Treatments with only chlorhexidine or chlorhexidine in combination with calcium hydroxide were effective for elimination of C. albicans. PMID:23538639

Evaluation of calcium ion, hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments: An in vitro study

PubMed Central

Fulzele, Punit; Baliga, Sudhindra; Thosar, Nilima; Pradhan, Debaprya

2011-01-01

Aims: Evaluation of calcium ion and hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments. Objective: The purpose of this study was to evaluate calcium and hydroxyl ion release and pH levels of calcium hydroxide based products, namely, RC Cal, Metapex, calcium hydroxide with distilled water, along with the new gutta-percha points with calcium hydroxide. Materials and Methods: The materials were inserted in polyethylene tubes and immersed in deionized water. The pH variation, Ca++ and OH- release were monitored periodically for 1 week. Statistical Analysis Used: Statistical analysis was carried out using one-way analysis of variance and Tukey's post hoc tests with PASW Statistics version 18 software to compare the statistical difference. Results: After 1 week, calcium hydroxide with distilled water and RC Cal raised the pH to 12.7 and 11.8, respectively, while a small change was observed for Metapex, calcium hydroxide gutta-percha points. The calcium released after 1 week was 15.36 mg/dL from RC Cal, followed by 13.04, 1.296, 3.064 mg/dL from calcium hydroxide with sterile water, Metapex and calcium hydroxide gutta-percha points, respectively. Conclusions: Calcium hydroxide with sterile water and RC Cal pastes liberate significantly more calcium and hydroxyl ions and raise the pH higher than Metapex and calcium hydroxidegutta-percha points. PMID:22346155

Sulfide mineralization: Its role in chemical weathering of Mars

NASA Technical Reports Server (NTRS)

Burns, Roger G.

1988-01-01

Pyrrhotite-pentlandite assemblages in mafic and ultramafic igneous rocks may have contributed significantly to the chemical weathering reactions that produced degradation products in the Martian regolith. By analogy with terrestrial processes, a model is proposed whereby supergene alteration of these primary Fe-Ni sulfides on Mars has generated secondary sulfides (e.g., pyrite) below the water table and produced acidic groundwater containing high concentrations of dissolved Fe, Ni and sulfate ions. The low pH solutions also initiated weathering reactions of igneous feldspars and ferromagnesian silicates to form clay silicate and ferric oxyhydroxide phases. Near-surface oxidation and hydrolysis of ferric sulfato- and hydroxo-complex ions and sols formed gossans above the water table consisting of poorly crystalline hydrated ferric sulfates (e.g., jarosite), oxides (ferrihydrite, goethite) and silica (opal). Underlying groundwater, now permafrost, contains hydroxo sulfato complexes of Fe, Al, Mg, Ni, etc., which may be stabilized in frozen acidic solutions beneath the surface of Mars. Sublimation of permafrost may replenish colloidal ferric oxides, sulfates and phyllosilicates during dust storms on Mars.

Weathering of sulfides on Mars

NASA Technical Reports Server (NTRS)

Burns, Roger G.; Fisher, Duncan S.

1987-01-01

Pyrrhotite-pentlandite assemblages in mafic and ultramafic igneous rocks may have contributed significantly to the chemical weathering reactions that produce degradation products in the Martian regolith. By analogy and terrestrial processes, a model is proposed whereby supergene alteration of these primary Fe-Ni sulfides on Mars has generated secondary sulfides (e.g., pyrite) below the water table and produced acidic groundwater containing high concentrations of dissolved Fe, Ni, and sulfate ions. The low pH solutions also initiated weathering reactions of igneous feldspars and ferromagnesian silicates to form clay silicate and ferric oxyhydroxide phases. Near-surface oxidation and hydrolysis of ferric sulfato-and hydroxo-complex ions and sols formed gossan above the water table consisting of poorly crystalline hydrated ferric sulfates (e.g., jarosite), oxides (ferrihydrite, goethite), and silica (opal). Underlying groundwater, now permafrost contains hydroxo sulfato complexes of Fe, Al, Mg, Ni, which may be stabilized in frozen acidic solutions beneath the surface of Mars. Sublimation of permafrost may replenish colloidal ferric oxides, sulfates, and phyllosilicates during dust storms on Mars.

Removal of nickel and cadmium from battery waste by a chemical method using ferric sulphate.

PubMed

Jadhav, Umesh U; Hocheng, Hong

2014-01-01

The removal of nickel (Ni) and cadmium (Cd) from spent batteries was studied by the chemical method. A novel leaching system using ferric sulphate hydrate was introduced to dissolve heavy metals in batteries. Ni-Cd batteries are classified as hazardous waste because Ni and Cd are suspected carcinogens. More efficient technologies are required to recover metals from spent batteries to minimize capital outlay, environmental impact and to respond to increased demand. The results obtained demonstrate that optimal conditions, including pH, concentration of ferric sulphate, shaking speed and temperature for the metal removal, were 2.5, 60 g/L, 150 rpm and 30 degrees C, respectively. More than 88 (+/- 0.9) and 84 (+/- 2.8)% of nickel and cadmium were recovered, respectively. These results suggest that ferric ion oxidized Ni and Cd present in battery waste. This novel process provides a possibility for recycling waste Ni-Cd batteries in a large industrial scale.

Enhancing the Process of Anaerobic Ammonium Oxidation Coupled to Iron Reduction in Constructed Wetland Mesocosms with Supplementation of Ferric Iron Hydroxides

NASA Astrophysics Data System (ADS)

Shuai, W.; Jaffe, P. R.

2017-12-01

Effective ammonium (NH4+) removal has been a challenge in wastewater treatment processes. Aeration, which is required for the conventional NH4+ removal approach by ammonium oxidizing bacteria, is an energy intensive process during the operation of wastewater treatment plant. The efficiency of NH4+ oxidation in natural systems is also limited by oxygen transfer in water and sediments. The objective of this study is to enhance NH4+ removal by applying a novel microbial process, anaerobic NH4+ oxidation coupled to iron (Fe) reduction (also known as Feammox), in constructed wetlands (CW). Our studies have shown that an Acidimicrobiaceae bacterium named A6 can carry out the Feammox process using ferric Fe (Fe(III)) minerals like ferrihydrite as their electron acceptor. To investigate the properties of the Feammox process in CW as well as the influence of electrodes, Feammox bacterium A6 was inoculated in planted CW mesocosms with electrodes installed at multiple depths. CW mesocosms were operated using high NH4+ nutrient solution as inflow under high or low sediment Fe(III) level. During the operation, NH4+ and ferrous Fe concentration, pore water pH, voltages between electrodes, oxidation reduction potential and dissolved oxygen were measured. At the end of the experiment, CW sediment samples at different depths were taken, DNAs were extracted and quantitative polymerase chain reaction and pyrosequencing were performed to analyze the microbial communities. The results show that the high Fe level CW mesocosm has much higher NH4+ removal ability than the low Fe level CW mesocosm after Fe-reducing conditions are developed. This indicates the enhanced NH4+ removal can be attributed to elevated Feammox activity in high Fe level CW mesocosm. The microbial community structures are different in high or low Fe level CW mesocosms and on or away from the installed electrodes. The voltages between cathode and anode increased after the injection of A6 enrichment culture in low Fe level CW mesocosm but remained stable in high Fe level CW mesocosm, indicating A6 may use electrodes as their electron acceptor in the scarcity of Fe(III). The application of Feammox process in Fe-rich CW is promising in providing a cost and energy effective NH4+ removal approach, and the electrogenesis of A6 may also be useful in enhancing the Feammox process.

Microbial arsenic oxidation in a shallow marine hydrothermal vent system

NASA Astrophysics Data System (ADS)

Amend, J. P.; Meyer-Dombard, D. R.; Pichler, T.; Price, R.; Herndon, E.; Hsia, N.

2005-12-01

The toxic effects of arsenic are well documented, but this Group V element can also serve as an energy source to a diverse group of microorganisms. Most of the attention has been on arsenate (AsV) reduction, but the focus is shifting to include arsenite (AsIII) oxidation and subsequent immobilization through coprecipitation with iron (oxy)hydroxides. The shallow marine hydrothermal fluids near Ambitle Island, Papua New Guinea are characterized by arsenite concentrations of up to 1,000 μg/L. Directly proximal to the vent orifices, arsenate coprecipitates with 2-line ferrihydrite, coating rocks and corals in red and green biofilms up to 1 cm thick. DNA extracted from these coatings was amplified with archaeal- and bacterial-specific primers, and the 16S rRNA gene was sequenced. Both biofilm samples revealed archaeal communities exclusively composed of uncultured Crenarchaea. The bacterial members are primarily gamma Proteobacteria and Planctomycetes in the red biofilm, but 60% of the community in the green biofilm affiliate with the alpha Proteobacteria and candidate group OP11; there is minimal overlap in bacterial phylotypes between the two coatings. Slurries from these coatings were also used to inoculate geochemically designed growth media supplemented with various redox couples, including aerobic and anaerobic As(III) oxidation. On a medium targeting anaerobic, chemolithoautotrophic arsenic oxidation coupled to ferric iron reduction at 50 °C, predominantly rod-shaped organisms (~5×105 cells/ml) were enriched. In contrast, on an aerobic arsenic oxidation medium, coccoid-shaped organisms (~3×106 cells/ml) were enriched. The respective thermophilic microbial communities may be taking advantage of overall metabolisms represented by H3AsO3(aq) + 2FeOOH(s) + 3H+ = H2AsO4- + 2Fe2+ + 3H2O (1) and H3AsO3(aq) + 1/2O2(aq) = H2AsO4- + H+. (2) To date, no arsenite oxidizers are known to use ferric iron as a terminal electron acceptor (reaction 1). However, this environment, where arsenite-laden vent waters flow past mineral surfaces that can serve both as physical template and as oxidant, may be ideal for these putative organisms. On the other hand, a number of aerobic arsenite oxidizers have been described, especially among the bacteria, and reaction (2) is likely to support a microbial community involved in the oxidation and subsequent precipitation of arsenic.

The Effect of Pressure on Iron Speciation in Silicate Melts at a Fixed Oxygen Fugacity: The Possibility of a Redox Profile Through a Terrestrial Magma Ocean

NASA Astrophysics Data System (ADS)

Armstrong, K.; Frost, D. J.; McCammon, C. A.; Rubie, D. C.; Boffa Ballaran, T.

2017-12-01

As terrestrial planets accreted, mantle silicates equilibrated with core-forming metallic iron, which would have imposed a mantle oxygen fugacity below the iron-wüstite oxygen buffer. Throughout Earth's history, however, the oxygen fugacity of at least the accessible portions of the upper mantle has been 4-5 orders of magnitude higher. The process that caused the rapid increase in the redox state of the mantle soon after core formation is unclear. Here we test the possibility that pressure stabilises ferric iron in silicate melts, as has been observed in silicate minerals. A deep magma ocean, which would have likely existed towards the end of accretion, could then develop a gradient in oxygen fugacity for a fixed ferric-ferrous ratio as a result of pressure. We have equilibrated an andesitic melt with a Ru-RuO2 buffer in a multianvil press between 5 and 24 GPa. Further experiments were performed on the same melt in equilibrium with iron metal. The recovered melts were then analysed using Mössbauer spectroscopy to determine the ferric/ferrous ratio. The results show that for the Ru-RuO2 buffer at lower pressures, the ferric iron content decreases with pressure, due to a positive volume change of the reaction FeO + 1/4O2 = FeO1.5. Ferric iron content also appears to be sensitive to water content at lower pressures. However, above 15 GPa this trend apparently reverses and the ferric iron content increases with pressure. This reversal in pressure dependence would drive the oxygen fugacity of a deep magma ocean with a fixed ferric/ferrous ratio down with increasing depth. This would create a redox gradient, where the magma ocean could potentially be in equilibrium with metallic iron at its base but more oxidised in its shallower regions. Crystallisation of this magma ocean could render an upper mantle oxygen fugacity similar to that in the Earth's accessible mantle today.

Kinetics of the Decomposition of Hydrogen Peroxide Catalyzed by Ferric Ethylenediaminetetraacetate Complex

PubMed Central

Walling, Cheves; Partch, Richard E.; Weil, Tomas

1975-01-01

Added substrates, acetone and t-butyl alcohol, strongly retard the decomposition of H2O2 brought about by ferric ethylenediaminetetraacetate (EDTA) at pH 8-9.5. Their relative effectiveness and the kinetic form of the retardation are consistent with their interruption of a hydroxyl radical chain that is propagated by HO· attack both upon H2O2 and on complexed and uncomplexed EDTA. Similar retardation is observed with decompositions catalyzed by ferric nitrilotriacetate and hemin, and it is proposed that such redox chains may be quite a general path for transition metal ion catalysis of H2O2 decomposition. PMID:16592209

21 CFR 184.1205 - Calcium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium hydroxide. 184.1205 Section 184.1205 Food... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration of...

21 CFR 184.1763 - Sodium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The empirical formula is NaOH. Sodium...

21 CFR 184.1205 - Calcium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium hydroxide. 184.1205 Section 184.1205 Food... GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration of lime. (b) The ingredient...

The alpha-form of the hydroxides of bivalent metals

NASA Technical Reports Server (NTRS)

Feitknecht, W.

1984-01-01

X-ray analyses were made of the hydroxides of the bivalent metals. The freshly pptd. hydroxide is usually in the alpha-form, which on standing is converted to another form or other forms. The alpha and c grating dimensions of the alpha-form and the C6-type of Co, Zn, C, Co-Zn and Ni-Zn hydroxides are tabulated. Ni hydroxide does not exhibit an alpha-form. The alpha-Co(OH)2, the blue form, is stabilized by sugar or by the higher alcohols: these compounds do not stabilize alpha-Zn(OH)2.

21 CFR 582.5306 - Ferric sodium pyrophosphate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ferric sodium pyrophosphate. 582.5306 Section 582.5306 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or...

21 CFR 582.5306 - Ferric sodium pyrophosphate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ferric sodium pyrophosphate. 582.5306 Section 582.5306 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or...

21 CFR 582.5306 - Ferric sodium pyrophosphate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Ferric sodium pyrophosphate. 582.5306 Section 582.5306 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or...

21 CFR 582.5306 - Ferric sodium pyrophosphate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Ferric sodium pyrophosphate. 582.5306 Section 582.5306 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or...

Ammonium hydroxide poisoning

MedlinePlus

Ammonium hydroxide is a colorless liquid chemical solution. It is in a class of substances called caustics. Ammonium hydroxide forms when ammonia dissolves in water. This article discusses poisoning from ...

Involvement of superoxide radical in extracellular ferric reduction by iron-deficient bean roots. [Phadeolus vulgaris L. var Prelude

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

Cakmak, I.; van de Wetering, D.A.M.; Marschner, H.

The recent proposal of Tipton and Thowsen that iron-deficient plants reduce ferric chelates in cell walls by a system dependent on the leakage of malate from root cells was tested. Results are presented showing that this mechanism could not be responsible for the high rates of ferric reduction shown by roots of iron-deficient bean (Phaseolus vulgaris L. var Prelude) plants. The role of O/sub 2/ in the reduction of ferric chelates by roots of iron-deficient bean plants was also tested. The rate of Fe(III) reduction was the same in the presence and in the absence of O/sub 2/. However, inmore » the presence of O/sub 2/ the reaction was partially inhibited by superoxide dismutase (SOD), which indicates a role for the superoxide radical, O/sub 2//sup -/, as a facultative intermediate electron carrier. The inhibition by SOD increased with substrate pH and with decrease in concentration of the ferrous scavenger bathophenanthroline-disulfonate. The results are consistent with a mechanism for transmembrane electron in which a flavin or quinone is the final electron carrier in the plasma membrane. The results are discussed in relation to the ecological importance that O/sub 2//sup -/ may have in the acquisition of ferric iron by dicotyledonous plants.« less

DOUBLE SHELL TANK (DST) HYDROXIDE DEPLETION MODEL FOR CARBON DIOXIDE ABSORPTION

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

OGDEN DM; KIRCH NW

2007-10-31

This document generates a supernatant hydroxide ion depletion model based on mechanistic principles. The carbon dioxide absorption mechanistic model is developed in this report. The report also benchmarks the model against historical tank supernatant hydroxide data and vapor space carbon dioxide data. A comparison of the newly generated mechanistic model with previously applied empirical hydroxide depletion equations is also performed.

21 CFR 186.1300 - Ferric oxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... food packaging. (2) The ingredient is used at levels not to exceed current good manufacturing practice... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ferric oxide. 186.1300 Section 186.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

21 CFR 186.1300 - Ferric oxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... food packaging. (2) The ingredient is used at levels not to exceed current good manufacturing practice... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ferric oxide. 186.1300 Section 186.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

21 CFR 73.2299 - Ferric ferrocyanide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Ferric ferrocyanide. 73.2299 Section 73.2299 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF... coloring externally applied cosmetics, including cosmetics applied to the area of the eye, in amounts...

21 CFR 73.2298 - Ferric ammonium ferrocyanide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ferric ammonium ferrocyanide. 73.2298 Section 73.2298 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL... ferrocyanide is safe for use in coloring externally applied cosmetics, including cosmetics applied to the area...

21 CFR 73.2298 - Ferric ammonium ferrocyanide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Ferric ammonium ferrocyanide. 73.2298 Section 73.2298 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL... ferrocyanide is safe for use in coloring externally applied cosmetics, including cosmetics applied to the area...

21 CFR 73.2299 - Ferric ferrocyanide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ferric ferrocyanide. 73.2299 Section 73.2299 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF... coloring externally applied cosmetics, including cosmetics applied to the area of the eye, in amounts...

ELECTRODE MEASUREMENT OF REDOX POTENTIAL IN ANAEROBIC FERRIC/FERROUS CHLORIDE SYSTEMS

EPA Science Inventory

The behaviour of two inert redox electrodes (Pt and wax-impregnated graphite) was investigated in anaerobic ferrous and ferric chloride solutions in order to establish if these electrodes respond to the Fe³⁺/Fe²⁺ couple in a Nernstian manner. A new method fo...

Iron Amendment and Fenton Oxidation of MTBE-Spent Granular Activated Carbon

EPA Science Inventory

Fenton-driven regeneration of Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) involves Fe amendment to the GAC to catalyze H2O2 reactions and to enhance the rate of MTBE oxidation and GAC regeneration. Four forms of iron (ferric sulfate, ferric chloride, fer...

21 CFR 186.1300 - Ferric oxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... food packaging. (2) The ingredient is used at levels not to exceed current good manufacturing practice... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ferric oxide. 186.1300 Section 186.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

21 CFR 186.1300 - Ferric oxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) The ingredient is used as a constituent of paper and paperboard used for food packaging. (2) The... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ferric oxide. 186.1300 Section 186.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD...

21 CFR 186.1300 - Ferric oxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... food packaging. (2) The ingredient is used at levels not to exceed current good manufacturing practice... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ferric oxide. 186.1300 Section 186.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

ANALYSIS OF FERRIC AND FERROUS IONS IN SOIL EXTRACTS BY ION CHROMATOGRAPHY

EPA Science Inventory

A method using ion chromatography (IC) for the analysis of ferrous (Fe 2+) and ferric (Fe 3+) ions in soil extracts has been developed. This method uses an ion exchange column with detection at 520 nm after post-column derivatization. Selectivity is achieved by using an anionic...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1205 - Calcium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

Magnesium Hydroxide

MedlinePlus

Magnesium hydroxide is used on a short-term basis to treat constipation.This medication is sometimes prescribed ... Magnesium hydroxide come as a tablet and liquid to take by mouth. It usually is taken as ...

Aluminum Hydroxide

MedlinePlus

Aluminum hydroxide is used for the relief of heartburn, sour stomach, and peptic ulcer pain and to ... Aluminum hydroxide comes as a capsule, a tablet, and an oral liquid and suspension. The dose and ...

21 CFR 582.1205 - Calcium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1205 - Calcium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1205 - Calcium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

Pretreatment of rapeseed straw by sodium hydroxide.

PubMed

Kang, Kyeong Eop; Jeong, Gwi-Taek; Park, Don-Hee

2012-06-01

Pretreatment method for rapeseed straw by sodium hydroxide was investigated for production of bioethanol and biobutanol. Various pretreatment parameters, including temperature, time, and sodium hydroxide concentration were optimized using a statistical method which is a central composite design of response surface methodology. In the case of sodium hydroxide pretreatment, optimal pretreatment conditions were found to be 7.9% sodium hydroxide concentration, 5.5 h of reaction time, and 68.4 °C of reaction temperature. The maximum glucose yield which can be recovered by enzymatic hydrolysis at the optimum conditions was 95.7% and the experimental result was 94.0 ± 4.8%. This experimental result was in agreement with the model prediction. An increase of surface area and pore size in pretreated rapeseed straw by sodium hydroxide pretreatment was observed by scanning electron microscope.

Sodium hydroxide poisoning

MedlinePlus

Sodium hydroxide is a very strong chemical. It is also known as lye and caustic soda. This ... poisoning from touching, breathing in (inhaling), or swallowing sodium hydroxide. This article is for information only. Do ...

Lifetime of Sodium Beta-Alumina Membranes in Molten Sodium Hydroxide

DTIC Science & Technology

2008-07-01

ABSTRACT Summary: Sodium metal can be made by electrolysis of molten sodium hydroxide in sodium beta-alumina membrane electrolysis cells... electrolysis of molten sodium hydroxide in sodium ”-alumina membrane electrolysis cells. However, there are some uncertainties about the lifetime of the...the properties of the membrane degrade upon long term contact with molten sodium hydroxide. Electrolysis cells were designed, but it proved

Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

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

Bortolaz de Oliveira, Henrique; Wypych, Fernando, E-mail: wypych@ufpr.br

Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO{sub 4}{sup 2−}/g of material, respectively. Although the removal values obtained for Zn/NiHN andmore » Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO{sub 4}{sup 2−}/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated. - Highlights: • Zinc hydroxide nitrate and Zn/Ni hydroxide nitrate or acetate were synthesized. • The interlayer anions were replaced by chromate anions at pH=8.0. • Only Zn/Ni hydroxide nitrate or acetate have the structure preserved after exchange. • Fast exchange reaction and high capacity of chromate removal were observed. • Magnetic materials were obtained to facilitate the solids removal the from solutions.« less

Effect of the Association of Nonsteroidal Anti-inflammatory and Antibiotic Drugs on Antibiofilm Activity and pH of Calcium Hydroxide Pastes.

PubMed

de Freitas, Rafaela Pignatti; Greatti, Vanessa Raquel; Alcalde, Murilo Priori; Cavenago, Bruno Cavalini; Vivan, Rodrigo Ricci; Duarte, Marco Antonio Hungaro; Weckwerth, Ana Carolina Villas Bôas; Weckwerth, Paulo Henrique

2017-01-01

The objective of the present study was to evaluate the in vitro antibiofilm activity and pH of calcium hydroxide associated with different nonsteroidal anti-inflammatory drugs (NSAIDs). The groups analyzed were as follows: group 1, calcium hydroxide paste with propylene glycol; group 2, calcium hydroxide paste with propylene glycol + 5% diclofenac sodium; group 3, calcium hydroxide paste with propylene glycol + 5% ibuprofen; group 4, calcium hydroxide paste with propylene glycol + 5% ciprofloxacin; and group 6, positive control (without medication). For analysis of the pH, the pastes were inserted into tubes and immersed in flasks containing ultrapure water. At the time intervals of 3, 24, 72, and 168 hours, the pH was measured with a calibrated pH meter. For microbial analysis, biofilm was induced in 30 bovine dentin blocks for 21 days. Subsequently, the pastes were placed on the blocks with biofilm for 7 days. Afterward, the pastes were removed by irrigation with sterile water, and the specimens were analyzed with a laser scanning confocal microscope with the 50 μL Live/Dead BacLight Bacterial Viability solution L7012 Kit (Molecular Probes, Inc, Eugene, OR). Data were subjected to statistical analysis at a significance level of 5%. The highest pH values were found for calcium hydroxide associated with ciprofloxacin in all periods analyzed. With the exception of pure calcium hydroxide paste, the other groups showed statistically significant differences (P < .05) in comparison with the positive control. The association of NSAIDs or antibiotic did not interfere with the pH of calcium hydroxide paste and increased the antimicrobial action of calcium hydroxide paste against Enterococcus faecalis biofilm formation. Published by Elsevier Inc.

Intercalation studies of zinc hydroxide chloride: Ammonia and amino acids

NASA Astrophysics Data System (ADS)

Arízaga, Gregorio Guadalupe Carbajal

2012-01-01

Zinc hydroxide chloride (ZHC) is a layered hydroxide salt with formula Zn5(OH)8Cl2·2H2O. It was tested as intercalation matrix for the first time and results were compared with intercalation products of the well-known zinc hydroxide nitrate and a Zn/Al layered double hydroxide. Ammonia was intercalated into ZHC, while no significant intercalation occurred in ZHN. Aspartic acid intercalation was only achieved by co-precipitation at pH=10 with ZHC and pH=8 with zinc hydroxide nitrate. Higher pH resistance in ZHC favored total deprotonation of both carboxylic groups of the Asp molecule. ZHC conferred more thermal protection against Asp combustion presenting exothermic peaks even at 452 °C while the exothermic event in ZHN was 366 °C and in the LDH at 276 °C.

Synthesis and adsorption properties of flower-like layered double hydroxide by a facile one-pot reaction with an eggshell membrane as assistant

NASA Astrophysics Data System (ADS)

Li, Songnan; Zhang, Jiawei; Jamil, Saba; Cai, Qinghai; Zang, Shuying

In this paper, flower-like layered double hydroxides were synthesized with eggshell membrane assistant. The as-prepared samples were characterized by a series of techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermal gravity-differential thermal analysis and Nitrogen sorption/desorption. The resulting layered double hydroxides were composed of nanoplates with edge-to-face particle interactions. The specific surface area and total pore volume of the as-prepared flower-like layered double hydroxides were 160m2/g and 0.65m3/g, respectively. The adsorption capacity of flower-like layered double hydroxides to Congo Red was 258mg/g, which was higher than that of layered double hydroxides synthesized by the traditional method.

Hydroxide Solvation and Transport in Anion Exchange Membranes

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

Chen, Chen; Tse, Ying-Lung Steve; Lindberg, Gerrick E.

Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationicmore » groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures.« less

The effect of calcium hydroxide on the antibiotic component of Odontopaste and Ledermix paste.

PubMed

Athanassiadis, M; Jacobsen, N; Nassery, K; Parashos, P

2013-06-01

To investigate the chemical interaction of calcium hydroxide with the antibiotics demeclocycline calcium in Ledermix Paste and clindamycin hydrochloride in Odontopaste. Validated methods were developed to analyse the interaction of calcium hydroxide in two forms, Pulpdent and calcium hydroxide powder, with the two antibiotics. High-performance liquid chromatography (HPLC) was used to analyse the mixed samples of the pastes and calcium hydroxide. The concentration of demeclocycline calcium over 0-, 1-, 18-, 24-, 72-h and 7-day time-points was determined. The concentration of clindamycin hydrochloride over 1-, 6-, 24-, 72-h and 7-day time-points was determined. All tests with HPLC involved testing of the standard in duplicate alongside the samples. Linearity, precision and specificity of the testing procedures and apparatus were validated. Descriptive statistics are provided. The antibiotics in both Odontopaste and Ledermix Paste were affected by the addition of calcium hydroxide. When mixed with calcium hydroxide powder, Odontopaste had a 2% loss of clindamycin hydrochloride over 7 days, but when mixed with Pulpdent, there was a 36% loss over 7 days. Ledermix Paste showed an 80% loss of demeclocycline calcium over 7 days when mixed with calcium hydroxide powder and a 19% loss when mixed with Pulpdent over the 7-day period. The addition of calcium hydroxide to Odontopaste or Ledermix Paste results in reductions of the respective antibiotic over a 7-day time period. © 2012 International Endodontic Journal. Published by Blackwell Publishing Ltd.

Hydroxide Solvation and Transport in Anion Exchange Membranes.

PubMed

Chen, Chen; Tse, Ying-Lung Steve; Lindberg, Gerrick E; Knight, Chris; Voth, Gregory A

2016-01-27

Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationic groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures.

Formation of Green Rust and Immobilization of Nickel in Response to Bacterial Reduction of Hydrous Ferric Oxide

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

Parmar, N.; Gorby, Yuri A.; Beveridge, Terrance J.

This investigation documents the formation of Green Rust (GR) and immobilization of Ni2+ in response to bacterial reduction of hydrous ferric oxide (HFO) reduction experiments provided evidence that the solid-phase partitioning of Ni2+ in GR extended from equilibrium solid-solution behavior.

Iron chelated cyclic peptide, ferrichrysin, for oral treatment of iron deficiency: solution properties and efficacy in anemic rats.

PubMed

Suzuki, Sachiko; Fukuda, Katsuharu; Irie, Motoko; Hata, Yoji

2007-01-01

Ferrichrysin (Fcy), which is produced by Aspergillus oryzae and is present in foods used for human consumption, belongs to a group of hydroxamate siderophore ferric iron chelators. Fcy (100 mg/mL) dissolves completely at both pH 2.0 and 7.0, being very stable at a wide range of pH, high temperatures and pressures, with little reactivity to dietary iron absorption inhibitors, phytic acid, tannic acid, and catechin. We studied the effect of Fcy in male Sprague-Dawley rats with iron-deficiency anemia, which were separated into three different dietary groups (n=5) and supplementing diets as follows: (i) ferric citrate, (ii) heme iron concentrate, and (iii) Fcy (35 mg Fe/kg diet) for three weeks. Fcy exhibited the same beneficial effect in improving iron deficiency anemia as ferric citrate, being significantly greater than the effect of heme iron. The iron concentration of liver in the Fcy group was 35% greater than that in the ferric citrate group. These findings indicate that Fcy could be an efficient oral iron supplement to prevent or treat iron deficiency.

Selective simplification and reinforcement of microbial community in autothermal thermophilic aerobic digestion to enhancing stabilization process of sewage sludge by conditioning with ferric nitrate.

PubMed

Jin, Ningben; Shou, Zongqi; Yuan, Haiping; Lou, Ziyang; Zhu, Nanwen

2016-03-01

The effect of ferric nitrate on microbial community and enhancement of stabilization process for sewage sludge was investigated in autothermal thermophilic aerobic digestion. The disinhibition of volatile fatty acids (VFA) was obtained with alteration of individual VFA concentration order. Bacterial taxonomic identification by 454 high-throughput pyrosequencing found the dominant phylum Proteobacteria in non-dosing group was converted to phylum Firmicutes in dosing group after ferric nitrate added and simplification of bacteria phylotypes was achieved. The preponderant Tepidiphilus sp. vanished, and Symbiobacterium sp. and Tepidimicrobium sp. were the most advantageous phylotypes with conditioning of ferric nitrate. Consequently, biodegradable substances in dissolved organic matters increased, which contributed to the favorable environment for microbial metabolism and resulted in acceleration of sludge stabilization. Ultimately, higher stabilization level was achieved as ratio of soluble chemical oxygen demand to total chemical oxygen demand (TCOD) decreased while TCOD reduced as well in dosing group comparing to non-dosing group. Copyright © 2016 Elsevier Ltd. All rights reserved.

Oxidation of basaltic tephras: Influence on reflectance in the 1 micron region

NASA Technical Reports Server (NTRS)

Farrand, William H.; Singer, Robert B.

1991-01-01

As part of a ongoing study into the products of hydrovolcanism, tuffs were examined from the Cerro Colorado and Pavant Butte tuff cones. The former resides in the northeastern corner of the Pinacate Volcanic Field in Sonara, Mexico and the latter is in the Black Rock Desert of southern Utah. Numerous samples were collected and many of these had their Vis/IR reflectance measured. It seems likely that in the palagonite tuffs there is a combination of nanocrystalline ferric oxide phases contributing to the UV absorption edge, but not to the 1 micron band, plus more crystalline ferric oxides which do contribute to that band as well as ferrous iron within unaltered sideromelane which is skewing the band center to longer wavelengths. This work has implications for the study of Mars. The present work indicates that when ferrous and ferric iron phases are both present, their combined spectral contribution is a single band in the vicinity of 1 micron. The center, depth, and width of that feature has potential to be used to gauge the relative proportions of ferrous and ferric iron phases.

Application of chemical coagulation aids for the removal of suspended solids (TSS) and phosphorus from the microscreen effluent discharge of an intensive recirculating aquaculture system

USGS Publications Warehouse

Ebeling, J.M.; Ogden, S.R.; Sibrell, P.L.; Rishel, K.L.

2004-01-01

An evaluation of two commonly used coagulation-flocculation aids (alum and ferric chloride) was conducted to determine optimum conditions for treating the backwash effluent from microscreen filters in an intensive recirculating aquaculture system. Tests were carried out to evaluate the dosages and conditions (mixing and flocculation stirring speeds, durations, and settling times) required to achieve optimum waste capture. The orthophosphate removal efficiency for alum and ferric chloride were greater than 90% at a dosage of 60 mg/L. Optimum turbidity removal was achieved with a 60-mg/L dosage for both alum and ferric chloride. Both alum and ferric chloride demonstrated excellent removal of suspended solids from initial total suspended solid values of approximately 320 mg/L to approximately 10 mg/L at a dosage of 60 mg/L. Flocculation and mixing speed and duration played only a minor role in the removal efficiencies for both orthophosphates and suspended solids. Both coagulation-flocculation aids also exhibited excellent settling characteristics, with the majority of the floc quickly settling out in the first 5 min.

Positive Active Material For Alkaline Electrolyte Storage Battert Nickel Electrodes

DOEpatents

Bernard, Patrick; Baudry, Michelle

2000-12-05

A method of manufacturing a positive active material for nickel electrodes of alkaline storage batteries which consists of particles of hydroxide containing mainly nickel and covered with a layer of a hydroxide phase based on nickel and yttrium is disclosed. The proportion of the hydroxide phase is in the range 0.15% to 3% by weight of yttrium expressed as yttrium hydroxide relative to the total weight of particles.

Synthesis, characterization, and evaluation of simple aluminum-based adsorbents for fluoride removal from drinking water.

PubMed

Du, Junyi; Sabatini, David A; Butler, Elizabeth C

2014-04-01

Simple aluminum (hydr)oxides and layered double hydroxides were synthesized using common chemicals and equipment by varying synthesis temperature, concentrations of extra sulfate and citrate, and metal oxide amendments. Aluminum (hydr)oxide samples were aged at either 25 or 200°C during synthesis and, in some cases, calcined at 600 °C. Despite yielding increased crystallinity and mineral phase changes, higher temperatures had a generally negative effect on fluoride adsorption. Addition of extra sulfate during synthesis of aluminum (hydr)oxides led to significantly higher fluoride adsorption capacity compared to aluminum (hydr)oxides prepared with extra citrate or no extra ligands. X-ray diffraction results suggest that extra sulfate led to the formation of both pseudoboehmite (γ-AlOOH) and basaluminite (Al4SO4(OH)10⋅4H2O) at 200 °C; energy dispersive X-ray spectroscopy confirmed the presence of sulfur in this solid. Treatment of aluminum (hydr)oxides with magnesium, manganese, and iron oxides did not significantly impact fluoride adsorption. While layered double hydroxides exhibited high maximum fluoride adsorption capacities, their adsorption capacities at dissolved fluoride concentrations close to the World Health Organization drinking water guideline of 1.5 mg L(-1) were much lower than those for the aluminum (hydr)oxides. Copyright © 2013 Elsevier Ltd. All rights reserved.