Sample records for 4-go bloka chaehs

  1. Facile synthesis and magnetorheological properties of superparamagnetic CoFe2O4/GO nanocomposites

    NASA Astrophysics Data System (ADS)

    Wang, Guangshuo; Ma, Yingying; Dong, Xufeng; Tong, Yu; Zhang, Lina; Mu, Jingbo; Bai, Yongmei; Hou, Junxian; Che, Hongwei; Zhang, Xiaoliang


    In this study, cobalt ferrite/graphene oxide (CoFe2O4/GO) nanocomposites were synthesized successfully by a facile sonochemical method. The microstructure and physical properties of CoFe2O4/GO nanocomposites were investigated in detail by TEM, XRD and SQUID. It was found that GO nanosheets were fully exfoliated and decorated homogeneously with CoFe2O4 nanoparticles having diameters of 8∼15 nm. The field-dependent magnetization curve indicated superparamagnetic behavior of as-prepared CoFe2O4/GO with saturation magnetization (Ms) of 34.9 emu/g at room temperature. The ferrofluid was prepared by the obtained CoFe2O4/GO with 25 wt% particles and its magnetorheological (MR) properties were tested using a Physica MCR301 rheometer fitted with a magneto-rheological module. The CoFe2O4/GO-based ferrofluid exhibited typical MR effect with increasing viscosity, shear stress and yield stress depending on the applied magnetic field strength.

  2. Highly Efficient Antibacterial and Pb(II) Removal Effects of Ag-CoFe2O4-GO Nanocomposite.


    Ma, Shuanglong; Zhan, Sihui; Jia, Yanan; Zhou, Qixing


    Ag-CoFe2O4-graphene oxide (Ag-CoFe2O4-GO) nanocomposite was synthesized by doping silver and CoFe2O4 nanoparticles on the surface of GO, which was used to purify both bacteria and Pb(II) contaminated water. The Ag-CoFe2O4-GO nanomaterial was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman, X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), cyclic voltammetry (CV), and magnetic property tests. It can be found that Ag-CoFe2O4-GO nanocomposite exhibited excellent antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus compared with CoFe2O4, Ag-CoFe2O4, and CoFe2O4-GO composite. This superior disinfecting effect was possibly attributed to the combination of GO nanosheets and Ag nanoparticles. Several antibacterial factors including temperature, time, and pH were also investigated. It was obvious that E. coli was more susceptible than S. aureus toward all the four types of nanomaterials. The structural difference of bacterial membranes should be responsible for the resistant discrepancy. We also found that Ag-CoFe2O4-GO inactivated both bacteria in an irreversibly stronger manner than Ag-CoFe2O4 and CoFe2O4-GO. The Pb(II) removal efficiency with all the nanomaterials showed significant dependence on the surface area and zeta potential of the materials. In this work, not only did we demonstrate the simultaneous superior removal efficiency of bacteria and Pb(II) by Ag-CoFe2O4-GO but also the antibacterial mechanism was discussed to have a better understanding of the interaction between Ag-CoFe2O4-GO and bacteria. In a word, taking into consideration the easy magnetic separation, bulk availability, and irreversibly high antibacterial activity of Ag-CoFe2O4-GO, it is the very promising candidate material for advanced antimicrobial or Pb(II) contaminated water treatment. PMID:25905556

  3. Covalently bonded sulfonic acid magnetic graphene oxide: Fe3O4@GO-Pr-SO3H as a powerful hybrid catalyst for synthesis of indazolophthalazinetriones.


    Doustkhah, Esmail; Rostamnia, Sadegh


    Multistep synthesis of covalently sulfonated magnetic graphene oxide was achieved by starting from Hummer's method to produce graphene oxide (GO) from chemical oxidation of graphite. Then, GO nanosheets were applied to support Fe3O4 nanoparticles (Fe3O4@GO) using co-precipitation method in the presence of GO sheets. This strategy led to formation of uniform particles of Fe3O4 on the surface of GO sheets. Then, it was sulfonated (Fe3O4@GO-Pr-SO3H) through modification with 3-mercaptopropyltrimethoxysilane (MPTMS) and subsequent oxidation with hydrogen peroxide (H2O2). In comparison, the covalently bonded propyl sulfonic acid groups were more prevailing rather to sulfonic acids of GO itself. The proposed catalyst was more active and recyclable at least for 11 runs. PMID:27309948

  4. BC4GO: a full-text corpus for the BioCreative IV GO Task

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gene function curation via Gene Ontology (GO) annotation is a common task among Model Organism Database (MOD) groups. Due to its manual nature, this task is time-consuming and labor-intensive, and thus considered one of the bottlenecks in literature curation. There have been many previous attempts a...

  5. Magnetic graphene oxide modified with choline chloride-based deep eutectic solvent for the solid-phase extraction of protein.


    Huang, Yanhua; Wang, Yuzhi; Pan, Qi; Wang, Ying; Ding, Xueqin; Xu, Kaijia; Li, Na; Wen, Qian


    Four kinds of green deep eutectic solvents (DESs) based on choline chloride (ChCl) have been synthesized and coated on the surface of magnetic graphene oxide (Fe3O4@GO) to form Fe3O4@GO-DES for the magnetic solid-phase extraction of protein. X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FESEM) and thermal gravimetric analysis (TGA) were employed to characterize Fe3O4@GO-DES, and the results indicated the successful preparation of Fe3O4@GO-DES. The UV-vis spectrophotometer was used to measure the concentration of protein after extraction. Single factor experiments proved that the extraction amount was influenced by the types of DESs, solution temperature, solution ionic strength, extraction time, protein concentration and the amount of Fe3O4@GO-DES. Comparison of Fe3O4@GO and Fe3O4@GO-DES was carried out by extracting bovine serum albumin, ovalbumin, bovine hemoglobin and lysozyme. The experimental results showed that the proposed Fe3O4@GO-DES performs better than Fe3O4@GO in the extraction of acidic protein. Desorption of protein was carried out by eluting the solid extractant with 0.005 mol L(-1) Na2HPO4 contained 1 mol L(-1) NaCl. The obtained elution efficiency was about 90.9%. Attributed to the convenient magnetic separation, the solid extractant could be easily recycled. PMID:26002214

  6. Claremont Reading Conference. Forty-Eighth Yearbook: Reading in the Age of the Computer; Proceedings of the Claremont Reading Conference (51st, Claremont, California, March 20-21, 1984).

    ERIC Educational Resources Information Center

    Douglass, Malcolm P., Ed.

    The articles in this collection approach the theme of "Reading in the Age of the Computer" in a variety of ways. Topics covered in the 26 articles include the following: (1) children, school, and computers; (2) new kinds of electronic learning environments; (3) the personal computer for creative learning and thinking; (4) going beyond rote and…

  7. Speakeasy: A Text for Speaking, Volume 2. English for Special Purposes Series: Autobody Repair.

    ERIC Educational Resources Information Center

    Peet, William, Jr.

    This is the second of two volumes devoted to dialogs designed for classroom use by students of English as a second language. Survival skills are emphasized. The dialogs are grouped under the following titles: (1) "Buying Furniture," (2) "Straightening Metal Surfaces," (3) "Opening a Checking Account," (4) "Going to the Doctor," (5) "Building…

  8. Ag3PO4/graphene-oxide composite with remarkably enhanced visible-light-driven photocatalytic activity toward dyes in water.


    Chen, Guodong; Sun, Meng; Wei, Qin; Zhang, Yongfang; Zhu, Baocun; Du, Bin


    Ag(3)PO(4)/graphene-oxide (Ag(3)PO(4)/GO) composite has been synthesized by a liquid phase deposition method, and used for the photodegradation of organic dyes in water under visible light. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscope, N(2) sorption-desorption, and UV-vis diffuse reflectance spectra. The SEM image indicated that Ag(3)PO(4) particles were mainly distributed on the surface of GO sheets uniformly. DRS analysis revealed that the samples had good visible light response. The photocatalytic activity of Ag(3)PO(4)/GO composite was evaluated by decomposing of dyes (such as methyl orange, rhodamine B) in water under visible or UV-vis light irradiation. The degradation results indicated that the photocatalytic performance of Ag(3)PO(4)/GO was greatly enhanced due to the improved adsorption performance and separation efficiency of photo-generated carriers. The Ag(3)PO(4)/GO composite with GO content of 15 wt.% exhibited superior activity under visible light irradiation. After 50 min of reaction, the degradation ratio of MO was about 86.7%, while RhB solution could be completely degraded within 30 min of reaction. Further study proved that the direct oxidation of pollutants by holes has played a major role in the degradation process. The results of this work would provide a new sight for the construction of visible light-responsive photocatalysts with high performance. PMID:23246944

  9. Amniocentesis - slideshow


    ... to slide 3 out of 4 Go to slide 4 out of 4 Indication Overview When you are about 15 weeks pregnant, your doctor may offer amniocentesis. Amniocentesis is a test that detects or rules out certain inherited disorders in a fetus. It ...

  10. Facile synthesis of manganese ferrite/graphene oxide nanocomposites for controlled targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Wang, Guangshuo; Ma, Yingying; Zhang, Lina; Mu, Jingbo; Zhang, Zhixiao; Zhang, Xiaoliang; Che, Hongwei; Bai, Yongmei; Hou, Junxian


    In this study, manganese ferrite/graphene oxide (MnFe2O4/GO) nanocomposites as controlled targeted drug delivery were prepared by a facile sonochemical method. It was found that GO nanosheets were fully exfoliated and decorated with MnFe2O4 nanoparticles having diameters of 5-13 nm. The field-dependent magnetization curve indicated superparamagnetic behavior of the obtained MnFe2O4/GO with saturation magnetization of 34.9 emu/g at room temperature. The in vitro cytotoxicity testing exhibited negligible cytotoxicity of as-prepared MnFe2O4/GO even at the concentration as high as 150 μg/mL. Doxorubicin hydrochloride (DOX) as an anti-tumor model drug was utilized to explore the application potential of MnFe2O4/GO for controlled drug delivery. The drug loading capacity of this nanocarrier was as high as 0.97 mg/mg and the drug release behavior showed a sustained and pH-responsive way.

  11. Investigation of the adsorption mechanism and preconcentration of sulfonamides using a porphyrin-functionalized Fe₃O₄-graphene oxide nanocomposite.


    Shi, Pengzhi; Ye, Nengsheng


    In this work, a novel type of porphyrin-functionalized Fe3O4-graphene oxide (TCPP/Fe3O4-GO) nanocomposite was synthesized. The adsorption mechanism of the prepared TCPP/Fe3O4-GO material was investigated and predicted. The π-π stacking and electrostatic attraction between the positively charged analytes and the negatively charged porphyrin-functionalized Fe3O4-GO accelerated the electron transfer between the materials. In addition, to investigate the preconcentration of the prepared TCPP/Fe3O4-GO, it was used as a magnetic solid-phase extraction adsorbent for the preconcentration of seven sulfonamides (SAs) from environmental water samples. Parameters that significantly affected the extraction of the SAs onto the sorbent, such as the elution solvent, extraction time and elution time, were optimized. Under the optimal conditions, the SAs in the environmental water samples were effectively detected. The linear range for the seven SAs was 0.5-20 μg mL(-1), and the limits of detection for all seven SAs were 0.2 μg mL(-1). Good reproducibility was obtained, along with relative standard deviations that ranged from 0.01 to 8.25%. The present method was applied to the determination of SAs in tap and river water samples, and the recoveries were satisfactory (83.7-116.7%). PMID:26078152

  12. Fe{sub 3}O{sub 4}@graphene oxide composite: A magnetically separable and efficient catalyst for the reduction of nitroarenes

    SciTech Connect

    He, Guangyu; Liu, Weifeng; Sun, Xiaoqiang; Chen, Qun; Wang, Xin; Chen, Haiqun


    Highlights: ► The Fe{sub 3}O{sub 4}@GO composite was prepared by a facile co-precipitation method. ► Fe{sub 3}O{sub 4} nanoparticles are well distributed on GO nanosheets. ► Fe{sub 3}O{sub 4}@GO was for the first time explored as a catalyst to reduce nitroarenes. ► Fe{sub 3}O{sub 4}@GO exhibits higher catalytic activity. ► The composite catalyst is easily recycled due to its magnetic separability. - Abstract: We reported a facile co-precipitation method to prepare a highly active Fe{sub 3}O{sub 4}@graphene oxide (Fe{sub 3}O{sub 4}@GO) composite catalyst, which was fully characterized by means of X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and N{sub 2} adsorption–desorption measurements. The results demonstrated that the Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4} NPs) with a small diameter of around 12 nm were densely and evenly deposited on the graphene oxide (GO) sheets. The as-prepared Fe{sub 3}O{sub 4}@GO composite was explored as a catalyst to reduce a series of nitroarenes for the first time, which exhibited a great activity with a turnover frequency (TOF) of 3.63 min{sup −1}, forty five times that of the commercial Fe{sub 3}O{sub 4} NPs. The dosages of catalyst and hydrazine hydrate are both less than those reported. Furthermore, the composite catalyst can be easily recovered due to its magnetic separability and high stability.

  13. Manipulating Migration Behavior of Magnetic Graphene Oxide via Magnetic Field Induced Casting and Phase Separation toward High-Performance Hybrid Ultrafiltration Membranes.


    Xu, Zhiwei; Wu, Tengfei; Shi, Jie; Wang, Wei; Teng, Kunyue; Qian, Xiaoming; Shan, Mingjing; Deng, Hui; Tian, Xu; Li, Cuiyu; Li, Fengyan


    Hybrid membranes blended with nanomaterials such as graphene oxide (GO) have great opportunities in water applications due to their multiple functionalities, but they suffer from low modification efficiency of nanomaterials due to the fact that plenty of the nanomaterials are embedded within the polymer matrix during the blending process. Herein, a novel Fe3O4/GO-poly(vinylidene fluoride) (Fe3O4/GO-PVDF) hybrid ultrafiltration membrane was developed via the combination of magnetic field induced casting and a phase inversion technique, during which the Fe3O4/GO nanocomposites could migrate toward the membrane top surface due to magnetic attraction and thereby render the surface highly hydrophilic with robust resistance to fouling. The blended Fe3O4/GO nanocomposites migrated to the membrane surface with the magnetic field induced casting, as verified by X-ray photoelectron spectroscopy, elemental analysis, and energy dispersive X-ray spectroscopy. As a result, the novel membranes exhibited significantly improved hydrophilicity (with a contact angle of 55.0°) and water flux (up to 595.39 L m(-2) h(-1)), which were improved by 26% and 206%, 12% and 49%, 25% and 154%, and 11% and 33% compared with those of pristine PVDF membranes and PVDF hybrid membranes blended with GO, Fe3O4, and Fe3O4/GO without the assistance of magnetic field during membrane casting, respectively. Besides, the novel membranes showed high rejection of bovine serum albumin (>92%) and high flux recovery ratio (up to 86.4%). Therefore, this study presents a novel strategy for developing high-performance hybrid membranes via manipulating the migration of nanomaterials to the membrane surface rather than embedding them in the membrane matrix. PMID:27355273

  14. Mixed hemimicelles solid-phase extraction of cephalosporins in biological samples with ionic liquid-coated magnetic graphene oxide nanoparticles coupled with high-performance liquid chromatographic analysis.


    Wu, Jianrong; Zhao, Hongyan; Xiao, Deli; Chuong, Pham-Huy; He, Jia; He, Hua


    A novel mixed hemimicelles solid phase extraction based on magnetic graphene oxide (Fe3O4/GO) and ionic liquid (IL) was developed for the simultaneous extraction and determination of trace cephalosporins in spiked human urine. The high surface area and excellent adsorption capacity of the graphene oxide after modification with1-hexadecyl-3-methylmidazoliumbromide(C16mimBr) were utilized adequately in the solid phase extraction(SPE) process. A comprehensive study of the parameters affecting the extraction recovery, such as the zeta-potential of magnetic graphene oxide, amounts of magnetic graphene oxide and surfactant, pH of solution, ionic strength, extraction time, and desorption condition were optimized. A comparative study on the use of different surfacant-coated Fe3O4/GO NPs as sorbents was presented. Good linearity (R(2)>0.9987) for all calibration curves was obtained. The LODs were ranged between 0.6 and 1.9ng mL(-1) for the cephalosporins and the LOQs were 1.5 to 5.5, respectively. Satisfactory recoveries(84.3% to 101.7%)and low relative standard deviations from 1.7% to 6.3% in biological matrices were achieved. The mixed hemimicelles magnetic SPE (MSPE) method based on ILs and Fe3O4/GO NPs magnetic separation has ever been successfully used for pretreatment of complex biological samples. PMID:27266334

  15. Supported cobalt oxide on graphene oxide: highly efficient catalysts for the removal of Orange II from water.


    Shi, Penghui; Su, Ruijing; Zhu, Shaobo; Zhu, Mincong; Li, Dengxin; Xu, Shihong


    The current paper investigated the removal of the azo dye Orange II from water using advanced oxidation processes based on sulfate radicals. The cobalt oxide catalyst immobilized on graphene oxide (GO) can activate peroxymonosulfate (PMS) for the degradation of Orange II in water. The Co(3)O(4)/GO catalyst system was characterized via X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and X-ray spectroscopy. Results showed that Co(3)O(4) was distributed on GO. The Co(3)O(4)/GO catalyst system exhibited high activity in Orange II oxidation when the Co(3)O(4)/GO catalyst has an optimum Co(3)O(4) loading. In addition, 100% decomposition could be achieved within 6 min with 0.2mM Orange II, 0.1 g L(-1) catalyst, and 2mM PMS. Meanwhile, inductively coupled plasma analysis revealed that the leach of cobalt ions was low. The catalyst also exhibited stable performance after several rounds of regeneration. Several operational parameters, such as catalyst amount, oxidant amount, pH, temperature, and oxidation rate, affected the degradation of Orange II. PMID:22738772

  16. Adsorption mechanism of magnetically separable Fe3O4/graphene oxide hybrids

    NASA Astrophysics Data System (ADS)

    Ouyang, Ke; Zhu, Chuanhe; Zhao, Ya; Wang, Leichao; Xie, Shan; Wang, Qun


    A reclaimable Fe3O4/graphene oxide (GO) magnetic hybrid was successfully synthesized via a facile one-pot polyol approach and employed as a recyclable adsorbent for Bisphenol A (BPA) in aqueous solutions. The maximum adsorption capacity (qm) of the Fe3O4/GO hybrid for BPA was 72.80 mg/g at 273 K. The kinetics of the adsorption process and the adsorption isotherm data were fitted using the Freundlich equation and a pseudo-second-order kinetic model. The results of the thermodynamic parameters ΔH°, ΔS° and ΔG° showed that the adsorption process was exothermic and spontaneous. Furthermore, the reusability of the samples was investigated, and the results indicated that the samples exhibited high stability. The magnetic characterization demonstrated that hybrids were superparamagnetic and could be recovered conveniently by magnetic separation. The strong π-π interaction was determined to be the predominant driving force behind the adsorption of BPA onto the Fe3O4/GO hybrid. Therefore, the Fe3O4/GO hybrid could be regarded as a potential adsorbent for wastewater treatment and purification processes.

  17. An "in-electrode"-type immunosensing strategy for the detection of squamous cell carcinoma antigen based on electrochemiluminescent AuNPs/g-C3N4 nanocomposites.


    Wu, Lin; Hu, Yufang; Sha, Yuhong; Li, Wenrou; Yan, Tiantian; Wang, Sui; Li, Xing; Guo, Zhiyong; Zhou, Jun; Su, Xiurong


    A novel "in-electrode"-type electrochemiluminescence (ECL) immunosensor for the sensitive detection of squamous cell carcinoma antigen (SCCA) was constructed using magnetic graphene oxide (nanoFe3O4@GO) and Au nanoparticles/graphitic-phase carbon nitride (AuNPs/g-C3N4). The capture probe was prepared by immobilizing the primary antibody of SCCA (Ab1) on the nanoFe3O4@GO, while the AuNPs/g-C3N4 nanocomposites labelled the secondary antibody of SCCA (Ab2), which acted as a signal tag. The recognition scaffold was the following: the capture probe was immobilized onto the magnetic electrode surface that caught the target SCCA and finally allowed the immobilization of the signal tag via the interaction between antigen and antibody. Importantly, a high ECL signal could be obtained due to the unique immunocomplex, which ensured all of the g-C3N4 on the outmost plane were directly fixed onto the electrode surface and became part of the electrode surface. This resulted in an enhanced efficiency of the g-C3N4 for electrochemical luminescence, thus extending the outer Helmholtz plane (OHP) of the proposed electrode and leading to high sensitivity. Taking advantage of both nanoFe3O4@GO and AuNPs/g-C3N4, the ECL intensity was found to increase logarithmically with SCCA concentration in a wide linear range from 0.001 to 10ng/mL and with a detection limit of 0.4pg/mL. The proposed "in-electrode"-type ECL immunosensor was used to analyse SCCA in human serum, and satisfactory recoveries were obtained, indicating that the proposed method was promising for practical applications in the clinical diagnosis of SCCA. PMID:27591611

  18. A new kinetic-mechanistic approach to elucidate electrooxidation of doxorubicin hydrochloride in unprocessed human fluids using magnetic graphene based nanocomposite modified glassy carbon electrode.


    Soleymani, Jafar; Hasanzadeh, Mohammad; Shadjou, Nasrin; Khoubnasab Jafari, Maryam; Gharamaleki, Jalil Vaez; Yadollahi, Mehdi; Jouyban, Abolghasem


    A novel magnetic nanocomposite was synthesized in one step using polymerization of magnetic graph oxide grafted with chlorosulfonic acid (Fe3O4-GO-SO3H) in the presence of polystyrene. The prepared magnetic nanocomposite was characterized using transmission electron microscopy (TEM), dynamic differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), (Thermo-gravimetric/differential thermal analysis (DTA)), Fourier transform infrared (FTIR), and UV-Vis techniques. Magnetic nanocomposite was casted on the surface of the glassy carbon electrode (PS/Fe3O4-GO-SO3H/GCE) and used for the detection and determination of doxorubicin hydrochloride (DOX) in human biological fluids. The cyclic voltammograms (CVs) of the modified electrode in aqueous solution displayed a pair of well-defined, stable and irreversible reductive/oxidation redox systems. CV study indicated that the oxidation process is irreversible and adsorption controlled. In addition, CV results indicated that DOX is oxidized via two electrons and three protons which is an unusual approach for the oxidation of DOX. A sensitive and time-saving procedure was developed for the analysis of DOX in plasma, cerebrospinal fluid, and urine with detection limit of 4.9 nM, 14 nM and 4.3 nM, respectively. PMID:26838892

  19. Synthesis and characterization of Ag₃PO₄ immobilized with graphene oxide (GO) for enhanced photocatalytic activity and stability over 2,4-dichlorophenol under visible light irradiation.


    Chen, Xiao-juan; Dai, You-zhi; Wang, Xing-yan; Guo, Jing; Liu, Tan-hua; Li, Fen-fang


    A series of visible-light responsive photocatalysts prepared using Ag3PO4 immobilized with graphene oxide (GO) with varying GO content were obtained by an electrostatically driven method, and 2,4-dichlorophenol (2,4-DCP) was used to evaluate the performance of the photocatalysts. The composites exhibited superior photocatalytic activity and stability compared with pure Ag3PO4. When the content of GO was 5%, the degradation efficiency of 2,4-DCP could reach 98.95%, and 55.91% of the total organic (TOC) content was removed within 60 min irradiation. Meanwhile, the efficiency of 91.77% was achieved for 2,4-DCP degradation even after four times of recycling in the photocatalysis/Ag3PO4-GO (5%) system. Reactive species of O2(˙-), OH˙ and h(+) were considered as the main participants for oxidizing 2,4-DCP, as confirmed by the free radical capture experiments. And some organic intermediates including 4-chlorophenol (4-CP), hydroquinone (HQ), benzoquinone (BZQ), 2-chlorohydroquinone and hydroxyhydroquinone (HHQ) were detected by comparison with the standard retention times from the high performance liquid chromatography (HPLC). In short, the enhanced photocatalytic property of Ag3PO4-GO was closely related to the strong absorption ability of GO relative to 2,4-DCP, the effective separation of photogenerated electron-hole pairs, and the excellent electron capture capability of GO. PMID:25781371

  20. Ethylenediamine-modified graphene oxide covalently functionalized with a tetracarboxylic Zn(ii) phthalocyanine hybrid for enhanced nonlinear optical properties.


    Li, Zongle; He, Chunying; Wang, Zhao; Gao, Yachen; Dong, Yongli; Zhao, Cheng; Chen, Zhimin; Wu, Yiqun; Song, Weina


    Tetracarboxylic Zn(ii) phthalocyanine-amino functionalized graphene oxide (ZnPcC4-NGO) hybrid materials have been prepared by a covalent functionalization method. The characterizations indicate that the amino-functionalization of GO has an important influence on the structure and photophysical properties of the ZnPcC4-NGO hybrid. The ZnPcC4-NGO hybrid exhibits enhanced photo-induced electron transfer or energy transfer (PET/ET), compared to the ZnPcC4 covalent functionalized GO (ZnPcC4-GO), owing to the presence of the extended sp(2) carbon configurations, along with the partial reduction of the NGO nanosheets and the introduction of electron-donating ethylenediamine. The nonlinear optical (NLO) properties of the hybrids were investigated using the Z-scan technique at 532 nm with 4 ns laser pulses. The results show that the efficient covalent functionalization and partial reduction of NGO cause the ZnPcC4-NGO hybrid to possess evidently larger NLO properties than the individual NGO, ZnPcC4 and the ZnPcC4-GO hybrid. The enhanced NLO performance can be attributed to the increased excited state absorption from the extended sp(2) carbon configurations of the NGO moiety, reverse saturable absorption arising from ZnPcC4 moiety, and the contribution of the efficient PET/ET process between the ZnPcC4 and NGO moieties in the hybrid. PMID:27296527

  1. Graphene oxide amplified electrochemiluminescence of graphitic carbon nitride and its application in ultrasensitive sensing for Cu(2+).


    Xia, Binyuan; Chu, Mingfu; Wang, Shaofei; Wang, Wanqing; Yang, Shanli; Liu, Chengbin; Luo, Shenglian


    Here for the first time, we present a novel electrochemiluminescence (ECL) sensor based on graphitic carbon nitride/graphene oxide (g-C3N4/GO) hybrid for the ultrasensitive detection of Cu(2+), which is a common pollutant in environmental system. The g-C3N4/GO shows stable ECL signal in the presence of the self-produced coreactant from oxygen reduction, and the ECL signal could be effectively quenched by Cu(2+), the possible ECL detection mechanism has been proposed in detail. GO can not only significantly enhance the cathodic ECL signal of g-C3N4 (∼3.8 times), but also serve as immobilization platform for g-C3N4. After optimization of experimental conditions, the proposed protocol can offer an ultrasensitive, highly selective and recyclable method for the detection of Cu(2+) with a low detection limit of 1.0 × 10(-11) M and a wide linear range from 1.0 × 10(-11) to 1.0 × 10(-7) M. Moreover, the practicability of the ECL sensor in real wastewater samples is also tested, showing that the proposed ECL sensor could be a promising alternative method for the emergency and routine monitoring of Cu(2+) in real sample. PMID:26388369

  2. Fe3O4@Graphene Oxide@Ag Particles for Surface Magnet Solid-Phase Extraction Surface-Enhanced Raman Scattering (SMSPE-SERS): From Sample Pretreatment to Detection All-in-One.


    Liu, Zhigang; Wang, Yi; Deng, Rong; Yang, Liyuan; Yu, Shihua; Xu, Shuping; Xu, Weiqing


    A multifunctional magnetic graphene surface-enhanced Raman scattering (SERS) substrate was fabricated successfully by the layer-by-layer assembly of silver and graphene oxide (GO) nanoparticles (NPs) on the magnetic ferroferric oxide particles (Fe3O4@GO@Ag). This ternary particle possesses magnetic properties, SERS activity, and adsorption ability simultaneously. Owing to the multifunction of this Fe3O4@GO@Ag ternary complex, we put forward a new method called a surface magnetic solid-phase extraction (SMSPE) technique, for the SERS detections of pesticide residues on the fruit peels. SMSPE integrates many sample pretreatment procedures, such as surface extraction, separation sample, and detection, all-in-one. So this method shows great superiority in simplicity, rapidity, and high efficiency above other standard methods. The whole detection process can be finished within 20 min including the sample pretreatment and SERS detection. Owing to the high density of Ag NPs, the detection sensitivity is high enough that the lowest detectable concentrations are 0.48 and 40 ng/cm(2) for thiram and thiabendazole, which are much lower than the maximal residue limits in fruit prescribed by the U.S. Environmental Protection Agency. This multifunctional ternary particle and its corresponding analytical method have been proven to be applicable for practical samples and also valuable for other surface analysis. PMID:27191584

  3. Nacre-like calcium carbonate controlled by ionic liquid/graphene oxide composite template.


    Yao, Chengli; Xie, Anjian; Shen, Yuhua; Zhu, Jinmiao; Li, Hongying


    Nacre-like calcium carbonate nanostructures have been mediated by an ionic liquid (IL)-graphene oxide (GO) composite template. The resultant crystals were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and X-ray powder diffractometry (XRD). The results showed that either 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) or graphene oxide can act as a soft template for calcium carbonate formation with unusual morphologies. Based on the time-dependent morphology changes of calcium carbonate particles, it is concluded that nacre-like calcium carbonate nanostructures can be formed gradually utilizing [BMIM]BF4/GO composite template. During the process of calcium carbonate formation, [BMIM]BF4 acted not only as solvents but also as morphology templates for the fabrication of calcium carbonate materials with nacre-like morphology. Based on the observations, the possible mechanisms were also discussed. PMID:25842135

  4. Analysis of surface potential and magnetic properties of Fe3O4/graphene oxide nanocomposites

    NASA Astrophysics Data System (ADS)

    Mishra, Amodini; Mohanty, Tanuja


    Nanocomposite of magnetite/graphene oxide (Fe3O4/GO) has been synthesized by co-precipitation method. The phase formation of the magnetite nanoparticles (Fe3O4 NPs) was confirmed by X-ray diffraction (XRD) analysis. Effect of Fe3O4 NPs on the Raman spectra and on the surface potential of GO has been analyzed. Due to incorporation of NPs, change in the characteristic Raman peaks and also on the surface potential of GO is observed. Transmission electron microscopic (TEM) study has been carried out for surface morphology. Magnetic property measurement was carried out by using physical property measurement system (PPMS) at two different temperatures (30 K and 300K).

  5. Poly(2-aminobenzothiazole)-coated graphene oxide/magnetite nanoparticles composite as an efficient sorbent for determination of non-steroidal anti-inflammatory drugs in urine sample.


    Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira


    In this study, for the first time, 2-aminobenzothiazole monomer was polymerized on Fe3O4 NPs, graphene oxide/Fe3O4 (GO/Fe3O4) and graphene/Fe3O4 (G/Fe3O4) nanocomposites. The synthesized magnetic nanosorbents were characterized by various techniques. The extraction ability of these nanosorbents including Fe3O4, GO/Fe3O4, G/Fe3O4, Fe3O4@poly(2-aminobenzothiazole) (Fe3O4@PABT), GO/Fe3O4@PABT and G/Fe3O4@PABT were compared for dispersive-micro-solid phase extraction of three non-steroidal anti-inflammatory drugs. The results revealed that GO/Fe3O4@PABT nanocomposite demonstrates higher extraction efficiency for naproxen, diclofenac and ibuprofen as selected model analytes. Following the sorption and elution steps, the model analytes were quantified by high performance liquid chromatography-photo diode array detection. Afterwards, a central composite design methodology combined with desirability function approach was applied to find out the optimal experimental conditions. Under the optimized conditions, the limits of detection and linear dynamic ranges were achieved in the range of 0.07-0.3μgL(-1) and 0.25-2000μgL(-1), respectively. The percent of extraction recovery was 87.4, 85.5 and 90.5% for naproxen, diclofenac and ibuprofen, respectively. The obtained relative standard deviation (n=5) was 7.2, 5.4 and 6.4% for naproxen, diclofenac and ibuprofen, respectively. Ultimately, this method was employed for urinary monitoring of the target analytes and satisfactory results were obtained. PMID:26839179

  6. Fabricating a graphene oxide—bayberry tannin sponge for effective radionuclide removal

    NASA Astrophysics Data System (ADS)

    Deng, Xiaodong; Liu, Xiaonan; Duan, Tao; Zhu, Wenkun; Yi, Zao; Yao, Weitang


    Bayberry tannin (BT)–reduced graphene oxide (rGO) sponges have been prepared by self–assembly, with bayberry tannin serving as both reductant and surface functionalization agent. The synthetic method is based on the self-assembly of graphene oxide (GO) sheets into porous hydrogel structures. By varying the weight ratio of GO to BT, a series of sorbents with different densities of organic molecules have been obtained and applied to remove Sr2+ from aqueous solutions. Adsorption isotherms (Langmuir and Freundlich) and kinetics (pseudo-first order and pseudo-second order) have been investigated to discuss the sorption performance of rGO/BT sponges. The rGO/BT (w/w 1:1) sponge shows excellent adsorption properties for Sr2+, with maximum capacities of 67.98 mg g‑1. The adsorption capacity is much higher than those in classic Sr2+ adsorbents, such as hydrous manganese dioxide, Egyptian soils, Hydroxyapatite nanoparticles, sodium hexa-titanate nanofibers, Graphene oxide, artificially altered phlogopite(Ca–Phl), and PB/Fe3O4/GO. Adsorption mechanisms have been examined using the x-ray photoelectron spectra of sorbents before and after Sr2+ adsorption, and the results indicate that the sorption of Sr2+ on GO and GO/BT 1.0 is largely depended on oxygen functional groups. The results show that the GO/BT sponge is a promising candidate for adsorbing Sr2+ ion.

  7. Effects of single- and multi-organic acid ligands on adsorption of copper by Fe3O4/graphene oxide-supported DCTA.


    Liu, Shaobo; Wang, Hui; Chai, Liyuan; Li, Meifang


    The Fe3O4/graphene oxide-supported 1,2-diaminocyclohexanetetraacetic acid composite (Fe3O4/GO/DCTA) was used as an adsorbent for Cu(II) removal. The effects of six organic acid ligands (formate, acetate, benzoate, oxalate, tartrate, and edetate) on the adsorption process were investigated in single- and multi-ligand systems. The results demonstrated that the adsorption processes were affected by solution pH and ionic strength. The experimental data of kinetics and isotherm followed the pseudo-second-order model and the Langmuir model, respectively. In the single-ligand systems, the presence of formate, acetate, and benzoate slightly altered the Cu(II) adsorption property, while the adsorption processes were significantly affected by the oxalate, tartrate, and edetate ligands. In the multi-ligand systems, the Cu(II) adsorption was influenced by the type and concentration of organic acid ligands. The sequence of the main effect was found to be: edetate>oxalate>benzoate>formate>tartrate>acetate, and the sequence of the two-factor interaction effect was found to be: AE (formate×tartrate)>BF (acetate×edetate)>AF (formate×edetate)>BD (acetate×oxalate)>AC (formate×benzoate)>AD (formate×oxalate)>AB (formate×acetate). PMID:27309949

  8. Communication: Studies of the Lennard-Jones fluid in 2, 3, and 4 dimensions highlight the need for a liquid-state 1/d expansion.


    Costigliola, Lorenzo; Schrøder, Thomas B; Dyre, Jeppe C


    The recent theoretical prediction by Maimbourg and Kurchan [e-print arXiv:1603.05023 (2016)] that for regular pair-potential systems the virial potential-energy correlation coefficient increases towards unity as the dimension d goes to infinity is investigated for the standard 12-6 Lennard-Jones fluid. This is done by computer simulations for d = 2, 3, 4 going from the critical point along the critical isotherm/isochore to higher density/temperature. In both cases the virial potential-energy correlation coefficient increases significantly. For a given density and temperature relative to the critical point, with increasing number of dimension the Lennard-Jones system conforms better to the hidden-scale-invariance property characterized by high virial potential-energy correlations (a property that leads to the existence of isomorphs in the thermodynamic phase diagram, implying that it becomes effectively one-dimensional in regard to structure and dynamics). The present paper also gives the first numerical demonstration of isomorph invariance of structure and dynamics in four dimensions. Our findings emphasize the need for a universally applicable 1/d expansion in liquid-state theory; we conjecture that the systems known to obey hidden scale invariance in three dimensions are those for which the yet-to-be-developed 1/d expansion converges rapidly. PMID:27334147

  9. Communication: Studies of the Lennard-Jones fluid in 2, 3, and 4 dimensions highlight the need for a liquid-state 1/d expansion

    NASA Astrophysics Data System (ADS)

    Costigliola, Lorenzo; Schrøder, Thomas B.; Dyre, Jeppe C.


    The recent theoretical prediction by Maimbourg and Kurchan [e-print arXiv:1603.05023 (2016)] that for regular pair-potential systems the virial potential-energy correlation coefficient increases towards unity as the dimension d goes to infinity is investigated for the standard 12-6 Lennard-Jones fluid. This is done by computer simulations for d = 2, 3, 4 going from the critical point along the critical isotherm/isochore to higher density/temperature. In both cases the virial potential-energy correlation coefficient increases significantly. For a given density and temperature relative to the critical point, with increasing number of dimension the Lennard-Jones system conforms better to the hidden-scale-invariance property characterized by high virial potential-energy correlations (a property that leads to the existence of isomorphs in the thermodynamic phase diagram, implying that it becomes effectively one-dimensional in regard to structure and dynamics). The present paper also gives the first numerical demonstration of isomorph invariance of structure and dynamics in four dimensions. Our findings emphasize the need for a universally applicable 1/d expansion in liquid-state theory; we conjecture that the systems known to obey hidden scale invariance in three dimensions are those for which the yet-to-be-developed 1/d expansion converges rapidly.

  10. Life goes on: the experiences of wives of multiply-deployed National Guard soldiers.


    Patzel, Brenda; McBride, Maryellen; Bunting, Judith; Anno, Tony


    Whether a service member is active duty or part of the National Guard, deployment of these service members is a major issue for most families. There is limited knowledge of the experience of multiple deployments on the family. The purpose of this study was to describe experiences of wives of National Guard soldiers that were deployed more than once. Nine wives were interviewed. An analysis of the interviews revealed four themes: (1) "Life Goes On" (i.e., despite the repeated deployments, life continues at home); (2) the "Guard is a Different Animal" (i.e., life as a National Guard spouse is different from that of an active duty spouse); (3) "It's a Mind-Set" (i.e., how wives cope their husband's deployment); and (4) "Going Back Again" (i.e., wives' experiences of multiple deployments). Exploring how multiple deployments affects wives of National Guard soldiers is helpful in understanding their experiences and the adjustments that must be made in family life. Knowledge of the experiences of these wives may help in formulating more effective interventions with families who have experienced multiple deployments. PMID:23663024

  11. Hybrid Iron Oxide-Graphene Oxide-Polysaccharides Microcapsule: A Micro-Matryoshka for On-Demand Drug Release and Antitumor Therapy In Vivo.


    Deng, Lin; Li, Qiujin; Al-Rehili, Safa'a; Omar, Haneen; Almalik, Abdulaziz; Alshamsan, Aws; Zhang, Jianfei; Khashab, Niveen M


    Premature drug release is a common drawback in stimuli-responsive drug delivery systems (DDS), especially if it depends on internal triggers, which are hard to control, or a single external stimulus, which can only have one function. Thus, many DDS systems have been reported that combined different triggers; however, limited success has been established in fine-tuning the release process, mainly due to the poor bioavailability and complexity of the reported designs. This paper reports the design of a hybrid microcapsule (h-MC) by a simple layer-by-layer technique comprising polysaccharides (sodium alginate, chitosan, and hyaluronic acid), iron oxide, and graphene oxide (GO). Electrostatic assembly of the oppositely charged polysaccharides and graphene sheets provided a robust structure in which to load drugs through pH control. The polysaccharide component ensured high biocompatibility, bioavailability, and tumor cells targeting. The alternative magnetic field and near-infrared laser triggerable Fe3O4@GO component provided for dual high-energy and high-penetration hyperthermia therapy. On-demand drug release from h-MC can be achieved by synchronizing these external triggers, making the release highly controllable. The synergistic effect of hyperthermia and chemotherapy was successfully confirmed in vitro and in vivo. PMID:26915062

  12. Enhancement of proton conductivity of chitosan membrane enabled by sulfonated graphene oxide under both hydrated and anhydrous conditions

    NASA Astrophysics Data System (ADS)

    Liu, Yahua; Wang, Jingtao; Zhang, Haoqin; Ma, Chuanming; Liu, Jindun; Cao, Shaokui; Zhang, Xiang


    In this study, sulfonated graphene oxide (SGO) nanosheets with controllable sulfonic acid group loading are synthesized via the facile distillation-precipitation polymerization, and then incorporated into chitosan (CS) matrix to prepare nanohybrid membranes. The microstructure and physicochemical properties of the resulting membranes are extensively investigated. Compared with CS control and GO-filled membranes, SGO-filled membranes attain enhanced thermal and mechanical stabilities due to the strong electrostatic attractions between -SO3H of SGO and -NH2 of CS, which inhibit the mobility of CS chains. Additionally, the inhibited mobility reduces the area swellings of SGO-filled membranes, reinforcing their structural stabilities. The incorporation of SGO generates acid-base pairs along CS-SGO interface, which work as facile proton-hoping sites and thus construct continuous and wide proton transfer pathways, yielding enhanced proton conductivities under both hydrated and anhydrous conditions. Meanwhile, the conductivity can be elevated by increasing the sulfonic acid group loading and content of SGO. Particularly, incorporating 2.0% S4GO can afford the nanohybrid membrane a 122.5% increase in hydrated conductivity and a 90.7% increase in anhydrous conductivity when compared with CS control membrane. The superior conduction properties then offered a significant enhancement in H2/O2 cell performances to the nanohybrid membranes, guaranteeing them to be promising proton exchange membranes.

  13. Mesoporous composite nickel cobalt oxide/graphene oxide synthesized via a template-assistant co-precipitation route as electrode material for supercapacitors

    NASA Astrophysics Data System (ADS)

    Xu, Yanjie; Wang, Lincai; Cao, Peiqi; Cai, Chuanlin; Fu, Yanbao; Ma, Xiaohua


    A simple co-precipitation method utilizing SDS (sodium dodecyl sulfate) as template and ammonia as precipitant is successfully employed to synthesize nickel cobalt oxide/graphene oxide (NiCo2O4/GO) composite. The as-prepared composite (NCG-10) exhibits a high capacitance of 1211.25 F g-1, 687 F g-1 at the current density of 1 A g-1, 10 A g-1 and good cycling ability which renders NCG-10 as promising electrode material for supercapacitors. An asymmetric supercapacitor (ASC) (full button cell) has been constructed with NCG-10 as positive electrode and lab-made reduced graphene oxide (rGO) as negative electrode. The fabricated NCG-10//rGO with an extended stable operational voltage of 1.6 V can deliver a high specific capacitance of 144.45 F g-1 at a current density of 1 A g-1. The as-prepared NCG-10//rGO demonstrates remarkable energy density (51.36 W h kg-1 at 1 A g-1), high power density (50 kW kg-1 at 20 A g-1). The retention of capacitance is 88.6% at the current density of 8 A g-1 after 2000 cycles. The enhanced capacitive performance can be attributed to the improved specific surface area and 3D open area of NCG-10 generated by the pores and channels with the substantial function of SDS.

  14. Non-covalent doping of graphitic carbon nitride with ultrathin graphene oxide and molybdenum disulfide nanosheets: an effective binary heterojunction photocatalyst under visible light irradiation.


    Hu, S W; Yang, L W; Tian, Y; Wei, X L; Ding, J W; Zhong, J X; Chu, Paul K


    A proof of concept integrating binary p-n heterojunctions into a semiconductor hybrid photocatalyst is demonstrated by non-covalent doping of graphite-like carbon nitride (g-C3N4) with ultrathin GO and MoS2 nanosheets using a facile sonochemical method. In this unique ternary hybrid, the layered MoS2 and GO nanosheets with a large surface area enhance light absorption to generate more photoelectrons. On account of the coupling between MoS2 and GO with g-C3N4, the ternary hybrid possesses binary p-n heterojunctions at the g-C3N4/MoS2 and g-C3N4/GO interfaces. The space charge layers created by the p-n heterojunctions not only enhance photogeneration, but also promote charge separation and transfer of electron-hole pairs. In addition, the ultrathin MoS2 and GO with high mobility act as electron mediators to facilitate separation of photogenerated electron-hole pairs at each p-n heterojunction. As a result, the ternary hybrid photocatalyst exhibits improved photoelectrochemical and photocatalytic activity under visible light irradiation compared to other reference materials. The results provide new insights into the large-scale production of semiconductor photocatalysts. PMID:24980624

  15. Preparation of graphene oxide/polyacrylamide composite hydrogel and its effect on Schwann cells attachment and proliferation.


    Li, Guicai; Zhao, Yinxin; Zhang, Luzhong; Gao, Ming; Kong, Yan; Yang, Yumin


    Various hydrogel materials have been developed for improving the regeneration of peripheral nerve. Among which the graphene related hydrogels with excellent mechanical properties have attracted great attention. However, the effect of these hydrogels on peripheral nerve regeneration is still unclear. In the present study, the graphene oxide/polyacrylamide (GO/PAM) composite hydrogels were fabricated by in-situ free radical polymerization. The morphology, wettability, composition, swelling ratio, mechanical property and degradation behavior of the prepared GO/PAM composite hydrogels were separately characterized. The effect of GO/PAM hydrogel on the attachment and proliferation of Schwann cells was evaluated. Moreover, the release of biofactors by Schwann cells and adsorption of matrix proteins were further measured. The results showed that the color of the hydrogel became darker with the increased GO concentration, while the surface pore structure also displayed large variation when GO concentration was increased. The hydrophobicity and mechanical properties of hydrogel were increased with the ascending GO concentration. In addition, the variation of GO concentration displayed no obvious influence on the degradation of the composite hydrogel in different medium. The GO/PAM composite hydrogel with 0.4% GO (G0.4) could effectively enhance the attachment and proliferation of Schwann cells. Furthermore, the cells on G0.4 hydrogel displayed higher biofactors release and larger matrix adsorption than other samples. The results demonstrated that GO with suitable concentration in PAM hydrogel could effectively promote Schwann cell growth. The study may provide an important experimental basis for the design and development of new nerve grafts with potential application for peripheral nerve regeneration. PMID:27058512

  16. The Oral Intake of Organic Germanium, Ge-132, Elevates α-Tocopherol Levels in the Plas-ma and Modulates Hepatic Gene Expression Profiles to Promote Immune Activation in Mice.


    Nakamura, Takashi; Takeda, Tomoya; Tokuji, Yoshihiko


    The common water-soluble organic germanium compound poly-trans-[(2-carboxyethyl) germasesquioxane] (Ge-132) exhibits activities related to immune responses and antioxidant induction. In this study, we evaluated the antioxidative effect of dietary Ge-132 in the plasma of mice. Male ICR mice (seven mice per group) received an AIN-76 diet with 0.05% Ge-132; three groups received the Ge-132-containing diet for 0, 1 or 4 days. The plasma alpha-tocopherol (α-tocopherol) concentration increased from 6.85 to 9.60 μg/ml after 4 days of Ge-132 intake (p<0.05). We evaluated the changes in hepatic gene expression related to antioxidative activity as well as in the entire expression profile after one day of Ge-132 intake, using DNA microarray technology. We identified 1,220 genes with altered expression levels greater than 1.5-fold (increased or decreased) as a result of Ge-132 intake, and α-tocopherol transfer protein (Ttpa) gene expression was increased 1.62-fold. Immune activation was identified as the category with the most changes (containing 60 Gene Ontology (GO) term biological processes (BPs), 41 genes) via functional clustering analysis of altered gene expression. Ge-132 affected genes in clusters related to ATP production (22 GO term BPs, 21 genes), lipid metabolism (4 GO term BPs, 38 genes) and apoptosis (5 GO term BPs). Many GO term BPs containing these categories were significantly affected by the Ge-132 intake. Oral Ge-132 intake may therefore have increased plasma α-tocopherol levels by up-regulating α-tocopherol transfer protein (Ttpa) gene expression. PMID:26098482

  17. Coextraction of acidic, basic and amphiprotic pollutants using multiwalled carbon nanotubes/magnetite nanoparticles@polypyrrole composite.


    Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira


    The simultaneous extraction of acidic, basic and amphiprotic pollutants from various samples is a considerable and disputable concept in sample preparation strategies. In this study, for the first time, coextraction of acidic, basic and amphiprotic pollutants (polar and apolar) with multiwalled carbon nanotubes/Fe3O4@polypyrrole (MWCNTs/Fe3O4@PPy) composite based dispersive micro-solid phase extraction followed by high performance liquid chromatography-photo diode array detection was introduced. Firstly, the extraction efficiency of various magnetic nanosorbents including Fe3O4, MWCNTs/Fe3O4, graphene oxide/Fe3O4 (GO/Fe3O4), Fe3O4@PPy, MWCNTs/Fe3O4@PPy and GO/Fe3O4@PPy were compared. The results revealed that MWCNTs/Fe3O4@PPy nanocomposite has higher extraction efficiency for five selected model analytes (4-nitrophenol, 3-nitroaniline, 2,4-dichloroaniline, 3,4-dichloroaniline and 1-amino-2-naphthol). Box-Behnken design methodology combined with desirability function approach was applied to find out the optimal experimental conditions. The opted conditions were: pH of the sample, 8.2; sorbent amount, 12 mg; sorption time, 5.5 min; salt concentration, 14% w/w; type and volume of the eluent, 120 μL acetonitrile; elution time; 2 min. Under the optimum conditions detection limits and linear dynamic ranges were achieved in the range of 0.1-0.25 μg L(-1) and 0.5-600 μg L(-1), respectively. The percent of extraction recovery and relative standard deviations (n=5) were in the range of 45.6-82.2 and 4.0-8.5, respectively. Ultimately, the applicability of this method was successfully confirmed by analyzing rain, snow and river water samples and satisfactory results were obtained. PMID:26278357

  18. Covalently coupled hybrid of graphitic carbon nitride with reduced graphene oxide as a superior performance lithium-ion battery anode

    NASA Astrophysics Data System (ADS)

    Fu, Yongsheng; Zhu, Junwu; Hu, Chong; Wu, Xiaodong; Wang, Xin


    An in situ chemical synthetic approach has been designed for the fabrication of a covalently coupled hybrid consisting of graphitic carbon nitride (g-C3N4) with reduced graphene oxide (rGO) with differing g-C3N4/rGO ratio. The epoxy groups of graphene oxide (GO) undergo a nucleophilic substitution reaction with dicyandiamide (C2H4N4) to form the C2H4N4-GO composite via a covalent C-N bond, and then both the in situ polymerization of C2H4N4 and the thermal reduction of GO can be achieved at higher temperatures, forming the covalently coupled g-C3N4-rGO. FT-IR, CP-MAS NMR and XPS analyses, clearly revealed a covalent interaction between the g-C3N4 and rGO sheets. The g-C3N4-rGO exhibits an unprecedented high, stable and reversible capacity of 1525 mA h g-1 at a current density of 100 mA g-1 after 50 cycles. Even at a large current density of 1000 mA g-1, a reversible capacity of 943 mA h g-1 can still be retained. The superior electrochemical performance of g-C3N4-rGO is attributed to the specific characteristics of the unique nanostructure of g-C3N4-rGO and the concerted effects of g-C3N4 and rGO, including covalent interactions between the two moieties, the good conductivity and high special surface area of the nanocomposite, as well as the template effect of the planar amino group of g-C3N4 for the dispersed decoration of Li+ ions.An in situ chemical synthetic approach has been designed for the fabrication of a covalently coupled hybrid consisting of graphitic carbon nitride (g-C3N4) with reduced graphene oxide (rGO) with differing g-C3N4/rGO ratio. The epoxy groups of graphene oxide (GO) undergo a nucleophilic substitution reaction with dicyandiamide (C2H4N4) to form the C2H4N4-GO composite via a covalent C-N bond, and then both the in situ polymerization of C2H4N4 and the thermal reduction of GO can be achieved at higher temperatures, forming the covalently coupled g-C3N4-rGO. FT-IR, CP-MAS NMR and XPS analyses, clearly revealed a covalent interaction between

  19. Single particle calculations for a Woods-Saxon potential with triaxial deformations, and large Cartesian oscillator basis

    NASA Astrophysics Data System (ADS)

    Mohammed-Azizi, B.; Medjadi, D. E.


    We present a computer program which solves the Schrodinger equation of the stationary states for an average nuclear potential of Woods-Saxon type. In this work, we take specifically into account triaxial (i.e. ellipsoidal) nuclear surfaces. The deformation is specified by the usual Bohr parameters. The calculations are carried out in two stages. In the first, one calculates the representative matrix of the Hamiltonian in the Cartesian oscillator basis. In the second stage one diagonalizes this matrix with the help of subroutines of the Eispack library. If it is wished, one can calculate all eigenvalues, or only the part of the eigenvalues that are contained in a fixed interval defined in advance. In this latter case the eigenvectors are given conjointly. The program is very rapid, and the run-time is mainly used for the diagonalization. Thus, it is possible to use a significant number of the basis states in order to insure a best convergence of the results. Program summaryProgram obtainable from:CPC Program Library, Queen's University of Belfast, N. Ireland Title of program:Triaxial Catalogue number:ADSK Program summary URL: Licensing provisions:None Computer:PC. AMD Athlon 1000 MHz Hard disk:40 Go Ram:256 Mo Swap file:4 Go Operating system:WINDOWS XP Software used:Microsoft Visual Fortran 5.0A (with full optimizations in the settings project options) Programming language:Fortran 77/90 (double precision) Number of bits in a word:32 Number of lines:7662 No. of bytes in distributed program, including test data, etc.:174 601 Distribution format:tar gzip file Nature of the problem: The single particle energies and the single particle wave functions are calculated from one-body Hamiltonian including a central field of Woods-Saxon type, a spin-orbit interaction, and the Coulomb potential for the protons. We consider only ellipsoidal (triaxial) shapes. The deformation of the nuclear shape is fixed by the usual Bohr parameters ( β,