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Enhanced the photoelectrochemical performance of Bi_(2)XO_6(X = W, Mo) for detecting hexavalent chromium by modification of CuS

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Journal of Environmental Sciences 2021年第5期33卷 185-195页

作者： Guangxue Zhang Di Cheng Mengying Li Chuanqi Feng Huimin Wu He Mei Hubei Key Laboratory of Radiation Chemistry and Functional Materials School of Nuclear Technology and Chemistry&BiologyHubei University of Science and TechnologyXianning 437100China Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules Hubei Key Laboratory of Polymer MaterialsKey Laboratory of regional development and environmental response in Hubei ProuinceFaculty of Resources and Enuironmental ScienceCollege of Chemistry cmd Chemical EngineeringHubei UniversityWuhan 430062China Health Assessment Center Zhejiang Provincial Key Laboratory of Watershed Science and HealthCollege of Public Health and ManagementUniversity TownChashanWenzhou Medical UniversityWenzhou 325035China

In this work, Bi2XO6(X = W, Mo) are synthesized at different temperatures. The results of tests find the optimal temperatures of Bi_(2)WO_(6) and Bi_(2)MoO_(6) are 180 and 160 °C(BW-180, BM-160). Then, BW-180 and BM-160 are further compounded with different contents of CuS. The results of photoelectrochemical(PEC) tests show that CuS can improve the PEC performance of semiconductor materials, and it has better performance when CuS mass fraction is 5%. These maybe the photoelectron potentials generated by Cu S/Bi_(2)XO_(6)(X = Mo, W) heterojunction reduce the combination of photogenerated electrons and holes. When the PEC sensor based on 5%-CuS/BW-180 detects Cr(VI), it has a linear range of 1–80 μmol/L with detection limit of 0.95 μmol/L, while the PEC sensor based on 5%-CuS/BM-160 detects Cr(VI) has a linear range of 0.5–230 μmol/L and a detection limit of 0.12 μmol/L. Thus, 5%-CuS/Bi_(2)XO_(6) has potential application in hexavalent chromium detection.

关键词： Photoelectrochemical Sensor hexavalent Chromium Heterojunction Detection

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Preparation,characterization and performance of an electrospun carbon nanofiber mat applied in hexavalent chromium removal from aqueous solution

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Journal of Environmental Sciences 2019年第3期31卷 75-84页

作者： Zhihua Yuan Xiaoxia Cheng Lubin Zhong Renxiang Wu Yuming Zheng CAS Key Laboratory of Urban Pollutant Conversion Institute of Urban Environment Chinese Academy of Sciences

hexavalent chromium, Cr(VI), a highly toxic oxyanion known as a carcinogen and mutagen,is an issue of concern due to its adverse impact on human health. Therefore, development of effective technologies and/or materials for Cr(VI) removal from water has been of great interest for researchers. In this study, an electrospun carbon nanofiber(CNF) mat was prepared via electrospinning polyacrylonitrile(PAN), followed by thermal pre-oxidation and carbonization. Scanning electron microscopy(SEM) observation showed that the fiber diameter of the CNF with carbonization temperature of 950°C(CNF_(950)) was about 266 *** titration analysis demonstrated that the point of zero charge p H(pHpzc) of CNF_(950) was around 7.93. CNF_(950) demonstrated high adsorption capacity and fast adsorption kinetics for Cr(VI) at pH < 3. Langmuir isotherm calculations showed that the maximum adsorption capacity of Cr(VI) on CNF_(950) was 118.8 mg/g at pH 2. The adsorption isotherm of Cr(VI) on CNF_(950) was well described by the Redlich–Peterson model, revealing that Cr(VI)adsorption was the result of a combination of monolayer and multilayer adsorption,depending on the initial Cr(VI) concentration. Solution pH greatly affected Cr(VI) adsorption onto CNF_(950) due to the electrostatic interaction, and the adsorption capacity was relatively high when pH was below 3. X-ray photoelectron spectroscopy(XPS) analysis revealed that the removal of Cr(VI) might be the result of a combination of redox reaction and electrostatic adsorption. The adsorption-saturated CNF_(950) could be regenerated by NaOH solution. This study extends the potential applicability of electrospun CNF mats for Cr(VI)-contaminated water purification.

关键词： Adsorption Carbon nanofiber mat Electrospinning hexavalent chromium Redox reaction

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Biogenic palladium prepared by activated sludge microbes for the hexavalent chromium catalytic reduction: Impact of relative biomass

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Frontiers of Environmental Science & Engineering 2020年第2期14卷 151-159页

作者： Luman Zhou Chengyang Wu Yuwei Xie Siqing Xia State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

Palladium,a kind of platinum group metal,owns catalytic capacity for a variety of *** this study,Pd nanoparticles(PdNPs)were generated through enzymatic recovery by microbes of activated sludge at various biomass/Pd,and further used for the Cr(VI)*** results show that biomass had a strong adsorption capacity for Pd(II),which was 17.25 mg Pd/g *** XRD and TEM-EDX results confirmed the existence of PdNPs associated with microbes(bio-Pd).The increase of biomass had little effect on the reduction rate of Pd(II),but it could cause decreasing particle size and shifting location of Pd(0)with the better dispersion degree on the cell *** the Cr(VI)reduction experiments,Cr(VI)was first adsorbed on bio-Pd with hydrogen and then reduced using active hydrogen as electron *** improved the catalytic activity of *** the biomass/Pd(w/w)ratio increased to six or higher,Cr(VI)reduction achieved maximum rate that 50 mg/L of Cr(VI)could be rapidly reduced in one minute.

关键词： Palladium nanoparticles Activated sludge hexavalent chromium

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Non-linear modeling of kinetic and equilibrium data for the adsorption of hexavalent chromium by carbon nanomaterials:Dimension and functionalization

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Chinese Journal of Chemical Engineering 2019年第4期27卷 912-919页

作者： Miguel de la Luz-Asunción Eduardo E.Pérez-Ramírez Ana L.Martínez-Hernández Victor M.Castano Víctor Sánchez-Mendieta Carlos Velasco-Santos Facultad de Quimica Universidad Autonoma del Estado de Mexico Km. 12 de la carretera Toluca-Atlacomulco C.P. 50200 San Cayetano Toluca Estado de Mexico Mexico Tecnologico Nacional de Mexico-Instituto Tecnologico de Queretaro Division de Estudios de Posgrado e Investigacion Av. Tecnologico s/n esq. GraL Mariano Escobedo Col. Centro Historico C.P. 76000 Santiago de Queretaro Queretaro Mexico Centro de Fisica Aplicada y Tecnologia Avanzada Universidad Nacional Autonoma de Mexico Boulevard Juriquilla 3001 Queretaro 76230 Mexico

The adsorption capacities for the removal of hexavalent chromium from aqueous solutions by six carbon nanomaterials have been evaluated. Single-walled and multi-walled carbon nanotubes as received and after oxidation treatment, graphene oxide and reduced graphene oxide are the materials with different dimension and functionalization compared in this research. Carbon nanotubes have been modified using hydrogen peroxide as oxidizing agent under microwave radiation. The oxidation treatment on carbon nanotubes has a positive effect increasing the adsorbent–adsorbate interaction. Rate-controlling mechanisms and equilibrium data are analyzed using non-linear models. Non-linear method is proposed as the most suitable method for determining the kinetic and equilibrium parameters. The values of adsorption energy(E) obtained from the Dubinin–Radushkevich isotherm,have been found around 0.371 and 0.870 k J·mol-1, indicating physical adsorption. Therefore, the pseudo-second order model represents better the kinetic experimental data. The results show that the Langmuir isotherm provides a slightly better fit to the experimental data compared with the Freundlich isotherm, indicating homogeneous distribution of active sites on carbon nanomaterials and monolayer adsorption. The separation factors RLare found in the range of 0–1, suggesting that the adsorption process is suitable for all adsorbents. The mechanisms for hexavalent chromium removal have been proposed as electrostatic interactions and hydrogen bonding.

关键词： Carbon nanotubes Graphene Adsorption hexavalent chromium Kinetic

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Removal of hexavalent chromium in aquatic solutions by pomelo peel

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Water Science and Engineering 2020年第1期13卷 65-73页

作者： Qiong Wang Cong Zhou Yin-jie Kuang Zhao-hui Jiang Min Yang Hunan Provincial Key Laboratory of Comprehensive Utilization of Agricultural and Animal Husbandry Waste Resources College of Urban and Environmental SciencesHunan University of TechnologyZhuzhou 412007China Hunan Provincial Engineering Laboratory of Key Technique of Non-metallic Packaging Waste Resources Utilization Hunan University of TechnologyZhuzhou 421007China People's Government of Luohong Town Longhui CountyShaoyang 422211China School of Chemistry and Food Engineering Changsha University of Science and TechnologyChangsha 410114China

This study investigated the removal of hexavalent chromium(Cr(VI)) in aqueous solutions using pomelo peel(PP) and FeCl3-modified pomelo peel(FPP) as novel biomass *** adsorption experiments were performed to evaluate the effects of pH,time,temperature,initial concentration,and adsorbent dose on Cr(VI) removal by PP and *** results show that the maximum adsorption capacity of Cr(VI)was 21.55 mg/g for FPP and 0.57 mg/g for PP at a pH of 2.0 and a temperature of 40℃.The surface shape,microstructure,and chemical composition of FPP were analyzed with scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),and energy dispersive spectroscopy(EDS),and compared with those of *** results show that the adsorption performance of FPP was much better than that of PP,indicating that FPP can be an alternative high-efficiency adsorbent for Cr(VI) removal.

关键词： Adsorption hexavalent chromium removal Biomass adsorbent Pomelo peel FeCl3-modified pomelo peel Aquatic solution

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Removal of hexavalent chromium from aqueous solution by iron nanoparticles

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2005年第10期6卷 1022-1027页

作者：牛少凤刘永徐新华楼章华 Department of Environmental Engineering Zhejiang University Department of Environmental Engineering Zhejiang University Hangzhou 310027 China School of Civil Engineering and Architecture Zhejiang University Hangzhou 310027 China

Groundwater remediation by nanoparticles has received increasing interest in recent years. This report presents a thorough evaluation of hexavalent chromium removal in aqueous solutions using iron (Fe0) nanoparticles. Cr(VI) is a major pollutant of groundwater. Zero-valent iron, an important natural reductant of Cr(VI), is an option in the remediation of contami- nated sites, transforming Cr(VI) to essentially nontoxic Cr(III). At a dose of 0.4 g/L, 100% of Cr(VI) (20 mg/L) was degraded. The Cr(VI) removal efficiency decreased significantly with increasing initial pH. Different Fe0 type was compared in the same con- ditions. The reactivity was in the order starch-stabilized Fe0 nanoparticles>Fe0 nanoparticles>Fe0 powder>Fe0 filings. Electro- chemical analysis of the reaction process led to the conclusion that Cr(OH)3 should be the final product of Cr(VI). Iron nanopar- ticles are good choice for the remediation of heavy metals in groundwater.

关键词： hexavalent chromium, Iron nanoparticles, Starch, Stabilize, Remediation

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Polyaniline-TiO2 composite photocatalysts for light-driven hexavalent chromium ions reduction

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Science Bulletin 2020年第2期65卷 105-112,87页

作者： Xiaoming Deng Yao Chen Jieya Wen Yun Xu Jian Zhu Zhenfeng Bian The Education Ministry Key Laboratory of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials Shanghai Normal UniversityShanghai 200234China

In order to develop efficient photocatalysts,great efforts have been made to reduce hexavalent chromium to trivalent *** photocatalytic efficiency of this reduction depends largely on the adsorption and diffusion of hexavalent chromium ions on the surface of the *** this paper,polyanilineTiO2 composite can effectively improve the photocatalytic reduction performance and stability of hexavalent chromium *** effect of polyaniline(PANI) thickness on Cr(VI) activity and stability of photocatalytic reduction was studied by adjusting the content of PANI on Mesoporous TiO2(MT) *** the irradiation conditions,the reaction results showed that the reduction rate was 100%,and the maximum reaction rate reached 0.62 min-1 when the PANI modification was 3.0%.Moreover,the results showed that the reduction performance remained 100% after ten *** main reason is that the PANI modified on the surface of TiO2 is rich in positively charged amino group,which can efficiently adsorb the reactant Cr(VI),and make the product Cr(III) leave the reaction interface quickly,thus ensuring the performance of photocatalyst.

关键词： Polyaniline Titanium dioxide Photo-reduction hexavalent chromium Trivalent chromium

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hexavalent Chromium Removal from Water Using Heat-Acid Activated Red Mud

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Open Journal of Applied Sciences 2014年第5期4卷 275-284页

作者： Min Ma Yifeng Lu Rongzhi Chen Lan Ma Ying Wang College of Resources and Environment University of Chinese Academy of Sciences Beijing China School of Life Sciences Yunnan University Kunming China Yunnan Academies of Science and Technology Development Kunming China

This study investigated the heat-acid activated red mud used for hexavalent chromium (Cr6+) removal from aqueous solution. The results showed that the heat-acid activated red mud enhanced hexavalent chromium removal capacity from 0.003 to 0.015 mg·g﹣1. Adsorption experiments were conducted as a function of adsorbent dosage, contact time, pH and reaction temperature. The removal efficiency was found to increase gradually when solution pH decreased and maximum removal was achieved at pH 2. The physico-chemical characteristics of heat-acid activated red mud were studied by using instrumental technique like Scanning Electron Microscope (SEM), X-ray diffraction (XRD) and X-ray fluorescence spectrometry (XRF). The experimental data fitted well to Langmuir isotherm model. Thermodynamic parameters indicated the adsorption process was exothermic reaction. The cost-effective performance and, simple operation suggest the heat-acid activated red mud can be taken as a promising sorbents for removal of Cr6+ from wastewater.

关键词： Red Mud Heat-Acid Treatment Adsorption Isotherm hexavalent Chromium Removal

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Application of Iron Nanoparticles Synthesized by Green Tea for the Removal of hexavalent Chromium in Column Tests

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Journal of Geoscience and Environment Protection 2014年第4期2卷 28-36页

作者： C. Mystrioti A. Xenidis N. Papassiopi School of Mining and Metallurgical Engineering National Technical University of Athens Athens Greece

Nano zero valent iron particles (nZVI) are popular the last few years because of the numerous applications in remediation of a wide range of pollutants in contaminated soils and aquifers. The nZVI particles can be 10 - 1000 times more reactive than granular or micro-scale ZVI particles due to the small particle size, large specific surface area and high reactivity. An alternative green synthesis procedure was used for the production of nano zero valent iron particles (nZVI) using green tea (GT) extract, which is characterized by its high antioxidant content. Polyphenols in green tea extract possess double role in the synthesis of nZVI, because they not only reduce ferric cations, but also protect nZVI from oxidation and agglomeration as capping agents. The objective of current study was to simulate ata laboratory scale the attachment of GT-nZVI particles on soil material and study the effectiveness of attached nanoparticles for removing hexavalent chromium (Cr(VI)) from contaminated groundwater flowing through the porous soil bed. Column tests were carried out with various flowrates in order to examine the effect of contact time between the attached on porous medium nZVI and the flow-through solution on Cr(VI) reduction. After the completion of column tests the soil material in each column was split in 5 vertical sections, which were further subjected to chemical analyses and leaching tests. According to the results of the study increasing the contact time favors the reduction and removal of Cr(VI) from the aqueous phase. The reductive precipitation of Cr can be described as a reaction that follows a pseudo-first order kinetic law, with rate constant equal to k = 0.0243 ± 0.0011 min-1. Leaching tests indicated that precipitated chromium is not soluble. In the examined soil material, the total amount of precipitated Cr was found to range between 280 and 890 mg/(kg soil), while soluble Cr was less than 1.4 mg/kg and most probably it was due to the presence of residual

关键词： Nanoscale Zero Valent Iron nZVI hexavalent Chromium Reductive Capacity Column Tests

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Evaluation of the Adsorption of hexavalent Chromium on Kaolinite and Illite

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Journal of Environmental Protection 2011年第10期2卷 1347-1352页

作者： Omar Ajouyed Charlotte Hurel Nicolas Marmier 不详

The adsorption of hexavalent chromium on Kaolinite and Illite was studied in order to evaluate their potential for the reduction of hexavalent chromium mobility and their possible application for the treatment of polluted sediment. The influence of various parameters affecting the adsorption of hexavalent chromium, such as the pH of aqueous solution, the ionic strength and the initial metal ion concentration were investigated. The optimal pH range corresponding to the hexavalent chromium adsorption maximum on the Kaolinite and Illite is 2 - 4 and 2 - 2.6, respectively. The results showed that hexavalent chromium sorption on Kaolinite and Illite was strongly influenced by the pH, the ionic strength and the initial metal ion concentration. Langmuir and Freundlich adsorption isotherms are employed to understand the nature of adsorption at room temperature. The characteristic parameters for each isotherm have been determined. This showed that the Freundlich isotherm model well described the equilibrium data. The data suggest that the charge of the clay mineral surface is one of the main factors controlling hexavalent chromium desorption at alkaline pHs.

关键词： hexavalent Chromium Clay Mineral Sediment Adsorption Stabilization

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