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Reductive Dechlorination of p-Chlorophenol by Nanoscale Iron
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作者 RONG CHENG JIAN-LONG WANG WEI-XIAN ZHANG 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2007年第5期410-413,共4页
Objective To investigate reductive dechlorination of 4-chlorophenol (4-CP) by nanoscale Fe^0 under different conditions. Methods Nanoscale Fe^0 was synthesized by using reductive method. 4-CP and its intermediate pr... Objective To investigate reductive dechlorination of 4-chlorophenol (4-CP) by nanoscale Fe^0 under different conditions. Methods Nanoscale Fe^0 was synthesized by using reductive method. 4-CP and its intermediate products were analyzed by HPLC. Chlorine ion was quantified with DX-100 ion chromatograph. Nano-iron particles were observed under a FEI Quanta 200 FEG environmental scanning electron microscope (ESEM). Results The size of the particles was in the range of 10-100 nm. The nano-iron particles could reduce 4-CP effectively. The initial concentration of 4-CP increased with the decrease of the relative degradation rate, whereas the reduced amount of 4-CP increased. Temperature could influence both the dechlorination rate and the reaction pathway. Moreover, the stability and durability of nanoscale Fe^0 was evaluated through batch studies over extended periods of time. Conclusion The nanoscale Fe^0 can be used for sustainable treatment of contaminants in groundwater. 展开更多
关键词 nanoscale iron 4-CP PHENOL DECHLORINATION Priority pollutant
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Assessing the effectiveness of nanoscale zero-valent iron particles produced by green tea for Cr(VI)-contaminated groundwater remediation
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作者 Hui Li Zhan-tao Han +2 位作者 Qiang Deng Chun-xiao Ma Xiang-ke Kong 《Journal of Groundwater Science and Engineering》 2023年第1期55-67,共13页
Nanoscale zero-valent iron particles(NZVI) produced by using green tea(GT) extract as a reductant can remove Cr(Ⅵ) from water effectively,which can be utilized in groundwater remediation.In order to define the reacti... Nanoscale zero-valent iron particles(NZVI) produced by using green tea(GT) extract as a reductant can remove Cr(Ⅵ) from water effectively,which can be utilized in groundwater remediation.In order to define the reaction mechanism and removal effect in the aquifer,in this study,GT-NZVI particles were prepared and measured by some characterization methods to define their surface performance,and then batch and one-dimensional experiments were carried out to reveal the reaction properties of GT-NZVI and Cr(Ⅵ) in groundwater.The results showed that the prepared GT-NZVI particles were regular spherical with a diameter of 10-20 nm,which could disperse in water stably.The main component of GT-NZVI wasα-Fe with superficial polyphenols as a stabilizer.GT-NZVI suspension had good ability to reduce the Cr(Ⅵ) to Cr(Ⅲ) in water.When the concentration of GT-NZVI was 1 g/L,the removal efficiency of Cr(Ⅵ)with an initial concentration of 100 mg/L reached 92.8% in 1 h reaction.In column tests,GT-NZVI passed through the natural sand column successfully with an average outflow percentage of 71.2%.The simulated in-situ reaction zone(IRZ) with GT-NZVI was used to remediate Cr(Ⅵ) contaminated groundwater.The oufflow concentration of Cr(Ⅵ) kept in 0.14-0.32 mg/L corresponding to the outflow rate below 0.32%within 15 days,and the removal efficiency of Cr(Ⅵ) by IRZ with GT-NZVI decreased with the increase of aquifer medium particle size,groundwater flow rate and ionic strength.Most of Cr(Ⅲ) as reduzate was adsorbed or immobilized on the surface or in the lattice of GT-NZVI,which indicated effective immobilization for chromium. 展开更多
关键词 nanoscale iron particles Green tea Hexavalent chromium Groundwater remediation
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Biochar Supported Nanoscale Zero-valent Iron Composites for the Removal of Petroleum from Wastewater 被引量:2
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作者 Qin Feifei Xu Wenfei +3 位作者 Hao Boyu Yin Linghao Song Jiayu Zhang Xiuxia 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2021年第4期47-57,共11页
Considering the need for efficiently and rapidly treating oily wastewater while preventing secondary pollution,the nanoscale zero-valent iron(nZVI)was supported on biochar prepared by using a spent mushroom substrate(... Considering the need for efficiently and rapidly treating oily wastewater while preventing secondary pollution,the nanoscale zero-valent iron(nZVI)was supported on biochar prepared by using a spent mushroom substrate(SMS),to produce an iron-carbon composite(SMS-nZVI).The ability of the SMS-nZVI to treat wastewater containing high concentration of oil was then comprehensively evaluated.The morphology,structure,and other properties of the composite were characterized by using scanning electron microscopy,transmission electron microscopy,the Brunauer-Emmett-Teller nitrogen sorption analysis,and the Fourier transform infrared spectroscopy.The results show that the biochar prepared by using the SMS can effectively prevent the agglomeration of nZVI and increase the overall specific surface area,thereby enhancing the absorption of petroleum by the composite.Experiments reveal that compared with the SMS and nZVI,the SMS-nZVI composite removes petroleum faster and more efficiently from wastewater.Under optimized conditions involving an nZVI to biochar mass ratio of 1:5 and a pH value of 4,the efficiency for removal of petroleum from wastewater with an initial petroleum concentration of 1000 mg/L could reach 95%within 5 h.Based on a natural aging treatment involving exposure to air for 30 d,the SMS-nZVI composite retained an oil removal rate of higher than 62%,and this result could highlight its stability for practical applications. 展开更多
关键词 oily wastewater nanoscale zero-valent iron(nZVI) spent mushroom substrate(SMS) SMS-nZVI composite
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Degradation of nitrobenzene-containing wastewater by sequential nanoscale zero valent iron-persulfate process 被引量:2
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作者 Jingjuan Qiao Weizhou Jiao Youzhi Liu 《Green Energy & Environment》 SCIE CSCD 2021年第6期910-919,共10页
As nitrobenzene(NB)is structurally stable and difficult to degrade due to the presence of an electron withdrawing group(nitro group).The sequential nanoscale zero valent iron-persulfate(NZVI-Na_(2)S_(2)O_(8))process w... As nitrobenzene(NB)is structurally stable and difficult to degrade due to the presence of an electron withdrawing group(nitro group).The sequential nanoscale zero valent iron-persulfate(NZVI-Na_(2)S_(2)O_(8))process was proposed in this study for the degradation NB-containing wastewater.The results showed that the NB degradation efficiency and the total organic carbon removal efficiency in the sequential NZVINa_(2)S_(2)O_(8)process were 100%and 49.25%,respectively,at a NB concentration of 200 mg L^(-1),a NZVI concentration of 0.75 g L^(-1),a Na_(2)S_(2)O_(8)concentration of 26.8 mmol L^(-1),an initial pH of 5,and a reaction time of 30 min,which were higher than those(88.53%and 35.24%,respectively)obtained in the NZVI/Na_(2)S_(2)O_(8)process.Sulfate radicals(SO_(4)·-)and hydroxyl radicals(·OH)generated in the reaction were identified directly by electron paramagnetic resonance spectroscopy and indirectly by radical capture experiments,and it was shown that both SO_(4)^(·-)and·OH played a major role in the sequential NZVI-Na_(2)S_(2)O_(8)process.The possible pathways involved in the reduction of NB to aniline(AN)and the further oxidative degradation of AN were determined by gas chromatography-mass spectrometry. 展开更多
关键词 nanoscale zero valent iron Impinging stream-rotating packed bed Sequential NZVI-Na2S2O8process NITROBENZENE Degradation pathways
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Corrosion behaviors and kinetics of nanoscale zero-valent iron in water:A review 被引量:1
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作者 Chenliu Tang Xingyu Wang +2 位作者 Yufei Zhang Nuo Liu Xiang Hu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2024年第1期391-406,共16页
Knowledge on corrosion behaviors and kinetics of nanoscale zero-valent iron(nZVI)in aquatic environment is particularly significant for understanding the reactivity,longevity and stability of nZVI,as well as providing... Knowledge on corrosion behaviors and kinetics of nanoscale zero-valent iron(nZVI)in aquatic environment is particularly significant for understanding the reactivity,longevity and stability of nZVI,as well as providing theoretical guidance for developing a cost-effective nZVI-based technology and designing large-scale applications.Herein,this review gives a holistic overview on the corrosion behaviors and kinetics of nZVI in water.Firstly,Eh-pH diagram is introduced to predict the thermodynamics trend of iron corrosion.The morphological,structural,and compositional evolution of(modified-)nZVI under different environmental conditions,assisted with microscopic and spectroscopic evidence,is then summarized.Afterwards,common analytical methods and characterization technologies are categorized to establish time-resolved corrosion kinetics of nZVI in water.Specifically,stable models for calculating the corrosion rate constant of nZVI as well as electrochemical methods for monitoring the redox reaction are discussed,emphasizing their capabilities in studying the dynamic iron corrosion processes.Finally,in the future,more efforts are encouraged to study the corrosion behaviors of nZVI in long-term practical application and further build nanoparticles with precisely tailored properties.We expect that our work can deepen the understanding of the nZVI chemistry in aquatic environment. 展开更多
关键词 nanoscale zero-valent iron(nZVI) Corrosion behaviors Corrosion kinetics nZVI evolution
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Amino acids modified nanoscale zero-valent iron:Density functional theory calculations,experimental synthesis and application in the Fenton-like degradation of organic solvents
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作者 Xingchen Yang Fucheng Ming +1 位作者 Jianlong Wang Lejin Xu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2024年第1期296-309,共14页
To improve the adsorption and catalytic performance of heterogeneous Fenton-like catalysts for oil wastes,amino acids were used to modify nanoscale zero-valent iron(AA@Fe^(0)),which were applied in the Fenton-like deg... To improve the adsorption and catalytic performance of heterogeneous Fenton-like catalysts for oil wastes,amino acids were used to modify nanoscale zero-valent iron(AA@Fe^(0)),which were applied in the Fenton-like degradation of organic solvents(tributyl phosphate and n-dodecane,named TBP and DD).Twelve amino acids,i.e.,glycine(Gly),alanine(Ala),leucine(Leu),proline(Pro),phenylalanine(Phe),methionine(Met),cysteine(Cys),asparagine(Asn),serine(Ser),glutamic acid(Glu),lysine(Lys)and arginine(Arg),were selected and calculated by density functional theory(DFT).The optimized structure,charge distribution,the highest occupied molecular orbital(HOMO),the lowest unoccupied molecular orbital(LUMO),interaction region indicator(IRI)isosurface map and adsorption energy of AA@Fe^(0),AA@Fe^(0)-TBP and AA@Fe^(0)-DD were studied,which indicated that Fe is more likely to approach and charge transfer with-COO and-NH_(3) on theα-carbon of amino acids.There is strong attraction between Fe and–COO,and Van der Waals force between Fe and-NH_(3),respectively.In the interaction of AA@Fe^(0)with TBP and DD,Van der Waal force plays an important role.AA@Fe^(0)was synthesized in laboratory and characterized to investigate physicochemical properties.In Fenton-like degradation of organic solvents,the change of COD in water phase during the degradation process as well as the volume of the organic phase after the reaction were investigated.The results of calculations combined with experiments showed that Ser-modified Fe^(0)performed the best in these amino acids,with 98%removal of organic solvents.A possible catalytic mechanism was proposed in which amino acids acted a linking role between Fe and organic solvents,activating H_(2)O_(2)to generate hydroxyl radicals for the degradation of organic solvents. 展开更多
关键词 Amino acids nanoscale zero-valent iron Density functional theory Organic solvents Fenton-like degradation
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Study of diclofenac removal by the application of combined zero-valent iron and calcium peroxide nanoparticles in groundwater
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作者 Wen Liang Nian-qing Zhou +3 位作者 Chao-meng Dai Yan-ping Duan Lang Zhou Yao-jen Tu 《Journal of Groundwater Science and Engineering》 2021年第3期171-180,共10页
Diclofenac(DCF)is one of the most frequently detected pharmaceuticals in groundwater,posing a great threat to the environment and human health due to its toxicity.To mitigate the DCF contamination,experiments on DCF d... Diclofenac(DCF)is one of the most frequently detected pharmaceuticals in groundwater,posing a great threat to the environment and human health due to its toxicity.To mitigate the DCF contamination,experiments on DCF degradation by the combined process of zero-valent iron nanoparticles(nZVI)and nano calcium peroxide(nCaO_(2))were performed.A batch experiment was conducted to examine the influence of the adding dosages of both nZVI and nCaO_(2)nanoparticles and pH value on the DCF removal.In the meantime,the continuous-flow experiment was done to explore the sustainability of the DCF degradation by jointly adding nZVI/nCaO_(2)nanoparticles in the reaction system.The results show that the nZVI/nCaO_(2)can effectively remove the DCF in the batch test with only 0.05 g/L nZVI and 0.2 g/L nCaO_(2)added,resulting in a removal rate of greater than 90%in a 2-hour reaction with an initial pH of 5.The degradation rate of DCF was positively correlated with the dosage of nCaO_(2),and negatively correlated with both nZVI dosage and the initial pH value.The order of significance of the three factors is identified as pH value>nZVI dosage>nCaO_(2)dosage.In the continuous-flow reaction system,the DCF removal rates remained above 75%within 150 minutes at the pH of 5,with the applied dosages of 0.5 g/L for nZVI and 1.0 g/L for nCaO_(2).These results provide a theoretical basis for the nZVI/nCaO_(2)application to remove DCF in groundwater. 展开更多
关键词 nanoscale zero-valent iron(nZVI) Nano calcium peroxide(nCaO_(2)) DICLOFENAC Fenton-like reaction Groundwater pollution
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Unraveling biochar surface area on structure and heavy metal removal performances of carbothermal reduced nanoscale zero-valent iron
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作者 Tharindu N.Karunaratne Prashan M.Rodrigo +3 位作者 Daniel O.Oguntuyi Todd E.Mlsna Jilei Zhang Xuefeng Zhang 《Journal of Bioresources and Bioproducts》 EI CSCD 2023年第4期388-398,共11页
Carbothermal reduction using biochar(BC)is a green and effective method of synthesizing BCsupported nanoscale zero-valent iron(nanoFe^(0))composites.However,the effect of BC surface area on the structure,distribution,... Carbothermal reduction using biochar(BC)is a green and effective method of synthesizing BCsupported nanoscale zero-valent iron(nanoFe^(0))composites.However,the effect of BC surface area on the structure,distribution,and performance such as the heavy metal uptake capacity of nanoFe^(0)particles remains unclear.Soybean stover-based BCs with different surface areas(1.7−1472 m^(2)/g)were prepared in this study.They have been used for in-situ synthesis BCs-supported nanoFe^(0)particlesthrough carbothermal reduction of ferrous chloride.The BCs-supported nanoFe^(0)particles were found to be covered with graphene shells and dispersed onto BC surfaces,forming the BC-supported graphene-encapsulated nanoFe^(0)(BC-G@Fe^(0))composite.These graphene shells covering the nanoFe^(0)particles were formed because of gaseous carbon evolved from biomass carbonization reacting with iron oxides/iron salts.Increasing BC surface area decreased the average diameters of nanoFe^(0)particles,indicating a higher BC surface area alleviated the aggregation of nanoFe^(0)particles,which resulted in higher heavy metal uptake capacity.At the optimized condition,BC-G@Fe^(0)composite exhibited uptake capacities of 124.4,121.8,254.5,and 48.0 mg/g for Cu^(2+),Pb^(2+),Ag^(+),and As^(3+),respectively(pH 5,25℃).Moreover,the BC-G@Fe^(0)composite also demonstrated high stability for Cu^(2+)removal from the fixed-bed continuous flow,in which 1 g of BC-G@Fe^(0)can work for 120 h in a 4 mg/L Cu^(2+)flow continually and clean 28.6 L Cu^(2+)contaminated water.Furthermore,the BC-G@Fe^(0)composite can effectively immobilize the bioavailable As^(3+)from the contaminated soil,i.e.,5%(w)of BC-G@Fe^(0)composite addition can immobilize up to 92.2%bioavailable As^(3+)from the contaminated soil. 展开更多
关键词 Carbothermal reduction nanoscale zero-valent iron Heavy metal Fix-bed sorption Soil remediation
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Optimizing synthesis conditions of nanoscale zero-valent iron (nZVI) through aqueous reactivity assessment 被引量:2
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作者 Yanlai HAN Michael D. Y. YANG +1 位作者 Weixian ZHANG Weile YAN 《Frontiers of Environmental Science & Engineering》 SCIE EI CAS CSCD 2015年第5期813-822,共10页
Nanoscale iron particles (nZVI) is one of the most important engineered nanomaterials applied to environmental pollution control and abatement. Although a multitude of synthesis approaches have been proposed, a faci... Nanoscale iron particles (nZVI) is one of the most important engineered nanomaterials applied to environmental pollution control and abatement. Although a multitude of synthesis approaches have been proposed, a facile method to screen the reactivity of candidate nZVI materials produced using different methods or under varying synthesis conditions has yet been established. In this study, four reaction parameters were adjusted in the preparation of borohydride-reduced nZVI. The reductive properties of the resultant nanoparticles were assayed independently using two model aqueous contaminants, Cu (II) and nitrate. The results confirm that the reductive reactivity of nZVI is most sensitive to the initial concentration of iron precursor, borohydride feed rate, and the loading ratio of borohydride to ferric ion during particle synthesis. Solution mixing speed, in contrast, carries a relative small weight on the reactivity of nZVI. The two probing reactions (i.e., Cu(II) and nitrate reduction) are able to generate consistent and quantitative inference about the mass-normalized surface activity of nZVI. However, the nitrate assay is valid in dilute aqueous solutions only (50 mg.L~ or lower) due to accelerated deactivation of iron surface at elevated nitrate concentra- tions. Additional insights including the structural and chemical makeup of nZVI can be garnered from Cu(II) reduction assessments. The reactivity assays investigated in this study can facilitate screening of candidate materials or optimization of nZVI production parameters, which complement some of the more sophisticated but less chemically specific material characterization methods used in the nZVI research. 展开更多
关键词 iron nanoparticles nanoscale iron particles(nZVI) SYNTHESIS characterization Cu(II) reduction nitratereduction
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Decolorization of Methyl Orange by a new clay-supported nanoscale zero-valent iron:Synergetic effect,efficiency optimization and mechanism 被引量:9
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作者 Xiaoguang Li Ying Zhao +5 位作者 Beidou Xi Xiaoguang Meng Bin Gong Rui Li Xing Peng Hongliang Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2017年第2期8-17,共10页
In this study, a novel nanoscale zero-valent iron(n ZVI) composite material was successfully synthesized using a low-cost natural clay, "Hangjin 2~#clay"(HJ clay) as the support and tested for the decolorization... In this study, a novel nanoscale zero-valent iron(n ZVI) composite material was successfully synthesized using a low-cost natural clay, "Hangjin 2~#clay"(HJ clay) as the support and tested for the decolorization of the azo dye Methyl Orange(MO) in aqueous solution by n ZVI particles. According to the characterization and MO decolorization experiments, the sample with 5:1 HJ clay-supported n ZVI(HJ/n ZVI) mass ratio(HJ-n ZVI5) showed the best dispersion and reactivity and the highest MO decolorization efficiency. With the same equivalent Fe0 dosage, the HJ-n ZVI1 and HJ-n ZVI5 samples demonstrated a synergetic effect for the decolorization of MO: their decolorization efficiencies were much higher than that achieved by physical mixing of HJ clay and n ZVIs, or the sum of HJ clay and n ZVIs alone. The synergetic effect was primarily due to the improved dispersion and more effective utilization of the n ZVI particles on/in the composite materials. Higher decolorization efficiency of MO was obtained at larger HJ-n ZVI dosage, higher temperature and under N2 atmosphere, while the MO initial concentration and p H were negatively correlated to the efficiency. HJ clay not only works as a carrier for n ZVI nanoparticles, but also contributes to the decolorization through an "adsorption-enhanced reduction" mechanism. The high efficiency of HJ-n ZVI for decontamination gives it great potential for use in a variety of remediation applications. 展开更多
关键词 nanoscale zero-valent iron CLAY Material optimization Methyl Orange
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Humic acid and metal ions accelerating the dechlorination of 4-chlorobiphenyl by nanoscale zero-valent iron 被引量:5
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作者 Yu Wang Dongmei Zhou +2 位作者 Yujun Wang Xiangdong Zhu Shengyang Jin 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2011年第8期1286-1292,共7页
Transformation of polychlorinated biphenyls (PCBs) by zero-valent iron represents one of the latest innovative technologies for environmental remediation. The dechlorination of 4-chlorobiphenyl (4-C1BP) by nanosca... Transformation of polychlorinated biphenyls (PCBs) by zero-valent iron represents one of the latest innovative technologies for environmental remediation. The dechlorination of 4-chlorobiphenyl (4-C1BP) by nanoscale zero-valent iron (NZVI) in the presence of humic acid or metal ions was investigated. The results showed that the dechlorination of 4-C1BP by NZVI increased with decreased solution pH. When the initial pH value was 4.0, 5.5, 6.8, and 9.0, the de.chlorination efficiencies of 4-CIBP after 48 hr were 53.8%, 47.8%, 35.7%, and 35.6%, respectively. The presence of humic acid inhibited the reduction of 4-CIBP in the first 4 hi', and then significantly accelerated the dechlorination by reaching 86.3% in 48 hr. Divalent metal ions, Co2+, Cu2+, and Ni2+, were reduced and formed bimetals with NZVI, thereby enhanced the dechlorination of 4-CIBP. The dechlorination percentages of 4-CIBP in the presence of 0.1 mmol/L Co2~, Cuz~ and Niz~ were 66.1%, 66.0% and 64.6% in 48 hr, and then increased to 67.9%, 71.3% and 73.5%, after 96 hr respectively. The dechlorination kinetics of 4-C1BP by the NZVI in all cases followed pseudo-first order model. The results provide a basis for better understanding of the dechlorination mechanisms of PCBs in real environment. 展开更多
关键词 4-chlorobiphenyl nanoscale zero-valent iron humic acid metal ions DECHLORINATION
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Nanoencapsulation of hexavalent chromium with nanoscale zero-valent iron:High resolution chemical mapping of the passivation layer 被引量:4
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作者 Xiao-yue Huang Lan Ling Wei-xian Zhang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第5期4-13,共10页
Solid phase reactions of Cr(Ⅵ) with Fe(0) were investigated with spherical-aberration-corrected scanning transmission electron microscopy(Cs-STEM) integrated with X-ray energy-dispersive spectroscopy(XEDS). N... Solid phase reactions of Cr(Ⅵ) with Fe(0) were investigated with spherical-aberration-corrected scanning transmission electron microscopy(Cs-STEM) integrated with X-ray energy-dispersive spectroscopy(XEDS). Near-atomic resolution elemental mappings of Cr(Ⅵ)–Fe(0) reactions were acquired. Experimental results show that rate and extent of Cr(Ⅵ) encapsulation are strongly dependent on the initial concentration of Cr(Ⅵ) in solution. Low Cr loading in nZⅥ(〈1.0 wt%) promotes the electrochemical oxidation and continuous corrosion of n ZⅥ while high Cr loading(〉1.0 wt%) can quickly shut down the Cr uptake. With the progress of iron oxidation and dissolution, elements of Cr and O counter-diffuse into the nanoparticles and accumulate in the core region at low levels of Cr(Ⅵ)(e.g., 〈 10 mg/L). Whereas the reacted n ZⅥ is quickly coated with a newly-formed layer of 2–4 nm in the presence of concentrated Cr(Ⅵ)(e.g., 〉 100 mg/L). The passivation structure is stable over a wide range of pH unless pH is low enough to dissolve the passivation layer. X-ray photoelectron spectroscopy(XPS) depth profiling reconfirms that the composition of the newly-formed surface layer consists of Fe(Ⅲ)–Cr(Ⅲ)(oxy)hydroxides with Cr(Ⅵ) adsorbed on the outside surface. The insoluble and insulating Fe(Ⅲ)–Cr(Ⅲ)(oxy)hydroxide layer can completely cover the n ZⅥ surface above the critical Cr loading and shield the electron transfer. Thus, the fast passivation of nZⅥ in high Cr(Ⅵ) solution is detrimental to the performance of nZⅥ for Cr(Ⅵ) treatment and remediation. 展开更多
关键词 nanoscale zero-valent iron (nZVI) Hexavalent chromium Solid phase reaction PASSIVATION Spherical-aberration-correctedscanning transmission electronmicroscopy (Cs-STEM)
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Sodium citrate and biochar synergistic improvement of nanoscale zero-valent iron composite for the removal of chromium(Ⅵ)in aqueous solutions 被引量:3
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作者 Hongyi Zhou Mengyao Ye +3 位作者 Yongkang Zhao Shams Ali Baig Ning Huang Mengyan Ma 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2022年第5期227-239,共13页
Sodium citrate(SC)is a widely-used food and industrial additive with the properties of com-plexation and microbial degradation.In the present study,nano-zero-valent iron reaction system(SC-nZVI@BC)was successfully est... Sodium citrate(SC)is a widely-used food and industrial additive with the properties of com-plexation and microbial degradation.In the present study,nano-zero-valent iron reaction system(SC-nZVI@BC)was successfully established by modifying nanoscale zero-valent iron(nZVI)with SC and biochar(BC),and was employed to remove Cr(Ⅵ)from aqueous solu-tions.The nZVI,SC-nZVI and SC-nZVI@BC were characterized and compared using X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),thermogravimetric analy-ses(TGA),vibrating sample magnetometer(VSM),scanning electron microscope(SEM),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).The results showed that nZVI was successfully loaded on the biochar,and both the agglomeration and surface pas-sivation problems of nanoparticles were well resolved.The dosage of SC,C∶Fe,initial pH and Cr(Ⅵ)concentration demonstrated direct effects on the removal efficiency.The maximum Cr(Ⅵ)removal rate and the removal capacity within 60 min were 99.7%and 199.46 mg/g,respectively(C∶Fe was 1∶1,SC dosage was 1.12 mol.%,temperature was 25℃,pH=7,and the original concentration of Cr(Ⅵ)was 20 mg/L).The reaction confirmed to follow the pseudo-second-order reaction kinetics,and the order of the reaction rate constant k was as follows:SC-nZVI@BC>nZVI@BC>SC-nZVI>nZVI.In addition,the mechanism of Cr(Ⅵ)removal by SC-nZVI@BC mainly involved adsorption,reduction and co-precipitation,and the reduction of Cr(Ⅵ)to Cr(Ⅲ)by nano Fe0 played a vital role.Findings from the present study demon-strated that the SC-nZVI@BC exhibited excellent removal efficiency toward Cr(Ⅵ)with an improved synergistic characteristic by SC and BC. 展开更多
关键词 nanoscale zero-valent iron Cr(Ⅵ)removal Sodium citrate BIOCHAR Synergistic promotion
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Removal of decabromodiphenyl ether (BDE-209) by sepiolite-supported nanoscale zerovalent iron 被引量:3
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作者 Rongbing FU Na MU +2 位作者 Xiaopin GUO Zhen XU Dongsu BI 《Frontiers of Environmental Science & Engineering》 SCIE EI CAS CSCD 2015年第5期867-878,共12页
Nanoscale zerovalent iron (nZVI) synthesized using sepiolite as a supporter was used to investigate the removal kinetics and mechanisms of decabromodiphenyl ether (BDE-209). BDE-209 was rapidly removed by the prep... Nanoscale zerovalent iron (nZVI) synthesized using sepiolite as a supporter was used to investigate the removal kinetics and mechanisms of decabromodiphenyl ether (BDE-209). BDE-209 was rapidly removed by the prepared sepiolite-supported nZVI with a reaction rate that was 5 times greater than that of the conventionally prepared nZVI because of its high surface area and reactivity. The degradation of BDE-209 occurred in a stepwise debromination manner, which followed pseudo- first-order kinetics. The removal efficiency of BDE-209 increased with increasing dosage of sepiolite-supported nZVI particles and decreasing pH, and the efficiency decreased with increasing initial BDE-209 concentrations. The presence of tetrahydrofuran (THF) as a cosolvent at certain volume fractions in water influenced the degrada- tion rate of sepiolite-supported nZVI. Debromination pathways of BDE-209 with sepiolite-supported nZVI were proposed based on the identified reaction intermedi- ates, which ranged from nona- to mono-brominated diphenylethers (BDEs) under acidic conditions and nonato penta-BDEs under alkaline conditions. Adsorption on sepiolite-supported nZVI particles also played a role in the removal of BDE-209. Our findings indicate that the particles have potential applications in removing environ- mental pollutants, such as halogenated organic contami- nants. 展开更多
关键词 sepiolite-supported nanoscale zerovalent iron decabromodiphenyl ether DEBROMINATION adsorption mechanism
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Debromination of decabromodiphenyl ether by organo-montmorillonitesupported nanoscale zero-valent iron: Preparation, characterization and influence factors 被引量:13
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作者 Zhihua Pang Mengyue Yan +2 位作者 Xiaoshan Jia Zhenxing Wang Jianyu Chen 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第2期483-491,共9页
An organo-montmorillonite-supported nanoscale zero-valent iron material (M-NZVI) was synthesized to degrade decabromodiphenyl ether (BDE-209). The results showed that nanoscale zero-valent iron had good dispersion... An organo-montmorillonite-supported nanoscale zero-valent iron material (M-NZVI) was synthesized to degrade decabromodiphenyl ether (BDE-209). The results showed that nanoscale zero-valent iron had good dispersion on organo-montmoriUonite and was present as a core-shell structure with a particle size range of nanoscale iron between 30-90 nm, characterized by XRD, SEM, TEM, XRF, ICP-AES, and XPS. The results of the degradation of BDE-209 by M-NZVI showed that the efficiency of M-NZVI in removing BDE-209 was much higher than that of NZVI. The efficiency of M-NZVI in removing BDE-209 decreased as the pH and the initial dissolved oxygen content of the reaction solution increased, but increased as the proportion of water in the reaction solution increased. 展开更多
关键词 supported nanoscale zero-valent iron organo-montmorillonite decabromodiphenyl ether (BDE-209) degradation influence factors
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Graphene-supported nanoscale zero-valent iron:Removal of phosphorus from aqueous solution and mechanistic study 被引量:12
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作者 Fenglin Liu JingHe Yang +5 位作者 Jiane Zuo Ding Ma Lili Gan Bangmi Xie Pei Wang Bo Yang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第8期1751-1762,共12页
Excess phosphorus from non-point pollution sources is one of the key factors causing eutrophication in many lakes in China,so finding a cost-effective method to remove phosphorus from non-point pollution sources is ve... Excess phosphorus from non-point pollution sources is one of the key factors causing eutrophication in many lakes in China,so finding a cost-effective method to remove phosphorus from non-point pollution sources is very important for the health of the aqueous environment. Graphene was selected to support nanoscale zero-valent iron(nZVI)for phosphorus removal from synthetic rainwater runoff in this article. Compared with nZVI supported on other porous materials,graphene-supported nZVI(G-nZVI) could remove phosphorus more efficiently. The amount of nZVI in G-nZVI was an important factor in the removal of phosphorus by G-nZVI,and G-nZVI with 20 wt.% nZVI(20% G-nZVI)could remove phosphorus most efficiently. The nZVI was very stable and could disperse very well on graphene,as characterized by transmission electron microscopy(TEM) and scanning electron microscopy(SEM). X-ray photoelectron spectroscopy(XPS),Fourier Transform infrared spectroscopy(FT-IR) and Raman spectroscopy were used to elucidate the reaction process,and the results indicated that Fe-O-P was formed after phosphorus was adsorbed by G-nZVI. The results obtained from X-ray diffraction(XRD) indicated that the reaction product between nZVI supported on graphene and phosphorus was Fe3(PO4)2·8H2O(Vivianite). It was confirmed that the specific reaction mechanism for the removal of phosphorus with nZVI or G-nZVI was mainly due to chemical reaction between nZVI and phosphorus. 展开更多
关键词 nanoscale zero valent iron Phosphorus Graphene Graphene-supported nZVI
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Microbes team with nanoscale zero-valent iron: A robust route for degradation of recalcitrant pollutants 被引量:1
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作者 Nuo Liu Jing Liu +2 位作者 Hong Wang Shaolin Li Wei-xian Zhang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2022年第8期140-146,共7页
Integrating nanoscale zero-valent iron(nZVI) with biological treatment processes holds the promise of inheriting significant advantages from both environmental nano-and biotechnologies. nZVI and microbes can perform i... Integrating nanoscale zero-valent iron(nZVI) with biological treatment processes holds the promise of inheriting significant advantages from both environmental nano-and biotechnologies. nZVI and microbes can perform in coalition in direct contact and act simultaneously, or be maintained in separate reactors and operated sequentially. Both modes can generate enhanced performance for wastewater treatment and environmental remediation. nZVI scavenges and eliminates toxic metals, and enhances biodegradability of some recalcitrant contaminants while bioprocesses serve to mineralize organic compounds and further remove impurities from wastewater. This has been demonstrated in a number of recent works that nZVI can substantially augment the performance of conventional biological treatment for wastewaters from textile and nonferrous metal industries. Our recent laboratory and field tests show that COD of the industrial effluents can be reduced to a record-low of 50 ppm. Recent literature on the theory and applications of the nZVI-bio system is highlighted in this mini review. 展开更多
关键词 Environmental microbiology nanoscale zero-valent iron(nZVI) REMEDIATION Wastewater nZVI-bio system
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Interaction between Cu^(2+) and different types of surface-modified nanoscale zero-valent iron during their transport in porous media 被引量:3
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作者 Haoran Dong Guangming Zeng +5 位作者 Chang Zhang Jie Liang Kito Ahmad Piao Xu Xiaoxiao He Mingyong Lai 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2015年第6期180-188,共9页
This study investigated the interaction between Cu^2+and nano zero-valent iron(NZVI)coated with three types of stabilizers(i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu^2+ uptake, coll... This study investigated the interaction between Cu^2+and nano zero-valent iron(NZVI)coated with three types of stabilizers(i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu^2+ uptake, colloidal stability and mobility of surface-modified NZVI(SM-NZVI) in the presence of Cu^2+. The uptake of Cu^2+ by SM-NZVI and the colloidal stability of the Cu-bearing SM-NZVI were examined in batch tests. The results showed that NZVI coated with different modifiers exhibited different affinities for Cu^2+, which resulted in varying colloidal stability of different SM-NZVI in the presence of Cu^2+. The presence of Cu^2+ exerted a slight influence on the aggregation and settling of NZVI modified with PAA or Tween-20. However, the presence of Cu^2+caused significant aggregation and sedimentation of starch-modified NZVI, which is due to Cu^2+complexation with the starch molecules coated on the surface of the particles. Column experiments were conducted to investigate the co-transport of Cu^2+ in association with SM-NZVI in water-saturated quartz sand. It was presumed that a physical straining mechanism accounted for the retention of Cu-bearing SM-NZVI in the porous media. Moreover, the enhanced aggregation of SM-NZVI in the presence of Cu^2+ may be contributing to this straining effect. 展开更多
关键词 Copper ion Colloidal stability Co-transport nanoscale zero valent iron Surface modification
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Degradation of chlorinated phenols by nanoscale zero-valent iron
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作者 Rong CHENG Jianlong WANG Weixian ZHANG 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2008年第1期103-108,共6页
Chlorophenols(CPs),as important contami-nants in groundwater,are toxic and difficult to biode-grade.Recentlynanoscalezero-valentironreceivedagreat deal of attention because of its excellent performance in treating rec... Chlorophenols(CPs),as important contami-nants in groundwater,are toxic and difficult to biode-grade.Recentlynanoscalezero-valentironreceivedagreat deal of attention because of its excellent performance in treating recalcitrant compounds.In this study,nanoscale zero-valent iron particles were prepared using chemical reduction,and the reductive transformations of three kinds of chlorinated phenols(2-CP,3-CP,and 4-CP)by nanoscale zero-valent iron under different conditions were investigated.The transformation process of the CPs was shown to be dechlorination first,then cleavage of the benzene ring.The removal efficiency of the CPs varied as follows:2-CP.3-CP.4-CP.The reactivity of CPs was associated with their energy of lowest unoccupied molecular orbit(E LUMO).With the increase in initial concentrations of CPs,removal efficiency decreased a little.But the quantities of CPs reduced increased evidently.Temperature had influence on not only the removal efficiency,but also the transformation pathway.At higher temperatures,dechlorination occurred prior to benzene ring cleavage.At lower temperatures,however,the oxidation product was formed more easily. 展开更多
关键词 nanoscale zero-valent iron CHLOROPHENOL DECHLORINATION molecular orbit theory
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The inactivation of bacteriophages MS2 and PhiX174 by nanoscale zero-valent iron:Resistance difference and mechanisms
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作者 Rong Cheng Yingying Zhang +6 位作者 Tao Zhang Feng Hou Xiaoxin Cao Lei Shi Peiwen Jiang Xiang Zheng Jianlong Wang 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2022年第8期247-256,共10页
Pathogenic enteric viruses pose a significant risk to human health.Nanoscale zero-valent iron(nZVI),a novel material for environmental remediation,has been shown to be a promising tool for disinfection.However,the exi... Pathogenic enteric viruses pose a significant risk to human health.Nanoscale zero-valent iron(nZVI),a novel material for environmental remediation,has been shown to be a promising tool for disinfection.However,the existing research has typically utilized MS2 or f2 bacteriophages to investigate the antimicrobial properties of nZVI,and the resistance difference between bacteriophages,which is important for the application of disinfection technologies,is not yet understood.Here,MS2 and PhiX174 containing RNA and DNA,respectively,were used as model viruses to investigate the resistances to nZVI.The bacteriophage inactivation mechanisms were also discussed using TEM images,protein,and nucleic acid analysis.The results showed that an initial concentration of 10^(6)PFU/mL of MS2 could be completely inactivated within 240 min by 40 mg/L nZVI at pH 7,whereas the complete inactivation of PhiX174 could not be achieved by extending the reaction time,increasing the nZVI dosage,or changing the dosing means.This indicates that the resistance of phage PhiX174 to nZVI was much stronger than that of MS2.TEM images indicated that the viral particle shape was distorted,and the capsid shell was ruptured by nZVI.The damage to viral surface proteins in both phages was examined by three-dimensional fluorescence spectrum and sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE).However,the nucleic acid analysis demonstrated that the nucleic acid of MS2,but not PhiX174,was destroyed.It indicated that bacteriophage inactivation was mainly attributed to the damage of nucleic acids. 展开更多
关键词 nanoscale zero-valent iron(nZVI) MS2 PhiΧ174 RESISTANCE INACTIVATION Pathogenic microorganisms
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