The capability of traditional ligand in countering rapid passivation on nanoscale zero-valent iron(nZVI)surface is inadequate,and the precise electron transfer mechanism remains elusive.In this study,we reported that ...The capability of traditional ligand in countering rapid passivation on nanoscale zero-valent iron(nZVI)surface is inadequate,and the precise electron transfer mechanism remains elusive.In this study,we reported that myo-inositol hexakisphosphate(IHP),a redox-inactive organophosphorus in soil,could highly enhance Cr(VI)reduction and immobilization in comparison with typical ligands(TPP,EDTA,oxalate and phosphate).And the effects of IHP concentration,Cr(VI)concentration and initial pH were systematically investigated.Cr Kedge XANES and XPS analysis revealed that Cr(III)was the exclusive form in solid products regardless of IHP existence.Results of ATR-FTIR and FESEM inferred that IHP was adsorbed on nZVI surface via inner-sphere complexation,thus averting encapsulation of[Fe,Cr](OH)_(3)coprecipitate and impeding solid particles agglomeration.Additionally,IHP expedited the production of surface-bound Fe(II),primarily attributable to the interaction between nZVI and oxygen.These surface-bound Fe(II)species played a pivotal role in Cr(VI)reduction.Electrochemical analysis unveiled that IHP lowered redox potential of Fe(III)/Fe(II),thereby facilitating reaction between Fe(II)and Cr(VI),whereas inhibited direct electron transfer from nZVI core to Cr(VI).Our findings proposed a novel potential ligand for alleviating nZVI passivation in Cr(VI)removal and deepened our understanding in the process of electron transfer.展开更多
A biochar-supported green nZVI(G-nZVI@MKB)composite was synthesized using mango kernel waste with“dual identity”as reductant and biomass of biochar.The G-nZVI@MKB with a Fe/C mass ratio of 2.0(G-nZVI@MKB2)was determ...A biochar-supported green nZVI(G-nZVI@MKB)composite was synthesized using mango kernel waste with“dual identity”as reductant and biomass of biochar.The G-nZVI@MKB with a Fe/C mass ratio of 2.0(G-nZVI@MKB2)was determined as the most favorable composite for hexavalent chromium(Cr(VI))removal.Distinct influencing parameters were discussed,and 99.0%of Cr(VI)removal occurred within 360 min under these optimized parameters.Pseudo-second order kinetic model and intra-particle diffusion model well depicted Cr(VI)removal process.The XRD,FTIR,SEM,and XPS analyses verified the key roles of G-nZVI and functional groups,as well as the primary removal mechanisms involving electrostatic attraction,reduction,and complexation.G-nZVI@MKB2 exhibited good stability and reusability with only a 16.4%decline in Cr(VI)removal after five cycles.This study offered evidence that mango kernel could be recycled as a beneficial resource to synthesize green nZVI-loaded biochar composite for efficient Cr(VI)elimination from water.展开更多
采用改进的两步法在原位基础上合成了以纳米零价铁(nano Zero Valent Iron,nZVI)为核芯的核壳型介孔二氧化硅(nZVI@mesoSiO_2).同时,通过简单地调控铁源用量得到具有单一nZVI核芯和不同壳层厚度的核壳型纳米复合材料.结果发现,铁源用量...采用改进的两步法在原位基础上合成了以纳米零价铁(nano Zero Valent Iron,nZVI)为核芯的核壳型介孔二氧化硅(nZVI@mesoSiO_2).同时,通过简单地调控铁源用量得到具有单一nZVI核芯和不同壳层厚度的核壳型纳米复合材料.结果发现,铁源用量的增加会导致核芯尺寸减小、壳层厚度增加及颗粒比表面积下降.当铁源用量为2.78 g时,得到的nZVI@mesoSiO_2不仅具有较高的比表面积和单一且均匀的孔径分布,而且对2,4,6-三氯苯酚(2,4,6-Trichlorophenol, 2,4,6-TCP)的去除表现出很高的性能.影响因素实验表明,材料的最佳投加量为1.0 g·L^(-1),体系适宜初始pH为5.0,污染物初始浓度升高会导致去除效果下降,并且反应体系内乙二胺四乙酸(EDTA)的存在可以提高2,4,6-TCP的去除率.材料的重复利用实验结果表明,经过多次循环反应后会导致材料nZVI核芯的失活和孔道的堵塞.本研究不仅为制备可控壳层厚度的核壳型介孔材料提供了理论指导,而且为进一步改性合成对2,4,6-TP具有高选择性的复合材料提供了依据.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42030709 and 42377303)the National Key Research and Development Program of China(No.2020YFC1806803).
文摘The capability of traditional ligand in countering rapid passivation on nanoscale zero-valent iron(nZVI)surface is inadequate,and the precise electron transfer mechanism remains elusive.In this study,we reported that myo-inositol hexakisphosphate(IHP),a redox-inactive organophosphorus in soil,could highly enhance Cr(VI)reduction and immobilization in comparison with typical ligands(TPP,EDTA,oxalate and phosphate).And the effects of IHP concentration,Cr(VI)concentration and initial pH were systematically investigated.Cr Kedge XANES and XPS analysis revealed that Cr(III)was the exclusive form in solid products regardless of IHP existence.Results of ATR-FTIR and FESEM inferred that IHP was adsorbed on nZVI surface via inner-sphere complexation,thus averting encapsulation of[Fe,Cr](OH)_(3)coprecipitate and impeding solid particles agglomeration.Additionally,IHP expedited the production of surface-bound Fe(II),primarily attributable to the interaction between nZVI and oxygen.These surface-bound Fe(II)species played a pivotal role in Cr(VI)reduction.Electrochemical analysis unveiled that IHP lowered redox potential of Fe(III)/Fe(II),thereby facilitating reaction between Fe(II)and Cr(VI),whereas inhibited direct electron transfer from nZVI core to Cr(VI).Our findings proposed a novel potential ligand for alleviating nZVI passivation in Cr(VI)removal and deepened our understanding in the process of electron transfer.
基金Projects(42077185,U22A20591)supported by the National Natural Science Foundation of China+5 种基金Projects(2022JDJQ0010,2022ZYD0040)supported by the Sichuan Science and Technology Program for Distinguished Young Scholars,ChinaProject(2020YFC1808300)supported by the National Key Research and Development Program of ChinaProject(SKLGP2020Z002)supported by the Research Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,China。
基金supported by the National Natural Science Foundation of China(51808253)the Science and Technology Planning Project of Jilin Province(20220508008RC)+1 种基金Science and Technology Project of Jilin Provincial Education Department(JJKH20220295KJ and JJKH20210272KJ)the Science and Technology Projects of the Ministry of Housing and Urban-Rural Development(2018-K6-003).
文摘A biochar-supported green nZVI(G-nZVI@MKB)composite was synthesized using mango kernel waste with“dual identity”as reductant and biomass of biochar.The G-nZVI@MKB with a Fe/C mass ratio of 2.0(G-nZVI@MKB2)was determined as the most favorable composite for hexavalent chromium(Cr(VI))removal.Distinct influencing parameters were discussed,and 99.0%of Cr(VI)removal occurred within 360 min under these optimized parameters.Pseudo-second order kinetic model and intra-particle diffusion model well depicted Cr(VI)removal process.The XRD,FTIR,SEM,and XPS analyses verified the key roles of G-nZVI and functional groups,as well as the primary removal mechanisms involving electrostatic attraction,reduction,and complexation.G-nZVI@MKB2 exhibited good stability and reusability with only a 16.4%decline in Cr(VI)removal after five cycles.This study offered evidence that mango kernel could be recycled as a beneficial resource to synthesize green nZVI-loaded biochar composite for efficient Cr(VI)elimination from water.
