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
Arsenic(As)detoxification in polluted soils by iron-based materials can be mediated by the endogenous soil organic matter(SOM),nevertheless the mechanisms remain unclear.Herein,endogenous SOM in a paddy soil was subst...Arsenic(As)detoxification in polluted soils by iron-based materials can be mediated by the endogenous soil organic matter(SOM),nevertheless the mechanisms remain unclear.Herein,endogenous SOM in a paddy soil was substantially removed to understand its roles on As immobilization by biochar-supported zero-valent iron(ZVI/BC).The results demonstrated that ZVI/BC application significantly decreased As bioavailability by 64.2%compared with the control soil under the anaerobic condition.XPS and HR-TEM suggested As immobilization by ZVI/BC mainly invoked the formation of ternary complexes(i.e.,As-Fe-SOM).However,SOM depletion compromised the efficacy of ZVI/BC for As immobilization by 289.8%.This is likely because SOM depletion increased the fulvic acid and OH−contents in soils.Besides,ZVI/BC increased the proportion of As(III)in available As fraction,but SOM depletion altered the mechanisms associated with As(V)reduction.That is,As(V)reduction resulted from the reductive capacity of ZVI in the pristine soil,but the As(V)-reducing bacteria contributed greater to As(V)reduction in the SOM-depleted soil.Additionally,SOM depletion boosted the abundances of Fe(III)-and As(V)-reducing bacteria such as Bacillus and Ammoniphilus in soils,which enhanced the dissimilatory arsenate reduction.Thus,this work highlighted the importance of SOM in the remediation of As-contaminated soils by ZVI/BC.展开更多
A series of new biochar-supported composite based on the combination of biochar and metallic nanoparticles(NPs)were produced through single-step pyrolysis of FeCl_3–Ti(OBu)_4 laden agar biomass under NH_3 environment...A series of new biochar-supported composite based on the combination of biochar and metallic nanoparticles(NPs)were produced through single-step pyrolysis of FeCl_3–Ti(OBu)_4 laden agar biomass under NH_3 environment.The physiochemical properties of composites were characterized thoroughly.It has found that heating temperature and N-doping through NH_3-ambiance pyrolysis significantly influence the visible-light sensitivity and bandgap energy of composites.The catalytic activities of composites were measured by degradation of Methylene Blue(MB)in the presence or absence of H_2O_2 and visible-light irradiation.Our best catalyst(N–TiO_2–Fe_3O_4-biochar)exhibits rapid and high MB removal competency(99.99%)via synergism of adsorption,photodegradation,and Fenton-like reaction.Continuous production of O_2U^-and UOH radicles performs MB degradation and mineralization,confirmed by scavenging experiments and degradation product analysis.The local trap state Ti^(3+),Fe_3O_4,and N-carbon of the catalyst acted as active sites.It has suggested that the Ti^(3+)and N-doped dense carbon layer improve charge separation and shuttle that prolonged photo-Fenton like reaction.Moreover,the catalyst is highly stable,collectible,and recyclable up to 5 cycles with high MB degradation efficiency.This work provides a new insight into the synthesis of highly visible-light sensitized biocharsupported photocatalyst through NH_3-ambiance pyrolysis of NPs-laden biomass.展开更多
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.
基金National Natural Science Foundation of China[Grant numbers 42277040,41977117,41977085]National Key Research and Development Program of China[Grant number 2021YFD1700800]+1 种基金Qing-Lan Project of Yangzhou University[2020]High-level Talent Support Plan of Yangzhou University[2019].
文摘Arsenic(As)detoxification in polluted soils by iron-based materials can be mediated by the endogenous soil organic matter(SOM),nevertheless the mechanisms remain unclear.Herein,endogenous SOM in a paddy soil was substantially removed to understand its roles on As immobilization by biochar-supported zero-valent iron(ZVI/BC).The results demonstrated that ZVI/BC application significantly decreased As bioavailability by 64.2%compared with the control soil under the anaerobic condition.XPS and HR-TEM suggested As immobilization by ZVI/BC mainly invoked the formation of ternary complexes(i.e.,As-Fe-SOM).However,SOM depletion compromised the efficacy of ZVI/BC for As immobilization by 289.8%.This is likely because SOM depletion increased the fulvic acid and OH−contents in soils.Besides,ZVI/BC increased the proportion of As(III)in available As fraction,but SOM depletion altered the mechanisms associated with As(V)reduction.That is,As(V)reduction resulted from the reductive capacity of ZVI in the pristine soil,but the As(V)-reducing bacteria contributed greater to As(V)reduction in the SOM-depleted soil.Additionally,SOM depletion boosted the abundances of Fe(III)-and As(V)-reducing bacteria such as Bacillus and Ammoniphilus in soils,which enhanced the dissimilatory arsenate reduction.Thus,this work highlighted the importance of SOM in the remediation of As-contaminated soils by ZVI/BC.
基金supported by the National Basic Research Program of China (973 Program, 2014CB238903)the National Natural Science Foundation of China (Nos. 41672144, 41173032, and 41373110)
文摘A series of new biochar-supported composite based on the combination of biochar and metallic nanoparticles(NPs)were produced through single-step pyrolysis of FeCl_3–Ti(OBu)_4 laden agar biomass under NH_3 environment.The physiochemical properties of composites were characterized thoroughly.It has found that heating temperature and N-doping through NH_3-ambiance pyrolysis significantly influence the visible-light sensitivity and bandgap energy of composites.The catalytic activities of composites were measured by degradation of Methylene Blue(MB)in the presence or absence of H_2O_2 and visible-light irradiation.Our best catalyst(N–TiO_2–Fe_3O_4-biochar)exhibits rapid and high MB removal competency(99.99%)via synergism of adsorption,photodegradation,and Fenton-like reaction.Continuous production of O_2U^-and UOH radicles performs MB degradation and mineralization,confirmed by scavenging experiments and degradation product analysis.The local trap state Ti^(3+),Fe_3O_4,and N-carbon of the catalyst acted as active sites.It has suggested that the Ti^(3+)and N-doped dense carbon layer improve charge separation and shuttle that prolonged photo-Fenton like reaction.Moreover,the catalyst is highly stable,collectible,and recyclable up to 5 cycles with high MB degradation efficiency.This work provides a new insight into the synthesis of highly visible-light sensitized biocharsupported photocatalyst through NH_3-ambiance pyrolysis of NPs-laden biomass.
