Polyethyleneimine(PEI)modified palygorskite(Pal)was used for the adsorption of Cr(VI)in aqueous solution.The absorbent was characterized by Fourier transform infrared spectroscopy(FT-IR)and thermogravimetric analysis(...Polyethyleneimine(PEI)modified palygorskite(Pal)was used for the adsorption of Cr(VI)in aqueous solution.The absorbent was characterized by Fourier transform infrared spectroscopy(FT-IR)and thermogravimetric analysis(TGA).Characterized results confirmed that the Pal has been successfully modified by PEI.The modification of PEI increased the Cr(VI)adsorption performance of the Pal by the adsorption combined reduction mechanism,and amino groups of the adsorbent play the main role in the enhanced Cr(VI)adsorption.The maximum adsorption capacity was 51.10 mg·g^-1 at pH4.0 and 25°C.The adsorption kinetics of Cr(VI)on the adsorbent conforms to the Langmuir isotherm model.The maximum adsorption occurs at pH3,and then the adsorption capacity of PEI-Pal was decreased with the increase of p H values.The adsorption kinetics of Cr(VI)on PEI-Pal was modeled with pseudo-second-order model.The addition of Cl^-,SO4^2-and PO4^3-reduced the Cr(VI)adsorption by competition with Cr(VI)for the active sites of PEI-Pal.The Cr(VI)saturated PEI-Pal can be regenerated in alkaline solution,and the adsorption capacity can still be maintained at 30.44 mg·g^-1 after 4 cycles.The results demonstrate that PEI-Pal can be used as a potential adsorbent of Cr(VI)in aqueous solutions.展开更多
Crop residue-based biochar(CRB)has shown great potential for removing trace elements(TEs)from aquatic matrices.Despite the increasing interest in this area,no review has focused specifically on the efficacy of CRB for...Crop residue-based biochar(CRB)has shown great potential for removing trace elements(TEs)from aquatic matrices.Despite the increasing interest in this area,no review has focused specifically on the efficacy of CRB for TEs removal in aquatic environments.This comprehensive review examines the global TEs water contamination status with an emphasis on their sources,compositional metrics for crop residue feedstock(proximate,ultimate,and lignocellulosic properties),and the potential use of CRB for TEs removal in aquatic media.It also evaluates the factors that affect the ability of CRB to remove TEs,such as feedstock type,production conditions,water pH,background electrolytes,water temperature,CRB/water ratio,and underlying pollutant sorption mechanisms.This review also discusses the practical applications of CRB in real water samples and engineering considerations for designing CRB with improved physicochemical properties,treatment efficiencies,and regeneration abilities.Additionally,the cost-benefit and economic assessment of CRB,challenges,and future research directions related to CRB are highlighted to promote research on this sustainable source of biochar.By elucidating the prospects of CRB as an adsorbent,this review emphasizes the need for continued research on its practical implications for environmentally relevant pollutant concentrations.展开更多
基金funded by the National Natural Science Foundation of China(21677092)the Scientific Research Program funded by Shaanxi Provincial Education Department(15JK1095)。
文摘Polyethyleneimine(PEI)modified palygorskite(Pal)was used for the adsorption of Cr(VI)in aqueous solution.The absorbent was characterized by Fourier transform infrared spectroscopy(FT-IR)and thermogravimetric analysis(TGA).Characterized results confirmed that the Pal has been successfully modified by PEI.The modification of PEI increased the Cr(VI)adsorption performance of the Pal by the adsorption combined reduction mechanism,and amino groups of the adsorbent play the main role in the enhanced Cr(VI)adsorption.The maximum adsorption capacity was 51.10 mg·g^-1 at pH4.0 and 25°C.The adsorption kinetics of Cr(VI)on the adsorbent conforms to the Langmuir isotherm model.The maximum adsorption occurs at pH3,and then the adsorption capacity of PEI-Pal was decreased with the increase of p H values.The adsorption kinetics of Cr(VI)on PEI-Pal was modeled with pseudo-second-order model.The addition of Cl^-,SO4^2-and PO4^3-reduced the Cr(VI)adsorption by competition with Cr(VI)for the active sites of PEI-Pal.The Cr(VI)saturated PEI-Pal can be regenerated in alkaline solution,and the adsorption capacity can still be maintained at 30.44 mg·g^-1 after 4 cycles.The results demonstrate that PEI-Pal can be used as a potential adsorbent of Cr(VI)in aqueous solutions.
基金financially supported by the National Key R&D Program of China (2017YFA0207202)the National Natural Science Foundation of China (52073230)+1 种基金the Joint Research Funds of Department of Science&Technology of Shaanxi Province and Northwestern Polytechnical University (2020GXLH-Z-013)the Fundamental Research Funds for the Central Universities。
基金supported by the National Natural Science Foundation of China(41,977,274,42,130,710)Shaanxi Province Science and Technology Innovation Team(2022TD-09)+1 种基金the Key Industrial Chain Project of Shaanxi Province(2019ZDLNY01-05-022022ZDLNY02-02).
文摘Crop residue-based biochar(CRB)has shown great potential for removing trace elements(TEs)from aquatic matrices.Despite the increasing interest in this area,no review has focused specifically on the efficacy of CRB for TEs removal in aquatic environments.This comprehensive review examines the global TEs water contamination status with an emphasis on their sources,compositional metrics for crop residue feedstock(proximate,ultimate,and lignocellulosic properties),and the potential use of CRB for TEs removal in aquatic media.It also evaluates the factors that affect the ability of CRB to remove TEs,such as feedstock type,production conditions,water pH,background electrolytes,water temperature,CRB/water ratio,and underlying pollutant sorption mechanisms.This review also discusses the practical applications of CRB in real water samples and engineering considerations for designing CRB with improved physicochemical properties,treatment efficiencies,and regeneration abilities.Additionally,the cost-benefit and economic assessment of CRB,challenges,and future research directions related to CRB are highlighted to promote research on this sustainable source of biochar.By elucidating the prospects of CRB as an adsorbent,this review emphasizes the need for continued research on its practical implications for environmentally relevant pollutant concentrations.
