To develop highly effective adsorbents for chromium removal,a nitrogen-doped biomass-derived carbon(NHPC)was synthesized via direct carbonation of loofah sponge followed by alkali activation and doping modification.NH...To develop highly effective adsorbents for chromium removal,a nitrogen-doped biomass-derived carbon(NHPC)was synthesized via direct carbonation of loofah sponge followed by alkali activation and doping modification.NHPC possessed a hierarchical micro-/mesoporous lamellar structure with nitrogen-containing functional groups(1.33 at%),specific surface area(1792.47 m2/g),and pore volume(1.18 cm^(3)/g).NHPC exhibited a higher Cr(Ⅵ)adsorption affinity than the HPC(without nitrogen doping)or the pristine loofah sponge carbon(LSC)did.The influence of process parameters,including pH,dosage,time,temperature,and Cr(Ⅵ)concentration,on Cr(Ⅵ)adsorption by NHPC were evaluated.The Cr(Ⅵ)adsorption kinetics matched with the pseudo-second-order model(R^(2)≥0.9983).The Cr(Ⅵ)adsorption isotherm was fitted with the Langmuir isotherm model,which indicated the maximum Cr(Ⅵ)adsorption capacities:227.27,238.10,and 285.71 mg/g at 298K,308K,and 318K,respectively.The model analysis also indicated that adsorption of Cr(Ⅵ)on NHPC was a spontaneous,endothermal,and entropy-increasing process.The Cr(Ⅵ)adsorption process potentially involved mixed reductive and adsorbed mechanism.Furthermore,computational chemistry calculations revealed that the adsorption energy between NHPC and Cr(VI)(-0.84 eV)was lower than that of HPC(-0.51 eV),suggesting that nitrogen doping could greatly enhance the interaction between NHPC and Cr(VI).展开更多
基金funded by the National Natural Science Foundation of China(Grant No.41872169)the Project of Education Department of Henan Province(No.21A610002)the Innovation and entrepreneurship training plan for college students of Henan Province in 2020(No.S202011517004)。
文摘To develop highly effective adsorbents for chromium removal,a nitrogen-doped biomass-derived carbon(NHPC)was synthesized via direct carbonation of loofah sponge followed by alkali activation and doping modification.NHPC possessed a hierarchical micro-/mesoporous lamellar structure with nitrogen-containing functional groups(1.33 at%),specific surface area(1792.47 m2/g),and pore volume(1.18 cm^(3)/g).NHPC exhibited a higher Cr(Ⅵ)adsorption affinity than the HPC(without nitrogen doping)or the pristine loofah sponge carbon(LSC)did.The influence of process parameters,including pH,dosage,time,temperature,and Cr(Ⅵ)concentration,on Cr(Ⅵ)adsorption by NHPC were evaluated.The Cr(Ⅵ)adsorption kinetics matched with the pseudo-second-order model(R^(2)≥0.9983).The Cr(Ⅵ)adsorption isotherm was fitted with the Langmuir isotherm model,which indicated the maximum Cr(Ⅵ)adsorption capacities:227.27,238.10,and 285.71 mg/g at 298K,308K,and 318K,respectively.The model analysis also indicated that adsorption of Cr(Ⅵ)on NHPC was a spontaneous,endothermal,and entropy-increasing process.The Cr(Ⅵ)adsorption process potentially involved mixed reductive and adsorbed mechanism.Furthermore,computational chemistry calculations revealed that the adsorption energy between NHPC and Cr(VI)(-0.84 eV)was lower than that of HPC(-0.51 eV),suggesting that nitrogen doping could greatly enhance the interaction between NHPC and Cr(VI).
