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 cm3/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(R2≥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).

Feng Chen;Shihao Guo;Yihao Wang;Lulu Ma;Bing Li;Zhimin Song;Lei Huang;Wen Zhang

School of Environmental and Biological Engineering,Henan University of Engineering,Zhengzhou 451191,China;School of Environmental Science and Engineering,Guangzhou University,Guangzhou 510006,China;Guangzhou University-Link?ping University Research Center on Urban Sustainable Development,Guangzhou University,Guangzhou 510006,China;John A.Reif,Jr.Department of Civil and Environmental Engineering,New Jersey Institute of Technology,Newark,NJ 07102,USA

环境科学与工程前沿

[1]Feng Chen;Shihao Guo;Yihao Wang;Lulu Ma;Bing Li;Zhimin Song;Lei Huang;Wen Zhang-.Concurrent adsorption and reduction of chromium(Ⅵ)to chromium(Ⅲ)using nitrogen-doped porous carbon adsorbent derived from loofah sponge)[J].环境科学与工程前沿,2022(05):27-37

loofah,318K,endothermal

Concurrent,adsorption,reduction,chromium,using,nitrogen,doped,derived,from,sponge,To,develop,highly,effective,adsorbents,removal,biomass,NHPC,was,synthesized,via,direct,carbonation,followed,by,alkali,activation,doping,modification,possessed,hierarchical,micro,mesoporous,lamellar,structure,containing,functional,groups,specific,surface,area,pore,volume,cm3,exhibited,higher,affinity,than,without,pristine,LSC,did,influence,process,parameters,including,dosage,temperature,concentration,were,evaluated,kinetics,matched,pseudo,second,order,model,isotherm,fitted,Langmuir,which,indicated,maximum,capacities,298K,308K,respectively,analysis,also,that,spontaneous,entropy,increasing,potentially,involved,mixed,reductive,adsorbed,mechanism,Furthermore,computational,chemistry,calculations,revealed,energy,between,eV,lower,suggesting,could,greatly,enhance,interaction

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