Co-adsorption and selective-adsorption of heavy metals and dyes from aqueous solution by bio-based humus/chitosan hydrogels  

作　　者：Rongping Chen Chenghao Gan Bingcai Cai Ruxue Liu Wenjie Xu Weize Yin Hongyi Li Lei Yu Qiang Yong 

机构地区：[1]College of Biology and the Environment,Nanjing Forestry University,Nanjing 210037,China [2]College of Chemical Engineering,Nanjing Forestry University,Nanjing 210037,China

出　　处：《Journal of Environmental Sciences》2024年第11期193-204,共12页环境科学学报（英文版）

基　　金：supported by the Project of Jiangsu industry university research cooperation(No.BY2021301).

摘　　要：An eco-friendly adsorbent was prepared by reverse suspension crosslinking method to remove multiple pollutants from aqueous solution.Both raw materials,derived from humus(HS)and chitosan(CS),are biodegradable and low-cost natural biopolymers.After combining HS with CS,the adsorption capacity was significantly improved due to compensation effects between the two components.HS/CS exhibited the features of amphoteric adsorption through pH adjustment,enabling it to adsorb not only anionic pollutants(Methyl Orange(MO)and Cr(VI)),but also cationic ones(Methylene Blue(MB)and Pb(II)).The adsorption capacities were approximately 242 mg/g,69 mg/g,188 mg/g and 57 mg/g for MO,Cr(VI),MB and Pb(II),respectively.HS/CS showed a slight preference for MO in MO/Cr(VI)co-adsorption system,whereas strong selectivity for MB over Pb(II)in MB/Pb(II)system under acidic condition(pH<3.0).This selective behavior would allow for potential applications in separating MB/Pb(II)effluents and selectively recycling Pb(II)in acidic environment.The isothermal and kinetic adsorption behaviors followed Langmuir model and pseudo-second-order model,respectively.The density functional theory(DFT)confirmed that the interaction between metal ions and adsorbents was primarily attributed to chelation and electrostatic adsorption,owing to nitric and oxygenic functional groups.Whereas,the adsorption mechanisms for dyes were involved in electrostatic attraction,H-bond andπ-πbond,due to available hydrogen,oxygen,nitrogen atoms and aromatic groups on the surface of adsorbent and adsorbates.The adsorbent could be efficiently regenerated and retained over 90%of its adsorption capacity after five cycles,which has a potential for practical applications in water treatment.

关 键 词：ADSORPTION Density functional theory(DFT) HUMUS Chitosan 

分 类 号：X703[环境科学与工程—环境工程]