改性茶叶渣生物炭对水体中Cr(VI)的吸附性能研究

Adsorption of Cr(VI)from Water by Modified Tea Residue Biochar

利用茶叶渣制备原始生物炭TBC,并对其进行锌铁负载改性得到改性生物炭MBC,探究MBC吸附水溶液中Cr(VI)的吸附性能。SEM和XRD分析结果表明,MBC表面形貌结构复杂,且成功负载有化合物。FTIR结果表明改性提高了生物炭表面的官能团含量,增强了生物炭的吸附性能。XPS结果表明MBC对Cr(VI)的去除主要是以还原作用和螯合作用为主。对MBC进行了单因素实验、吸附动力学实验、等温吸附实验和热力学实验等,在pH值为2,Cr(VI)初始质量浓度为100 mg/L的条件下,MBC对Cr(VI)的最大吸附量能达到124.37 mg/g。MBC对Cr(VI)的吸附过程符合Langmuir等温吸附模型和准二级动力学模型,说明MBC对Cr(VI)的吸附原理是以单分子层的化学吸附为主,热力学结果表明MBC的吸附过程是自发的吸热反应。

In this paper,tea residue was used to prepare the original biochar TBC,and the modified biochar MBC was modified by zinc and iron loading,and the adsorption performance of MBC for Cr(VI)in aqueous solution was investigated.SEM and XRD analysis results show that the surface morphology of MBC is complex and successfully loaded with compounds.FTIR results showed that the modification increased the content of functional groups on the surface of biochar and enhanced the adsorption performance of biochar.XPS results showed that the removal of Cr(VI)by MBC was mainly through reduction and chelation.Single factor experiments,adsorption kinetics experiments,isothermal adsorption experiments and thermodynamic experiments were carried out on MBC.The maximum adsorption capacity of Cr(VI)on MBC was 124.37 mg/g under the condition of pH value 2 and initial concentration of Cr(VI)100 mg/L.The adsorption process of Cr(VI)on MBC was consistent with Langmuir isothermal adsorption model and quasi-second-order kinetic model,which indicated that the adsorption principle of Cr(VI)on MBC was based on monomolecular chemisorption.The thermodynamic results showed that the adsorption process of Cr(VI)on MBC was spontaneous endothermic reaction.