茶叶渣吸附水中砷的动力学与热力学研究  

Arsenic Adsorption from Aqueous Solution by Waste Tea:Kinetic and Thermodynamics Studies

作　　者：吴云海[1] 谢正威[1] 胡玥[1] 胡忻[2] 

机构地区：[1]河海大学环境科学与工程学院,南京210098 [2]南京大学现代分析中心,南京210093

出　　处：《湖北农业科学》2010年第4期859-862,共4页Hubei Agricultural Sciences

基　　金：国家自然科学基金项目(20607010)

摘　　要：研究了茶叶渣对水中三价砷离子(As3+)的去除效果,考察了溶液的pH值、反应时间和温度对吸附平衡的影响。结果表明,当pH值为7.0,吸附时间为150min时,As3+的去除率最高;当温度由20℃升至40℃时,茶叶渣对0.2mg/L的As3+的最大吸附率由33.2%升至37.8%,表明该吸附过程为吸热反应。茶叶渣对As3+的吸附机理符合Langmuir和Freundlich等温线方程;通过对动力学参数的计算表明,准二级动力学模型比准一级动力学模型能更好地描述茶叶渣对As3+的吸附动力学行为;不同温度下热力学的吉布斯自由能△G°,熵变△H°和焓变△S°的值表明该吸附过程为自发吸热反应。This study is to assess the uptake of tervalent arsenic from aqueous solutions onto waste tea; The variables （pH, contact time and temperature） affecting process was investigated in order to found optimum biosorption conditions. The results showed that the maximum adsorption was noted at pH 7.0 and attained at 150 min; the maximum efficiency increased from 33.2% to 37.8% with an increase in temperature from 20 to 40℃ at 0.2 mg / L of initial As3＋ ion concentration. The adsorption of As3＋ ions increased with increasing temperature indicating endothermic of the adsorption process. The adsorption data follow the Langmuir model and the Freundlich model; Kinetic parameters were evaluated and found that Pseudo-second-order rate kinetic model showed the better correlation at different temperature; Various thermodynamic parameters, such as △G°, △H° and △S°have been calculated at different temperature. It indicated that the adsorption process was spontaneous and endothermic.

关 键 词：茶渣 砷 吸附 动力学 热力学 

分 类 号：O643.1[理学—物理化学] O643.2[理学—化学]