花生壳吸附Cu^(2+)的动力学和热力学研究  

Research on the kinetics and isotherms for Cu^(2+) adsorption on peanut hull

作　　者：祝春水[1] 魏涛 陈文宾[1] 余成根 徐国想[1] 朱美红[1] 

机构地区：[1]淮海工学院化学工程学院,江苏连云港222005 [2]五环科技股份有限公司,湖北武汉430079 [3]开化县环境监测站,浙江开化324300

出　　处：《环境污染与防治》2008年第8期14-18,23,共6页Environmental Pollution & Control

基　　金：江苏省海洋生物技术重点建设实验室开放课题(No.2006HS020);淮海工学院自然科学基金资助项目(No.Z2006008)

摘　　要：采用平衡吸附法,研究了pH、时间及温度对花生壳吸附水溶液中Cu2+的影响。结果表明,pH显著影响花生壳对Cu2+的吸附,pH为3.00~5.00时,吸附效果最好;初始吸附过程非常快,30 min时即达到最大吸附量的97%左右,其动力学行为更好地符合Lagergren准二级反应动力学模型,随着温度增加,初始吸附速率和平衡吸附量增加。吸附过程的表观活化能(Ea)为17.02 kJ/mol,表明花生壳吸附水溶液中Cu2+是吸热的化学过程。吸附活化熵为负值,表明Cu2+从水溶液本体中溶解的自由状态到被吸附的状态是有序增加的过程。吸附活化焓呈正值,意味着升温有利于吸附。花生壳对Cu2+的吸附较好地符合Langmuir吸附等温线。吸附过程中吉布斯自由能变化呈负值,说明吸附过程为自发的过程。Removal of Cu^2＋ from aqueous solutions by sorption onto peanut hull was investigated. Batch adsorption studies were carried out as a function of pH, contact time and temperature. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH increased from 3.00 to 5.00 The process was very fast initially and the sorption capacity reached 97% of the maximum within 30 rain. The kinetics of the interactions showed better agreement with the Lagergren second order kinetics, and indicated that the initial sorption rate and capacity increased with increasing temperature. The activation energy of biosorption （Ea） was determined to be 17.02 kJ/mol using Arrhenius equation, suggesting that the adsorption was an endothermic reaction. The activation enthalpy and entropy derived from Eyring equation showed that it was a process with increasing degree of order when the free Cu^2＋ in the solution were fixed, and higher temperature was favorable for the adsorption. The adsorption data showed a good fit with Langmuir isotherm, and the maximum biosorption capacity was found to be 22. 016 7 mg （Cu^2＋ ）/g （peanut hull）. The free energy value （△G） calculated from Van＇t Hoff equation was negative,indicating that the Cu^2＋ adsorption was a spontaneous process.

关 键 词：花生壳 吸附CU^2+ 活化能 动力学 

分 类 号：X703[环境科学与工程—环境工程]