碳羟基磷灰石除废水中铬(VI)吸附动力学和热力学研究  

STUDY ON KINETICS AND THERMODYNAMICS FOR REMOVAL OF CHROMIUM(VI) FROM AQUEOUS SOLUTION BY CARBONATE HYDROXYAPATITE

作　　者：唐文清[1] 曾荣英[1] 冯泳兰[1] 许金生[1] 李小明[2] 曾光明[2] 

机构地区：[1]衡阳师范学院化学与材料科学系,衡阳421008 [2]湖南大学环境科学与工程学院,长沙410082

出　　处：《离子交换与吸附》2009年第1期9-16,共8页Ion Exchange and Adsorption

基　　金：国家高技术研究发展计划(2004AA649370);国家高技术研究发展计划(2004AA649370);国家杰出青年科学基金(50425927,50225926);湖南省自然科学基金(07JJ6013);湖南省重点学科建设项目资助.

摘　　要：利用废弃蛋壳合成碳羟基磷灰石(CHAP)对含铬(VI)离子废水进行吸附实验研究,考查了溶液的pH值、吸附时间和温度对吸附平衡的影响,并探讨了吸附动力学和热力学行为。结果表明:常温下,吸附时间为30min、pH=3.0、5g/LCHAP对50mg/L的铬(VI)离子的吸附率达到98.3%以上,CHAP对铬(VI)离子的吸附机理符合Langmuir和Freundlich方程;准二级动力学模型比准一级动力学模型能更好地描述CHAP对含铬(VI)离子吸附动力学行为;不同温度下的吸附热力学的吉布斯自由能以及熵变和焓变显示该吸附过程为自发吸热反应。Adsorption equilibrium, Kinetics and thermodynamics of chromium（Ⅵ） ions onto carbonate hydroxylapatite （CHAP） synthesized by using waste eggshell as raw material were studied in a batch system with respect to temperature and pH and contact time. The results showed that the removal efficiency of chromium（Ⅵ） by CHAP could reach 98.3%, when the initial chromium（Ⅵ） concentration 50mg/L and the liquid/solid ratio was 5g/L and pH was 3.0 and adsorption period is 60rain at room temperatures. The equilibrium sorption data for single metal systems at room temperature could be described by the Langmuir and Freundlich isotherm models. The second-order kinetic model provided the better correlation of the used experimental data compared to the first-order kinetic model. The paper discussed the thermodynamic parameters of the adsorption （the Gibbs free energy, entropy and enthalpy） at different temperatures. The results demonstrated that the adsorption process was spontaneous and endothermic.

关 键 词：碳羟基磷灰石 44b(Ⅵ) 吸附 动力学 热力学 

分 类 号：X703.1[环境科学与工程—环境工程] TU991.2[建筑科学—市政工程]