Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第21卷    第11期    总第152期    2011年11月

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文章编号:1004-0609(2011)11-2971-07
纳米TiO2对镉(Ⅱ)的吸附性能
刘雪岩1, 杨丽君1, 金燕利2, 张 蕾1, 徐天赐1, 李 娜1

(1. 辽宁大学 化学学院,沈阳 110036;2. 海军装备部 驻沈阳军事代表局,沈阳 110031)

摘 要: 通过吸附实验研究纳米TiO2对Cd(Ⅱ)的吸附行为,考察溶液的pH值、吸附时间和温度等因素对吸附的影响。结果表明:在pH为 4~7范围内,纳米TiO2对Cd(Ⅱ)的吸附率均超过97%,吸附于纳米TiO2上的Cd(Ⅱ)可用7.0 mL 0.1 mol/L HCl于70 ℃恒温水浴中定量洗脱;该吸附过程符合准二级反应动力学模型,其反应的表观活化能为3.16 kJ/mol,粒子内部扩散过程是其吸附过程的速率控制步骤,但液相边界层向粒子表面的扩散过程亦不能忽略;等温吸附数据与Langmuir和D-R等温模型拟合较好。在室温下,纳米TiO2对Cd(Ⅱ)的饱和吸附容量为6.34 mg/g,平均吸附能为11.54 kJ/mol;吸附反应的焓变和熵变均为正值,自由能为负值,说明该吸附过程为自发的吸热过程。

 

关键字: Cd(Ⅱ);纳米TiO2;吸附;动力学;热力学

Adsorption properties of nano-TiO2 for Cd(Ⅱ)
LIU Xue-yan1, YANG Li-jun1, JIN Yan-li2, ZHANG Lei1, XU Tian-ci1, LI Na1

1. College of Chemistry, Liaoning University, Shenyang 110036, China;
2. Military Representative Bureau in Shenyang, Navy Equipment Department, Shenyang 110031, China

Abstract:The titanium dioxide nanoparticles were employed for the sorption of Cd(Ⅱ) ions from aqueous solution. The process was studied by varying the pH, sorption time and temperature. The adsorption rate of Cd(II) by the sorbent is over 97% at pH of 4−7. The adsorbed Cd(Ⅱ) are desorbed by 7.0 mL 0.1 mol/L HCl in constant temperature water bath at 70 ℃. The kinetic experimental data properly correlate with the second-order kinetic model. The apparent activation energy is 3.16 kJ/mol. The overall rate process is mainly controlled by the intraparticle diffusion, while the boundary layer resistance cannot be ignored. The sorption data can be well interpreted by the Langmuir and D-R type sorption isotherms. At room temperature, the static saturated adsorption capacity is 6.34 mg/g, and the average sorption energy is 11.54 kJ/mol. The thermodynamic parameters: ∆HΘ>0, ∆SΘ>0 and ∆GΘ<0, which indicates a spontaneous and decalescence adsorption process.

 

Key words: Cd(Ⅱ); nano-TiO2; adsorption; kinetics; thermodynamics

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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