Cu^(2+)和Ni^(2+)在磁性高岭土上的吸附动力学和热力学研究  

COMPETITIVE ADSORPTION KINETICS AND THERMODYNAMICS OF Cu^(2+) AND Ni^(2+) ON MAGNETIC KAOLIN

作　　者：黄明[1,2] 鲁秀国[1] 李绍峰[2] 冉治霖[3] HUANG Ming LU Xiuguo LI Shaofeng RAN Zhilin(School of Civil Engineering and Architecture, East China Jiaotong University Nanchang 330013, China Shenzhen Key Laboratory of Industrial Water Saving and Municipal Sewage Reclamation Technology, Shen Zhen Polytechnic, Shenzhen 518055, China Department of Transportation and Environment, Shenzhen Institute of Information Technology Shenzhen 518172, China)

机构地区：[1]华东交通大学土木建筑学院,南昌330013 [2]深圳职业技术学院深圳市工业节水及城市污水资源化技术重点实验室,深圳518055 [3]深圳信息职业技术学院交通与环境学院,深圳518172

出　　处：《离子交换与吸附》2017年第2期97-106,共10页Ion Exchange and Adsorption

基　　金：国家自然科学基金项目(51168013);国家科技支撑计划项目(2014BAC04B03)

摘　　要：通过Cu^(2+)或Ni^(2+)单一体系和竞争体系的吸附实验,研究了Cu^(2+)和Ni^(2+)在磁性高岭土上的竞争吸附动力学和热力学。实验结果表明,二级动力学方程和颗粒内扩散方程能较好地拟合Cu^(2+)和Ni^(2+)在磁性高岭土上的单一吸附和竞争吸附,吸附过程主要由化学吸附控制,吸附颗粒内扩散过程是该吸附速率的控制步骤,但不是唯一的速率控制步骤,吸附速率同时还受颗粒外扩散过程(如表面吸附和液膜扩散)的控制。Langmuir吸附等温方程能更好地拟合磁性高岭土对Cu^(2+)和Ni^(2+)的吸附,在单一体系和竞争体系中,磁性高岭土对Cu^(2+)和Ni^(2+)的吸附都是优惠吸附;在竞争体系中,磁性高岭土对Cu^(2+)和Ni^(2+)的吸附量均有所减弱,但Ni^(2+)的吸附量下降更明显,且对Cu^(2+)的吸附能力大于Ni^(2+)。热力学参数表明,Cu^(2+)和Ni^(2+)在磁性高岭土上的竞争吸附是自发、吸热和熵值增加过程,有竞争离子存在时会影响吸附热力学特性。Magnetic kaolin was used as sorbent for Cu2＋and Ni2＋ in single or competitive system. The adsorption kinetics and thermodynamics of competitive adsorption were investigated to obtain physico-chemical parameters based on different models. The results of adsorption experiments showed that the adsorption kinetics was abided by Pseudo-second-order equation and intra-particle diffusion model, the adsorption process was mainly controlled by chemical adsorption, and the adsorption rate was controlled not only by intra-particle diffusion, but also by extra-particle diffusion （for example the surface adsorption and film diffusion）. The adsorption isotherms of Cu2＋ and Ni2＋ on magnetic kaolin were fitted with Langmuir equations, and and the adsorption process was concluded to be a favorable adsorption in single or binary system. In competitive system, adsorption capacity of magnetic kaolin for Cu2＋and Ni2＋ decreased, but the adsorption capacity of Ni2＋ decreased more significantly than that of Cu2＋, and the adsorption stability of Cu2＋ on magnetic kaolin was better than that of Ni2＋. The thermodynamic parameters indicated that the adsorption of CuE＋ and Ni2＋ on magnetic kaolin was a spontaneously endothermic reaction with entropy increase, and the adsorption thermodynamic characteristics was influenced by competing ions.

关 键 词：CU^2+ NI^2+ 磁性高岭土 竞争吸附 动力学 热力学 

分 类 号：X703[环境科学与工程—环境工程]