摘要
通过提纯的坡缕石黏土对水溶液中Cu^(2+)的静态吸附实验,考察了吸附过程的动力学特征,研究了吸附过程的动力学模型、表观活化能和活化热力学参数,并对吸附速率的控制进行了分析。结果表明:在实验条件下坡缕石黏土对水中的Cu^(2+)具有较快的吸附速率,60min可基本达到平衡;吸附过程能较好地符合Lagergren pseudo-second-order吸附动力学方程,速率常数k_2随温度的升高而增大,随Cu^(2+)初始浓度的增加而减小;吸附过程的表观活化能为18.82kJ/mol,是活化的化学吸附,活化焓为16.26kJ/mol,活化Gibbs自由能为75.40～79.38kJ/mol,活化熵为-198.50 J/(mol·K),活化为吸热过程,是缔合反应机制:吸附速率由液膜扩散和颗粒内扩散共同控制,低浓度时主要受液膜扩散控制,高浓度时颗粒内扩散的影响更为明显。
The adsorption kinetics characteristics of Cu^（2＋） in water on palygorskite based on the purification of palygorskite clay were studied through static adsorption experiments,with a discussion on the adsorption kinetics models,the apparent activation energy, activation thermodynamic parameters of adsorption and the rate-limiting step of adsorption.The results show that the adsorption proceeds rapidly and the equilibrium is reached after about 60min under the experimental conditions.The adsorption processes are found to follow Lagergren pseudo-second-order equation most effectively and the rate constant of pseudo-second-order equation increases with decreasing initial concentration and the rise of temperature.The apparent adsorption activation energy is 18.82kJ/mol and the adsorption belongs to active chemical adsorption.The adsorption activation enthalpy is 16.26 kJ/mol,activation Gibbs free energy varies in the range of 75.40-79.38 kJ/mol and the activation entropy of adsorption is-198.50 J/（mol·K）.The activation process is endothermic and it belongs to the association reaction mechanism.The adsorption rate is controlled by film diffusion and intra -particle diffusion simultaneously through the entire adsorption period.The film diffusion plays an important role at low initial concentration and the effect of intra-particle diffusion is more obvious at high initial concentration.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2010年第11期2138-2142,共5页
Journal of The Chinese Ceramic Society
基金
甘肃省自然科学研究基金计划(0803RJZA107)资助项目
关键词
坡缕石黏土
吸附
铜离子
吸附动力学
palygorskite clay
adsorption
copper ion
adsorption kinetics
