蚯蚓粪吸附水中Cu2+的动力学和热力学分析

以蚯蚓粪为吸附剂，测定了Cu2+初始质量浓度、温度、pH、吸附时间对水中Cu2+吸附性能的影响，并对等温吸附特征、吸附动力学和热力学进行了系统分析。结果表明:在温度25℃、Cu2+初始质量浓度87.9～575.0 mg/L、蚯蚓粪用量0.25 g/10mL、振荡速率200 rpm、吸附时间12 h的条件下，吸附效率可达95.27%～98.07%；pH对吸附影响甚小；蚯蚓粪对溶液中Cu2+的吸附过程符合伪二级动力学模型；不同温度下吸附呈现相似的非线性吸附等温线，且Freundlich模型对吸附过程有良好的拟合；反应的吉布斯自由能?G0，表明吸附过程是自发进行的吸热反应。

Kinetic and Thermodynamic Analyses of Cu2+ Adsorption by Vermicompost

The study investigated the effects of the initial Cu2+ concentrations, temperature, pH and time on the adsorption of Cu2+ by vermicompost. The isothermal characterization, kinetics and thermodynamics of the adsorption process were also analyzed. The results show that the vermicompost has excellent adsorption performance to Cu2+ in water solution. Under the adsorption conditions of 25oC, initial Cu2+ concentrations of 87.925 to 574.95 mg/L, vermicompost dosage of 0.25 g/10 mL, oscillation rate of 200 rpm, and adsorption time of 12 h, the adsorption efficiency reached 95.27% to 98.07%. pH has little influence on the adsorption. The adsorption behaviors of Cu2+ on vermicompost conformed to pseudo second order kinetics equation. At different temperature, the adsorption process presents nonlinear adsorption isotherm, and fitted very well by Freundlich model. Gibbs free energy (?G) of the adsorption was smaller than 0, indicating a spontaneous endothermic reaction of Cu2+ on vermicompost.