改性玉米秸秆吸附Cu^(2+)的动力学和热力学

Kinetics and thermodynamics for Cu^(2+) adsorption by modified corn straw

本研究用ZnCl2作为活化剂,使用功率640 W的微波照射4 min的方法制备改性玉米秸秆。考察投加量、pH、吸附时间对吸附性能的影响,并对等温吸附特征、吸附动力学和热力学进行了系统研究。结果表明:投加量为0.2 g,pH为6,改性玉米秸秆对Cu2+具有很好的吸附效果,吸附在8 h后达到平衡。该吸附过程符合Langmuir及Freundlich等温吸附模型和准二级动力学方程,其反应的吉布斯自由能△G<0,为自发反应过程。

A sort of modified corn straw by using ZnCl2 as activating agent was used as adsorbent for removal of Cu^2 ＋from aqueous solution. The influences of dosage, pH, adsorption time, initial concentration and reaction temperature were investigated on adsorption properties through dynamic tests. Adsorption isotherm models, thermodynamics models and kinetics models of the adsorption process between modified corn straw and Cu^2＋ were systematically studied. The results showed that the modified corn straw had maximum adsorption efficiencies when the dosage was 0.2 g, the pH was 6. The adsorption reached equilibrium after 8 hours. The adsorption process can be fitted very well by Langmuir and Freundlich adsorption isotherms and the quasi-second order kinetics equation. Gibbs free energy was less than zero. which showed that reaction process was spontaneous.