木薯羧甲基淀粉对Cu（Ⅱ）的吸附行为和机理研究

Adsorption Behavior and Mechanism of the Cassava Carboxymethyl Starch on Cu（Ⅱ）

摘要:

以机械活化60 min的木薯淀粉为原料，采用干法工艺合成羧甲基淀粉。研究了羧甲基淀粉对Cu（Ⅱ）的静态吸附行为和吸附热力学，吸附动力学性质，表征了产物结构，对吸附机理进行了探讨。结果表明，在考察条件下，羧甲基淀粉对Cu（Ⅱ）的吸附符合Freundlich方程和Langmuir方程；在303K、313K、323K三种温度下，羧甲基淀粉对Cu（Ⅱ）的吸附焓变△H、吸附自由能变△G、吸附熵变△S 均为负值；CMS60对Cu(Ⅱ)的吸附是以颗粒内扩散为控制步骤。吸附机理是物理吸附，离子交换和配位作用综合作用的结果。

Abstract:

The carboxymethyl starch was prepared by dry method using the cassava starch, mechanically activated for 60 min, as a starting material. The static adsorption behavior of the carboxymethyl starch , the adsorption thermodynamics and kinetics of the the carboxymethyl starch on Cu（Ⅱ）were investigated, meanwhile the product was characterized and the adsorption mechanism was stutied. The results show that the adsorption characteristic of carboxymethyl starcht on Cu（Ⅱ） is adapted to Freundlich and Langmuir adsorption isotherm equation. The adsorption thermodynamic parameters including enthalpy change △H, free energy △G change and entropy change △S were all negatived under the temperituer of 303K, 313K and 323K. The adsorption of the Cu（Ⅱ） on the carboxymethyl starch was an intraparticle diffusion process, and the adsorption mechanism including physical adsorption, ion-exchange and coordination.