Abstract

In order to effectively treat wastewater containing heavy metal ions and form comprehensive utilization of resources, we prepared a novel diatom-based Cd(II) ion-imprinted polymer (Dt-IIP) based on surface imprinting technique by using the diatomite as a matrix material and 3-mercaptopropyltrimethoxysilane (MPS) as a functional monomer. Through SEM, XRD, XPS, TGA, FTIR and Elemental analysis to confirm the structural transformation and composition changes of the materials during the preparation process. The optimal pH, kinetics, adsorption isotherms and thermodynamics of ion-imprinted polymer for Cd(II) adsorption process were investigated. The experimental results showed that the optimal pH value of the adsorption process was 6.0 and the theoretical maximum adsorption capacity was 5.5025 mg g⁻¹. The adsorption reaction conformed to the Langmuir isotherm model and kinetic data was more suitable to be explained by pseudo-second-order model. Furthermore, the thermodynamic adsorption process was spontaneous and endothermic. The analysis of XPS and FTIR revealed that the adsorption of Cd(II) ions was achieved mainly through the interaction of Cd(II) ions with thiol groups. Compared with non-imprinted polymer (Dt-NIP), Dt-IIP possessed a higher adsorption capacity and superior selectivity for target ions. In addition, test of regeneration showed that the Dt-IIP was reusable and stable.

摘要

为有效处理含重金属离子废水，形成资源综合利用，以硅藻土为基体材料，基于表面印迹技术制备了新型硅藻基Cd(II)离子印迹聚合物（Dt-IIP）。和 3-巯基丙基三甲氧基硅烷 (MPS) 作为功能单体。通过SEM、XRD、XPS、TGA、FTIR和元素分析，确认材料在制备过程中的结构转变和成分变化。研究了离子印迹聚合物对Cd(II)吸附过程的最佳pH、动力学、吸附等温线和热力学。实验结果表明，吸附过程的最适pH值为6.0，理论最大吸附容量为5.5025 mg g ^-1. 吸附反应符合朗缪尔等温线模型，动力学数据更适合用准二级模型解释。此外，热力学吸附过程是自发的和吸热的。XPS和FTIR分析表明，Cd(II)离子的吸附主要是通过Cd(II)离子与硫醇基团的相互作用来实现的。与非印迹聚合物（Dt-NIP）相比，Dt-IIP对目标离子具有更高的吸附容量和优异的选择性。此外，再生试验表明Dt-IIP可重复使用且稳定。