摘要
采用表面印迹技术,以硅胶为载体、Cd(Ⅱ)为模板离子、γ-脲基丙基三甲氧基硅烷为偶联剂和功能单体、环氧氯丙烷为交联剂,合成了脲基功能化的镉离子表面印迹材料.用制备好的印迹材料为吸附剂进行静态吸附实验,考察了溶液的不同p H值、反应时间、温度和Cd(Ⅱ)的初始浓度等因素对镉离子吸附效果的影响.并用准一级动力学和准二级动力学对实验数据进行拟合,计算出相应的速率常数.结果表明,表面印迹材料对Cd(Ⅱ)的吸附是一个快速的过程,在20 min内即可达到吸附平衡,且准二级动力学方程(R2>0.99)能更好地描述其吸附动力学行为.吸附等温线符合Langmuir等温吸附模型,这表明了吸附过程是以单层吸附为主.在最佳的吸附条件下,Cr(Ⅱ)的吸附量可达到83 mg·g-1.此外吸附热力学研究表明该吸附过程是一个自发的、吸热过程.
Urea-functionalized cadmium ion imprinted polymer was synthesized by surface imprinting technique with Cd（ Ⅱ） as the template,silica gel as carrier,epichlorohydrin as the crosslinking agent,γ-ureidopropyltrimethoxysilane as coupling agent and functional monomer. The influence of pH value,time,temperature and Cd（ Ⅱ） initial concentration on the adsorption were investigated in static adsorption experiments. In addition,pseudo-first-order and pseudo-second-order models were used to illustrate the adsorption kinetic behavior, and the characteristic rate constants were presented,respectively. Results showed that the pseudo-second-order model（ R^2〉 0. 99） had the best agreement with the experimental data. Moreover,the adsorption was a fast process and the adsorption equilibrium was reached within 20 minutes. Langmuir adsorption isotherm model described the experimental data well,which indicated that the adsorption was mainly monolayer adsorption. The adsorption capacity reached 83 mg·g^-1 under the optimal conditions. Furthermore,the adsorption thermodynamics suggested that the adsorption process was spontaneous and endothermic.
出处
《环境化学》
CAS
CSCD
北大核心
2016年第4期793-799,共7页
Environmental Chemistry
基金
国家自然科学基金(21276174)
山西省基础研究计划项目(2013011040-1)资助~~
关键词
Cd(Ⅱ)
表面印迹
吸附动力学
吸附热力学
Cd（Ⅱ）
surface imprinting
adsorption kinetics
adsorption thermodynamics
