基于SI-ATRP技术制备聚丙烯酰胺树脂及研究其对2,4-二氯苯氧乙酸的吸附性能

Polyacrylamide Resin Preparation Based on SIATRP and Adsorption Property Research of the Resin to 2,4-dichlorophenoxyacetic Acid

本试验以氯甲基化交联聚苯乙烯树脂(CMCPS)为载体和大分子引发剂,溴化亚铜/2,2'-联吡啶为催化剂体系,采用了表面引发原子转移自由基聚合技术(SI-ATRP),使丙烯酰胺接枝到CMCPS树脂表面,制得了新型的聚丙烯酰胺树脂(PAM-CMCPS),并且用元素分析和扫描电镜对其进行了表征。考察了该树脂对2,4-二氯苯氧乙酸的吸附性能、动力学和热力学参数。试验结果表明:该树脂对2,4-二氯苯氧乙酸的吸附量随溶液初始浓度和温度的升高而增加,当初始浓度为8 mmol/L时吸附效果最佳,树脂的静态饱和吸附容量为111.01 mg/g,Langmuir和Freundlich方程都能呈现良好的拟合度。热力学平衡方程计算得ΔG<0,ΔH=268.23 k J/mol,ΔS>0,表明该吸附过程是一个自发、吸热、熵增加的过程。

Polyacrylamide resin was synthesized via surface- initiated atom transfer radical polymerization （SI-ATRP） method. Acrylic amide （AM） was grafted onto the surface of the chloromethyl polystyrene resin by SI-ATRP in the CuBr/2,2＆#39;-bipyridine （Bpy） system as catalyst. The compositions of polyacrylamide resin have been determined by means of elementary analysis, and the surface morphology of resin has been observed by scanning electron microscopy （SEM）. And the adsorption properties, parameters of kinetics and the thermodynamics of the resin have been evaluated in details, respectively. As the results, Adsorption capacity of 2,4-dichlorophenoxyacetic acid （2,4-D） increases with the increasing of initial concentrations of solution and temperature, and its highest adsorption capacity was obtained with solution concentration of 8 mmol/L, and the static saturation adsorption capacity of resin was 111.01 mg/g. Adsorption isotherm at room temperature has been determined and modeled with Langmuir and Freundlich equations. The thermodynamic equilibrium functions have been calculated to be△G＆lt;0,△H =268.23 kJ/mol,ΔS＆gt;0, hence, the adsorption is spontaneous, endothermic and entropy increasing.