阴离子型聚丙烯酰胺在离子交换膜上的吸附规律

研究了阴离子交换膜对阴离子型聚丙烯酰胺的吸附规律和影响因素.采用静态吸附的方法,测定了不同温度、不同浓度的阴离子型部分水解聚丙烯酰胺(HPAM)溶液在阴离子交换膜上的吸附量、吸附平衡时间,考察了初始HPAM溶液浓度、pH值以及溶液中其他离子浓度对其在离子交换膜上吸附的影响,目的是阐明阴离子交换膜对HPAM分子的吸附动力学过程、探讨各影响因素对吸附过程的影响.结果表明,阴离子型部分水解聚丙烯酰胺在阴离子交换膜上有明显的吸附作用,但在阳离子交换膜上吸附量几乎为0;阴离子交换膜对聚合物的吸附平衡时间随聚合物溶液初始浓度的增大而延长,且不同浓度、不同温度下的吸附过程动力学特征都能很好地遵循准二级动力学模型;303、308和313 K温度下,阴离子交换膜对聚合物的等温吸附可用Freundlich等温吸附模型很好地拟合,相关系数R2均达到0.99以上,温度越高,吸附量越大;聚合物溶液pH值和离子浓度对吸附效果有显著影响:pH=6时,吸附量达到最大值;吸附量随着离子浓度的增加而增大.

Adsorption of Anionic Polyacrylamide on the Surface of Ion Exchange Membranes

Regular pattern and impact factors of adsorption of partly hydrolysis of anionic polyacrylamide (HPAM) on the surface of ion exchange membrane were studied. Static adsorption experiments were carried out to measure the adsorption capacity and time to absorption equilibrium when HPAM was adsorbed on the surface of ion exchange membrane under different temperatures and HPAM concentrations. Effects of the initial HPAM concentrations, pH value, and ion concentrations in the HPAM solution, on the adsorption were also studied. The objectives of this study were to illuminate the adsorption kinetics of HPAM on the ion exchange membrane and to investigate the influences of some impact factors on the adsorption. Results showed that anion exchange membranes had a strong affinity adsorption for HPAM, but the adsorption capacity of cation exchange membranes was almost none. The adsorption equilibrium time of HPAM onto anion exchange membranes was increased with the increasing of initial concentration of HPAM. The adsorption kinetics could be described by the pseudo-second-order kinetics model under different initial concentrations and temperatures. Under different temperatures of 303, 308 and 313 K, the process of isothermal adsorption of HPAM onto anion exchange membranes could be fitted well by Freundlich equations with a high correlation coefficient R² (>0.99). Increasing of temperature could be able to enhance the process of adsorption. The pH value and ion concentrations of HPAM solution affected significantly on the adsorption. When pH is 6, the adsorption capacity reached the maximum value. The adsorption capacity was also increased with the increasing of ion concentrations.