半互穿网络法制备聚偏氟乙烯复合超滤膜

Preparation of PVDF composite ultrafiltration membrane by semi-IPN method

利用半互穿网络法制备聚偏氟乙烯(PVDF)复合超滤膜,根据膜性能参数及扫描电子显微镜(SEM)结构分析确定,聚乙烯醇(PVA)与戊二醛(GD)发生缩醛化反应构建PVA/PVDF半互穿网络结构的最佳条件为,铸膜液中聚乙烯醇的添加量为4.0%(质量分数)、戊二醛与聚乙烯醇加入量的比率为0.5,筛选出的PVDF/PVA/PVP/GD/NMP=16/4/3/2/75配方制备的半互穿网络结构复合膜性能最佳,纯水通量为612.3L/(m^2.h),接触角48.3°,BSA截留率98.7%,爆破压力1.0MPa,BSA吸附量45.3μg/cm^2,使用X射线光电子能谱仪(XPS)、红外分析测试仪(FTIR)等对制备的膜组成及结构进行了表征,用于处理实际石化废水运行一个月后,水通量为144.4L/(m^2·h),COD去除率为80.4%,浊度去除率为97.2%,与未含这种结构的配方制备的PVDF膜性能参数相比,PVA/PVDF半互穿网络复合膜的水通量增大,亲水性能增强,抗污染、抗反洗能力加强,膜的综合性能明显提高。

The polyvinylidene fluoride(PVDF)composite ultrafiltration membrane was prepared using semi-interpenetrating polymer network(semi-IPN)method.According to the membrane properties and its structure observed by SEM,the best conditions for building PVA/PVDF semi-IPN structure by acetalation of polyvinyl alcohol(PVA)and glutaraldehyde(GD)were that the addition of polyvinyl alcohol was4.0%(mass percentage)and the ratio of glutaraldehyde to PVA was0.5in the casting solution.Performance of the semi-IPN structure composite membrane reached the best when the casting solution formula was PVDF/PVA/PVP/GD/NMP=16/4/3/2/75,with the flux=612.3L/(m2·h),the contact angle=48.3°,the BSA rejection=98.7%,the blasting pressure=1.0MPa,and the adsorption capacity of BSA45.3μg/cm2.The composition and structure of the membrane were characterized by X-ray photoelectron spectroscopy(XPS)and infrared analyzer(FTIR).After treating practical petrochemical wastewater for a month,the water flux was144.4L/(m2·h),the removal rate of COD was80.4%,and the turbidity removal rate was about97.2%.Compared with the parameters of the membrane prepared by the formula without the semi-IPN structure,the PVA/PVDF composite membrane had larger water flux enhanced hydrophilicity,higher anti-pollution and backwashing capacity and therefore the comprehensive performance of the membrane was increased significantly.