阴离子交换膜改性及抗污染性能研究进展

Research progress on modification and antifouling properties of anion exchange membrane

电渗析技术应用于工业废水脱盐时,废水中有机物及其它杂质组分等会造成膜污染,进而影响脱盐性能。电渗析膜污染防治对促进电渗析在工业废水处理中的应用有重要意义。相比于阳离子交换膜,阴离子交换膜更易形成有机污染,且更严重。阴离子交换膜污染主要由腐殖酸、牛血清蛋白、阴离子表面活性剂等有机物造成,污染过程主要受静电作用、亲和作用和几何因素的影响。膜改性提高阴离子交换膜的抗污染性能是电渗析膜污染防治的有效方法,目前已有许多有关膜改性提高阴离子交换膜抗污染性能的报道。膜改性方法主要有化学改性法、等离子体改性法、表面涂覆改性法、电沉积改性法、自聚合改性法及改进基膜结构法等。本工作对阴离子交换膜改性及抗污染性能的研究进展进行了综述,对不同改性方法的优缺点进行了分析和评价。这些改性方法能提高阴膜表面的负电荷密度和亲水性、降低膜表面粗糙度和基膜含水率等,因此可以改善阴离子交换膜的抗污染性能。然而,目前研究获得的改性阴离子交换膜仍存在修饰层不稳定、抗污染性能不理想和性能测试不系统等缺点,需进一步优化改性方法、改性工艺、组分修饰及性能测试等,以获得抗污染性能稳定且效果良好的改性阴离子交换膜。

When electrodialysis technology is used in desalination of industrial wastewater, its desalination performance degraded by membrane fouling caused by organic matter and other impurities in the wastewater. The prevention and control of electrodialysis membrane fouling play an important role in promoting the application of electrodialysis in industrial wastewater treatment. Compared to cation exchange membrane(CEM), anion exchange membrane(AEM) is more susceptible to fouling by organic matter. The organic fouling of AEM is mainly caused by organic substances such as humic acid, bovine serum albumin and anionic surfactant, which is mainly affected by electrostatic action, affinity interaction and geometrical factor. Improving the antifouling performance of AEM by membrane modification is an effective way to the prevention and control of electrodialysis membrane fouling. Many investigations related to the membrane modification to improve the antifouling performance of AEM have been reported up to now. Some methods such as chemical modification, plasma modification, surface coating modification, electrodeposition modification, self-polymerization modification and improved basement membrane structure, etc., are used for improving the antifouling performance of AEM. The research progress of anion exchange membrane modification and their antifouling performance were reviewed in this work. The advantages and disadvantages of different methods were analyzed and evaluated systematically. It was found that the physicochemical properties including the negative charge density, hydrophilicity, surface roughness and water uptake, etc. of AEM could be improved by the modification methods, which were beneficial to ameliorate the antifouling performance of membranes. However, the research of modified membranes still has some deficiencies such as the unstable modified layer, unsatisfactory antifouling performance and incompleted antifouling performance test. It is necessary to optimize further the modification method, technology process and modification components to obtain the modified AEM with good and stable antifouling performance in the future.