Meng Qing-Wei, Ge Qingchun
College of Environment and Resources, Fuzhou University, Fujian 350116, China.
ACS Appl Mater Interfaces. 2020 Aug 5;12(31):35393-35402. doi: 10.1021/acsami.0c05176. Epub 2020 Jul 21.
Poor resistance to free chlorine severely impairs the service of conventional polyamide (PA) membrane in water treatment. Here we design a series of superhydrophilic aromatic sulfonate materials (ASMs) comprising successively increasing conjugated systems and ionizable groups (ASM-1, ASM-2, ASM-3) to develop a chlorine-resistant membrane via chemical modification. By altering the membrane physicochemical properties and surface structure, ASMs substantially improve the chlorine resistance and water permeability of membrane. With 0.5 M NaCl as the draw solution, all ASMs enhance membrane water fluxes by more than 60% relative to those of the nascent PA membrane in forward osmosis (FO) processes. After exposed to a 1000 ppm sodium hypochlorite solution for 2-8 h, the modified membranes exhibit smaller variations in FO performance than the PA membrane. Having the largest conjugated system and the most sulfonate groups, ASM-3 enables the membrane to sustain a chlorination strength of up to 8000 ppm·h with an insignificant NaCl loss during the FO process, surpassing other recently developed PA membranes in chlorine resistance. These results manifest that the combination of a large conjugated system and ionizable group is key for imbuing membrane with excellent chlorine resistance and water permeability.
对游离氯的抗性较差严重损害了传统聚酰胺（PA）膜在水处理中的应用。在此，我们设计了一系列具有逐渐增加的共轭体系和可电离基团的超亲水芳香磺酸盐材料（ASM-1、ASM-2、ASM-3），通过化学改性来制备耐氯膜。通过改变膜的物理化学性质和表面结构，ASM 显著提高了膜的耐氯性和水渗透性。以 0.5 M NaCl 作为汲取液，在正向渗透（FO）过程中，所有 ASM 相对于新生 PA 膜均使膜水通量提高了 60%以上。在暴露于 1000 ppm 次氯酸钠溶液 2 - 8 小时后，改性膜在 FO 性能方面的变化比 PA 膜小。具有最大共轭体系和最多磺酸基团的 ASM-3 使膜能够承受高达 8000 ppm·h 的氯化强度，且在 FO 过程中 NaCl 损失不显著，其耐氯性超过了其他最近开发的 PA 膜。这些结果表明，大共轭体系和可电离基团的组合是赋予膜优异耐氯性和水渗透性的关键。
