Abstract Polyamide (PA) based thin-film composite (TFC) membranes experience a high degree of organic fouling due to their hydrophobic and rough membrane surfaces during forward osmosis (FO) process. In this study, an ultrathin silica layer was grown in situ on the PA surface to enhance the antifouling property of TFC membrane by silicification process. Surface characterization confirmed the development of a silica layer on the PA surface. The superhydrophilic surface of silica-deposited TFC membrane (contact angle of 20°) with 3 h silicification time (STFC-3h) displayed a 53% higher water flux than the pristine TFC membrane without significantly affecting the membrane selectivity. The silica-modified TFC FO membranes also exhibited excellent stability when subjected to long-term cross-flow shear stress rinsing using deionized (DI) water, including exposure to salty, acidic and basic solutions. Moreover, the fouling tests showed that STFC-3h membrane lost only 4.2%, 9.1% and 12.1% of its initial flux with bovine serum albumin (BSA), humic acid (HA) and sodium alginate (SA), respectively, which are considerably lower compared to the pristine TFC FO membrane where flux losses were 18.7%, 23.2% and 37.2%, respectively. The STFC-3h membrane also revealed higher flux recovery ratio (FRR) of 99.6%, 96.9% and 94.4% with BSA, HA and SA, respectively, after physical cleaning than the pristine membrane (91.4%, 88.7%, and 81.2%, respectively). Overall, the in situ formation of an ultrathin hydrophilic silica layer on the PA surface reported in this work shows that the TFC membrane's water flux and antifouling property could be improved without diminishing the membrane selectivity.

中文翻译：

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在聚酰胺薄膜复合膜表面原位形成超薄二氧化硅层以提高正向渗透性能

摘要 基于聚酰胺 (PA) 的薄膜复合 (TFC) 膜在正向渗透 (FO) 过程中由于其疏水性和粗糙的膜表面而遭受高度有机污染。在这项研究中，超薄二氧化硅层在 PA 表面原位生长，以通过硅化过程提高 TFC 膜的防污性能。表面表征证实了 PA 表面上形成了二氧化硅层。硅化时间为 3 小时 (STFC-3h) 的二氧化硅沉积 TFC 膜（接触角为 20°）的超亲水表面显示出比原始 TFC 膜高 53% 的水通量，而不会显着影响膜选择性。当使用去离子 (DI) 水进行长期错流剪切应力冲洗时，二氧化硅改性的 TFC FO 膜也表现出优异的稳定性，包括暴露于咸、酸和碱溶液。此外，污染测试表明，STFC-3h 膜与牛血清白蛋白 (BSA)、腐植酸 (HA) 和海藻酸钠 (SA) 分别仅损失了其初始通量的 4.2%、9.1% 和 12.1%，这是相当大的。与原始 TFC FO 膜相比，通量损失分别为 18.7%、23.2% 和 37.2%。物理清洁后，STFC-3h 膜还显示出比原始膜（91.4%、88.7% 和 81.2%，分别）。总体而言，这项工作中报道的 PA 表面上原位形成超薄亲水二氧化硅层表明，可以在不降低膜选择性的情况下提高 TFC 膜的水通量和防污性能。