Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment, School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona 85287, United States.
Department of Land, Water and Environment Research, Korea Institute of Civil Engineering and Building Technology, 283, Goyang-Daero, Ilsanseo-Gu, Goyang-Si, Gyeonggi-Do 10223, Republic of Korea.
Environ Sci Technol. 2021 May 18;55(10):6984-6994. doi: 10.1021/acs.est.0c07844. Epub 2021 May 5.
A new optimized ultraviolet (UV) technique induced a photooxidation surface modification on thin-film composite (TFC) polyamide (PA) brackish water reverse osmosis (BWRO) membranes that improved membrane performance (i.e., permeability and organic fouling propensity). Commercial PA membranes were irradiated with UV-B light (285 nm), and the changes in the membrane performance were assessed through dead-end and cross-flow tests. UV-B irradiation at 12 J·cm enhanced the pure water permeability by 34% in the dead-end tests without decreasing the mono- or divalent ion rejections, as compared with the pristine PA membrane, and led to less fouling by natural organic matter in the cross-flow tests. Scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) confirmed that UV-B irradiation opened the pore structure and created carboxylic and amine groups on the PA surface, leading to increased membrane surface charge and hydrophilicity. Thus, an optimal UV-B dose appears to modify only a thin layer of the PA membrane surface, which favorably enhances the membrane performance. UV-B did not alter the structure, flux, or salt rejection for cellulose triacetate (CTA)-based membranes. While other membrane surface modifications include oxidants, strong acids, and bases, the UV-B facile treatment is chemical-free, thus reducing chemical wastes, and easy to apply in roll-to-roll fabrication processes of PA membranes. The results also showed that a low UV irradiation dose could be applied to PA or CTA membranes for disinfection or photocatalytic oxidation.
一种新的优化紫外线（UV）技术在薄膜复合（TFC）聚酰胺（PA）苦咸水反渗透（BWRO）膜上诱导光氧化表面改性，改善了膜性能（即渗透性和有机污染倾向）。商业 PA 膜用 UV-B 光（285nm）照射，通过死端和错流测试评估膜性能的变化。与原始 PA 膜相比，在死端测试中，12J·cm 的 UV-B 辐照将纯水透过率提高了 34%，而单或二价离子截留率没有降低，在错流测试中导致天然有机物的污染较小。扫描电子显微镜（SEM）、衰减全反射傅里叶变换红外（ATR-FTIR）光谱和 X 射线光电子能谱（XPS）证实，UV-B 辐照打开了 PA 表面的孔结构，并在 PA 表面上形成了羧酸和胺基，导致膜表面电荷和亲水性增加。因此，最佳的 UV-B 剂量似乎只改性 PA 膜表面的一个薄层，从而有利地提高了膜性能。UV-B 没有改变基于纤维素三乙酸酯（CTA）的膜的结构、通量或盐截留率。虽然其他膜表面改性包括氧化剂、强酸和强碱，但 UV-B 简便处理是无化学物质的，因此减少了化学废物，并易于应用于 PA 膜的卷对卷制造工艺。结果还表明，低剂量的 UV 照射可用于 PA 或 CTA 膜进行消毒或光催化氧化。
