Abstract Reverse osmosis (RO) is a mature desalination technology that provides an effective solution to solve global water scarcity issues. In this study, thin film nanocomposite (TFN) membrane for RO desalination was fabricated by depositing positively charged titania nanosheet (pTNS) and negatively charged titania nanosheet (nTNS) on the surface of polyamide (PA) layer through layer by layer (LbL) assembly. The pTNS was synthesized through solid-state calcination and acid ion-exchange. Though the additional step of exfoliation, single sheet nTNS with improved hydrophilicity property was obtained. The hydration layer created on the surface of TNS-PA could hinder the direct contact of salt ions with the surface of TFN membrane, hence significantly enhance the water permeability and salt rejection. The membrane surface hydrophilicity was improved and surface roughness was decreased with the increasing number of bilayers. However, the excessive pTNS/nTNS bilayer coating has imposed additional hydraulic resistance hence resulted in the reduction of water permeability. The highest water permeability of 0.8 L·m−2·h−1·bar−1 (60% improvement) was achieved with the 2 bilayers of TNS-PA TFN as compared to the pristine PA membrane. The sodium chloride (NaCl) rejection was 98.45% which was also higher than pristine membrane with rejection of 96.65%.

中文翻译：

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通过带相反电荷的二氧化钛纳米片的逐层组装提高薄膜复合膜的脱盐性能

摘要 反渗透（RO）是一种成熟的海水淡化技术，为解决全球水资源短缺问题提供了有效的解决方案。在这项研究中，通过逐层（LbL）组装在聚酰胺（PA）表面沉积带正电荷的二氧化钛纳米片（pTNS）和带负电荷的二氧化钛纳米片（nTNS），制备了用于反渗透海水淡化的薄膜纳米复合（TFN）膜. pTNS 是通过固态煅烧和酸离子交换合成的。通过额外的剥离步骤，获得了具有改进亲水性的单片 nTNS。TNS-PA 表面形成的水化层可以阻碍盐离子与 TFN 膜表面的直接接触，从而显着提高水的渗透性和脱盐率。随着双层数量的增加，膜表面亲水性提高，表面粗糙度降低。然而，过多的 pTNS/nTNS 双层涂层施加了额外的水力阻力，从而导致透水性降低。与原始 PA 膜相比，使用 2 个双层 TNS-PA TFN 实现了 0.8 L·m-2·h-1·bar-1（提高 60%）的最高透水性。氯化钠 (NaCl) 截留率为 98.45%，也高于原始膜截留率为 96.65%。与原始 PA 膜相比，使用 2 个双层 TNS-PA TFN 实现了 8 L·m-2·h-1·bar-1（提高了 60%）。氯化钠 (NaCl) 截留率为 98.45%，也高于原始膜截留率为 96.65%。与原始 PA 膜相比，使用 2 个双层 TNS-PA TFN 实现了 8 L·m-2·h-1·bar-1（提高了 60%）。氯化钠 (NaCl) 截留率为 98.45%，也高于原始膜截留率为 96.65%。