The introduction of hydrophilic nanomaterials into the polyamide (PA) layer of forward osmosis (FO) membranes usually leads to the enhancement in water flux but a reduction in salt rejection. The decrease in salt rejection, however, inevitably influences the osmotic efficiency and operation cost. In this work, -phenylenediamine (MPD), one of the chemicals of interfacial polymerization, was utilized as a precursor to synthesize carbon dots (MPD-C-dots) with a good photosensitization functionality. The MPD-C-dots were introduced into the PA layer of FO membranes through -interfacial polymerization (denoted as Single-C-dots-M), and further grafted onto the PA layer by the conjugation of the residual acyl chloride of trimesoyl chloride with the amine of MPD-C-dots (denoted as Double-C-dots-M). The as-prepared Double-C-dots-M exhibited more outstanding FO performances than the pristine membrane (Control-M) and Single-C-dots-M. Most unexpectedly, the dual-enhancement in water flux and salt rejection of Double-C-dots-M was found. The further studies reveal that Double-C-dots-M had smaller and more uniform pore size, but larger porosity than the other two. In addition, the biofouling-resistance tests demonstrate that MPD-C-dots-M had an excellent anti-biofouling performance by generating singlet oxygen (O) under light irradiation. The proposed Double-C-dots-M provided a typical protocol for improving the performances of FO membrane, especially for the synchronous enhancement in water flux and salt rejection.

中文翻译：

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碳点调节正渗透膜聚酰胺层的微观结构，用于抗生物污垢并意外地双重增强水通量和脱盐率

将亲水性纳米材料引入正向渗透（FO）膜的聚酰胺（PA）层通常会导致水通量增强，但脱盐率降低。然而，脱盐率的降低不可避免地影响渗透效率和操作成本。在这项工作中，界面聚合化学物质之一的邻苯二胺（MPD）被用作合成具有良好光敏功能的碳点（MPD-C-dots）的前驱体。通过界面聚合将MPD-C-dots引入FO膜的PA层（记为Single-C-dots-M），并通过均苯三甲酰氯的残余酰氯与均苯三甲酰氯的残留酰氯的缀合进一步接枝到PA层上。 MPD-C-点的胺（表示为双-C-点-M）。所制备的双碳点-M 比原始膜 (Control-M) 和单碳点-M 表现出更出色的 FO 性能。最出乎意料的是，发现双碳点-M 具有水通量和脱盐率的双重增强作用。进一步的研究表明，Double-C-dots-M 的孔径更小且更均匀，但孔隙率比其他两者更大。此外，抗生物污垢测试表明，MPD-C-dots-M在光照射下产生单线态氧（O），具有优异的抗生物污垢性能。所提出的双碳点-M 为提高 FO 膜的性能，特别是同步增强水通量和脱盐率提供了典型的方案。