Surface modification of nanofiltration membranes is a productive approach to improve separation performance. In this study, we synthesized branched bis- and tris-quaternary assemblies, denoted as BQTE and TQTE, through the quaternization reaction of triethanolamine with 1,4-bis(bromomethyl)benzene and 1,3,5-tris(bromomethyl)benzene. These assemblies were then grafted onto a nascent polyamide (PA) membrane via forming ester bonds. This modification induced the formation of nanobubbles within the PA matrix due to reaction heat-induced gas expansion during grafting. Compared to TQTE, BQTE had fewer hydroxyl-quaternary ammonium entities, resulting in a much looser PA film. Additionally, the positively charged quaternary ammonium groups reduced the negative charge and mitigated Donnan exclusion against ions. Both PA-BQTE and PA-TQTE membranes demonstrated exceptional performance in antibiotic desalination. Specifically, PA-BQTE had a water permeance of 9.7 L·m−2·h−1·bar−1 in a 10 g·L−1 NaCl solution, with a NaCl/tetracycline selectivity of 42.5. Furthermore, these modified membranes demonstrated improved antifouling property and enhanced resistance to chlorine, underscoring their potential for practical applications.

中文翻译：

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定制的纳滤膜，通过使用支链季铵盐三乙醇胺组件进行表面改性来增强抗生素脱盐


纳滤膜的表面改性是提高分离性能的一种有效方法。在这项研究中，我们通过三乙醇胺与 1,4-双（溴甲基）苯和 1,3,5-三（溴甲基）苯的季铵化反应合成了支链双和三四元组装体，表示为 BQTE 和 TQTE。然后通过形成酯键将这些组件接枝到新生的聚酰胺 （PA） 膜上。由于接枝过程中反应热诱导的气体膨胀，这种修饰诱导了 PA 基质内纳米气泡的形成。与 TQTE 相比，BQTE 具有较少的羟基季铵实体，导致 PA 膜更松散。此外，带正电荷的季铵基团减少了负电荷并减轻了对离子的 Donnan 排斥。PA-BQTE 和 PA-TQTE 膜在抗生素脱盐方面均表现出卓越的性能。具体而言，PA-BQTE 在 10 g·L−1 NaCl 溶液，NaCl/四环素选择性为 42.5。此外，这些改性膜表现出更好的防污性能和增强的耐氯性，凸显了它们的实际应用潜力。