In the preparation of nanofiltration (NF) membranes, the introduction of acid acceptors into the aqueous phase generates heat through their interaction with the byproduct HCl from interfacial polymerization (IP), potentially leading to the formation of bubbles. This work aims to dissect the combined influences of heat and nanobubbles on NF membrane structure and performance. Three representative alkalis (i.e., NaHCO, NaOH, and Ca(OH)) were employed as acid acceptors into the aqueous phase, resulting in an increase of the consumption of PIP in the IP reaction from 10.75% to 23.65%, 19.35%, and 12.90%, respectively. The use of NaOH and Ca(OH) released more heat led to a thicker polyamide layer which reduced flux. While the use of NaHCO simultaneously released heat and bubbles, which promoted the development of a rougher surface polyamide layer, resulting in an increased flux from 20.3 to 28.3 L/m h bar, while maintaining a salt rejection rate of 97.7%. The attendance of acid acceptors also enhanced the degree of crosslinking and resulted in a decrease in negative charge of the prepared membrane. This study advances the understanding of the impact of heat and bubbles release induced by the addition of acid acceptors on NF membrane structure and performance.

中文翻译：

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剖析纳米气泡和聚合过程中产生的热量对聚酰胺纳滤膜的影响

在纳滤 (NF) 膜的制备过程中，将酸受体引入水相中，通过与界面聚合 (IP) 副产物 HCl 的相互作用产生热量，可能导致气泡的形成。这项工作旨在剖析热量和纳米气泡对纳滤膜结构和性能的综合影响。采用三种代表性碱（即 NaHCO、NaOH 和 Ca(OH)）作为水相中的酸受体，导致 IP 反应中 PIP 的消耗量从 10.75% 增加到 23.65%、19.35% 和分别为 12.90%。使用 NaOH 和 Ca(OH) 会释放更多热量，导致聚酰胺层变厚，从而降低通量。而NaHCO的使用同时释放热量和气泡，促进了表面更粗糙的聚酰胺层的形成，导致通量从20.3 L/m h bar增加到28.3 L/m h bar，同时保持97.7%的脱盐率。酸受体的存在也增强了交​​联程度并导致所制备的膜的负电荷减少。这项研究加深了人们对添加酸受体引起的热量和气泡释放对纳滤膜结构和性能影响的理解。