Abstract In recent years, Membrane Distillation (MD) has emerged either as a promising alternative or as a complement to Reverse Osmosis (RO) in seawater desalination. However, the performance of MD is significantly offset by temperature polarization, a phenomenon intrinsically related to water evaporation that causes the decrease of the solution temperature at the membrane surface and, ultimately, the loss of driving force. In this work, we show that temperature polarization can be withdrawn by exploiting thermal collective effects activated by the excitation of plasmonic modes in UV-irradiated Mixed Matrix Membranes composed of silver nanoparticles (Ag NPs) incorporated in polyvinylidene fluoride (PVDF) microporous films. For experimental tests carried out under vacuum (VMD) and with an absorbed radiant heating power of 2.3 · 104 W/m2, best results were obtained using PVDF membranes loaded with 25%Ag NPs. In this case, measured transmembrane fluxes to pure water and 0.5 M NaCl solution were 32.2 and 25.7 L/m2 h, respectively, i.e. about 11- and 9- fold higher than the corresponding values for unloaded membranes. Remarkably, energy analysis revealed that the heat generation of Ag NPs under plasmonic resonance was able to withdrawn temperature polarization, resulting in estimated temperature polarization factor (TPF) values of 106.5% for 0.5 M NaCl solution.

中文翻译：

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通过聚合物膜中的银纳米填料激活的热等离子体效应克服膜蒸馏中的温度极化

摘要 近年来，膜蒸馏 (MD) 已成为海水淡化中反渗透 (RO) 的一种有前途的替代方法或补充。然而，MD 的性能被温度极化显着抵消，温度极化是一种与水蒸发本质相关的现象，导致膜表面溶液温度降低，最终导致驱动力损失。在这项工作中，我们表明可以通过利用由紫外辐射混合基质膜中的等离子体模式激发激活的热集体效应来消除温度极化，该膜由掺入聚偏二氟乙烯 (PVDF) 微孔膜中的银纳米粒子 (Ag NP) 组成。对于在真空 (VMD) 下进行的实验测试，吸收的辐射加热功率为 2.3 · 104 W/m2，使用负载 25% Ag NPs 的 PVDF 膜获得最佳结果。在这种情况下，测得的纯水和 0.5 M NaCl 溶液的跨膜通量分别为 32.2 和 25.7 L/m2 h，即比卸载膜的相应值高约 11 和 9 倍。值得注意的是，能量分析表明，Ag NPs 在等离子体共振下的发热能够消除温度极化，导致 0.5 M NaCl 溶液的估计温度极化因子 (TPF) 值为 106.5%。