Water and energy are two intimately interconnected issues of strategic relevance for a sustainable industrial development. Herein, we integrated light-harvesting/self-heating membranes and salinity gradient technology with the aim to implement the innovative concept of light-to-heat-to-power conversion.

Novel photothermal membranes, prepared by immobilizing silver nanoparticles (AgNPs) on the top layer of microporous polyvinylidene fluoride (PVDF) matrix, were tested – for the first time – in a Sweep Gas Membrane Distillation (SGMD) unit applied to the desalination of synthetic seawater solution (0.5M NaCl). As a result of the ability of noble metal nanofillers to act as localized thermoplasmonic nano-heaters at membrane-feed interface for efficient water evaporation, an increase of transmembrane flux under UV radiation by about 2.5-fold with respect to unloaded PVDF membrane was observed.

The SGMD retentate, consisting in hypersaline brine (progressively concentrated up to 4M NaCl and rejected at about 40°C) was fed to a Reverse Electrodialysis unit with the aim to harvest electrochemical energy. The maximum power density, measured for a retentate concentration increasing from 1M to 4M, raised from 0.13 to 0.9 W/m²_MP (MP: RED membrane pair). Overall, the proposed integrated membrane system allowed to extract about 10% of the energy not employed for water evaporation.

水和能源是与可持续工业发展具有战略相关性的两个紧密联系的问题。在此，我们集成了采光/自热膜和盐度梯度技术，以实现光热能转换的创新概念。

通过将银纳米颗粒（AgNPs）固定在微孔聚偏二氟乙烯（PVDF）顶层上制备的新型光热膜，首次在用于合成海水淡化的扫气膜蒸馏（SGMD）装置中进行了测试。溶液（0.5M NaCl）。由于贵金属纳米填料在膜-进料界面上充当局部热等离子体纳米加热器以有效蒸发水的能力的结果，相对于未加载的PVDF膜，观察到在UV辐射下跨膜通量增加了约2.5倍。

将由高盐盐水（逐渐浓缩至4M NaCl并在约40°C下排出）组成的SGMD截留液送入反向电渗析装置，以收集电化学能。对于截留物浓度从1M增加到4M的最大功率密度，从0.13 W / m ² _MP（MP：RED膜对）提高到0.9 W / m ² _MP。总体而言，所提出的集成膜系统允许提取约10％的未用于水蒸发的能量。