Aquino Marco, Santoro Sergio, Politano Antonio, D'Andrea Giuseppe, Siciliano Alessio, Straface Salvatore, La Russa Mauro Francesco, Curcio Efrem
Department of Environmental Engineering, University of Calabria (DIAm-UNICAL), Via P. Bucci, CUBO 44/A, 87036 Rende, Italy.
Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio, 67100 L'Aquila, Italy.
Membranes (Basel). 2024 Apr 10;14(4):87. doi: 10.3390/membranes14040087.
Modern society and industrial development rely heavily on the availability of freshwater and minerals. Seawater reverse osmosis (SWRO) has been widely adopted for freshwater supply, although many questions have arisen about its environmental sustainability owing to the disposal of hypersaline rejected solutions (brine). This scenario has accelerated significant developments towards the hybridization of SWRO with membrane distillation-crystallization (MD-MCr), which can extract water and minerals from spent brine. Nevertheless, the substantial specific energy consumption associated with MD-MCr remains a significant limitation. In this work, energy harvesting was secured from renewables by hotspots embodied in the membranes, implementing the revolutionary approach of brine mining via photothermal membrane crystallization (PhMCr). This method employs self-heating nanostructured interfaces under solar radiation to enhance water evaporation, creating a carefully controlled supersaturated environment responsible for the extraction of minerals. Photothermal mixed matrix photothermal membranes (MMMs) were developed by incorporating graphene oxide (GO) or carbon black (CB) into polyvinylidene fluoride (PVDF) solubilized in an eco-friendly solvent (i.e., triethyl phosphate (TEP)). MMMs were prepared using non-solvent-induced phase separation (NIPS). The effect of GO or GB on the morphology of MMMs and the photothermal behavior was examined. Light-to-heat conversion was used in PhMCr experiments to facilitate the evaporation of water from the SWRO brine to supersaturation, leading to sodium chloride (NaCl) nucleation and crystallization. Overall, the results indicate exciting perspectives of PhMCr in brine valorization for a sustainable desalination industry.
现代社会和工业发展严重依赖淡水和矿物质的供应。海水反渗透（SWRO）已被广泛用于淡水供应，尽管由于高盐度浓盐水的排放，其环境可持续性引发了诸多问题。这种情况加速了SWRO与膜蒸馏-结晶（MD-MCr）杂交技术的重大发展，该技术可以从废盐水中提取水和矿物质。然而，与MD-MCr相关的大量特定能耗仍然是一个重大限制。在这项工作中，通过膜中体现的热点从可再生能源中获取能量，采用了通过光热膜结晶（PhMCr）进行盐水开采的革命性方法。该方法利用太阳辐射下的自热纳米结构界面来增强水的蒸发，创造一个精心控制的过饱和环境以实现矿物质的提取。通过将氧化石墨烯（GO）或炭黑（CB）掺入溶解在环保溶剂（即磷酸三乙酯（TEP））中的聚偏氟乙烯（PVDF）中来制备光热混合基质光热膜（MMMs）。MMMs采用非溶剂诱导相分离（NIPS）制备。研究了GO或GB对MMMs形态和光热行为的影响。在PhMCr实验中利用光热转换促进SWRO浓盐水中的水蒸发至过饱和，导致氯化钠（NaCl）成核和结晶。总体而言，结果表明PhMCr在可持续海水淡化行业的盐水增值方面具有令人兴奋的前景。
