Alternative photothermal/electrothermal hierarchical membrane for hypersaline water treatment

Abstract

Abstract Over the last decades, the treatment of the large quantities of hypersaline wastewater generated by conventional industries, inland desalination, and fossil‐fueled power plants has been an important economic issue and also an inescapable green issue. Here, we developed a versatile interfacial heating membrane with alternating utilization of electricity or solar energy for hypersaline water treatment. This hierarchical membrane functions both as a separation membrane and an interface heater, which can quickly (<0.1 s) convert electricity or solar energy into heat to evaporate the outermost layer of hypersaline water. For 10 wt% hypersaline water, the freshwater production rate can reach 16.8 kg/m 2 ·h by applying a voltage of 10 V and 1.36 kg/m 2 ·h under 1‐sun illumination. Moreover, it exhibits high electrochemical resistance to corrosion and therefore remains stable tackling hypersaline water (>5 wt%), with a high salt rejection rate of 99.99%. This system shows an efficient desalination strategy that can provide fresh water from brines for agriculture and industry, and even for daily life.