Photothermal/magnetothermal coupled polyphenylene sulfide composite membranes for ultra-efficient and continuous seawater desalination

Abstract

As the population continues to expand and industrialization gathers pace, the rate at which freshwater resources are dwindling is alarming. Solar desalination technology has shown encouraging results in generating clean water. However, solar-driven interfacial evaporation technology still faces a series of major challenges, specifically manifested in its low efficiency, poor chemical stability, and the tendency for salt crystallization to accumulate on the evaporation surface during operation. In this work, we proposed a novel magneto/photo-thermal coupled evaporator based on polyphenylene sulfide (PPS) fibrous membrane, which showed excellent high temperature and corrosion resistance. This non-contact responsive interfacial evaporator exhibited outstanding photothermal and magnetothermal conversion performance properties. Under one solar illumination, the evaporation rate of this evaporator could reach 1.52 kg m−2 h−1, corresponding to an evaporation efficiency of 91.84 %. In addition, under a magnetic field power of 2 kW m−2, the evaporator could achieve a remarkable evaporation rate of 4.2 kg m−2 h−1 under one solar illumination, with an evaporation efficiency of up to 93.77 %. Moreover, it also exhibited superb salt resistance, great mechanical properties, long-term operational stability, and outstanding dye purification property. Furthermore, by integrating the thermoelectric generator with the evaporator and utilizing the waste heat from the evaporation process to generate electricity, the efficiency of energy utilization has been improved. The interfacial evaporator opens up vast prospects for efficient and rapid clean water production, demonstrating significant potential and advantages.