Efficient solar seawater desalination constructed by oxide composite hydrogel with chitin as the base

Abstract

Solar desalination is a sustainable and promising pathway for alleviating water shortages crisis in the future. However, the whole process is energy intensive and expensive with a low water yield under natural sunlight. In order to overcome these drawbacks, developing new economic materials with less energy use and low environmental impact is urgently desirable. Here, we present a novel composite film which consist of chitin as a porous supporting carrier and black oxide materials as a light-to-heat conversion medium for seawater desalination. The maximum desalination efficiency of these composite materials can reach up to about 80%. Besides, under one sun (1 kW/m2), the evaporation efficiency of MnO2 composite materials under one sun is 95.77%, the corresponding evaporation rate is 1.526 kg/m2/h. The evaporation efficiency of CuO composite materials under one sun is 96.08%, the corresponding evaporation rate is 1.531 kg/m2/h. Based on its low cost, microporous structure, simple manufacture process, highly recyclability, and excellent mechanical stability, the oxide/chitin composite film display potential applications for efficient solar seawater desalination. It also highlights the utilization of natural polymer in developing creative low cost/energy-driven desalination technologies.