Preparation of polyvinyl alcohol/sodium alginate composite aerogel and its application in efficient seawater desalination

The desalination evaporator based on the solar interface water evaporation technology can realize the desalination and purification of seawater, but the evaporation rate of the evaporator is low at present. In this work, the composite aerogel of polyvinyl alcohol and sodium alginate was prepared by directional freezing. At the same time, carbon nanotube materials were used as light absorbing materials. The effects of the composition, proportion and content of light absorbing materials of the composite aerogel on the evaporation performance of evaporator water were explored. The research found that the composite aerogel evaporator has a light absorption rate of up to 97% and excellent seawater desalination performance. The water evaporation rate under a sun light can reach 2.7 kg·m⁻²·h⁻¹. In the long-term alternating process of light and darkness, the salt crystals accumulated on the surface of the evaporator will automatically melt and disappear, playing a self-cleaning effect, and can achieve long-term sustainable evaporation. It has broad application prospects in the field of seawater desalination.