Preparation of Phase-Change Composite Aerogel Materials and Its Application in Solar Saline-Alkali Water Desalination

Solar energy is an inexhaustible clean energy, and solar evaporation salt water desalination is a promising technology. However, the low evaporation efficiency caused by intermittent solar irradiation is still the main obstacle in the practical application of interface evaporation. A new type of interfacial evaporation material is developed by using the porous adsorption method to fill the phase change material (PCM) paraffin (IPW) into the halloysite nanotubes (HNTs), using polydopamine (PDA) as the photothermal material and encapsulation agent and bacterial cellulose (BC) as the carrier. The low-temperature crosslinking method prepares the IPW@HNTs@ PDA-BC phase change composite aerogel. The novel interfacial evaporation material preparation process is simple, and the aerogels can be prepared quickly under normal pressure, which overcomes the disadvantages of the traditional porous adsorption method and long-time freeze-drying of aerogels. Under 1 kW m-2 light, the evaporation rate of the PCM is 3.43 kg m-2 h-1, and the photothermal conversion efficiency is 95%. In the dark environment (10 min), the evaporation rate is 2.80 kg m-2 h-1, and the photothermal conversion efficiency is 52.8%. The material exhibits excellent evaporation in acidic, alkaline water, and industrial wastewater. Shortly, it can be used as a promising material for evaporating clean water. Schematic diagram of interfacial evaporation structure of phase change composite materials, divided into sunlight and no sunlight, is presented. Phase change composite materials evaporate clean water when there is sunlight, store heat, and release heat to continue to evaporate clean water when there is no sunlight.image