Achieving ultra-low latent heat of water evaporation in capillary water by regulating hydrophilic groups and pore structure of cellulose/chitosan gel

Given the abundant solar energy resources and remarkable heat utilization efficiency, solar interfacial evaporation is a promising approach in addressing the global freshwater crisis. The primary bottleneck impeding the industrial implementation of solar interfacial evaporation lies in its relatively low production rate because of the high latent heat of water evaporation. Here, we effectively reduce the latent heat by synergistically optimizing hydrophilic groups, regulating pore network structure, and adjusting interfacial water state of the cellulose/chitosan gel. The latent heat of water evaporation in this evaporator can be reduced from 2444 kJ kg −1 (bulk water) to 786 kJ kg −1 , and the evaporation rate can be high as 3.99 kg m −2  h −1 under 1 sun irradiation. This study of reducing latent heat of water evaporation holds immense significance in designing efficient evaporation systems for industrial applications.