Research on water evaporation efficiency of porous cement-based photothermal conversion materials

Rational storage and efficient utilization of rainwater resources are effective means to solve the problems of urban waterlogging and clean water shortage. Many new photothermal conversion devices have been developed for seawater desalination, but the photothermal conversion function has rarely been applied to building materials for water purification. In this study, porous cement-based photothermal conversion materials (PCPCM) were prepared by coating a layer of photothermal conversion materials on the surface of porous cement products, and their photothermal conversion efficiency and water evaporation efficiency were investigated. The results show that PCPCM with graphene as photothermal conversion layer has the highest photothermal conversion efficiency and water evaporation rate of 76.08% and 1.162 kg m−2 h−1, respectively, under one sunlight intensity (1.0 KW m−2). This work presents a key step towards efficient, low-cost and sustainable purification of rainwater into clean water with renewable solar energy, providing new ideas for functional sponge city design.