Photothermal converting polypyrrole/polyurethane composite foams for effective solar desalination

As a green and renewable energy source , solar energy is one of the best options to drive desalination and water purification processes. In this paper, a lightweight commercial polyurethane foam (PUF) was chosen as the support modified with a black polypyrrole (PPy) layer to obtain a simple and effective photothermal conversion “black foam” (PPy-PUF). Due to the excellent spectral absorption capacity of the polypyrrole layer as well as surficial PPy micro-wrinkles, the surface temperature of the black foam rapidly increased when irradiated with solar illumination. Combined with the porous structure , low thermal conductivity , and hydrophilicity of the polyurethane foam, it can be continuously used for desalination and water purification purposes. The evaporation rate of water can be as 3.789 kg·m −2 ·h −1 under 4-sun and the evaporation efficiencies as 86.9% under 1-sun. The internal microstructure and photothermal conversion performance of the PPy-PUF materials proved that they are highly suitable for practical applications such as desalination and water purification, which provide feasible solutions for water shortage, sustainable energy, and environmental improvement.