Flexible and double-layered photothermal material based on resorcinol-formaldehyde foam for solar assisted water desalination

Abstract

Solar-assisted steam generation is considered as an environmental-friendly and feasible technology to effectively harvest solar energy, which has been widely in water purification, seawater desalination and steam sterilization. In this work, we demonstrated flexible and scalable double-layered photothermal material (named as ppy-RF) based on phenolic aldehyde foam and polypyrrole coating as a light adsorption layer for solar steam generation. The resulting ppy-RF foam possessed interpenetrated and macroporous network with high porosity (>86%), superhydrophilicity, low thermal conductivity (0.0396 W m-1 K-1) and almost 100% absorbance (500-2500 nm). These characteristics make ppy-RF foam rapid water transportation and steam generation with an energy conversion efficiency of 90% under solar illumination of 1 kW h-1. Furthermore, the ppy-RF foam exhibits outstanding salt-resistant performance and long-term stability for desalination even in high salinity brine (20 wt%). By combination of its porous, flexible and monolithic configuration obtained by a simple and scalable fabrication method with efficient solar-thermal conversion ability and salt-resistance, the ppy-RF foam shows great potential in the application of clean water production and brine desalination.