Janus biomass aerogel for Highly-Efficient steam Generation, Desalination, degradation of organics and water disinfection

Abstract

Solar-driven water purification has been deemed as a cheap, green and renewable technology to mitigate water shortage and pollution. Herein, a biomass aerogel with hydrophilic-hydrophobic Janus structure has been prepared as solar water evaporator, which is achieved by partially modifying hydrothermal-treated loofah sponge (HLS) with reduced graphene oxide (rGO). It's a rare design philosophy that HLS serves as a substrate with large pores and hydrophilic properties to ensure continuous and effective water transport, and the hydrophobic layer with rGO modification guarantees good salt resistance in seawater desalination with high photothermal conversion efficiency. As a result, the obtained Janus aerogel, p-HLS@rGO-12, exhibits impressive solar-driven evaporation rates of 1.75 kg m-2h−1 and 1.54 kg m-2h−1 for pure water and seawater respectively, with good cycling stability in the evaporation process. Furthermore, p-HLS@rGO-12 also demonstrates outstanding photothermal degradation of rhodamine B (greater than98.8 % in 2 h) and sterilization of E. coli (nearly 100 % in 2 h). This work offers an unusual approach to achieve highly efficient solar-driven steam generation, seawater desalination, organic pollutant degradation, and water disinfection simultaneously. The prepared Janus biomass aerogel holds great potential application in the field of seawater desalination and wastewater purification.