Foam-loaded carbon nanotubes aerogel for solar-driven water evaporation via air-water interfacial heating

Solar-driven interfacial evaporation has emerged as a highly promising technology for fresh water production from seawater. However, two critical challenges remain: preventing salt accumulation on evaporators and minimizing volatile organic compounds (VOCs) from entering the condensed fresh water. In this work, a CNTs-PVA-PU aerogel evaporator with both salt-rejection and VOCs adsorption property were fabricated using carbon nanotubes (CNTs), polyvinyl alcohol (PVA) and polyurethane (PU) foam as the building bricks. The CNTs-PVA-PU aerogel exhibits a good evaporation rate of 1.42 kg·m -2 ·h -1 with a photothermal conversion efficiency of 97.75% under 1 kW·m -2 irradiation. The superhydrophilic nature of the CNTs-PVA-PU aerogel enables efficient brine reflux, returning the concentrated brine to the bottom feed water, thus achieving stable salt-rejection property. The salt-rejection property allows the aerogel to maintain a consistent evaporation rate over 10 consecutive solar evaporation cycles without performance reduction. Furthermore, the aerogel effectively adsorbs phenol in the concentration range of 1-20 mg·L -1 from feed water, thereby producing pure condensed fresh water. This work demonstrates the strong potential of the CNTs-PVA-PU aerogel for practical seawater desalination applications. A CNTs-PVA-PU aerogel with both salt-rejection and VOCs adsorption property was fabricated for solar evaporation. • A CNTs-PVA-PU aerogel with salt-rejection and VOCs removal property was prepared. • The CNTs-PVA-PU aerogel had evaporation rate of 1.42 kg·m -2 ·h -1 under 1 sun. • Salt-rejection was achieved by flowing concentrated brine back into the feedwater. • Phenol was adsorbed by the CNTs-PVA-PU aerogel resulting in purified freshwater.