Aerogel-based evaporator for simultaneous seawater desalination and VOCs removal in oily wastewater

Solar-driven interfacial evaporation holds significant potential for treating oily wastewater. Traditional evaporators may become clogged due to residues or contamination caused by the release of volatile organic compounds (VOCs). We have developed a novel evaporator that combines oil-water interfacial evaporation with photocatalytic removal of VOCs. In experiments using simulated seawater, oily wastewater, phenol (PNP), and p-nitrophenol (PhOH)-contaminated water, we evaluated water evaporation efficiency and VOCs degradation. The temperature gradient on the aerogel surface, combined with interfacial evaporation and photocatalysis, enhanced evaporation efficiency. The oil-modified surface prevents oil blockage, while the photocatalytic coating effectively removes VOCs and enhances thermal regulation. Under 1 kW m −2 solar irradiance, the O-PPy/PTh-PI/MXene aerogel treated 10% oil-contaminated wastewater with an evaporation rate of 1.37 kg m −2  h −1 and an evaporation efficiency of 89.75%. Interface evaporation desalination treatment of source water contaminated with PNP and PhOH achieved a TOC removal rate exceeding 98%. An expanded aerogel evaporator array produced approximately 9.21 kg/(m 2 ·d) of pure water under actual sunlight. This successful demonstration highlights the evaporator's efficient evaporation potential at the interface for treating oily wastewater, showcasing its broad application prospects.