Superhydrophobic MXene based fabric composite for high efficiency solar desalination

Abstract Solar desalination via interfacial evaporation is an effective, green and convenient method to solve the shortage of fresh water. It remains challenging to develop high quality light absorber materials that can both reduce the heat loss and avoid salt accumulation during the seawater evaporation and be also used in different harsh conditions. Here, we, for the first time, propose an emulsion dip-coating strategy to fabricate a superhydrophobic fabric composite for high-efficiency interfacial evaporation. During the dip-coating in the oil-in-water emulsion, MXene in the water phase together with the polydimethylsiloxane in the oil phase is decorated onto the polydopamine modified elastic fabric through the interfacial hydrogen bonding. The obtained superhydrophobic/superoleophilic fabric composite is able to separate the oil from the polluted seawater. Air bubbles are trapped between the fabric and water, reducing the heat conduction to bulk water. Furthermore, the salt is prevented from accumulation on the fabric surface even in a very high salinity condition. The solar interfacial evaporation rate and efficiency reach 1.526 kg m−2 h−1 and 93.3% under 1 sun, respectively, and can be almost maintained after a long-time use. This study provides a new avenue to prepare multifunctional light absorbers for efficiency solar desalination and oil-water separation.