Metal–Organic Framework Composite Photothermal Membrane for Removal of High-Concentration Volatile Organic Compounds from Water via Molecular Sieving

Water-soluble volatile organic compounds (VOCs) are among the most difficult-to-treat species during wastewater treatment. The current purification and removal of high-concentration VOCs still rely on the energy-consuming distillation and high-pressure driven reverse osmosis technology. There is an urgent need for an advanced technology that can effectively remove high-concentration VOCs from water. Here, we report a metal-organic framework (MOF)/polyaniline (PANI) nanofiber array composite photothermal membrane for removal of high-concentration VOCs from water via molecular sieving during a solar-driven evaporation process. The modified zeolitic imidazole framework-8 (ZIF-8) layer grown on a PANI nanofiber array acts as a molecular sieving layer to evaporate water but intercept VOCs. The composite membrane exhibits high VOCs rejection and a high-water evaporation rate for water containing different concentrations of VOCs. When treating water containing VOCs with a concentration of up to 400 mg L-1, the VOCs rejection rate is up to 99% and the water evaporation rate is 1.0 kg m-2 h-1 under 1 sun irradiation (1 kW m-2). Our work effectively combines the molecular sieve effect with a solar-driven evaporation process, which provides an effective strategy for the treatment of water containing VOCs.