A Flow-Through Solar Evaporator Integrating Photothermal Evaporation and Photo-Fenton Catalysis for Seawater Desalination and Pollutant Degradation

Solar-driven interfacial evaporation offers a sustainable solution to global freshwater scarcity. However, conventional evaporators often suffer from severe salt fouling and are incapable of degrading persistent organic pollutants coexisting in real seawater, significantly limiting their practical application. Herein, a flow-through solar evaporator integrating photo-Fenton technology is proposed to achieve efficient pollutant degradation and desalination. A novel nanocomposite (BS-FWO) synthesized by bismuth sulfide (Bi2S3) and iron tungstate (FeWO4) was immobilized on graphite felt (GF) to form a bifunctional photothermal catalytic fabric, where optimized Bi2S3 doping markedly enhances charge separation and mutual photothermal-catalytic synergy boosts solar-driven degradation and desalination. Under a light intensity of 1 kW m–2 (1 sun), the flow-through evaporator based on this photothermal catalytic fabric exhibited excellent catalytic performance in degrading various organic pollutants including 97.7% removal of methylene blue and effective elimination of tetracycline antibiotics. Meanwhile, a high evaporation rate of 1.862 kg m–2 h–1 is obtained for pure water and stable evaporation is maintained for 10 h of operation with 15 wt % brine, without salt accumulation. This integrated system provides a promising strategy for long-term, pollution-resistant solar desalination and advanced wastewater purification.