Tailoring Defective Tungsten Oxide Aerogel Evaporator for Enhanced Solar Steam Generation and Heavy Metal Adsorption Toward Agricultural Irrigation

Abstract

Freshwater scarcity and industrial wastewater pollution present dual challenges that severely hinder sustainable development. Solar-driven interfacial evaporation (SDIE) strategy, combined with heavy metal ion removal, offers a cost-effective solution for wastewater purification by harnessing solar energy. Herein, inspired by the integration of photothermal conversion and adsorption capabilities, a multifunctional aerogel (r-WCTOA) evaporator was engineered by introducing oxygen vacancies in WO₃ (r-WO_3-x) to enhance its photothermal conversion efficiency, followed by compositing with wastepaper-derived cellulose. The enhanced localized surface plasmon resonance (LSPR) of r-WO_3-x particles, coupled with the porous structure of a cellulose fiber substrate exhibiting excellent mechanical integrity, enables efficient light absorption up to 92.89%. The r-WCTOA evaporator achieves an average water evaporation rate of 1.812 kg m^-2 h^-1 with a desalination efficiency of 99.8% under one sun irradiation. Additionally, r-WCTOA evaporator demonstrates superior heavy metal removal capacity with a maximum Pb²⁺ adsorption performance of 171.86 mg g^-1, producing purified water that meets WHO drinking water standards. Notably, the freshwater recovered from evaporated leachate could be directly reused for subsequent irrigation, ensuring a sustainable and resource-efficient remediation cycle. This multifunctional r-WCTOA evaporator with porous structures synergistically achieves efficient wastewater purification and heavy metal removal during solar-driven evaporation, providing a scalable, cost-effective and eco-friendly solution for solar water treatment systems.

Keywords

agricultural irrigation / defective WO_3-x / heavy metal adsorption / oxygen vacancy / solar driven interface evaporation

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