Asymmetric Ba0.7Sr0.3CoO3-δ/MXene solar evaporators for enhanced treatment of high salinity organic wastewater: Improving salt deposition control and pollutant removal

Abstract

Solar-driven interfacial evaporation (SIE) utilizes solar thermal energy to produce clean water, addressing the water-energy paradox. However, challenges like photothermal conversion performance and salt deposition limit its adoption. Additionally, when SIE is applied to organic wastewater treatment, volatile organic compounds (VOCs) in the distilled water can diminish water purification efficiency. In this study, we developed a Ba0.7Sr0.3CoO3-δ/MXene composite solar evaporator capable of simultaneous removal of organic matters (93.70 % removal of 4-chlorophenol) with high evaporation performance (1.50 kg m−2 h−1) during the evaporation of salt-containing organic wastewater. The incorporation of Ba0.7Sr0.3CoO3-δ into the composite significantly enhanced the photothermal conversion capacity, improving the evaporation efficiency. The organic pollutant removal activity of Ba0.7Sr0.3CoO3-δ stemmed from lattice oxygen, which was activated by photothermal conversion heat. The incorporation of Ba0.7Sr0.3CoO3-δ and MXene in the solar evaporator significantly enhances the photothermal conversion performance. Additionally, the innovative asymmetric edge structure effectively addresses the salt deposition issue and enables the removal of organic pollutants through in situ utilization of heat generated from photothermal conversion. This approach offers a subtle yet effective strategy for mitigating pollutant accumulation in the solar interfacial evaporation process, ensuring long-term water purification and clean water production.