Integrating solar-driven interfacial evaporation with peroxymonosulfate activation by BiFeO₃-decorated PVA-based aerogel for simultaneous seawater desalination and tetracycline degradation

A 3D BiFeO 3 /biomass carbon black/PVA aerogel was fabricated for integrated solar evaporation and PMS activation. • The optimized BCPA-3 achieved an evaporation rate of 3.15 kg m −2  h −1 under 1 sun and maintained stable desalination in 3.5 wt% saline water. • The BCPA/PMS system enabled tetracycline degradation with 65% removal and a rate constant of 0.02407 min −1 . • The coupling effect of porous structure, photothermal heating, and radical oxidation was elucidated for complex saline wastewater purification. Solar-driven interfacial evaporation represents a sustainable strategy for freshwater production. However, the simultaneous elimination of coexisting antibiotic pollutants remains a critical challenge. Herein, we report a robust, multifunctional composite aerogel (BCPA) fabricated via a freeze-casting strategy, integrating bismuth ferrite (BiFeO₃), waste green tea residue-derived biomass carbon black (CB), and polyvinyl alcohol (PVA). The optimized BCPA-3 features a hierarchical three-dimensional (3D) porous architecture that ensures rapid water transport (infiltration time: 7.0 s) and broadband solar absorption. Consequently, the evaporator achieves a high evaporation rate of 3.15 kg m −2  h −1 under 1 kW m −2 irradiation and maintains a rate above 2.6 kg m −2  h −1 in 3.5 wt% brine, demonstrating exceptional salt-rejection stability. The produced condensate meets WHO and EPA drinking water standards with major ion concentrations reduced to negligible levels. Beyond desalination, the BCPA-3 system exhibits superior catalytic activity in activating peroxymonosulfate (PMS) for tetracycline degradation, achieving 65% removal efficiency with a rate constant of 0.02407 min −1 . Mechanism investigations reveal that the degradation is dominated by a radical pathway involving SO₄· − , ·OH, and O₂· − species. Collectively, this work presents a novel material design paradigm that synergizes solar steam generation with advanced oxidation processes, offering an integrated solution for seawater desalination and antibiotic wastewater remediation. Download: Download high-res image (178KB) Download: Download full-size image