Synergistic degradation of polystyrene nanoplastics in water: Harnessing solar and water-driven energy through a Z-scheme SnO2/g-C3N4/PVDF-HFP piezo-photocatalytic system

The rise of nanoplastics (NPs) as a water pollutant poses threats to aquatic ecosystems and human health. This study presents an approach that combines solar and water-driven energy sources with advanced materials to degrade NPs. For this purpose, a SnO2/g-C3N4/PVDF-HFP piezo-photocatalyst has been developed. The SnO2/g-C3N4 photocatalyst with Z-Scheme charge transfer demonstrates high activity under simulated solar light. Simultaneously, ultrasound waves, employed to mimic water motion, serve to activate the piezoelectric properties of g-C3N4, thereby enhancing charge separation. Moreover, the immobilization of SnO2/g-C3N4 onto piezoelectric poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber mats augments its piezocatalytic efficiency and prevents dispersion in the reaction media. During the piezo-photocatalytic process, generated reactive species attack polystyrene (PS) NPs and introduce oxygen-based functional groups. This leads to surface corrosion, fragmentation, and 46 % mineralization in just 15 h under mild conditions, outperforming existing literature. Overall, this research emphasizes the importance of harnessing renewable energy sources for NP remediation.