High-Efficiency photocatalytic degradation of polystyrene microplastics using In2O3-rGO nanocomposite catalysts under visible Light

Abstract

Polystyrene, when present as microplastics, is a significant pollutant with detrimental effects on human health. In light of this issue, our study introduces a method for the degradation of polystyrene through photocatalysis and its subsequent removal from drinking water via filtration. We investigated the photocatalytic degradation of 500 nm polystyrene (PS) using the highly efficient In₂O₃-rGO nanocomposite under visible light. FESEM analysis demonstrated that, after 12 h of visible light exposure, the size of the polystyrene beads decreased from 500 to 280 nm. This process resulted in a 56% degradation efficiency of polystyrene by the In₂O₃-rGO nanocomposite. Furthermore, the degraded polystyrene beads began to form networks, and with continued exposure to visible light, they merged into larger aggregates, as observed in FESEM images. Raman spectroscopy showed an increase in the peak at 1003.20 cm⁻¹ with extended visible light exposure, indicating a crucial step in the degradation process. Additionally, FTIR analysis confirmed the formation of carbonyl groups with increased light exposure, supporting the degradation of polystyrene. Our study presents a method and mechanism demonstrating how the In₂O₃-rGO nanocomposite not only reduces the size of polystyrene but also facilitates the formation of networks among degraded polystyrene beads, aiding in the filtration of smaller polystyrene particles.