Recent advances and protocol summaries for degradation of polyethylene microplastics using TiO₂-based photocatalysts

The amount of plastic waste is increasing exponentially worldwide, and the environmental impact of microplastics (MPs) is correspondingly significant. Developing photocatalysts capable of degrading MPs is a critical area of research. However, the wide variation in experimental conditions for photocatalytic MPs degradation poses challenges for conducting comparative studies and advancing efficient photocatalyst design. Since polyethylene (PE) and TiO₂ are among the most extensively studied materials for MPs and photocatalysts, respectively, this review focuses on recent advances in the degradation of PE MPs using TiO₂-based photocatalysts. The review examines the mechanisms of photocatalytic degradation of PE MPs and summarizes protocols for the preparation of PE MPs, TiO₂-based photocatalysts, and photocatalytic assessment systems. Additionally, it introduces methods for quantifying degraded PE MPs and compares recently reported PE MPs degradation efficiencies, accounting for variations in photocatalytic assessment parameters. This review aims to contribute to the establishment of a standardized laboratory-scale protocol for photocatalytic PE MPs degradation research.