Enhanced photocatalytic degradation of polyethylene microplastics under simulated sunlight using Fe3O4@TiO2/Ag nanocomposite and optimization via response surface methodology

Microplastics (MPs) pose significant environmental and health risks, and conventional disposal methods often suffer from inefficiency and potential ecological harm. Photocatalytic degradation has emerged as a promising solution. However, traditional TiO 2 -based photocatalysts are limited by high electron–hole recombination rates, narrow visible light absorption, and poor reusability. In this study, we develop and optimize a Fe 3 O 4 @TiO 2 /Ag nanocomposite for the efficient degradation of polyethylene (PE) MPs with facile recovery. The synergistic integration of Fe 3 O 4 and Ag with TiO 2 enhances visible light absorption and mitigates charge carrier recombination. Notably, the Fe 3 O 4 @TiO 2 /Ag nanocomposite exhibits a degradation efficiency of 15.54%, outperforming Fe 3 O 4 @TiO 2 (12.63%) and pristine TiO 2 (1.15%). Moreover, the composite maintains its performance over five consecutive cycles, underscoring its durability. The degradation efficiency of Fe 3 O 4 @TiO 2 /Ag was further optimized using response surface methodology. Overall, the developed Fe 3 O 4 @TiO 2 /Ag nanocomposite exhibits excellent photocatalytic efficiency, magnetic recoverability, and long-term stability, highlighting its potential for practical applications in mitigating microplastic pollution.