Feasible Degradation of Polyethylene Terephthalate Fiber‐Based Microplastics in Alkaline Media with Bi₂O₃@N‐TiO₂ Z‐Scheme Photocatalytic System

Abstract Fiber‐based microplastic (FMP) pollution in the wastewater of the textile industry and urban sewage has become an emerging issue and a potential threat to marine life and human health. However, most reported reduction strategies, such as physical adsorption/filtration and chemical‐catalytic degradation are limited by the secondary pollution caused by the desorption of FMPs and inferior degradation performance. Advanced technologies for efficient FMP control remain largely insufficient and underdeveloped. This work reports a Z‐scheme Bi₂O₃@N‐TiO₂ heterojunction synthesized by a solvothermal and wet‐impregnation strategy. Bi₂O₃@N‐TiO₂ degrades ≈10.23 ± 1.91 wt% of polyethylene terephthalate (PET)‐FMPs (a major FMP existing in the environment) at pH = 9, which is nearly three times higher than that at pH = 7. Experimental results show that the hydrolysis of PET‐FMPs in alkaline media is the main reason for the superior performance. Importantly, the hydrophilic, weight‐average molecular weight and crystallinity of PET‐FMP are the key factors affecting the photocatalytic degradation performance of PET‐FMPs. This study demonstrates an eco‐friendly strategy for remediation of FMP contamination.