Polyethylene terephthalate microfiber release from textiles in coastal seawater ecosystems under sunlight-driven photochemical transformation

Microfibers are ubiquitous in marine environments and are widely believed to be derived from synthetic textiles. While the forces driving microfiber formation in aquatic environments have yet to be clarified. In this study, we investigated the formation of polyethylene terephthalate (PET) microfibers released from textiles when subjected to long-term photoaging in coastal seawater environments. Results revealed that after 12 d of laboratory–accelerated UV irradiation, microfiber fragments were observed to be released from colored textiles. Specifically, 47,400, 37,020, 23,250, and 14,400 microfiber fragments were released from 0.1 g of purple, green, yellow, and blue textiles, respectively. This demonstrates that long-term photoaging can effectively convert PET textiles to microfiber. Furthermore, purple PET microfiber was demonstrated to have a higher photoaging rate compared to green, blue, and yellow ones, which is attributed to the dispersed dyes in purple textiles (0.0287) having higher light absorption than those in yellow (0.0237), blue (0.0252), and green (0.0287). Additionally, purple PET microfiber (6.20 × 10−15 M) generated more hydroxyl radicals than green, blue, and yellow microfibers (5.50 × 10−15, 4.84 × 10−15, and 4.17 × 10−15 M), which further accelerated the PET microfiber photoaging. The presented data offers new insights unraveling the formation and associated ecological risks of microfibers in coastal seawater environments.