Leaching-driven transformations of tire wear particles (TWPs): Uncovering the neglected environmental implications

Extensive research has been conducted on the leaching behavior and risks of the leachate of tire wear particles (TWPs) in aquatic environments. However, the leaching-driven transformations of TWPs and the subsequent environmental impacts have been largely overlooked. This work examines the changes in physicochemical properties of TWPs during leaching in several water bodies, thereby facilitating a more thorough assessment of the environmental impacts. The results revealed that the environmental behavior related properties of TWPs, including surface morphology, pores, contact angel, zeta potential, functional groups, and surface adsorption sites varied at different levels during leaching. The ionic strength and organic matter content of water body highly determine the above transformations. The carbon index (CI) and O/C ratio of TWPs increased by 55.40 % and 14.27 % after leached in the water for 30 days, while the adsorption capacity of the TWPs for tetracycline (TC) and oxytetracycline (OTC) decreased by 27 % and 24.63 %, respectively. Herein, the changes in the functional groups and polarity during leaching highly influenced the adsorption performance of leached-TWPs. This study provides novel insight into understanding the leaching behavior of TWPs in aquatic environments and highlights an urgent need to assess the environmental implications of leaching-driven transformations of TWPs.