Insights into the controlling factors of the transport of tire wear particles in saturated porous media: The facilitative role of aging and fulvic acid

• Published in: The Science of the total environment 2024-11, Vol.951, p.175665, Article 175665
• Main Authors: Zi, Shaoxin, Wu, Di, Zhang, Yingxin, Jiang, Xiangtao, Liu, Jin
• Format: Article
• Language: English
• Subjects: CFT; Hydrus-1D; Tire wear particles; Transport; XDLVO theory
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.175665

The widespread distribution and potential adverse effects of tire wear particles (TWPs) on soil and groundwater quality pose a growing environmental concern. This study investigated the transport behavior of TWPs in saturated porous media and elucidated the underlying mechanisms influenced by environmental factors. Additionally, the effects of key environmental factors, such as aging, ionic strength, cation species, medium type, and natural organic matter (NOM), on the transport of TWPs were evaluated. The results showed that aging processes simulated through O3 and UV irradiation altered the physicochemical properties of TWPs, increased the mobility of TWPs at low ionic strengths. However, the high ionic strengths and the presence of Ca2+ significantly inhibited the mobility of TWPs due to enhanced aggregation. The transport mechanism of the original and aged TWPs shifted from blocking to ripening under favorable retention conditions (i.e., high ionic strengths, divalent cations, and fine sands). Interestingly, the presence of fulvic acid (FA) inhibited the ripening of the three TWPs, significantly promoting their transport through a spatial site resistance mechanism. The two-site kinetic attachment model (TSKAM), extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, and colloid filtration theory (CFT) were applied to describe the transport behavior of the TWPs. The study provided a comprehensive understanding of the transport behavior of TWPs in groundwater environments, highlighting the environmental risks associated with their widespread distribution. [Display omitted] •Aging enhances TWPs mobility under unfavorable retention conditions.•Under favorable retention conditions, ripening dominates with no significant TWPs mobility difference.•FA eliminates ripening, greatly increasing TWPs mobility.•When ripening occurs, TSKAM explains TWPs' fate in the effluent better than CFT.