Hydrophobic sorption behaviors of 17β-Estradiol on environmental microplastics

Microplastics (MPs) have been regarded as a vector for contaminants and greatly affect the migration and fate of hydrophobic organic compounds (HOCs) in marine water. In this study, the sorption behavior of 17β-estradiol (E2) on MPs was investigated in marine water system. The sorption capacity of E2 varied greatly with the chemical structures of MPs. The adsorption or partition contribution of E2 sorption on MPs was well quantified with adsorption-partition dual-mode model mechanism. The hydrophobic partition dominantly regulates the sorption of E2 due to the high crystallinity of MPs and high accessibility of amorphous domain of rubbery MPs. Smaller particle size benefits the sorption of E2 on same kind of MPs. The salinity and dissolved organic matter (DOM) have minor effect on E2 sorption by MPs in real marine water. The result shows that the MPs greatly influence the transportation of E2 and cause potential environmental risk to marine ecosystem. [Display omitted] •The sorption ability of E2 on MPs followed the order of PA > HD/LLD-PE > PP > LD/MD-PE > PS > PC > PMMA > PVC.•Hydrophobic partition of E2 on MPs was dominant sorption mechanism.•The E2 sorption capacity on MPs was positively correlated with the crystallinity of MPs.•The flexible rubbery state of amorphous domain of MPs is more favorable for E2 sorption.