Identification of the aged microplastics film and its sorption of antibiotics and bactericides in aqueous and soil compartments

Abstract

Here, thin-film microplastics (MPs) from black garbage bags were simulated aged by artificially ultraviolet radiation, and their sorption behavior toward antibiotics and bactericides in water and soil was explored. The chemical structure, surface functional groups, and the aged degree indicators of the identified polyethylene microplastics (PE-MPs) were studied by FT-IR spectra. The decreased crystallinity and hydrophobicity of PE-MPs-16 demonstrated by XRD and contact angle measurements and enhanced carbonyl index (0.0105) were highly related to the enhanced sorption capacities, especially for crystal violet (18.10 mg/g) in water. Moreover, PE-MPs-16 mitigated the adsorption rate and had little influence on the sorption capacity in soil. The sorption data fitted well to Henry (water) or Freundlich (soil) isotherm model, indicating the hydrophobic partition was involved in the sorption. Our research helps to clarify the interaction between MPs and organic pollutants and better understand the fate of virgin and aged PE-MPs in the varied compartments.