Uv and Chemical Aging Alter the Adsorption Behavior of Microplastics for Tetracycline

This study evaluates the potential carrier effects of different microplastics (MPs) on coexisting pollutants. The adsorption behavior of biodegradable plastics Poly (butylene adipate-co-terephthalate) (PBAT) and non-biodegradable plastics Polystyrene (PS), Polypropylene (PP), and Polyethylene (PE) to Tetracycline (TC) after UV aging and chemical aging were investigated. Compared with conventional plastics, the physical and chemical properties of PBAT changed more obviously after UV radiation and chemical aging. Pores and cracks appear on the smooth surface of the aged PBAT. The crystallinity increased from 29.2% to 52.62%. In adsorption experiments, pristine and aged PBAT had higher carrier effects on TC than non-biodegradable plastics. The adsorption capacity on antibiotics of chemical aged PBAT was increased from 0.7980 mg g-1 to 1.2669 mg g-1. On this basis, the adsorption mechanism was investigated. Moreover, the results indicated that electrostatic interactions and hydrogen bonds controlled the adsorption process. In addition, in the process of PS adsorption of TC, π-π conjugation was involved in the adsorption process, and the adsorption mechanism was not considerably altered by aging. In conclusion, this study demonstrates that biodegradable plastics have a more substantial carrier effect on coexisting pollutants at the end of their life cycle, which may cause a more significant health threat to humans.