Sorption properties of tylosin on four different microplastics.

After oxidation, abrasion and crushing, microplastics (MPs) can enter the aqueous environment and may adsorb surrounding organic pollutants, altering its migration and spatial distribution. Therefore, an investigation of the sorption properties and mechanism of organic pollutant on MPs can offer a theoretical basis for scientific evaluation of their ecological risks. Using tylosin (TYL) as a model pollutant, the sorption performance of MPs was examined via a series of batch equilibrium experiments which resulted the sorptive removal of TYL on MPs reached equilibrium at 36 h, and the sorption ability of TYL on the MPs followed the order of PE (polyethylene) < PP (polypropylene) < PS (polystyrene) < PVC (polyvinyl chloride). The pseudo-second-order model well fit for the sorption kinetics data, and the adsorption isotherms could be better described by Freundlich equation rather than Langmuir model. Additionally, the initial solution pH and ionic strength played important roles across the adsorption. The sorption procedure of TYL on MPs was dominated by electrostatic interaction, surface complexation and hydrophobic interaction.