Comparison of aging behavior and adsorption processes of biodegradable and conventional microplastics

With the increasing severity of the plastic pollution issue, biodegradable plastics are considered a critical approach to addressing plastic pollution. However, the aging process of biodegradable plastics and the resulting microplastics adsorption of pollutants in the environment are not clearly understood. This study investigated the physicochemical property changes of different microplastics (Biodegradable microplastics and nonbiodegradable microplastics) during aging, examined the adsorption processes and mechanisms of biodegradable plastics and non-degradable plastics towards typical pollutants in the environment, and elucidated the different aging mechanisms and adsorption mechanisms of biodegradable plastics and non-biodegradable plastics. The experimental results indicated that compared to non-biodegradable microplastics, biodegradable microplastics are more prone to aging in the environment, forming smaller microplastic particles and easier adsorption of environmental pollutants. Biodegradable microplastics have abundant oxygen-containing functional groups on the surface, which enhance age biodegradable microplastics adsorption capacity for pollutants through electrostatic interactions, chelation, and hydrogen bonding. The experimental results show that a strong oxidation system has unique advantages in the aging removal of biodegradable microplastics and can effectively reduce the adsorption equilibrium capacity of biodegradable microplastics. This research contributes to a deeper understanding of biodegradable microplastics' aging and adsorption behaviors in the environment, highlighting their significant role as carriers of pollutants.