Impact of Digestion on Surface Microstructures of Microplastics

Abstract Recently, there have been more reports and concerns about microplastics from various media and journals in the world. Except for land and water pollutions, much attention has been given to the impact of microplastics on animal and human health. However, previous studies have shown that digestion could not affect the particles of various microplastics due to their stable behavior. This work focuses on the impact of artificial digestion on the surface microstructures of microplastics from well recognized popular sources such as PP, PE, PET, PS and PVC. SEM and AFM were used to study the impact of artificial digestion on the surface morphologies of microplastics; while ATR-FTIR and XPS were used to investigate the impact of artificial digestion on the chemical properties of the surface of the microplastics. There were no physical differences observed by both SEM and AFM. There were no significant chemical differences detected by both FTIR and XPS after treatment. The slight differences of resolved C1s spectra for PS and PET samples detected by XPS should be further investigated. The study results show that the digestion system could not decompose the microplastics. Generally, plastic particles are widely considered to be inert due to their low chemical reactivity.