Microplastics as an Emerging Vector of Cr(Vi) in Water: Correlation of Aging Properties and Adsorption Behavior

Abstract

Microplastics (MPs) have attracted rising concern from the community due to their potential threat to human health. The aged MPs and their adsorption behavior were mostly studied to evaluate the capability of MPs to be pollutant’ carriers. However, knowledge about the correlation among the MPs structure, aging rule and adsorption behavior remains unclear, and it’s critical to understand the environmental fate of MPs. In this study, we developed a correlation equation to describe polyethene MPs’ physical-chemical properties (including size, surface area, crystallinity, melting temperature and so on) changes over time in an accelerated weathering environment. The applicability of this equation was tested by mutual validation relationship using the data collected from the molecular weight. Moreover, the adsorption behavior of polyethene MPs and Cr(VI) cations at different aging periods was observed. Through the verification analysis of the carbonyl index and molecular weight, molecular weight is an important parameter for characterizing aging. The equation obtained by fitting the data can be used to judge the aging degree, residence time and adsorption degree of polyethene MPs in water environments. It is proposed that this model can be beneficial to understand the related research of MPs, such as aging characteristics, adsorption behavior and risk assessment.

Keywords: Microplastics, Photoaging, Correlation, Polyethene, Adsorption