Work

Insights into How Degradable Microplastics Enhance Cu2+ Mobility in Soil Through Interfacial Interaction

Year: 2025

Type: article

Abstract: The incomplete degradation of degradable plastics may pose potential ecological risks, as it can generate degradable microplastics (DMPs), especially when these DMPs coexist with heavy metals in soil. Taking petrochemical-based poly(butylene adipate-co-terephthalate) (PBAT) and bio-based polylactic acid (PLA) as representative DMPs, this study investigated how DMPs affect the adsorption–desorption behavior of Cu2+ in soil and the underlying mechanisms via batch equilibrium experiments and characterization analyses. The experiments revealed that ion exchange (accounting for 33.6–34.3%), oxygen-containing functional group complexation, and electrostatic interactions were the primary adsorption driving forces, with chemical adsorption playing the main role. Compared to the soil, the PBAT and PLA had smaller specific surface areas and pore volumes, fewer oxygen-containing functional groups, and especially lacked O-metal functional groups. They can dilute soil, clog its pores, and cover its active sites. 1% DMPs significantly reduced the soil’s equilibrium adsorption capacity (Qe) (3.7–4.7%) and increased equilibrium desorption capacity (QDe) (1.7–2.6%), thereby increasing the mobility and ecological risk of Cu2+. PBAT and PLA had no significant difference in effects on the adsorption, but their specific mechanisms were somewhat distinct. Faced with the prevalent, worsening coexistence of DMPs and heavy metals in soil, these findings contribute to the ecological risk assessment of DMPs.

Source: Toxics

DOI: 10.3390/toxics13090795

Authors: Hongjia Peng, Bolun Yu, Zuhong Lin, Haipu Li

Institution: Central South University

Language: English

Topic: Microplastics and Plastic Pollution

Subfield: Pollution

Field: Environmental Science

Domain: Physical Sciences

SDG: Life on land

Open Access status: gold

Estimated APC paid: $3,137