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Research on the effect of dissolved organic matter on the adsorption of oxytetracycline by high-density polyethylene

Qitian XIAO, Hui Liu , Jiying Zou, Haonan He, Jia Wei, Zhesheng Hou

Abstract

Rationale Dissolved organic matter (DOM) influences the migration and transformation of environmental pollutants through its diverse functional groups and properties. Microplastics, as emerging pollutants, adsorb organic contaminants, but how DOM from different sources (e.g., commercial fulvic acid vs. soil-extracted DOM) affects these adsorption mechanisms remains poorly understood. Methodology This study investigated the adsorption of oxytetracycline (OTC) by high-density polyethylene (HDPE) microplastics in the presence of FA and soil DOM. Batch adsorption experiments, combined with UV-Vis and FTIR spectroscopy, were conducted to analyze the mechanisms. Results The results showed that HDPE adsorption of FA was primarily physical. DOM addition significantly enhanced OTC adsorption by HDPE, with FA exhibiting a stronger promoting effect than soil DOM. Spectral analysis revealed that DOM acted as a bridge in the HDPE-OTC system, without altering the physical adsorption mechanism. Although FA and soil DOM exhibited similar adsorption mechanisms, their effects differed, likely due to structural and functional group variations. Discussion This study highlights the critical role of DOM in microplastic-pollutant interactions and emphasizes the impact of DOM sources on adsorption behavior. Future research should incorporate more environmentally relevant DOM sources to better simulate natural conditions and advance understanding of pollutant migration and transformation.

EN24101  Accepted 02 May 2025

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