The role of humic substances’ hydrophobicity in heterogeneous adsorption onto microplastics: Insights from two-dimensional correlation hydrophilic interaction chromatography

IF 6.7 2区环境科学与生态学 Q1 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Environmental Technology & Innovation Pub Date : 2025-03-05 DOI:10.1016/j.eti.2025.104136

Tae Jun Park, Rabia Zafar, Jin Hur

{"title":"The role of humic substances’ hydrophobicity in heterogeneous adsorption onto microplastics: Insights from two-dimensional correlation hydrophilic interaction chromatography","authors":"Tae Jun Park, Rabia Zafar, Jin Hur","doi":"10.1016/j.eti.2025.104136","DOIUrl":null,"url":null,"abstract":"<div><div>The heterogeneous composition of humic substances (HS) complicates understanding their interactions with microplastics (MPs), which is critical for assessing the environmental roles of MPs in aquatic systems. This study investigated the adsorption behavior of HS onto pristine and aged polyethylene (PE) MPs, with a focus on how hydrophobic properties influence these interactions. Hydrophilic interaction chromatography (HILIC) revealed preferential adsorption of HS molecules with higher log K<sub>ow</sub> values onto MPs compared to those with lower values. This trend was more pronounced for aged MPs than pristine MPs and was stronger under acidic conditions. Two-dimensional correlation HILIC (2D-Co-HILIC) provided further insights, revealing sequential adsorption of HS subfractions based on hydrophobicity. For pristine MPs, Freundlich adsorption affinity (K<sub>F</sub>) values followed the log K<sub>ow</sub> order of 3.2 > 3.4 > 2.5, with corresponding K<sub>F</sub> values of 4.64 ± 0.12 > 0.71 ± 0.05 > 0.70 ± 0.08 (Abs/g)(Abs)<sup>1/n</sup>. For aged MPs, the order was 3.2 > 3.4 > 3.0 > 2.5, with K<sub>F</sub> values of 5.44 ± 0.07 > 5.02 ± 0.06 > 0.77 ± 0.07 > 0.23 ± 0.05. Hydrophobic interactions played a dominant role, particularly for aged MPs, where greater competition among HS molecules for adsorption sites occurred. Changes in the molecular weight of residual HS, inferred from fluorescence component ratios, indicated molecular size as a secondary factor in adsorption. This study highlights the critical role of hydrophobicity in HS-MP interactions and calls for further research into how these interactions impact the environmental behavior of HS and MPs in aquatic systems.</div></div>","PeriodicalId":11725,"journal":{"name":"Environmental Technology & Innovation","volume":"38 ","pages":"Article 104136"},"PeriodicalIF":6.7000,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Environmental Technology & Innovation","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2352186425001221","RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"BIOTECHNOLOGY & APPLIED MICROBIOLOGY","Score":null,"Total":0}

引用次数: 0

Abstract

The heterogeneous composition of humic substances (HS) complicates understanding their interactions with microplastics (MPs), which is critical for assessing the environmental roles of MPs in aquatic systems. This study investigated the adsorption behavior of HS onto pristine and aged polyethylene (PE) MPs, with a focus on how hydrophobic properties influence these interactions. Hydrophilic interaction chromatography (HILIC) revealed preferential adsorption of HS molecules with higher log K_ow values onto MPs compared to those with lower values. This trend was more pronounced for aged MPs than pristine MPs and was stronger under acidic conditions. Two-dimensional correlation HILIC (2D-Co-HILIC) provided further insights, revealing sequential adsorption of HS subfractions based on hydrophobicity. For pristine MPs, Freundlich adsorption affinity (K_F) values followed the log K_ow order of 3.2 > 3.4 > 2.5, with corresponding K_F values of 4.64 ± 0.12 > 0.71 ± 0.05 > 0.70 ± 0.08 (Abs/g)(Abs)^1/n. For aged MPs, the order was 3.2 > 3.4 > 3.0 > 2.5, with K_F values of 5.44 ± 0.07 > 5.02 ± 0.06 > 0.77 ± 0.07 > 0.23 ± 0.05. Hydrophobic interactions played a dominant role, particularly for aged MPs, where greater competition among HS molecules for adsorption sites occurred. Changes in the molecular weight of residual HS, inferred from fluorescence component ratios, indicated molecular size as a secondary factor in adsorption. This study highlights the critical role of hydrophobicity in HS-MP interactions and calls for further research into how these interactions impact the environmental behavior of HS and MPs in aquatic systems.

查看原文本刊更多论文

求助全文

约1分钟内获得全文求助全文

来源期刊

Environmental Technology & Innovation Environmental Science-General Environmental Science

CiteScore

14.00

自引率

4.20%

发文量

435

审稿时长

74 days

期刊介绍： Environmental Technology & Innovation adopts a challenge-oriented approach to solutions by integrating natural sciences to promote a sustainable future. The journal aims to foster the creation and development of innovative products, technologies, and ideas that enhance the environment, with impacts across soil, air, water, and food in rural and urban areas. As a platform for disseminating scientific evidence for environmental protection and sustainable development, the journal emphasizes fundamental science, methodologies, tools, techniques, and policy considerations. It emphasizes the importance of science and technology in environmental benefits, including smarter, cleaner technologies for environmental protection, more efficient resource processing methods, and the evidence supporting their effectiveness.