Gao Juntong, Ju Ziqian, Yang Qimeng, Zhou Xinwei
College of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China.
College of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, China; College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
Sci Total Environ. 2025 Jan 1;958:178156. doi: 10.1016/j.scitotenv.2024.178156. Epub 2024 Dec 20.
Microplastics entering the aqueous environment are susceptible to the surrounding environmental processes, including biofilm formation and natural organic matter (NOM) adsorption, which significantly alters their properties and environmental fate. In this study, polyethylene (PE), polyvinyl chloride (PVC) and polyethylene terephthalate (PET) microplastics were respectively incubated in the untreated and disinfected freshwater to investigate the different effects of biofilm formation and only NOM adsorption on the properties of microplastics. The results showed that the total amount of fouling biomass driven by biofilm formation was markedly higher than that of NOM adsorption. The changes in microplastic surface morphologies and special surface area dominated by biofilm formation and NOM adsorption were different; biofilm formation induced various shaped bacteria and a dense layer of extracellular polymeric substances adhering on microplastic surfaces with the decreased special surface area, whereas NOM adsorption mainly resulted in the obvious pores, cracks and winkles and the increased special surface area, indicating the initial degradation of microplastics. Moreover, both biofilm formation and NOM adsorption could reduce the hydrophobicity of three microplastics. The decreased trends of the hydrophobicity of microplastics were closely related to the amount of fouling biomass in a linear relationship with different influenced coefficients (slope a), subsequently verifying that NOM adsorption played a key role in the alternation of the hydrophobicity of microplastics. Surface chemical characterization by FTIR and 3D-EEMs presented the generation of additional functional groups and components on the microplastic surface attributed to the biofilm formation and NOM adsorption in different extent and sequence. This study provides more detailed information about the different effects of biofilm formation and NOM adsorption on the properties of microplastics in the aqueous environment.
进入水环境的微塑料易受周围环境过程的影响，包括生物膜形成和天然有机物（NOM）吸附，这会显著改变它们的性质和环境归宿。在本研究中，将聚乙烯（PE）、聚氯乙烯（PVC）和聚对苯二甲酸乙二酯（PET）微塑料分别在未处理和消毒的淡水中进行培养，以研究生物膜形成和仅NOM吸附对微塑料性质的不同影响。结果表明，生物膜形成驱动的污垢生物量总量明显高于NOM吸附。生物膜形成和NOM吸附主导的微塑料表面形态和比表面积变化不同；生物膜形成诱导各种形状的细菌和一层致密的细胞外聚合物附着在微塑料表面，比表面积减小，而NOM吸附主要导致明显的孔隙、裂缝和褶皱以及比表面积增加，表明微塑料开始降解。此外，生物膜形成和NOM吸附都能降低三种微塑料的疏水性。微塑料疏水性的降低趋势与污垢生物量密切相关，呈线性关系，影响系数（斜率a）不同，随后验证了NOM吸附在微塑料疏水性变化中起关键作用。通过傅里叶变换红外光谱（FTIR）和三维激发发射矩阵光谱（3D-EEMs）进行的表面化学表征表明，由于生物膜形成和NOM吸附，微塑料表面在不同程度和顺序上产生了额外的官能团和成分。本研究提供了关于生物膜形成和NOM吸附对水环境中微塑料性质的不同影响的更详细信息。
