• 关键词：微塑料  聚乙烯（PE）  聚苯乙烯（PS）  吸附行为  吸附机理  农田土壤  多环芳烃（PAHs）

• 基金项目：国家重点基础研究发展计划（973计划）项目（No.2014CB441106）

• 李珍
• 沈阳大学环境学院区域环境与生态修复教育部重点实验室，沈阳 110044;沈阳大学建筑工程学院，沈阳 110044

• 孙丽娜
• 沈阳大学环境学院区域环境与生态修复教育部重点实验室，沈阳 110044

• 范琪
• 沈阳大学建筑工程学院，沈阳 110044

• 杨昊
• 沈阳大学建筑工程学院，沈阳 110044

• 刘文浪
• 沈阳大学建筑工程学院，沈阳 110044

• 李宣枝
• 沈阳大学建筑工程学院，沈阳 110044

• 肖雅婷
• 沈阳大学建筑工程学院，沈阳 110044

• 摘要：本研究旨在探讨微塑料对土壤基质中16种多环芳烃（PAHs）吸附的影响.通过批实验考察了PAHs在聚乙烯（PE）和聚苯乙烯（PS）微塑料上的吸附过程，系统地评价了pH和腐殖酸（HA）浓度等环境因素对微塑料吸附土壤PAHs的影响.结果表明，微塑料对土壤中PAHs的吸附动力学符合准二级动力学模型，且Freundlich模型对吸附结果的拟合程度（R²=0.9868~0.9931）明显高于Langmuir模型（R²=0.8638~0.8927）， 说明微塑料对PAHs的吸附过程主要为化学吸附.通过吸附热力学计算的ΔH均为正值，ΔG为负值，表明微塑料对土壤PAHs的吸附是自发的吸热过程.pH和HA对PE和PS微塑料吸附PAHs的影响显著，PE和PS微塑料对PAHs的吸附量分别在pH=5.0和pH=7.0时达到峰值；腐殖酸浓度的增加抑制了PAHs在PE微塑料上的吸附，吸附量从9363.95 ng·g^-1降到4877.42 ng·g^-1，但促进了PAHs在PS微塑料上的吸附，吸附量从9422.71 ng·g^-1增加到13259.73 ng·g^-1，这表明PAHs对腐殖酸的亲和力高于对PE微塑料的亲和力.微塑料对土壤PAHs的吸附主要与静电 作用、π-π作用和疏水作用有关.

• Abstract：The purpose of this paper was to investigate the effect of microplastics （MPs） on the adsorption of the 16 polycyclic aromatic hydrocarbons （PAHs） in the soils. Through batch experiments， the sorption process of PAHs on polyethylene （PE） and polystyrene （PS） MPs was investigated， and the effects of environmental factors such as pH and humic acid （HA） concentration on the adsorption of PAHs by MPs were systematically evaluated. The results showed that the adsorption kinetics of PAHs on MPs was fitted well with the pseudo-second-order kinetic model. The fitting degree of Freundlich model （R²=0.9868~0.9931） to the adsorption results was significantly higher than that of Langmuir model （R²=0.8638~0.8927）， which indicated that the adsorption process of PAHs on MPs was mainly chemical adsorption. It's calculated by adsorption thermodynamics that the ΔH was positive and the ΔG was negative， which indicated that the adsorption of PAHs was spontaneous and endothermic processes. The pH and HA had a significant effect on the adsorption of PAHs by PE and PS MPs， and the adsorption capacity of PAHs by PE and PS MPs reached the peak at pH 5.0 and pH 7.0， respectively. Additionally， the increasing concentration of HA restrained the sorption of PAHs on PE MPs， and the adsorption amount decreased from 9363.95 ng·g^-1 to 4877.42 ng·g^-1， but promoted the adsorption of PAHs on PS MPs， and the adsorption amount increased from 9422.71 ng·g^-1 to 13259.73 ng·g^-1， which indicated that the affinity of PAHs to HA was greater than that of PAHs to PE MPs. Furthermore， the adsorption of the PAHs by MPs were mainly related to electrostatic interaction， π-π interactions， and hydrophobic interaction.

• Key words：microplastics  polyethylene （PE）  polystyrene （PS）  adsorption behavior  adsorption mechanism  farmland soil  polycyclic aromatic hydrocarbons

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