| 老化作用对微塑料吸附四环素的影响及其机制 |
| 摘要点击 2231 全文点击 1142 投稿时间：2021-12-29 修订日期：2022-02-25 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 微塑料(MPs) 老化作用 表面官能团 吸附 四环素(TC) 机制 |
| 英文关键词 microplastics (MPs) aging surface functional groups adsorption tetracycline (TC) mechanism |
|
| 中文摘要 |
| 微塑料（MPs）和抗生素同为新型污染物，微塑料可以在水环境中吸附抗生素并作为其载体而共同迁移，而微塑料会在环境中不断地老化，其吸附能力和吸附机制也会随之改变.以聚乙烯（PE）和聚苯乙烯（PS）为目标MPs，通过紫外法（UV-254）进行照射，对比老化前后微塑料颜色、表面形态和官能团等理化特性改变，以及其对四环素（TC）吸附的影响，探讨了相关影响机制.结果表明，准二级动力学模型能较好地模拟吸附过程，在24 h内达到吸附平衡，老化微塑料对TC的吸附量明显高于原始微塑料，且PS的吸附量高于PE.Langmuir和Freundlich等温吸附方程均能较好地描述吸附等温试验数据，TC在微塑料上的吸附是自发的和吸热的物理吸附过程，老化作用对微塑料吸附热力学特性无明显影响.随着pH值的增加，吸附量先增大后减小，老化前后的微塑料均在pH=5时达到最大吸附量.紫外老化增加了微塑料的比表面积，生成了—C＝O、—OH和O＝C＝O等含氧官能团，改变了微塑料的理化特性，从而改变了微塑料对TC的吸附机制：相比原始PE微塑料，老化PE除了疏水分配、范德华力和静电作用外，孔填充也是吸附的重要机制；原始PS微塑料的主要吸附机制为疏水分配、范德华力、π-π作用和静电作用，老化PS则增加了氢键和孔填充作用. |
| 英文摘要 |
| As new pollutants, microplastics (MPs) can adsorb antibiotics in the water environment and migrate together as carriers. However, microplastics will age continuously in the environment, and their adsorption capacity and adsorption mechanism will change accordingly. With polyethylene (PE) and polystyrene (PS) as the target MPs, which were irradiated by ultraviolet (UV-254), the changes in the physical and chemical properties of MPs before and after aging, such as the color, surface morphology, and functional groups, were compared, and their effects on the adsorption of tetracycline (TC) as well as the related mechanism were explored. The results showed that the pseudo-second-order model could better fit the adsorption process, the adsorption equilibrium was reached within 24 hours, the adsorption capacity of aged MPs for TC was significantly higher than that of original MPs, and the adsorption capacity of PS was higher than that of PE. Langmuir and Freundlich isothermal adsorption equations could both describe the adsorption isothermal test data, and the adsorption of TC on MPs was a spontaneous and endothermic physical adsorption process, whereas aging had no obvious effect on the adsorption thermodynamic characteristics of MPs. With the increase in pH value, the adsorption capacity first increased and then decreased. The maximum adsorption capacity of MPs before and after aging was reached at pH=5. UV aging increased the specific surface area of MPs, generating oxygen-containing functional groups such as -C＝O, -OH, and O＝C＝O, changing the physical and chemical properties of MPs, and thus changing the adsorption mechanism of MPs for TC. Compared with the original PE MPs, in addition to hydrophobic distribution, van der Waals forces, and electrostatic interactions, pore filling was also an important adsorption mechanism of aged PE. The main adsorption mechanisms of original PS microplastics were hydrophobic distribution, van der Waals forces, electrostatic interaction, and π-π interaction, whereas there was hydrogen bonding for aged PS. |
|
|
|
