| 老化前后微塑料对富里酸的吸附 |
| 摘要点击 2075 全文点击 613 投稿时间：2021-07-05 修订日期：2021-08-15 |
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| 中文关键词 聚酰胺66(PA66) 聚丙烯(PP) 富里酸(FA) 老化 吸附 微塑料(MPs) |
| 英文关键词 polyamide 66 (PA66) polypropylene (PP) fulvic acid (FA) aging adsorption microplastics (MPs) |
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| 中文摘要 |
| 由于微塑料（MPs）在地表水环境中的广泛存在以及对水中有机污染物的较强吸附能力，其与地表水中天然有机物间的相互作用不容忽视.为深入了解微塑料对天然有机物的影响，开展了老化前后聚酰胺66（PA66）和聚丙烯（PP）两种微塑料吸附富里酸（FA）的研究.结果表明，老化前后的微塑料吸附富里酸的试验数据较好地拟合了准二级动力学模型（R2>0.94），吸附平衡在48 h以内达到，且PA66对富里酸的吸附能力要好于PP，老化过程可促进微塑料对富里酸的吸附.吸附等温数据则较好地拟合了Freundlich模型，吸附过程以多层不均匀的物理吸附为主，热力学结果显示该吸附过程是自发的吸热反应.随着pH的增加，老化前后微塑料对富里酸的吸附能力先降低后增加.解吸试验表明富里酸在超纯水中的解吸率皆高于地表水，且老化后的解吸率皆小于老化前.老化过程对微塑料的结构有较大的影响，老化后两种微塑料的比表面积都大幅增加且表面粗糙度增大，但官能团的变化较小.微塑料的比表面积和极性是影响吸附过程的主要因素，老化前后微塑料对富里酸的吸附机制主要是疏水作用和π-π相互作用. |
| 英文摘要 |
| Due to the wide distribution and strong adsorption ability of microplastics (MPs) for organic matter in aquatic environments, the interaction between MPs and natural organic matter (NOM) cannot be ignored. In this study, virgin and aging polyamide 66 (PA66) and polypropylene (PP) MPs were used to adsorb fulvic acid (FA) in order to understand the effect of MPs on NOM. The results indicated that the kinetics experimental data of FA adsorption on virgin and aging MPs well fitted the pseudo-second-order model (R2>0.94), and the adsorption equilibrium was reached at 48 h. Compared to that of PP, the adsorption capacity of FA on PA66 were relatively higher, and the aging process improved the adsorption ability of MPs for FA. Freundlich models were well fitting with the adsorption isotherms experimental data compared to Langmuir models, indicating that the adsorption of FA on the virgin and aging MPs was a multi-layer heterogeneous physical process. The thermodynamics analysis revealed that the adsorption was spontaneous and endothermic. With the increase in pH, the adsorption capacity of FA first decreased and then increased. The desorption experiment indicated that the FA desorbed from the tested MPs in ultrapure water obtained higher desorption rates than that in surface water, and the desorption rates of aging MPs were less than that of the corresponding virgin ones. The aging process had a great influence on the structure of MPs, which resulted in a distinct increase in surface area and roughness of MPs, but slightly affected functional groups. Specific surface area and polarity of MPs were the main influencing factors for the adsorption process, and the main mechanism of FA adsorption on the tested MPs was hydrophobic and π-π interactions. |
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