| 纳米塑料颗粒在饱和多孔介质中的迁移规律 |
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| 引用本文： | 叶芯瑶,吴鸣,胡晓农,程洲,莫测辉.纳米塑料颗粒在饱和多孔介质中的迁移规律[J].地质科技通报,2022,41(4):225-233. |
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| 作者姓名： | 叶芯瑶 吴鸣 胡晓农 程洲 莫测辉 |
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| 作者单位： | 1a.暨南大学广东省环境污染与修复材料工程技术研究中心, 广州 510632 |
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| 基金项目： | 国家自然科学基金项目41902246广东省自然科学基金项目2020A1515010447 |
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| 摘 要： | 针对纳米塑料颗粒在饱和多孔介质中的迁移及其影响因素, 以纳米聚苯乙烯(PSNPs)作为典型纳米塑料颗粒, 通过实验和理论相结合的方法研究纳米塑料颗粒的迁移规律。以经典DLVO理论计算出PSNPs与石英砂颗粒之间的相互作用能, 分析预测PSNPs与石英砂之间的吸附、聚沉。在柱实验中, 以石英砂作为多孔介质填充到砂柱中, 让PSNPs在一维饱和砂柱中迁移, 研究不同条件下PSNPs的迁移行为和影响因素。结果表明, 当离子强度由1 mmol/L增至50 mmol/L(电解质为NaCl), PSNPs与石英砂颗粒之间的相互作用能的势垒则从215.13 KT逐渐降低至45.9 KT使得PSNPs更易于吸附在石英砂介质表面, 从而降低PSNPs在多孔介质中的迁移能力, PSNPs的穿透率由62.16%降至3.65%。当离子强度由0.1 mmol/L增至5 mmol/L(电解质为CaCl2)时, 势垒则由33.72 KT降至14.03 KT, PSNPs的穿透率从82.46%降至4.27%。这些实验现象说明增加离子强度对PSNPs的穿透起到抑制作用, 且Ca2+比Na+具有更强的电荷屏蔽作用。同时提高PSNPs的初始浓度、流速和介质粒径均可增大PSNPs的穿透率, 而大粒径PNSPs颗粒的穿透率则较小。研究中构建了PSNPs实际运移与理论之间的关系, 进一步推进PSNPs的环境行为和机理研究, 为系统全面评价纳米塑料颗粒在土壤-地下水中的环境风险和生态安全提供科学依据。
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| 关 键 词： | 纳米塑料 多孔介质 迁移 DLVO理论 实验 |
| 收稿时间： | 2021-05-13 |
Migration mechanism of nanoplastic particles in saturated porous media |
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| Institution: | 1a.Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, Jinan University, Guangzhou 510632, China1b.College of Life Science and Technology, Jinan University, Guangzhou 510632, China2.School of Water Conservancy and Environment, University of Jinan, Jinan 250022, China3.Guangdong Provincial Academy of Environmental Science, Guangzhou 510045, China |
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| Abstract: | To investigate the migration of nanoplastic particles in saturated porous media and the associated influencing factors, polystyrene nanoparticles (PSNPs) are selected as typical nanoplastics in this study. The migration behavior and mechanism of PSNPs in saturated porous media is investigated through a combination of physical experiments and DLVO theory. First, the interaction energy between PSNPs and quartz sand particles is calculated based on DLVO theory, and then a column experiment is conducted to investigate the characteristics of PSNP migration in porous media under different conditions.According to the experimental results, when the ionic strength (NaCl) increases from 1 mmol/L to 50 mmol/L, the value of the energy barrier between PSNPs and quartz sand based on DLVO theory gradually decreases from 215.13 KT to 45.9 KT. PSNPs are easier to be adsorbed on the surface of quartz sand media, thereby reducing the migration ability of PSNPs in porous media, the penetration rate consequently decreases from 62.16% to 3.65%. When the ionic strength (CaCl2) increases from 0.1 mmol/L to 5 mmol/L, the value of the energy barrier decreases from 33.72 KT to 14.03 KT, and the penetration rate decreases from 82.46% to 4.27%. These experimental phenomena indicate that increasing the ionic strength can inhibit the penetration of PSNPs, and Ca2+ has a stronger charge shielding effect than Na+. At the same time, increasing the initial concentration, flow rate and particle size of the medium can increase the penetration rate of PSNPs, while the penetration rate of large-diameter PNSPs particles is smaller. The implementation of this research will contribute to further understanding the environmental behavior and risks of nanoplastics in porous media and provide a scientific basis for accurately predicting and assessing the environmental risks of nanoplastics in soil-groundwater systems. |
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