State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China.
State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China; Jiaxing Research Institute, Zhejiang University, Jiaxing, 314000, China.
Chemosphere. 2023 Mar;317:137815. doi: 10.1016/j.chemosphere.2023.137815. Epub 2023 Jan 11.
The huge amount of plastic waste accumulated in landfills has caused serious microplastic (MP) pollution to the soil environment, which has become an urgent issue in recent years. It is challenging to deal with the non-biodegradable MP pollutants in actual soil from landfills. In this study, a coaxial dielectric barrier discharge (DBD) system was proposed to remediate actual MP-contaminated landfill soil due to its strong oxidation capacity. The influence of carrier gas type, applied voltage, and air flow rate was investigated, and the possible degradation pathways of MP pollutants were suggested. Results showed the landfill soil samples contained four common MP pollutants, including polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) with sizes ranging from 50 to 1500 μm. The MP pollutants in the soil were rapidly removed under the action of reactive oxygen species (ROS) generated by DBD plasma. Under the air flow rate of 1500 mL min, the maximum remediation efficiency represented by mass loss reached 96.5% after 30 min treatment. Compared with nitrogen, when air was used as the carrier gas, the remediation efficiency increased from 41.4% to 81.6%. The increased applied voltage from 17.5 to 24.1 kV could also promote the removal of MP contaminants. Sufficient air supply was conducive to thorough removal. However, when the air flow rate reached 1500 mL min and continued to rise, the final remediation efficiency would be reduced due to the shortened residence time of ROS. The DBD plasma treatment proposed in this study showed high energy efficiency (19.03 mg kJ) and remediation performance (96.5%). The results are instructive for solving MP pollution in the soil environment.
大量积累在垃圾填埋场中的塑料废物对土壤环境造成了严重的微塑料（MP）污染，这成为近年来的一个紧迫问题。处理实际垃圾填埋场中不可生物降解的 MP 污染物具有挑战性。在这项研究中，由于具有较强的氧化能力，提出了同轴介电阻挡放电（DBD）系统来修复实际的 MP 污染的垃圾填埋场土壤。研究了载气类型、施加电压和空气流量的影响，并提出了 MP 污染物的可能降解途径。结果表明，垃圾填埋场土壤样品中含有四种常见的 MP 污染物，包括尺寸在 50 至 1500 μm 之间的聚乙烯（PE）、聚丙烯（PP）、聚苯乙烯（PS）和聚氯乙烯（PVC）。在 DBD 等离子体产生的活性氧（ROS）的作用下，土壤中的 MP 污染物迅速被去除。在空气流量为 1500 mL min 的条件下，经过 30 min 处理，以质量损失表示的最大修复效率达到 96.5%。与氮气相比，当空气作为载气时，修复效率从 41.4%提高到 81.6%。增加施加电压从 17.5 千伏提高到 24.1 千伏也可以促进 MP 污染物的去除。充足的供气有利于彻底去除。然而，当空气流量达到 1500 mL min 并继续增加时，由于 ROS 的停留时间缩短，最终的修复效率将会降低。本研究提出的 DBD 等离子体处理具有较高的能量效率（19.03 mg kJ）和修复性能（96.5%）。研究结果对解决土壤环境中的 MP 污染具有指导意义。
