School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215000, China.
School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215000, China.
J Contam Hydrol. 2024 Jul;265:104395. doi: 10.1016/j.jconhyd.2024.104395. Epub 2024 Jul 14.
Microplastics (MPs) are emerging contaminants that are attracting increasing interest from researchers, and the safety of drinking water is greatly affected by their transportation during filtration. Polystyrene (PS) was selected as a representative MPs, and three filter media (quartz sand, zeolite, and anthracite) commonly found in water plants were used. The retention patterns of PS-MPs by various filter media under various background water quality conditions were methodically investigated with the aid of DLVO theory and colloidal filtration theory. The results show that the different structures and elemental compositions of the three filter media cause them to exhibit different surface roughnesses and surface potentials. A greater surface roughness of the filter media can provide more deposition sites for PS-MPs, and the greater surface roughness of zeolite and anthracite significantly enhances their ability to inhibit the migration of PS-MPs compared with that of quartz sand. However, surface roughness is not the only factor affecting the migration of MPs. The lower absolute value of the surface potential of anthracite causes the DLVO energy between it and PS-MPs to be significantly lower than that between zeolite and PS-MPs, which results in stronger retention of PS-MPs by anthracite, which has a lower surface roughness, than zeolite, which has a higher surface roughness. The transport of PS-MPs in the medium is affected by the combination of the surface roughness of the filter media and the DLVO energy. Under the same operating conditions, the retention efficiencies of the three filter materials for PS-MPs followed the order of quartz sand < zeolite < anthracite. Additionally, the conditions of the solution markedly influenced the transport ability of PS-MPs within the simulated filter column. The transport PS-MPs in the simulated filter column decreased with increasing solution ionic strength and cation valence. Naturally, dissolved organic matter promoted the transfer of PS-MPs in the filter layer, and humic acid had a much stronger facilitating impact than fulvic acid. The study findings might offer helpful insight for improving the ability of filter units ability to retain MPs.
微塑料（MPs）是一种新兴的污染物，引起了越来越多研究人员的关注，其在过滤过程中的迁移对饮用水的安全性有很大的影响。聚苯乙烯（PS）被选为代表性的 MPs，使用了三种在水厂中常见的过滤介质（石英砂、沸石和无烟煤）。借助 DLVO 理论和胶体过滤理论，系统研究了不同背景水质条件下各种过滤介质对 PS-MPs 的截留模式。结果表明，三种过滤介质的不同结构和元素组成导致它们具有不同的表面粗糙度和表面电位。过滤介质的表面粗糙度越大，可以为 PS-MPs 提供更多的沉积点，沸石和无烟煤的表面粗糙度更大，显著增强了它们抑制 PS-MPs 迁移的能力，而与石英砂相比，其表面粗糙度更大。然而，表面粗糙度并不是影响 MPs 迁移的唯一因素。无烟煤的表面电位绝对值较低，导致其与 PS-MPs 之间的 DLVO 能量显著低于沸石与 PS-MPs 之间的 DLVO 能量，从而导致表面粗糙度较低的无烟煤对 PS-MPs 的保留能力强于表面粗糙度较高的沸石。 MPs 在介质中的传输受过滤介质表面粗糙度和 DLVO 能量的综合影响。在相同的操作条件下，三种过滤材料对 PS-MPs 的保留效率顺序为：石英砂<沸石<无烟煤。此外，溶液条件明显影响 PS-MPs 在模拟滤柱中的传输能力。在模拟滤柱中，PS-MPs 的传输量随溶液离子强度和阳离子价态的增加而降低。天然存在的溶解有机物促进了 PS-MPs 在滤层中的转移，腐殖酸的促进作用比富里酸强得多。研究结果可能为提高滤单元保留 MPs 的能力提供有益的见解。
