Motiejauskaitė Dovilė, Barčauskaitė Karolina
Lithuanian Research Centre for Agriculture and Forestry, Institute of Agriculture Instituto al. 1, Akademija, LT-58344, Kėdainiai distr., Lithuania.
Lithuanian Research Centre for Agriculture and Forestry, Institute of Agriculture Instituto al. 1, Akademija, LT-58344, Kėdainiai distr., Lithuania.
Chemosphere. 2025 Sep;384:144517. doi: 10.1016/j.chemosphere.2025.144517. Epub 2025 Jun 7.
Optimization of microplastic (MP) extraction methods is still an active research topic. Although a number of studies have been conducted on the extraction of MP from various water samples, sewage sludge remains a relatively new entity. Being highly complex, sludge is not particularly friendly when it comes to the isolation of MP. This study focused on combining the two main methods used for the isolation of microplastics: digestion and density separation, and optimizing their conditions using dried sewage sludge, which has one of the most complex matrices. Moreover, after optimization of the method, it was adapted to isolate MP from different scale wastewater treatment plants (WWTP) dewatered sewage sludge. The color, shape and size of MP were evaluated. Fenton's reagent was used to remove organic matter (OM) followed by density separation with NaBr (1.53 g cm) to remove inorganic matrices. The efficiency of OM removal varied from 6.76 to 63.38 % depending on the applied conditions. The study confirmed that the OM removal efficiency can be increased by adding additional HO every hour of the reaction. Regardless of the applied conditions Raman spectroscopic analyze confirmed that Fenton's reagent had no significant effect on standard (HDPE, LDPE, PP, PA) MP particles. Therefore, the most efficient OM removal method was further applied, and MP were isolated from an environmental sample - sewage sludge. Regardless of the scale of the WWTP, the dominant shape of the particles was fragment, the color - transparent, and as the size of the particles decreased, their percentage increased.
微塑料（MP）提取方法的优化仍是一个活跃的研究课题。尽管已经对从各种水样中提取MP进行了多项研究，但污水污泥仍是一个相对较新的研究对象。污泥高度复杂，在MP的分离方面不太友好。本研究重点结合了用于分离微塑料的两种主要方法：消解和密度分离，并使用具有最复杂基质之一的干燥污水污泥对其条件进行优化。此外，在方法优化后，将其应用于从不同规模的污水处理厂（WWTP）脱水污泥中分离MP。对MP的颜色、形状和尺寸进行了评估。使用芬顿试剂去除有机物（OM），然后用NaBr（1.53 g/cm）进行密度分离以去除无机基质。根据应用条件，OM去除效率在6.76%至63.38%之间变化。研究证实，通过在反应的每小时添加额外的H₂O₂可以提高OM去除效率。无论应用何种条件，拉曼光谱分析证实芬顿试剂对标准（HDPE、LDPE、PP、PA）MP颗粒没有显著影响。因此，进一步应用了最有效的OM去除方法，并从环境样品——污水污泥中分离出MP。无论WWTP的规模如何，颗粒的主要形状为碎片状，颜色为透明，并且随着颗粒尺寸的减小，其百分比增加。
