The municipal wastewater collection system is recognized as an initial point of interaction between microplastics (MPs) and the urban wastewater matrix. The raw wastewater contains a wide variety of organic and inorganic substances including chemicals and heavy metals. However, the fate of MPs in urban sewer systems is not yet well understood. In this work two types of virgin polypropylene (PP) samples, isotactic (iPP) and atactic (aPP), were exposed to two synthetic wastewater solutions in order to study their effects on the physical properties of the hydrophobic polymer surfaces. Particular attention was paid to the pollution adhesion at the air-liquid-solid interfaces of the surface air pockets entrapped on the polymer surfaces. The first wastewater solution consists of mixed fat, oil and grease (FOG) - surfactant and another which is an exclusively contained wastewater surfactant. The interaction experiment over a period of 10 min between the polymer’s air pocket and solutions indicated that the size of the bubble in the mixed FOG-surfactant solution increased more pronouncedly for iPP (%152) in contrast to aPP (%31) and was also compared with the greater surface roughness of the polymers. The size variation of the spherical cap on the immersed polymer surfaces were measured between 17 µm and 85 µm using image processing techniques while the data was analyzed by the Young-Laplace equation. The corresponding technical surface roughness of the polymers, the surface tension of the liquids and their air/water contact angle on the flat polymer surfaces were also measured. The results of this study indicated that surface air pockets influence the adsorption capacity of MPs and thus their buoyancy and contamination potential.

市政污水收集系统被认为是微塑料 (MP) 与城市污水基质之间相互作用的初始点。未经处理的废水含有多种有机和无机物质，包括化学品和重金属。然而，城市下水道系统中 MP 的命运尚不清楚。在这项工作中，两种类型的原生聚丙烯 (PP) 样品，全同立构 (iPP) 和无规立构 (aPP)，暴露于两种合成废水溶液中，以研究它们对疏水聚合物表面物理性质的影响。特别注意在聚合物表面截留的表面气穴的气-液-固界面处的污染粘附。第一种废水溶液由混合脂肪组成，油和油脂 (FOG) - 表面活性剂和另一种是专门包含的废水表面活性剂。聚合物的气穴和溶液之间在 10 分钟内的相互作用实验表明，与 aPP (%31) 相比，iPP (%152) 混合 FOG-表面活性剂溶液中气泡的大小增加更明显，并且与较大的聚合物表面粗糙度相比。使用图像处理技术在 17 µm 和 85 µm 之间测量浸入聚合物表面球冠的尺寸变化，同时通过 Young-Laplace 方程分析数据。还测量了聚合物的相应技术表面粗糙度、液体的表面张力和它们在平坦聚合物表面上的空气/水接触角。