Dataset on settling of polystyrene microplastic aggregates through density transition between distilled water and saltwater

Settling experiments were conducted in a water column consisting of an upper layer (distilled water), a lower layer (saltwater—NaCl solution in distilled water), and a density transition between the two. The sinking of aggregates formed by polystyrene microplastics was examined using visualization methods to track the position of the aggregate centroid over time, as well as the evolution of size and shape factors during sinking. The dataset includes (1) measurements of settling dynamics, (2) measurements of size and shape factors of sinking aggregates, and (3) density profiles of the water column. The experiment demonstrates delayed settling of porous aggregates through the density gradient of the surrounding liquid, illustrating diffusion-limited retention and the evolution of aggregate shape during sinking.

沉降实验于由三层结构构成的水柱中开展：上层为蒸馏水，下层为以蒸馏水为溶剂的氯化钠（NaCl）盐水溶液，两层之间设有密度过渡区域。本研究采用可视化观测方法，对聚苯乙烯微塑料形成的聚集体的沉降过程进行研究，实时追踪聚集体质心的位置随时间的变化，同时记录沉降过程中聚集体尺寸与形状因子的演化规律。本数据集包含三类数据：(1) 沉降动力学测量数据；(2) 沉降聚集体的尺寸与形状因子测量数据；(3) 水柱密度剖面数据。实验结果表明，多孔聚集体在周围液体的密度梯度环境中会出现沉降延迟现象，该发现阐释了扩散限制滞留效应以及沉降过程中聚集体形状的演化机制。