0
Article ? AI-assigned paper type based on the abstract. Classification may not be perfect — flag errors using the feedback button. Tier 2 ? Original research — experimental, observational, or case-control study. Direct primary evidence. Sign in to save

Settling behaviors of microplastic disks in acceleration fall

Marine Pollution Bulletin 2024 6 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Yang Ge, Yang Ge, Zijian Yu, Xinzai Peng, Yongchao Zhou, Abul B. M. Baki, Wenming Zhang

Summary

Researchers studied the settling behavior of disk-shaped microplastics during free-fall in water, using high-speed imaging to track the orientation and velocity of particles as they descended. Disk-shaped particles exhibited oscillating and tumbling motions that slowed settling compared to spheres of equivalent mass, with implications for predicting microplastic transport and deposition in aquatic environments.

The settling of microplastics (MPs) in the initial acceleration fall stage, i.e., before reaching the terminal settling velocity, has not been investigated, which is however important for understanding MP transport and fate. MP disks sized 3-5 mm, of three shapes and made of three polymers (1.038-1.343 g/cm3) were examined. Five release ways and three release angles (0°, 45°, 90°) were used. MP disks with the release angle of 0° start to zigzag immediately after the release, while the MP disks with the release angles of 45° and 90° first adjust to a horizontal position and then zigzag. The adjustment distances in the vertical and horizontal directions, as well as the maximum vertical settling velocity, are influenced by MP density, size, release angle and release way. The detailed settling trajectory and velocity were also analyzed. Finally, the time-changing drag coefficient of MP disks was examined and discussed.

Share this paper