Laboratory data on dynamics of microplastic particles sinking in seawater with dispersed xanthan gum and kappa-carrageenan and rheological properties of these dispersions.

This paper presents a dataset comprising measurements of the sinking dynamics of microplastics settling in artificial seawater (AS) and in dispersions of polymers in seawater: xanthan gum, kappa-carrageenan, and their mixtures in two concentrations: 0.5 g/L and 1 g/L. Plastic particles are classified into fifteen groups representing various shapes: disks, rods, blades, spheres, and materials: PS, POM, PET, PA6.

Settling of microplastics in mucus-rich water column: The role of biologically modified rheology of seawater.

Non-buoyant microplastics (MPs) sink through the marine water column, adversely affecting the ecosystem. The manner in which MPs influence the water environment depends to a large extent on their settling dynamics, driven by their properties and the physio-chemical characteristics of water column. However, some properties of seawater remain elusive, limiting our ability to fully explain the sinking processes of MPs.

Dataset on rheological measurements of xanthan gum aqueous dispersions containing sodium chloride and settling dynamics of spheres and disks in these dispersions.

This paper presents a dataset collected in laboratory experiments on the settling of solid spheres and disks in shear-thinning and viscoelastic aqueous solutions of xanthan gum with sodium chloride addition. Two types of spheres with density of 1.41 g/cm varying in diameter (3.

Influence of pycnocline on settling behaviour of non-spherical particle and wake evolution.

Settling of non-spherical particles in a stratified fluid exhibits complex dynamics in a low-to-moderate inertia regime. Although this process is involved in a wide variety of phenomena in natural fluid systems, its fundamental mechanisms are still unexplored. Understanding of particle settling in microscale is particularly important to explain challenging problems associated with ecological and biogeochemical processes in the ocean due to the delayed settling of particulate matter at pycnoclines.

Viscoelastic and shear-thinning effects of aqueous exopolymer solution on disk and sphere settling.

In this study, xanthan gum is used as a model exopolymer to demonstrate potential effects of non-Newtonian properties of natural aquatic systems on settling dynamics of particles. Rheological measurements combined with settling experiments using visualization methods revealed that instantaneous velocity fluctuations and a flow pattern formed around a particle are the effects of solution viscoelasticity and shear-thinning properties and that the average settling velocity depends on the exopolymer concentration and particle size. Our study showed that in the considered conditions a disk-shaped particle settles preferably in vertical position with a negative wake behind.

Stratification-induced reorientation of disk settling through ambient density transition.

Settling due to gravity force is a basic transport mechanism of solid particles in fluids in the Earth. A large portion of particles occurring in nature and used in technical applications are non-spherical. Settling of particles is usually studied in homogeneous ambient conditions, however, stratification is inherent of natural fluids.