Papers

20 results
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Article Tier 2

Settling velocity of microplastic particles having regular and irregular shapes

Researchers measured how quickly microplastic particles of various shapes settle through water, testing 66 different particle types including spheres, cylinders, fibers, and irregular fragments. They found that particle shape significantly affects settling speed, with fibers and flat shapes sinking more slowly than spheres of the same size. The study provides new equations for predicting where microplastics end up in oceans and waterways based on their shape.

2023 Environmental Research 86 citations
Article Tier 2

Settling velocities of microplastics with different shapes in sediment-water mixtures

Researchers studied how the shape of microplastic particles affects how quickly they sink in water containing suspended sediment. They found that fibers and films settle much more slowly than fragments and pellets, and that sediment in the water significantly slows the settling of all microplastic types. These findings are important for predicting where microplastics accumulate in lakes, rivers, and oceans.

2025 Environmental Pollution 14 citations
Article Tier 2

Empirical Shape-Based Estimation of Settling Microplastic Particles Drag Coefficient

This study experimentally measured the settling behavior of flat square microplastic particles in water, finding that shape significantly affects sinking speed and drag compared to spherical particles. Understanding how microplastic shapes influence settling is essential for modeling where plastics accumulate in rivers and ocean sediments.

2023 Journal of Marine Science and Engineering 2 citations
Article Tier 2

Settling velocity of irregularly shaped microplastics under steady and dynamic flow conditions

The settling velocities of irregularly shaped microplastics were measured under both still water and dynamic flow conditions, finding that shape strongly affected settling speed and that turbulence caused non-spherical particles to orient and settle differently than spheres, with implications for predicting microplastic vertical transport in rivers and coastal waters.

2021 Environmental Science and Pollution Research 92 citations
Article Tier 2

Sinking velocity of sub-millimeter microplastic

Researchers measured the sinking velocities of irregularly shaped microplastic particles (polyamide, PMMA, and PET, 6–251 μm) and found they sink considerably slower than theoretical predictions for spheres of equivalent size, developing a predictive model based on particle size and excess density to better represent how real-world microplastics settle through the water column.

2018 Marine Pollution Bulletin 109 citations
Article Tier 2

Settling behaviour of irregular-shaped polystyrene microplastics

Researchers studied the settling behavior of irregular-shaped polystyrene microplastics in water, finding that shape significantly affects how fast particles sink. Understanding settling behavior is important for predicting how microplastics distribute vertically in rivers and ocean water columns.

2021 Science & Technology Development Journal - Engineering and Technology 7 citations
Article Tier 2

Towards better predicting the settling velocity of film-shaped microplastics based on experiment and simulation data

Researchers combined experimental and simulation data to better predict how film-shaped microplastics settle through water, since most existing models are based on spherical particles. They found that the particle definition approach was more suitable than equivalent spherical diameter for characterizing flat, irregular microplastics. The improved settling velocity predictions could help scientists better understand how film-shaped microplastics travel and accumulate in aquatic environments.

2024 Marine Pollution Bulletin 10 citations
Article Tier 2

Modeling Microplastic Transport in the Marine Environment: Testing Empirical Models of Particle Terminal Sinking Velocity for Irregularly Shaped Particles

Researchers tested multiple drag models for predicting the terminal settling velocity of irregularly shaped microplastic particles in seawater, identifying three high-precision models and demonstrating that settling velocity is largely stable across ocean depths and independent of initial particle velocity, improving the accuracy of marine microplastic transport simulations.

2023 ACS ES&T Water 12 citations
Article Tier 2

Sinking rates of microplastics and potential implications of their alteration by physical, biological, and chemical factors

Researchers conducted sinking experiments with diverse microplastic particles and found that sinking velocity depends not only on density and size but also on particle shape, and that biofouling and weathering can substantially alter sinking rates with implications for how microplastics distribute through the water column.

2016 Marine Pollution Bulletin 595 citations
Article Tier 2

Characteristics and Sinking Behavior of Typical Microplastics Including the Potential Effect of Biofouling: Implications for Remediation

Researchers characterized how microplastics of different shapes sink through water, finding that shape is a critical factor, with films behaving very differently from spheres and fibers. The study also examines how biofouling on floating plastics can cause them to sink, with implications for designing filtration and remediation systems.

2020 Environmental Science & Technology 257 citations
Article Tier 2

Effects of Shape and Size on Microplastic Atmospheric Settling Velocity

Researchers measured atmospheric settling and horizontal drift velocities of various microplastic shapes and sizes in controlled settling chambers, providing empirical data needed to improve atmospheric transport models that explain how microplastics reach remote environments.

2023 Environmental Science & Technology 39 citations
Article Tier 2

A settling velocity formula for irregular shaped microplastic fragments based on new shape factor: Influence of secondary motions

Researchers developed a new shape factor for irregular microplastic fragments and derived a settling velocity formula based on it, using numerical modeling to show that fragment shape governs whether particles sink stably or oscillate — providing more accurate predictions of microplastic transport in rivers and lakes than existing methods.

2024 The Science of The Total Environment 7 citations
Article Tier 2

A new model for the terminal settling velocity of microplastics

A new empirical model for the terminal settling velocity of microplastics was developed and validated using 1,343 experimental measurements covering a range of particle shapes and materials. The model improves predictions of microplastic sedimentation rates, which are critical for understanding how plastic particles are transported and deposited in water bodies.

2022 Marine Pollution Bulletin 68 citations
Article Tier 2

Machine learning-based prediction for settling velocity of microplastics with various shapes

Researchers developed machine learning models to predict the settling velocity of microplastics based on their size, density, and shape. They classified microplastic shapes into fiber, film, and fragment categories and identified the optimal shape parameter for each, achieving significantly better prediction accuracy than existing theoretical models. The study reveals that particle size has the greatest influence on settling velocity, which is important for understanding how microplastics move and distribute in water environments.

2023 Water Research 59 citations
Article Tier 2

Improved Settling Velocity for Microplastic Fibers: A New Shape-Dependent Drag Model

A new shape-dependent drag model was developed to improve the accuracy of settling velocity predictions for microplastic fibers, addressing a major limitation of existing drag models that significantly underpredict fiber settling in aquatic environments.

2021 Environmental Science & Technology 85 citations
Article Tier 2

Experimental investigation of settling velocity for cuboidal microplastic

Researchers used 3D-printed cube-shaped microplastics to experimentally measure how fast these particles sink in water, testing 150 shapes ranging from fiber-like to flat plate forms across a wide range of flow conditions. Their new mathematical formulas predict sinking speed with about 88% accuracy, improving scientists' ability to model where microplastics end up in ocean environments.

2025 Applied Ocean Research
Article Tier 2

Settling of inertial nonspherical particles in wavy flow

Lab experiments showed that plastic particles of different shapes — rods, disks, and spheres — settle at different rates in wavy water, and waves can both speed up and slow down their sinking. Understanding how particle shape affects transport in ocean currents is key to predicting where microplastics accumulate.

2020 Physical Review Fluids 21 citations
Article Tier 2

Settling Velocities of Small Microplastic Fragments and Fibers

Researchers precisely measured the settling speeds of over 4,000 small microplastic particles in water and found that existing prediction models designed for larger microplastics do not work well for these tiny fragments and fibers. The settling speed depends on each particle's size, density, and shape, with the smallest particles sinking extremely slowly. Understanding how quickly microplastics settle in water is important because it determines how far they travel and how long they remain available to be consumed by aquatic organisms that humans may eventually eat.

2024 Environmental Science & Technology 63 citations
Article Tier 2

Terminal Settling Velocity of Cylindrical Rods with Various Geometries Applicable to Atmospheric Microplastics

Researchers measured how the shape of cylindrical microplastic fibers affects their settling speed through air, finding that curved and V-shaped fibers fall significantly faster than straight ones — up to 57% faster for V-shaped rods — which matters for predicting how airborne microplastics disperse in the atmosphere.

2024 Proceedings of the ... International Conference on Fluid Flow, Heat and Mass Transfer
Article Tier 2

Settling of nonuniform cylinders at intermediate Reynolds numbers

This study investigated the settling behavior of non-uniform cylindrical particles at intermediate Reynolds numbers, providing new data on how particle shape and aspect ratio influence drag and settling velocity. The findings are relevant to predicting the transport and deposition of microplastic fibers in water.

2024 Physical Review Fluids 7 citations