We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Important Role of Concave Surfaces in Deposition of Colloids under Favorable Conditions as Revealed by Microscale Visualization
AI summary Read the abstract
Researchers found that concave surface features on sand, glass beads, and soil particles play a critical role in microplastic colloid deposition, with attachment efficiency increasing with flow velocity below a threshold value due to enhanced delivery to sheltered surface pockets.
This study conducted saturated column experiments to systematically investigate deposition of 1 μm positively charged polystyrene latex micro-colloids (representing microplastic particles) on negatively charged rough sand, glass beads, and soil with pore water velocities (PWV) from 4.9 × 10-5 to 8.8 × 10-4 m/s. A critical value of PWV was found below which colloidal attachment efficiency (AE) increased with increasing PWV. The increase in AE with PWV was attributed to enhanced delivery of the colloids and subsequent attachment at concave locations of rough collector surfaces. The AE decreased with further increasing PWV beyond the threshold because the convex sites became unavailable for colloid attachment. By simulating the rough surfaces using the Weierstrass-Mandelbrot equation, the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) interaction energy calculations and torque analysis revealed that the adhesive torques could be reduced to be comparable or smaller than hydrodynamic torques even under the favorable conditions. Interestingly, scanning electron microscopic experiments showed that blocking occurred at convex sites at all ionic strengths (ISs) (e.g., even when the colloid-colloid interaction was attractive), whereas at concave sites, blocking and ripening (i.e., attached colloids favor subsequent attachment) occurred at low and high ISs, respectively. To our knowledge, our work was the first to show coexistence of blocking and ripening at high ISs due to variation of the collector surface morphology.
More Papers Like This
AQuantitative Relationshipbetween Settling and Wettabilityfor Weathered Microplastics in Aquatic Systems
AI summary Read the abstract
Researchers quantified the relationship between surface wettability and settling velocity for weathered microplastics in aquatic systems, demonstrating that wettability-driven microscale changes at the particle-water interface modify drag forces and thus govern the transport and fate of submillimeter plastic particles.
The effects of stream water velocity, streambed celerity, and particle properties on microplastic deposition in streams
AI summary Read the abstract
Researchers conducted laboratory flume experiments to examine how stream water velocity, bedform movement, and microplastic particle properties (material type PET/PP/PA and fiber length 25-200 µm) influence the deposition dynamics of microplastics in sandy streambeds, finding that bedform movement and particle characteristics significantly affected deposition rates and sediment distribution patterns.
Sedimentation of Irregular Shaped Microplastics Under Steady and Dynamic Flow Conditions
AI summary Read the abstract
Researchers conducted experiments to study how irregularly shaped microplastic particles settle under both steady and turbulent water flow conditions, finding that shape significantly affects sinking rates in ways not captured by models designed for spherical particles. Improved understanding of how real-world plastic particle shapes affect transport is needed for accurate environmental fate modeling.
Modeling microplastic deposition in sandy streams with moving bedforms
AI summary Read the abstract
Researchers developed a coupled model combining improved mechanistic colloid attachment predictions with a bedform transport model to quantify microplastic deposition in sandy streams with moving dune bedforms, running numerical simulations to assess how streambed characteristics, flow conditions, and particle properties interact to control microplastic retention. The model addressed the poor predictive power of classical colloid filtration theory for microplastics by incorporating bedform dynamics into deposition calculations.
Role of Ripening in the Deposition of Fragments: The Case of Micro- and Nanoplastics
AI summary Read the abstract
Researchers used transparent two-dimensional porous media to directly observe how irregularly shaped micro- and nanoplastic fragments deposit and accumulate in soil-like environments. They found that a process called ripening, where previously deposited particles promote the capture of additional particles, plays a significant role in how plastic fragments are retained. The study provides new understanding of why real-world microplastic fragments behave differently than the uniform spherical particles typically used in laboratory experiments.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.