We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Visualizing surface chemical heterogeneity of aged microplastics via TOF-SIMS to elucidate their transport in porous media
AI summary Read the abstract
When plastic waste breaks down in the environment, it doesn't age evenly—scientists found that "weathered" microplastics develop patchy, oxygen-rich hotspots on their surface rather than an all-over coating, and these spots make the particles more negatively charged and water-attracting. This matters because it helps explain why older, more degraded microplastics move more easily through soil and sand, meaning they could travel farther and potentially reach groundwater or drinking water sources than previously assumed.
The environmental fate of microplastics (MPs) is largely controlled by surface alterations that occur during aging. Conventional bulk spectroscopy has fostered an assumption of uniform surface oxidation, yet this cannot explain the high mobility of severely aged MPs. Here, time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to map the surface chemistry of four MPs, polyethylene, polypropylene, polystyrene, and poly(lactide), subjected to chemical, photo, and discharge plasma aging. Saturated column experiments with quartz sand showed that more intensive aging consistently enhanced MP transport. TOF-SIMS imaging revealed that aging produces localized oxidation hotspots enriched in oxygenated fragments (CHO and CHO), rather than a uniform oxidized layer. These oxygen-containing functional groups include carbonyl species (CO) together with carboxyl (-COOH) and hydroxyl (-OH) moieties. Deprotonation of the carboxyl groups in aqueous media yields carboxylate anions (-COO), which combine with the polar hydroxyl groups to increase both surface hydrophilicity and negative charge density. XDLVO calculations show that the oxidation-driven increase in hydrophilicity and negative charge raises the interaction energy barrier and suppresses hydrophobic attraction toward quartz sand, consistent with the enhanced transport observed at alkaline pH (mass recovery of 63.49% for plasma-treated PLA at pH 9). The TOF-SIMS mapping provides direct spectroscopic evidence of nanoscale chemical heterogeneity on aged MP surfaces, complementing bulk-scale interaction models and contributing to a physical basis for predicting aged MP mobility.
More Papers Like This
Weathering of nanoplastics reduces the effect of sand surface heterogeneity on their attachment in saturated porous media
AI summary Read the abstract
Tiny plastic particles (nanoplastics) behave differently in soil and sand once they've been "weathered" by sunlight and natural organic matter — this aging process actually makes them travel more easily through sand instead of getting stuck, because it changes their surface charge. This matters because it suggests weathered nanoplastics — the kind actually found in the environment — may move through soil and groundwater more readily than lab tests on fresh, unweathered plastic suggest, potentially reaching drinking water sources faster than previously assumed.
Different Weathering Strategies Result in Different Surface Properties and Adsorption Behavior in Aged Microplastics
AI summary Read the abstract
Scientists found that when microplastics break down in the environment, *how* they weather (from sunlight, ozone, or other chemical exposure) changes their surface in different ways—and this affects how well they absorb other pollutants, like a compound related to fuel and pesticide breakdown. This matters because microplastics don't just pollute on their own; depending on how they've aged, they can act like sponges that pick up and carry additional harmful chemicals into our bodies and environment, meaning "aged" plastic isn't a single, predictable risk.
Transport of reduced PBAT microplastics in saturated porous media: Synergistic effects of enhanced surface energy and roughness
AI summary Read the abstract
This study examined how biodegradable PBAT microplastics move through soil after undergoing chemical aging in oxygen-depleted environments. Researchers found that the aging process changed the surface properties of the plastics, making them more mobile in some conditions, which has important implications for understanding how degraded microplastics spread through groundwater systems.
The individual transport, cotransport and immobilization with solar pyrolysis biochar of microplastics and plasticizer in sandy soil
AI summary Read the abstract
Researchers tracked the individual transport, co-transport, and immobilization of microplastics in porous media, finding that plastic particle behavior differs significantly depending on surface charge and pore structure interactions. The results improve predictions of where microplastics migrate and accumulate in soils and aquifers.
The transport of polystyrene microplastics in saturated porous media: Impacts of functional groups and solution chemistry
AI summary Read the abstract
Researchers studied how surface chemistry and water conditions affect the movement of polystyrene microplastics through sand, comparing unmodified particles with those carrying carboxyl or amino groups that mimic natural aging. They found that factors like water acidity, salt concentration, and the type of chemical groups on the plastic surface all significantly influenced how far the particles traveled. The study provides important insights into how weathered microplastics may spread through soil and groundwater differently than fresh particles.
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.