We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Cation dependent dynamics of sequential and cotransport processes of micro-polystyrene and soil colloids in porous media.
AI summary Read the abstract
Researchers showed that the co-transport of polystyrene microplastics and soil colloids through saturated sand is governed by cation valence and concentration: calcium enables bridging that locks both particles in place, while switching from calcium to sodium electrolytes releases large quantities of both, with soil colloids responding more sensitively than microplastics.
Interactions between microplastics (MPs) and soil colloids critically influence pollutant mobility in subsurface environments, yet remain insufficiently characterized under transient flow conditions. This study explored the effects of ionic strength, ion type, and cation exchange on the co-transport and release of polystyrene (PS) MPs and soil colloids in saturated quartz sand. In NaCl solutions, pre-deposited PS particles or soil colloids increased surface roughness and chemical heterogeneity of the sand, inhibiting subsequent particle transport. PS particles preferentially attached to pre-deposited soil colloids, whereas most subsequent soil colloids adhered directly onto sand surfaces. Flushing with deionized water induced significant remobilization of both particles due to reduced ionic strength, which was well captured by a transport model coupled with ion dynamics. In CaCl solutions, the impact of pre-deposited particles varies with ionic strength. At lower ionic strength, competition for attachment sites promoted particle transport, while at higher ionic strength, increased surface roughness and heterogeneity inhibited mobility. Unlike Na, Ca facilitated a staggered arrangement of soil colloids and pre-deposited PS particles through cation bridging, resulting in strong retention and minimal release during deionized water flushing. Subsequent cation exchange from Ca to Na weakened adhesive forces and triggered substantial release, with soil colloids showing greater sensitivity than PS. Overall, the interactions between suspended soil colloids and PS MPs are governed by cation valence and concentration, reflecting a balance between steric hindrance and surface heterogeneity. These findings provide insights into how pre-deposited and suspended PS and soil colloids influence each other's transport behavior and highlight the critical role of cation exchange in regulating mobility in subsurface environments.
More Papers Like This
[Transport and Model Calculation of Microplastics Under the Influence of Ionic Type, Strength, and Iron Oxide].
AI summary Read the abstract
Laboratory column experiments showed that calcium ions strongly inhibit the transport of polystyrene microplastics through quartz sand via bridging and charge neutralization effects, while iron oxide coatings on sand grains further reduce microplastic mobility through surface adsorption. Understanding these transport dynamics is important for predicting how microplastics move through soil and groundwater systems and assessing contamination risks to drinking water sources.
Co-impacts of cation type and humic acid on migration of polystyrene microplastics in saturated porous media
AI summary Read the abstract
Researchers investigated how different cation types and humic acid concentrations affect the movement of polystyrene microplastics through saturated soil. The study found that aging accelerated microplastic migration under all conditions, while calcium ions and humic acid had complex interactive effects on microplastic transport and retention in porous media.
Co-transport of negatively charged nanoparticles in saturated porous media: Impacts of hydrophobicity and surface O-functional groups
AI summary Read the abstract
Researchers studied how graphene oxide (GO) and polystyrene nanoplastics co-transport through saturated soil, finding that in sodium-rich conditions GO can carry nanoplastics through the medium, while calcium ions suppress movement of both by bridging particles to sand grains — with more abundant surface oxygen groups on GO amplifying this effect.
Mechanism of coupled phosphate‑calcium modulation of nanoplastic transport in porous media: Role of solution chemistry and surface interactions
AI summary Read the abstract
Scientists used laboratory experiments and molecular simulations to study how phosphate and calcium ions in soil water affect whether polystyrene nanoplastics move freely through the ground or get trapped in soil particles. They found that pH was a key factor: at lower pH levels, phosphate helped nanoplastics travel farther while calcium restricted movement, with both effects linked to how these ions change the surface charge of both the particles and the soil. Understanding nanoplastic mobility in soil is essential for predicting contamination of groundwater and crops.
Effects of physicochemical factors on transport and retention of polystyrene microplastics (PS-MPs) in homogeneous and heterogeneous saturated porous media
AI summary Read the abstract
Researchers studied how polystyrene microplastics move through different types of underground soil and sand formations. They found that smaller sand grains, higher salt concentrations, and the presence of calcium ions all increased microplastic retention, while mixed soil layers created preferential flow paths that allowed some particles to break through faster. The findings help explain how microplastics could potentially contaminate groundwater aquifers.
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.