Colloid Transport Dynamics in Porous Media

Colloid transport in porous media encompasses the migration, retention and remobilisation of finely dispersed particles—ranging from engineered nanoparticles to natural microbial cells—within the interconnected voids of soils, sediments and man-made filter beds. This process is governed by the interplay of advection by pore fluid flow, molecular diffusion, and a spectrum of physicochemical interactions at solid–liquid interfaces. Electrostatic forces, van der Waals attractions and hydrodynamic shear collectively determine whether colloids traverse pore throats, become immobilised in energy minima or detach under changing flow or chemistry. Pore-scale heterogeneity in grain size, surface roughness and chemical patches gives rise to spatial variability in deposition and clogging, with significant consequences for permeability and contaminant fate. Colloid transport underpins diverse applications: predicting the spread of groundwater pollutants, optimising drinking-water filtration, designing subsurface drug-delivery systems and managing microplastic migration. Modelling approaches range from continuum advection–dispersion equations augmented by kinetic deposition terms to fully resolved simulations coupling computational fluid dynamics (CFD) with discrete element or lattice-Boltzmann methods. Experimental advances, including microfluidic chips and column dissections, now allow direct visualisation of bridging, pore clogging and remobilisation phenomena. Emerging insights into aggregation-driven size evolution, nanoscale roughness effects and physicochemical triggers for detachment are refining our capacity to forecast colloid-facilitated transport under variable environmental conditions.

Research from Nature Portfolio

Recent studies have integrated aggregation dynamics into three-dimensional transport models to reveal that nanoparticle aggregation can, under specific ionic and flow conditions, enhance long-distance mobility through size exclusion effects and modifications of diffusivity and settling behaviour. These improvements in theoretical predictivity demonstrate non-monotonic changes in breakthrough curves and retention profiles when aggregation is accounted for. Foundational experiments comparing aluminium oxide, titanium dioxide and silicon dioxide nanoparticles in quartz-sand, limestone and dolomite columns have shown that nanoparticle recoveries depend strongly on surface charge, suspension stability and mineralogy. The observed transport trends closely mirror predictions from classical filtration theory and extended interaction-energy calculations, underscoring the pivotal role of particle–surface electrostatics and roughness in determining retention and release patterns.

Colloid Transport Dynamics in Porous Media publication trend

The graph below shows the total number of articles in colloid transport dynamics in porous media across all publications each year (not limited to Nature Index journals).

Technical terms

Advection–dispersion: Combined transport of particles by bulk fluid motion and spreading due to velocity variations and molecular diffusion.

Breakthrough curve: Temporal profile of colloid concentration in effluent, used to assess transport and retention trends.

DLVO theory: A classical framework describing colloid–surface interaction energy as the sum of electrostatic repulsion and van der Waals attraction.

Permeability: A measure of the ease with which fluids and suspended particles traverse a porous medium.

Pore throat: The narrow constriction between adjacent pore bodies that governs particle passage and clogging behaviour.

References

1. Particle Migration and Clogging in Porous Media: A Convergent Flow Microfluidics Study. Journal of Geophysical Research: Solid Earth (2019).
2. Transport of Microplastic Particles in Saturated Porous Media. Water (2019).
3. The impact of nanoparticle aggregation on their size exclusion during transport in porous media: One- and three-dimensional modelling investigations. Scientific Reports (2019).
4. Transport and retention of engineered Al2O3, TiO2 and SiO2 nanoparticles through various sedimentary rocks. Scientific Reports (2015).
5. Pore-scale simulation of fine particles migration in porous media using coupled CFD-DEM. Powder Technology (2022).
6. Non-linear, non-monotonic effect of nano-scale roughness on particle deposition in absence of an energy barrier: Experiments and modeling. Scientific Reports (2015).
7. Pore-Scale Simulations of Particles Migration and Deposition in Porous Media Using LBM-DEM Coupling Method. Processes (2021).
8. Migration trajectories and blocking effect of the fine particles in porous media based on particle flow simulation. AIP Advances (2024).
9. Colloid retention and mobilization mechanisms under different physicochemical conditions in porous media: A micromodel study. Powder Technology (2021).