Effects of temperature and pH on permeation and migration of suspended particles in porous media

Based on the classical model for migration of suspended particles, the release effect is considered in the Kinetic equation for deposition of particles, and the analytical solution to the one-dimensional migration problem of suspended particles in case of instantaneous injection is obtained. The soil column experiments are carried out considering two different suspended particles (i.e., silicon powder and polystyrene microspheres), different pH (i.e., 4, 7 and 10), different temperatures (i.e., 20,30 and 40℃) and different flow rates (i.e., 0.042, 0.127 and 0.212 cm/s) to obtain a series of migration curves. The analytical solution is used to fit the experimental data, and the migration parameters are then determined. The effects of temperature and velocity of flows on the migration parameters are discussed, and the temperature, pH and particle type are found to be the important factors affecting the migration of suspended particles in porous media. At pH=7 and T≤30℃, the repulsive force of suspended particles plays a leading role, while the Brownian motion dominates at T >30℃. At the same time, the hydrodynamic effect increases with the increase of the flow rate, and the temperature has little effect on the peak concentration. With the increase of pH, the migration curve of polystyrene microspheres is different from that of silicon powder at different temperatures.