SiO2 and microparticle transport in a saturated porous medium: effects of particle size and flow rate

Abstract

SiO2 and polystyrene (PS) are carriers of microorganisms and metals in porous media, which can produce changes in groundwater quality and cause issues related to clogging of the porous medium. Although SiO2 and PS particle transport in porous media has been previously studied, what influences transport at various particle sizes and flow rates remains unclear. Here, we looked at how pH and ionic strength affected the surface zeta potentials as well as how particle size and flow rate affected the transport of suspended SiO2/PS particles in a porous media. The results indicate that increasing pH and decreasing ionic strength increased the negative surface charges on both the SiO2 and PS particles, thereby yielding greater electrostatic repulsion between particles. At the same flow rate, the retention rate of 10 μm PS particles in the porous medium was 46.1% better than that of 2 μm particles, whereas the retention rate of 10 μm SiO2 particles was 7.88% better than that of 2 μm particles. For the same particle size, increasing the flow rate decreased SiO2 and PS retention in the porous medium. Thus, particle size and flow rate substantially impact the transport of SiO2 and PS-suspended particles in a porous media.