Experimental study of the filtration of nanofluid with SiO2 nanoparticles in porous media

The paper considers the filtration of ethylene glycol with SiO2 nanoparticles through the porous sample formed by microsphere packed bed. The experiments were performed for nanoparticles size of 7 nm, microspheres size of 150 mu m, and particles volume concentration varying from 0.005 to 0.02. The data on local permeability reduction were obtained for various pressure gradients, and the peculiarities of nanoparticles retention were discussed. It was shown that nanoparticles could be transported through the porous sample, and the retention mechanism could be reversible adsorption on the pore wall. The reversible absorption mechanism of the nanoparticles retention was confirmed by the equilibrium permeability reduction determined by the magnitude of the pressure gradient.