Settling velocity of clay with zinc oxide and aluminium oxide nanoparticles

Clays are ubiquitous earth minerals that are used globally in various fields such as in the ceramic, pharmaceutical, construction, chemical and drilling industries. Various industrial processes involve clay dispersal in liquids that form colloids of which the settling velocity is critical, necessitating enhanced or delayed sedimentation. It has been reported that the presence of some nanoparticles such as aluminum oxide (Al2O3) and zinc oxide (ZnO) can speed up clay sedimentation. It is therefore the primary objective in this study to determine and compare the settling velocities of a clay composition of Montmorillonite, Kaolinite and Illite in the presence of Al2O3 and ZnO nanoparticles, and to find out the effect of crude oil on the rate of deposition. The experiments were conducted using distilled water, brine of 30g/l salinity and ethanol as dispersing mediums for the clay particles and nanoparticles. Experimental results show that Al2O3 nanoparticles settle particles of clay at a faster velocity of about 2.80x10-4m/s and 3.08x10-4m/s in the absence and presence of crude oil respectively. ZnO nanoparticles settle clayey particles at about 2.65x10-4m/s and 2.91x10-4m/s in the absence and presence of crude oil respectively. It is speculated that Al2O3 nanoparticles which initiated a higher settling velocity occurred as a result of a strong attractive force between the nanoparticles and clay minerals. It was also observed that the presence of crude oil in the liquid columns increased the settling velocities of the clays.