The effect of pre-treatment on crossflow microfiltration of titanium dioxide dispersions

The influence of a coagulant type and operating parameters on crossflow microfiltration of aqueous dispersions of titanium dioxide was examined. Two types of coagulant for series of crossflow microfiltration experiments were used: inorganic—Al2(SO4)3 and organic—PRAESTOL. The experiments were carried out on a tubular ceramic microfiltration membrane with nominal size of pores 0.1 μm at various operating parameters. Preliminary tests were performed before crossflow microfiltration experiments and from results of these tests were chosen optimal doses of coagulants.The value of steady state permeate flux was experimentally evaluated for crossflow microfiltration with and without pre-treatment. The results of the experiments show that aluminium sulphate is a better coagulant for this system and its optimal concentration is 40 mg/L. The results also show that pre-treatment of the feed led to four or five times higher permeate flux than that without any pre-treatment.