EFFECT OF SOLUTION ENVIRONMENT ON DEAD-END MICROFILTRATION CHARACTERISTICS OF RUTILE SUSPENSIONS

Microfiltration experiments were conducted under a constant pressure o f 196 kPa, using a dead-end filter. The filtration properties were stu died using titanium dioxide suspensions of the rutile form to determin e the effects of such solvent environments as pH and the added salt. B oth the average porosity and the average specific filtration resistanc e of the filter cake were determined. It was highlighted through this study that the electrical nature of particles depending on the solutio n environment plays a significant role in determining the structure of the filter cake which, in turn, influenced the filtration rate in mic rofiltration of dispersions of metal oxides. It was demonstrated unequ ivocally that the average porosity in the filter cake had a maximum an d the average specific filtration resistance was minimal around the is oelectric pH. These results were in contrast to those observed with ul trafiltration of protein solutions. Such charge effects of particles w ere weakened in the presence of salts.