Faculty of Chemistry, Tabriz University, Tabriz, I.R. IRAN
Polymerization rates of silica at various concentrations and pHs have been studied via nephelometry. The ability and potency of ultrasonic radiation on the coagulation process in aqueous samples with and without silica colloidal particles have been extensively investigated. Factors affecting the rate and filtration volume such as silica concentration, time of radiation, temperature, and frequency of radiation have also been studied. The results indicate that ultrasonic radiation has two folded effect: on the one hand it breaks down the large flocs and on the other it results in the flocculation of small particles. The above mentioned effects lead to a reduced uniformity coefficient for the filter beds made of such coagulated particles.