Flocculation studied with the ESA technique

The aim of this paper is to show that the ESA (electrokinetic sonic amplitu de) technique can be used to study the flocculation between cationic polyel ectrolytes and negatively charged silica particles. The ESA signal was Meas ured when cationic polyacrylamide (CPAM) or cationic polyamine (POL) was mi xed with silica particles. The dynamic mobility of the formed flocs was cal culated from the corrected ESA signal. The amount of nonadsorbed polyelectr olyte was determined by viscosity. The flee sediment volume was also measur ed. It was found that the polyacrylamide molecule was more efficient than t he polyamine molecule in neutralizing the charges on the silica particles d ue to the longer CPAM molecules and the larger distance between the CPAM ch arges which was in better accordance with the distance between the silica c harges compared to POL. (C) 1999 Academic Press.