ADSORPTION AND FLOCCULATION BEHAVIOR FOR SYSTEMS OF COPOLYMERS AND PARTICLES OF OPPOSITE CHARGE

The authors investigated dilute aqueous suspensions of negatively charged particles (Na-bentonite platelets and precipitated silica beads) in the presence of homemade cationic copolymers of acrylamide with various percentages of cationic monomer and various molecular weights. They also studied the effect of several parameters on the adsorbed amount GAMMA , flocculation performances and hydrodynamic layer thicknesses delta //H. For the less charged polymers ( tau less than 5%), i. e. for low polymer-solid interaction, the authors observed strong molecular weight effects on GAMMA , optimum flocculation concentration (o. f. c. ) and delta //H, especially for silica on which nonionic acrylamide units do not adsorb. The polymer conformation is flexible and the hydrodynamic layer thicknesses are rather large.