FLOCCULATION BEHAVIOR AND PROPERTIES OF Na-MONTMORILLONITE TREATED WITH FOUR ORGANIC POLYMERS

Abstract

Four organic polymers were mixed with Na-montmorillonite. Two cationic polymers include a high molecular weight polyacrylamide (494C) and a low molecular weight polymer (587C). Two anionic polymers include a high molecular weight polyacrylamide (836A) and a low molecular weight polymer (Aerotil). Each clay suspension series were allowed to stand for 24 hours and were centrifuged, and the clay plugs were washed and dried. The dried samples were investigated by XRD, IR and CEC measurement.
The suspended clay containing anionic polymers was not flocculated at any concentrations of polymer. But the suspensions containing two cationic polymers were rapidly flocculated at almost all concentrations. The d (001) montmorillonite spacings after treated with cationic polymer 587C showed 1.55 nm suggesting the polymers may have entered the interlayer spaces. The polymer 494C-treated sample produced double peaks of 1.26 and 1.48 nm in XRD. It indicates that the low molecular weight polymer was more apt to penetrate into interlayers of montmorillonite than the high molecular weight polymer. And cationic polymer 494 may be adsorbed mainly on the outside surface of clay, and some polymers may penetrate into only interlayers in the margin of montmorillonite particles because of its high molecular weight. Cationic polymer 587 is most strongly bonded to Na-montmorillonite because of high positive charge. CEC of polymer 587-treated sample was reduced markedly suggesting polymer blocks CEC sites. But anionic polymers are not effective in flocculating Na-montmorillonite, and may not be adsorbed on clay.