Comparison of the Performance of Chitosan and a Cationic Polyacrylamide as Flocculants of Emulsion Systems

PINOTTI. A; BEVILACQUA; ZARITZKY, N

JOURNAL OF SURFACTANTS AND DETERGENTS

AOCS

Año: 2001 vol. 4 p. 57 - 63

1097-3958

Food industries contribute significantly to water streams pollution. Besides, oil in wastewaters must be removed to prevent fouling of process equipment, to reduce interference with subsequent water-treatment units, and to comply with water-discharge requirements. Polyelectrolytes are frequently used to coagulate and flocculate colloidal systems. The influence of different factors on the doses of chitosan (natural polyelectrolyte) and a cationic polyacrylamide necessary to neutralize electrical charge and to get flocculation in a model system of a sunflower oil/water emulsion was analyzed. Methods used were: turbidimetry, jar test, colloidal titration and light microscopy observation. Results showed that the increase of NaCl concentration reduces the doses of chitosan and polyacrylamide to reach zero colloidal charge; these doses increase with the surfactant chain length; pH variation did not show any influence on the chitosan dose necessary to flocculate the system. Redispersion of the emulsion was observed in chitosan and polyacrylamide treatments.