Polyelectrolyte Characteristics and Flocculation

Abstract

The relationships among the characteristics of cationic polyelectrolytes, mixing conditions, and flocculated particle size distribution were studied in an attempt to develop a rational basis for selecting polyelectrolytes. Charge density was found to be the predominant factor in selecting an optimum dosage of polyelectrolyte for flocculating particles with a primary charge opposite to that of the polyelectrolyte. The initial periods of both rapid and slow mixing are critical in the formation of flocs. Large, strong flocs were obtained with high‐molecular‐weight (>;10 5 ) polymers. A simplified model was developed to predict the average floc size based on the molecular weight of the polyelectrolyte and the mixing intensity.