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 (>;105) polymers. A simplified model was developed to predict the average floc size based on the molecular weight of the polyelectrolyte and the mixing intensity.

The multicomponent equilibrium theory for ion-exchange columns (chromatography) has been extended to systems accompanied by reactions in either or both phases. Based on the concept of coherence of concentration waves in the original theory, the proposed approach includes a systematic way to determine the thermodynamic variance and a general mathematical formulation to construct the composition path grid by means of numerical techniques. With proper adjustments, this approach can be applied as well to adsorption columns involving reactions. As a practical example, a comparison of predicted and observed effluent histories for an anion-exchange system with dissociation-association reactions is shown.

No abstract

No abstract

No abstract