Influence of Surfactants on the Performance of Calcium Phosphate Scale Inhibitors

The pH-stat technique was used to study the influence of various types of surfactants on the performance of polymers used as inhibitors for preventing the precipitation of calcium phosphate in industrial water systems. Four types of surfactants were evaluated: 1) anionic, 2) non-ionic, 3) amphoteric, and 4) cationic. The polymeric inhibitors studied include homo-, co-, and terpolymers containing different functional groups such as carboxylic acid, sulfonic acid, ester, and amide. It has been found that polymer dosage and polymer architecture play important roles in inhibiting calcium phosphate precipitation. The results on the evaluation of surfactants reveal that all surfactants are ineffective calcium phosphate inhibitors. Comparative inhibition data collected for various calcium phosphate inhibiting polymers in the presence surfactants containing different ionic charges are presented. Results are also discussed on the influence of cationic polymeric flocculant in preventing the precipitation of calcium phosphate by anionic polymeric inhibitors.