Enhanced Flocculation Efficiency in High Ionic Strength Environment by the aid of Anionic ABA Triblock Copolymers.

The flocculation efficiency of polyelectrolytes in high ionic strength environment is often affected and reduced due to shielding of the active ionizable functional groups, as well as changes in the surface chemistry of the solid slurry. To address this problem, a series of well-defined novel ABA triblock copolymers were employed for the flocculation of high ionic strength kaolin slurries at three different Ca2+ concentrations (0.05 M, 0.10 M, and 0.50 M). The primary focus was placed on the advancement in architecture, where the anionic functionalities were localized to the terminal ends. Typical commercial flocculants tend to have anionic functionalities randomly distributed throughout the polymer chain and hence a higher propensity towards condensed conformation and formation of insoluble species. In comparison to a control random copolymer, the ABA triblock copolymers were able to flocculate the kaolin suspension at a faster rate, particularly at the high Ca2+ concentrations of 0.10 M and 0.50 M. In addition, these polymers had significantly better clarification ability compared to control random copolymer, despite all increments in the Ca2+ concentration. ABA triblock copolymer architecture may therefore have potential as flocculants in high ionic strength applications.