Scale Inhibition by a Carboxylate-Terminated Double-Hydrophilic Block Copolymer in Industrial Recycling Water

Abstract

Acrylic acid (AA)-allylpolyethoxy carboxylate (APEL) copolymer was synthesized. The performance of AA-APEL on inhibition of Ca₃(PO₄)₂, CaCO₃ and CaSO₄ precipitation was compared with that of current commercial inhibitors. It was shown that AA-APEL exhibited excellent ability to control inorganic minerals, with approximately 95.6% CaSO₄ inhibition and 99.8% Ca₃(PO₄)₂ inhibition at levels of 3 and 6 mg/L, respectively. AA-APEL also displayed ability to prevent the formation of CaCO₃ scales. Surface morphology characterization of Ca₃(PO₄)₂, CaCO₃ and CaSO₄ was investigated with scanning electronic microscopy. The inhibition mechanism was proposed that the formation of the excellent solubility of AA-APEL-Ca complexes due to high hydrophilic PEG segments in the AA-APEL matrix.