Carboxylate-terminated double-hydrophilic block copolymer as an effective and environmental inhibitor in cooling water systems Original Research Article

In an attempt to control Ca3(PO4)2, CaCO3, and CaSO4 deposits in industrial recycling water systems, an acrylic acid (AA)-allyloxy poly(ethylene glycol) polyglycerol carboxylate (APEG-PG-COOH) copolymer was synthesized as a nonphosphorus inhibitor. The synthesized polymer was characterized by 1H NMR. The performance of PAA/APEG-PG-COOH on inhibition of Ca3(PO4)2, CaCO3 and CaSO4 precipitation was studied through static scale inhibition tests. It was shown that PAA/APEG-PG-COOH exhibited excellent ability to control inorganic minerals, with approximately 100% CaSO4 inhibition and 99.89% Ca3(PO4)2 inhibition at levels of 3 and 6 mg/L PAA/APEG-PG-COOH, respectively. PAA/APEG-PG-COOH also displayed ability to prevent the formation of CaCO3 scales. The effects on formation of Ca3(PO4)2, CaCO3 and CaSO4 were investigated with combination of Scanning electronic microscopy (SEM), Transmission electron microscopy (TEM), and X-ray powder diffraction (XRD) analysis, respectively.