Acrylic acid-diphenylamine sulphonic acid copolymer threshold inhibitor for sulphate and carbonate scales in cooling water systems Original Research Article

Formation of mineral scales of carbonate and sulphate poses significant problems in cooling water systems. For the control of calcium carbonate and calcium sulphate scales, copolymer of acrylic acid-diphenyl amine sulphonic acid (AA-DPSA) was tried as the anticalant in the respective brines. The copolymer of AA-DPSA was synthesized by following a free radical polymerization procedure. AA-DPSA was characterized by Fourier transform infra-red spectroscopy (FT -IR). The molecular weight of the polymer was measured by using Efllex viscometer. The antiscaling properties of the polymer towards CaCO3 and CaSO4 scales were studied through a chemical screening test and electrochemical techniques such as constant potential electrolysis and electrochemical impedance measurements at different pH, temperature and inhibitor concentrations. The effect of the polymer addition on the crystals of CaCO3 and CaSO4 scales morphology and structures were examined through scanning electron microscopic (SEM) and X-ray diffraction studies (XRD). The results show that the AA-DPSA polymer acts as a very good antiscaling inhibitor both in the carbonate and sulphate brines. Copolymer of acrylic acid-diphenyl amine sulphonic acid can be used safely in cooling water industries.