Abstract
The precipitation of calcium sulfate (CaSO4) scale on heat transfer surfaces widely occurs in numerous industrial processes. For the control of calcium sulfate scale, a novel environmentally friendly type of scale inhibitor Acrylic acid–oxalic acid–allypolyethoxy carboxylate (AA-APEM9) was synthesized and characterized, and the anti-scale property of the AA-APEM9 copolymer towards calcium sulfate in the artificial cooling water was studied through static scale inhibition tests. It was shown that AA-APEM9 exhibited excellent ability to control calcium sulfate scale, with approximately 97.1% calcium sulfate inhibition at a level of 4 mg/L AA-APEM9. Scanning electron microscopy and X-ray powder diffraction studies have been performed to identify the change in crystal surfaces by the addition of the copolymer. Inhibition mechanism is proposed that PAA can recognize and react with positively charged calcium ions on the surface of inorganic minerals and water-compatible PEG segments increase its solubility in water.
Acknowledgements
This work was supported by the Prospective Joint Research Project of Jiangsu Province (BY2012196); the National Natural Science Foundation of China (51077013); special funds for Jiangsu Province Scientific and Technological Achievements Projects of China (BA2011086); Scientific Innovation Research Foundation of College Graduate in Jiangsu Province (CXLX13-107); and program for Training of 333 High-Level Talent, Jiangsu Province of China (BRA2010033).