Scale Inhibition Performance and Mechanism of Terpolymer IA-PEG-SAMS

This research aims to develop an effective scale inhibitor to prevent calcium carbonate and calcium sulfate scaling in industrial circulating cooling water systems. Terpolymer IA-PEG-SAMS was synthesized via free-radical polymerization using itaconic acid (IA), polyethylene glycol (PEG), and sodium methacryl sulfonate (SAMS) as monomers. The optimal synthesis parameters for the terpolymer IA-PEG-SAMS were investigated using the single-factor method. FT-IR, ¹H-NMR, and GPC characterized the terpolymer and monomers obtained. The impact of various factors on calcium scale inhibition under optimal synthesis conditions was examined. The scale inhibition performance of IA-PEG-SAMS on calcium carbonate and calcium sulfate scales was compared with current commercial scale inhibitors. The findings indicated that IA-PEG-SAMS demonstrated superior efficacy in inhibiting calcium scaling compared to most commercially available scale inhibitors. The scale inhibition efficiency was 95.16% for calcium carbonate and 92.13% for calcium sulfate at 90 mg/L and 0.2 mg/L IA-PEG-SAMS concentrations. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses demonstrated that IA-PEG-SAMS markedly altered the calcium scale’s morphology, crystal shape, and crystal structure. The terpolymer can effectively adsorb on the active component of calcium scale crystals and chelating calcium ions. The process involves a synergistic effect of lattice aberration and chelation solubilization, resulting in a loose and porous crystal structure of the calcium scale. The water flow can easily wash away this structure. Based on the above characteristics, the scale inhibitor shows considerable potential in water treatment.