Synthesis, scale inhibition and dispersion performance evaluation of the environmentally benign additive IA–AMPS–APEG copolymer

Abstract

In order to control the formation of inorganic calcium scale and improve the environmental benefits of coal water slurry, a non-phosphorus-containing and multipurpose copolymer IA–AMPS–APEG was successfully prepared. The chemical structure, molecular weight and thermal stability of the copolymer were characterized by FTIR, GPC and TGA. FTIR confirmed that the structure of the copolymer was consistent with the expected structure. The results of GPC and TGA showed that the copolymer's number average molecular weight was 31 870, and it had excellent thermal stability. The scale inhibition performance of the copolymer was investigated to determine the optimal synthesis conditions: n(IA) : n(AMPS) : n(APEG) = 1 : 2 : 0.33, the dosage of initiator is 4% of the total mass of the monomers, and the reaction temperature and time were optimized to 80 °C and 4 hours, respectively. The maximum scale inhibition efficiencies against CaCO₃ and CaSO₄ scale deposits were 94.35% (24 mg L⁻¹) and 85.69% (22 mg L⁻¹). Morphologies and crystal structures of the scale deposits were studied with SEM, TEM and XRD techniques. The results demonstrated that the surface morphologies and crystal structures of the inorganic scale deposits were significantly destroyed by the copolymer. In addition, the prepared coal water slurry using IA–AMPS–APEG as a dispersing additive had a high concentration, low viscosity, and good fluidity and stability. In short, the novel and multifunctional copolymer in this work is considered to be an increasingly promising candidate not only as a scale inhibitor in cooling water and reverse osmosis systems but also as a dispersant used in the preparation of coal water slurry.