Synthesis, scale inhibition and dispersion performance evaluation of 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 and multipurpose copolymer of 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 copolymer was consistent with the expected structure. The results of GPC and TGA showed that the copolymer’s number average molecular weight was 31870, 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, dosage of initiator is 4% of total mass of monomers, the reaction temperature and time were optimized to 80 °C and 4 hours，respectively. The maximum scale inhibition efficiencies for CaCO3 and CaSO4 scales were 94.35% (24 mg•L-1) and 85.69% (22 mg•L-1). Morphologies and crystal structures of the scale depositions were studied with SEM, TEM and XRD techniques. The results demonstrated that the surface morphologies and crystal structures of the inorganic scales were significantly destroyed by the copolymer. In addition, the prepared coal water slurry using IA-AMPS-APEG as a dispersion additive had high concentration, low viscosity, 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 the scale inhibitor of cooling water and reverse osmosis systems, but also as the dispersant used in preparation of coal water slurry.