Preparation, Characterization and Performance Evaluation of a Novel Scale Inhibiting and Dispersing Copolymer Containing Natural Tannin

Based on the principle of free radical polymerization, a novel scale inhibiting and dispersing copolymer was successfully prepared using the monomers of itaconic acid (IA), 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and tannic acid (TA). The chemical structure, molecular weight and thermal stability of the copolymer were characterized by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC) and thermogravimetric analysis (TGA), respectively. The effects of synthesis and water conditions on the scale inhibition performance of the copolymer were investigated by static scale inhibition method. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to study the microscopic morphology and crystal structure of the scale deposits. When the reaction time was 3.5 h, the reaction temperature was 75 °C, the amount of tannic acid added was 4 g, and the amount of initiator was 5% of the total mass of the monomers, the copolymer had the excellent scale inhibition performance. With the test temperature raised, the basicity of the simulated cooling water increased, and the concentration of CO 3 2− /HCO 3 − enhanced, scale inhibition efficiency of the copolymer decreased. TGA analysis proved that the significant thermal degradation of copolymer occurred at 220 °C, which demonstrated that the copolymer had outstanding temperature resistance. Characterization of the inorganic calcium scale deposits indicated that the copolymer markedly destroyed the surface morphology and crystal structure of the scale deposits. The novel scale inhibiting and dispersing copolymer containing natural tannin prepared in this work will have a bright application prospect in controlling the formation of inorganic calcium scale deposits,which is about to have potential strategic implications for water conservation and energy efficiency.