Synthesis and scale inhibition performance of a novel environmental friendly and hydrophilic terpolymer inhibitor

A novel environmental friendly and hydrophilic terpolymer with the sulfonic group and ether group was synthesized by maleic anhydride (MA), 2-acrylamido-2-methylpropanesulphonic acid (AMPS) and 3-allyloxy-2-hydroxy-1-propanesulfonate (AHPSE) in free radical polymerization. The structure of MA/AMPS/AHPSE was characterized by the ¹³C nuclear magnetic resonance, Fourier transform infrared spectroscopy spectra, Ultraviolet Visible spectrophotometer and gel permeation chromatography. The inhibition performance of CaCO₃ and zinc scales and the dispersion property of ferric oxide were investigated by static scale inhibition methods. The terpolymer had the best inhibition performance when the weight-average molecular weight (M_w) was 2.41 × 10⁴, namely the ratio of MA/AMPS/AHPSE was 6/2/0.8. With the optimal M_w, the inhibition performance of the terpolymer was superior to that of MA/AMPS, AA/AMPS and PAA. The transmittance ratio of ferric oxide solution was 44.9% at 14 mg/L and the inhibition efficiency of zinc scales reached 89.8% at 10 mg/L. The results revealed that the suitable M_w and pluralistic functional groups of this typical terpolymer were the main keys for the excellent inhibition performance. The modified CaCO₃ scales in the presence of MA/AMPS/AHPSE were analyzed by X-ray powder diffraction and scanning electron microscope.