Nanosilica modified with polyaspartic acid as an industrial circulating water scale inhibitor

Given the special performance of nanosilica with its small size, large specific surface area and high surface activity, nanosilica containing reactive amino group (denoted as SiO2-NH2) and polysuccinimide were allowed to take part in polymerization reaction to afford SiO2-NH2 modified polyaspartic acid (denoted as SiO2-NH2/PASP), a potential polymer scale inhibitor with good water solubility for industrial circulating water. The scale inhibition performance of the as-prepared SiO2-NH2/PASP was evaluated by static scale inhibition test; and its scale inhibition mechanism was explored by means of scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Results indicated that SiO2-NH2/PASP exhibits excellent scale inhibition performance against CaSO4 and CaCO3 at very low concentrations (optimum scale inhibition rate of 100% and 68%, respectively), and the presence of 5 mg/L of SiO2-NH2/PASP greatly increases the inhibition efficiency of CaSO4 and CaCO3 scale by 21% and 53%, obviously higher than that of pure PASP.