The Synthesis And Performance Evaluation Of The Green Scale Inhibiter, Polyaspartic Acid

The scaling phenomenon of service water seriously impacts the running of the industrial production, and it is the industrial technologic problems to be solved on edge. Adding scale inhibitors is a main measure to solve the scaling of service water. Currently many scale inhibitors are applied in the water treatment, for example, inorganic polyphosphates, phosphorus-containing scale inhibitors, low-molecular-weight polymer, natural scale inhibitors. non-phosphorus green scale inhibitors have been developed since 1990, which indicates green scale inhibitors have became one of developmental aspects in water treatment medicaments.This paper studies a Polymerization process,which synthesizes polyaspartic acid(PASP) by maleic anhydride and ammonia as raw materials, polysuccinimide(PSI) was synthesized by liquid polymerization. Hydrolysising Polysuccinimide under alkaline conditions can obtain pure sodium products. Systematically study the amination reaction of maleic anhydride and ammonia, molar ratio, reaction time, polymerization time,polymerization temperature on the properties of the products; and the use of orthogonal experiment to determine the optimal reaction conditions: molar ratio is 1:1.1; polymerization temperature is 160℃; reaction time is 2.5h;: the yield of PASP under the optimal conditions is 93% ,inhibition rate is 91%. viscosity-average molecular weight is 1.3×104g/mol. Inhibition performance of PASP is Evaluated by static anti-scaling method, in 80℃, alkalinity 300mg/L, calcium concentration 300mg/L conditions, inhibiting efficiency of l5mg/L PASP can reach over 95% inhibition. Under the same conditions, compare inhibiting effect of PASP, polyacrylic acid (604), HEDP and ATMP to calcium carbonate, which determine PASP has very close effect with the traditional scale inhibitors. At the same time we find that the PASP has good dispersion and inhibition properties to iron oxide scale. Effects of temperature, concentration and alkalinity of PASP on inhibition to PASP scale is studied by experiments. The results indicate that the concentration of PASP correspondingly increases with temperature and alkalinity increased. Compare PASP performance with phosphorous scale inhibiter with shaking-bottle incubating test, we find PASP has good biodegradation. The PASP in this study has the characters of cheap material, simple technology, it will have bright features for industrial application.