Development And Performances Of An Environmentally Friendly Corrosion Scale Inhibitor

Chemical treatment of cooling water on industry had taken decades of practical experience. With industrial development rapidly, water treatment chemicals are demanded the higher level. A new type of water treatment chemicals with double scale and corrosion inhibitor performance is the direction of workers. Along with social progress and human awareness of environmental protection, development and application of scale and corrosion inhibitor is more attention to environmentally protection requirements. Only those environmental-friendly scale and corrosion inhibitors which can be soon biodegradable, inexpensive,efficient and no pollution is really popular. Polyaspartic acid (PASP) belongs to a category of polyamino acids. With consideration of environmental compatibility and biodegradability makes it as a particularly valuable water treatment agent. After utilization,polyaspartic acid can be degraded by microbes, fungi stably and effectively to environmentally friendly final product.It was discussed that polyaspartic acid (PASP) is synthesized with by the materials of maleic anhydride and ammonium salt.After optimization of reaction conditions, Synthetic product's scale and corrosion inhibition performances were tested. On the basis of its scale and corrosion inhibition mechanism, it had been developed by environment-friendly scale and corrosion inhibitor based on polyaspartic acid,discussing on influencing factors of scale and corrosion inhibition properties.Finally, primary biodegradation of the product had been evaluated. The following results were obtained:(1)The best preparation condition was:the molar ratio maleic anhydride and ammonium salt (as NH2 dollars):1:1.2,catalyst 1.5mL, polymeric temperature 180℃, polymeric time 0.5 hour. According to good reproducibility of experiments, The best conditions were available for the universality;(2)polyaspartic acid had good scale inhibitor performance for sulphuric acid and calcium carbonate.The optimal concentrations were six milligrams per liter and two milligrams per liter. It had the superior ability of scale inhibition,and applied to the water system of high calcium concentration,staying in the water system of high temperature for a long time; (3)Scale crystal of sulphuric acid and calcium carbonate was measured by TEM. The results showed that polyaspartic acid can damage the lattice structure and normal growth pattern.It made scale becomes loose and easy off;(4)the complex product with adsorption, chelation, deposit action formed with polyaspartic acid, sodium gluconate, Zn2+. The results showed that the complex product formed with polyaspartic acid fifty milligrams per liter, sodium gluconate eighty milligrams per liter, Zn2+ two milligrams per liter had both scale and corrosion inhibition of the double effect, inhibition rate of 90.15 percentage, corrosion rate of 85.47 percentage;(5)The primary biodegradability of the complex product has been evaluated by oscillating culture method. The results showed that degradation of polyaspartic acid have been completed after the forth day. The addition of Zn2+ didn't produce the inhibition, but can enhance the biodegradation degree of its initial.