Environmentally Friendly Water Treatment, Polyaspartic Acid And Its Mixture With Material Research And Scale And Corrosion Inhibition Performance

With the globally increasing demand of green chemicals, polyaspartic acid (PASP) has been paid more and more attention as a kind of biodegradable green chemicals with excellent properties. Recently the research on the application of water treatment about PASP is popular in other countries, but in China less work has been done.PASP is synthesized by thermal polymerization with L-aspartic acid in this paper. It is stable for high temperature. Furthermore it is nontoxic, and has no thrill to skin.Thorough research has been done on the scale-inhibition properties to CaCO₃, CaSO₄ and BaSO₄,consequently the optimum molecular weight is set .Simultaneously the effect of Ca²⁺ and Ba²⁺ concentration, temperature. pH and time on the scale-inhibition is evaluated. A conclusion is drawn that PASP could be used in water system with high Ca²⁺ and Ba²⁺ concentration, temperature and high pH, and could stay long time in high temperature water system. The research by SEM and XRD on crystal cell dimension change of three kinds of scale caused by PASP and discussion of scale inhibition mechanism indicates that the scale inhibition effect could be achieved through changing crystal cell shape, minishing volume and preventing crystal from growing and depositing regularly .For the first time the combination system of PASP with oxided starch has been developed and the optimum concentration has been set. The combination system has better scale inhibition properties and a lower cost than PASP .The corrosion inhibition effect of PASP with different molecular weight has been systematically analised. The addition of Zn²⁺ will dramatically improve the corrosion inhibition properties. For the first time the practically complex scale and corrosion inhibitors of PASP and tungstate has been developed.