Maleic Anhydride - Acrylic Scale Inhibitor Synthesis And Applications

Maleicanhydride-acylic acid copolymer is a kind of scale inhibitor, which do not contain of organic and inorganic phosphor. It wouldn't be hydolyzated to produce scale of Ca2(PO4)3, and can also be compounded with many kinds of chemical reagents being used in water treatment. The consequence of compounding is very good, so MA-AA copolymer scale inhibitor is a kind of ideal Ca2+ inhibitor. This article take water as solvent, and use catalyst being made by us to produce MA-AA binary copolymer, the best synthesis condition is: the best ratio of maleic anhydride acrylic acid and initiating agent is 1:1:0.47, the quantity of catalyst is 0.9%of unit total concentration. With this ratio, the productivity of copolymer is highest. The studying of MA-AA copolymer shows that: with the increasing of unit proportion, the characteristic viscosity of copolymer is raising also. When the characteristic viscosity is on a special value, the inhibiting scale ratio is highest. The best using quantity is 12mg/L. Lower than the value, the inhibiting scale ratios to CaSO4and Ca2(PO4)3 raise with the increasing of using quantity. Higher than the value, the inhibiting scale ratios decrease with the increasing of using quantity. With inspecting scale sample, we find that the scale of CaCO3 CaSO4 and Ca2(PO4)3 in static inhibiting test are all soft scale that is weaker flocculu and no adhesive. This shows the copolymer has strong ability of dispersal inhibiting. The PH value between 6.0~9.0 has little influence on inhibiting scale ratios. With the increasing of alkalinity in water, the inhibiting scale ratio of MA-AA copolymer has little decreasing, but it will be 94.6% until the alkalinity to 700 x10-6. This shows MA-AA copolymer not only fit high hardness water but also fit high alkalinity water.The inhibition mechanism of MA-AA copolymer is that the copolymer adsorb on inorganic salt crystal core or microcrystalline, restrain the growing speed of crystal. The copolymer embedded into growing crystal makes inorganic saline crystal produce distortion, and make crystal particle suspend in solution, so check the growing of crystal particle. Without scale inhibitor hut pre-adding crystal steeds, the crystallization of CaSO4 directly happen on the surface of crystal steeds, doesn't produce nucleation and spontaneous precipitation. MA-AA copolymer can successfully control the growing of CaSO4.2H2O crystal. The apparent speed constant is getting lower with increasing of copolymer concentration. To the MA-AA copolymer used in this article, the scale inhibitor concentration showing induction period is 0.3%mg/L. the adsorption of MA-AA copolymer on CaCOs microcrystalline tally with Langmuir isothermal adsorption, belong to single molecule layer adsorption. And it produces striking control of the crystallization growing of CaCO3. The MA-AA copolymer has good inhibiting consequence, its inhibiting mainly is adsorption to the surface of microcrystalline, companying with making crystalline distortion, dispersing, solubilizatiom chelation and so on.The consequence of on-spot using show that MA-AA copolymer can successfully control the crystallization and precipitation of Ca2+. It is a kind of ideal scale dispersal inhibitor.