Synthesis Of Heterocyclic And Sulfonic Acid Modified Polyaspartic Acid Composite Scale Inhibitors And Study Of Synergistic Performance

Environmentally-friendly high-efficiency water treatment agent is a research focus in the field of water treatment.As recognized currently one of the green,biodegradable water treatment agents,Polyaspartic acid?PASP?has an amide bond structure similar to proteins and excellent resistance to CaCO₃and CaSO₄ scale,but the performance of resistance to Ca₃?PO₄?₂ scale,corrosion inhibition properties,and dispersion of iron oxide properties are not outstanding,limiting its scope of application.Therefore,the industrial uses modified and complex agents to improve the overall performance of water treatment agent.In this paper,we use three special functional group to modify polyaspartic acid,and use the synthesis products to optimize by orthogonal experiments with 2-phosphonic acid-1,2,4-tricarboxylic acid butane?PBTCA?,zinc sulfate,and polycyclic ring.Concentration ratio of oxysuccinic acid?PESA?.The scale inhibition,corrosion inhibition,and biodegradability were investigated by means of static scale inhibition,weight loss,electrochemical,dynamic simulation,and aerobic biodegradation.?1?A polyaspartic acid was synthesized by thermal polycondensation using Aminomethanesulfonic acid,furfurylamine,4-Aminopyridine,maleic anhydride,urea and the like,respectively./Amino methanesulfonic acid grafts?PASP/ASA?,polyaspartic acid/guanamine grafts?PASP/FA?,polyaspartic acid/4-methylaminopyridine grafts?PASP/4-AMPY?was characterized by ¹H-NMR spectroscopy.?2?We use orthogonal experiment to design the concentration ratios of PBTCA,ZnSO4 and PESA with synthesis products.The results showed that the optimum concentration ratio of composite scale inhibitor?Comp-1?containing PASP/ASA grafts was 10 mg/L for PASP/ASA,20 mg/L for PESA,2 mg/L for zinc sulfate and 8 mg/L for PBTCA.The optimal concentration ratio of composite scale inhibitor?Comp-2?containing PASP/FA grafts was 30 mg/L for PASP/FA,40 mg/L for PESA,4 mg/L for zinc sulfate and 8 mg/L for PBTCA.The optimal concentration of composite scale inhibitor?Comp-3?containing PASP/4-AMPY grafts:20 mg/L for PASP/4-AMPY,30 mg/L for PESA,and 4 mg/L for zinc sulfate Land 15 mg/L for PBTCA.?3?We use static scale inhibition method to study the scale inhibition performance of the three composite agents.The results show all three agent that Comp-1,Comp-2 and Comp-3 have excellent scale inhibition efficiency.Performance of Comp-2 to resist CaCO₃ is as high as 92.3%in heating 10 h at 80°C.?4?The corrosion inhibition properties of three composite agents were studied by weightlessness and electrochemical methods.The results showed that Comp-1,Comp-2 and Comp-3 showed excellent corrosion inhibition performance,and Comp-3 was a kind of compound scale inhibitor based on cathodic reaction,with the highest corrosion inhibition rate of 98.1%.?5?The surface morphology of CaCO₃,CaSO₄ and Ca₃?PO₄?₂ and the surface of carbon steel were studied by scanning electron microscopy?SEM?.The results show that the crystal structures of the three kinds of calcium scale are seriously damaged,the particle size becomes smaller,the compact structure becomes loose and the irregular shape,and there is no obvious corrosion area and corrosion pit on the surface of carbon steel sheet.?6?Dynamic simulation tests of three kinds of compound agents were carried out by using WKMZ-II type device.The annual corrosion rates of Comp-1,Comp-2 and Comp-3 were 0.123 mm/a,0.049 mm/a and 0.056 mm/a respectively,and the fouling resistance was 1.0564 m2.K/W,2.0759 m2.K/W and 0.8646m2.K/W,respectively with 3 times concentration ratio was controlled.?7?The biodegradability of three composite agents was investigated by aerobic biodegradation.The results showed that Comp-2 and Comp-3 exhibited excellent biodegradability,and the degradation rates were 61.6%and 69.5% respectively.