Research Of Scale Inhibition And Dispersion Capacity Of Polyaspartic Acid Graft Copolymer Containing Acetal And Heterocyclc Group

Large quantities of water are required to support power industry,petrochemical industry and fertilizer industry,especially in the circulating cooling water system.Therefore,water scarcity has become a serious problem that constrains the sustainable development of industry in many areas worldwide.In this case,secondary-treated municipal wastewater(MWW)is now being recognized as a significant source of water for cooling water.However,primary challenges with MWW reuse for cooling arise from its low quality,especially its usually contains appreciable amounts of hardness and phosphate.However,a series of problems such as eutrophication,toxic and so on are brought about most of the scale inhibitors.So it is highly desired that the“green inhibitors”for non-toxic and environ-ment-friendly.Polyaspartic acid(PASP)was a no-phosphorus,biodegradable and environmental friendly scale inhibitor.As a scale inhibitor,it has excellent inhibition performance for CaCO3 and CaSO4 scale.Nevertheless,only containing carboxylic group on the structure,PASP has low relatively inhibition performance for Ca3(PO4)2 scale,which seriously limits its application.Details are as follows:1.Polysuccinimide(PSI)was synthesized by means of the thermal polycondensation reaction of maleic anhydride and carbamide.Some novel scale inhibitor,polyaspartic acid/L-carnosine(PASP/L-carnosine);polyaspartic acid/N-Aminoethylpiperazine(PASP/AEP);polyaspartic acid/N-(3-Aminopropyl)morpholine(PASP/APM);polyaspartic acid/Methylaminoacetaldehyde dimethyl acetal(PASP/ADA);polyaspartic acid/2,2-Diethoxyethylamine(PASP/AED)and polyaspartic acid/Tryptamine(PASP/TAM)graft copolymer,was synthesized using PSI and L-camosine;AEP;APM;ADA;AED;TAM as raw materials respectively.Their structures were characterized by 1H NMR.2.Their scale inhibition performances against CaCO3,CaSO4 and Ca3(PO4)2 were investigated by static scale method respectively.Results showed the introduction of acetal and heterocyclc group could increase the scale inhibition property of PASP for Ca3(PO4)2 greatly,the best inhibition efficiency for Ca3(PO4)2 can reach 99.6%when graft copolymer is 4 mg/L.In addition,all of graft copolymer could maintain the scale inhibition property of PASP for CaCO3 and CaSO4.3.Their scale inhibition performances in high phosphorus;high hardness and high temperature were investigated by static scale method.The PASP/L-carnosine,PASP/APM,PASP/ADA,PASP/AED inhibition performance of showed a satisfactory effect of high phosphorus;high hardness and high temperature.4.We investigated the performance of dispersing ferric oxide of PASP/APM and PASP/ADA,The best transmittance for ferric oxide is 70%when PASP/APM is 35 mg/L,while PASP/ADA is 44%at 30 mg/L.5.We investigated the performance of fluorescent properties of PASP/TAM.The fluorescence intensity rises with an increase of inhibitor dosage,and the relationship between the fluorescence intensity and the concentration of PASP/TAM is linear in the range of 1-6 mg/L.