Synthesis Of Fluorescent-tagged Polyaspartic Acid Derivatives And Evaluation Scale And Corrosion Inhibition Performance

There are always scale and corrosion problems in the circulating cooling water system,and the most economical and effective way to solve these problems mentioned above is to add scale and corrosion inhibitors.Fluorescent tracer technique can realize the real-time monitoring of water treatment agent concentration,and meet the requirements of energy conservation and emission reduction,But the development of fluorescent water treatment agent is the key to the application of fluorescent tracer technique.In this paper,specific fluorescent functional groups were used to carry out the graft modification of PASP,which enables it to have better fluorescence performance on the basis of maintaining the scale and corrosion inhibition performance of PASP grafts.?1?Polyaspartic acid/5-methoxytryptamine?PASP/OTAM?,polyaspartic acid/2-amino-5-?aminomethyl?-1-naphthalenesulfonic acid?PASP/APS?and polyaspartic acid /3-aminomethyl-pyridine?PASP/3-AMPY?were prepared by amino open ring reaction using 5-methoxytryptamin-e,2-amino-5-?aminomethyl?-1-naphthalenesulfonic acid and 3-aminomethylpyridine as fluoresc-ent functional groups,the structures of these products were characterized by 1H NMR and FTIR.?2?The scale and corrosion inhibition properties of PASP/OTAM,PASP/APS and PASP/3-AMPYwere evaluated by static scale inhibition method and rotation specimen method.Compared with PASP monomer,PASP/OTAM,PASP/APS and PASP/3-AMPY have better scale and corrosion inhibition performance.The fluorospectrophotometry was used to investigate the fluorescence properties of grafts.The results showed that the grafts had good fluorescence properties,and the fluorescence intensity and the concentration linear correlation coefficient R² were 0.99963,0.99919 and 0.99966,respectively.When the heating temperature was 25-80 ?,the p H value of the solution was 5-11,and the heating time was 8-14 h,the fluorescence intensity of the grafts remained basically constant.?3?The corrosion inhibition performance of PASP/OTAM,PASP/APS and PASP/3-AMPY in 3.5% Na Cl solution was evaluated by electrochemical method.The results showed the corrosion inhibition efficiency was 71.49%,68.53% and 77.99%,respectively.At the same concentration,the corrosion inhibition rate of the pure PASP was only 36%.The calculation results of density functional theory?DFT?proved that the grafts can adsorbe on the metal surface by physical adsorption and chemical coordination bond to play a good role in scale inhibition and corrosion inhibition.?5?By using experimental idea with the step-by-step amplification,the synthesis route of PASP/3-AMPY graft was optimized,the pilot scale production line of 500L-2000 L reactor was established,and the pilot scale production technical route of Polyaspartic acid derivatives was preliminarily mastered,so as to lay a solid foundation for the promotion and application of Polyaspartic acid derivatives with fluorescent tracer.?6?The synergistic properties between the grafts and PAPEMP,HPMA,Glu and Zn²⁺ were studied by orthogonal experiment.The results showed that the composite water treatment agent could be applied in some fields with high temperature,high alkali and high p H.SEM and XRD studies show that the compound agents can change the structure of scale crystals,thus it easy to be washed away by water flow,so as to avoid the deposition of scale crystals on the surface of metal pipes.