Corrosion Inhibition Performance Of Synthetic Inhibitor For A3 Carbon Steel In Simulated Circulating Cooling Water

At present,the corrosion of carbon steel has become a significant industrial and academic topic.Protecting metal corrosion can reduce the waste of resources and property,not only lengthen the service life of facility but also reduce the content of toxic metals in the environment.Adding high-efficiency green corrosion inhibitors to the corrosive environment is currently a more convenient and low-cost protection measure,which has attracted more and more attention from researchers.The plant extract corrosion inhibitors containing N,S,O and other atoms are widely used in industrial production.This paper studies the performance of a new corrosion inhibitor synthesized with zinc acetate(AC)and chicory leaf extract(CIL.L)to inhibit metal corrosion.The structure of the synthetic corrosion inhibitor(AC-CIL.L)was characterized by Fourier infrared spectrometer and X-ray photoelectron spectrometer.The infrared spectrum showed that compared with inorganic Zn2+,the organiU compone nts of chicory leaves occupies the main part of AC-CIL.L,and a new peak of Zn-O proves that the corrosion inhibitor is successfully synthesized;the photoelectron spectrogram shows that the main three peaks of AC-CIL.L are C1s,O1s and Zn2p,which are related to-OH,O-Zn,O-C and C=O in the molecular structure.Then the inhibition effect of AC?CIL.L and AC-CIL.L on A3 carbon steel in simulated circulating cooling water at different temperatures was investigated by rotating sample experiment,which can provide feasibility verification for the later electrochemical mechanism analysis.The results show that the optimal concentration ofAC?CIL.L and AC-CIL.L is 0.5g/L,0.65g/L,0.65g/L,the inhibition efficiency is 90.49%,79.58%,96.81%.It can be seen that the AC-CIL.L has the best effect.For the three kinds of corrosion inhibitors,when the temperature is increased from room temperature to 35? and 45?,the efficiency of corrosion inhibitor is reduced at the same concentration.Using polarization curve,electrochemical impedance spectroscopy to further analyze the mechanism of AC-CIL.L on A3 carbon steel,the results show that the Ecorr deviates to the anode is less than 85mV,and AC-CIL.L is a kind of mixed corrosion inhibitor mainly for anode inhibition.The corrosion current density Icorrshows a decreasing trend as the concentration increases,and shows an increasing trend as the temperature increases,indicating that the adsorption of AC-CIL.L molecules belongs to physical adsorption.The phenomenon of desorption will occur with the temperature increases.The adsorption model conforms to the Langmuir isotherm,and there is no interaction between the molecules covering the metal surface.The Nyquist diagram shows that AC-CIL.L does not change the mechanism of the metal corrosion reaction.The shape of Nyquist diagram with different AC-CIL.L remains unchanged,and the diameter the loop increases as the concentration of AC-CIL.L increases.The adsorption of AC-CIL.L on A3 steel restrains the resolution of Fe,thus the value of Rct increases with the concentration of AC-CIL.I increases as result of the increased difficulty of electron transfer.The Rf increases with the increases of the AC-CIL.L concentration,because the Zn(OH)2 protective film generated by Zn2+ in the cathode becomes thicker and thicker,which hinders the contact between carbon steel and corrosive ions such as Cl-and SO42-in the cooling water.Through experiments,the optimal concentration of AC-CIL.L on A3 steel is obtained,and analysis the mechanism of corrosion inhibition.The results show that AC-CIL.L has excellent corrosion inhibition performance and it is a green non-pollution inhibitor.If it is applied to the actual environment,it can increase the cycle times of cooling water and the concentration rate,which has a certain practical value for solving the corrosion inhibition of the circulating cooling system in the power plant.