Study On The Extract Of Citian Eggplant Fruit As A Corrosion Inhibitor For Pickling

In this paper,the soaking method and ultrasonic method were used to prepare the Solanum violaceum fruit extract(SV),and the corrosion inhibition of A3 steel in lmol/L HCl solution was studied by weight loss method,electrochemical polarization curve and AC impedance spectroscopy,and the effect of compounding properties and impurity ions on SV was studied.The adsorption model and inhibitor type of SV were analyzed by thermodynamics and kinetics calculations.The corrosion inhibition mechanism of SV was analyzed by FT-IR,SEM and EDS.Orthogonal experiments show that the optimum extraction process of SV is as follows:The soaking temperature,soaking time and ultrasonic time are 70 ?,16h and 60min,respectively.The stability of the extraction process is proved by the stability experiment;FT-IR spectroscopy experiments show that the extraction of Solanum violaceum fruit contains polar groups centered on N?O and S,which are easily protonated and electrostatically attracted to the metal surface.The metal matrix is isolated from the corrosive medium and it has a certain corrosion inhibition performance.The weight loss test results show that when the temperature is 30 ? and the SV concentration is 1000mg/L,the corrosion rate is the minimum,which is 0.6 g·m-2·h-;when the temperature is 30 ? and the corrosion inhibitor concentration is 1000mg/L,the The corrosion efficiency is as high as 93.31%;Electrochemical test results show that SV has both inhibitory effects on the cathode and the anode,The ratio of the anodic interaction coefficient to the cathode interaction coefficient fO/fc>1,proves that SV is an Anode inhibited mixed inhibitors;the AC impedance test shows that the corrosion inhibition efficiency of A3 steel is up to 88.20%in 1mol/L HCl solution.The results of kinetics and thermodynamics show that the adsorption of SV on the surface of A3 steel is satisfies the Langmuir adsorption isotherm model.That is,the adsorption is a monomolecular layer with a geometrical coverage effect;The adsorption of SV molecules on the steel surface is a spontaneous process;SV molecules on the metal surface are both physical and chemical absorption,but the main adsorption method is still physical adsorption.The results of the influence of impurity ions(Cu2+,Fe3+)on the corrosion inhibition performance of SV shows that the corrosion inhibition performance of Cu2+ on SV was both inhibited and promoted on the condition of 30?,500mg/L SV,and lmol/L HCl solution.The low concentration inhibits corrosion and the high concentration promotes corrosion.When the Cu2+ concentration is 100mg/L,the corrosion inhibition efficiency is 86.58%,When the Cu2+concentration is 500mg/L,the corrosion inhibition efficiency is 61.44%.Fe3+ reduces the corrosion inhibition of SV,and the corrosion inhibition efficiency is 64.06%when the Fe3+concentration is 500mg/L.The compounding experiment shows that SVI is a mixed type corrosion inhibitor,and the inhibition efficiency at the same concentration is higher than that of the single component.When the I-concentration is 400mg/L and the SV concentration is 500mg/L,the corrosion inhibition efficiency is as high as 81.76%.The corrosion inhibition factor(S1)values of SV and I' compounds indicate that the adsorption of SV and I-on the surface of A3 steel in 1 mol/L HCl solution at 30 ? is promoted at low concentrations and competitively at higher concentrations.Regardless of the interaction,the coverage of the A3 steel surface increases with the increase of the inhibitor concentration,and the corrosion inhibition efficiency increases.