Study of Inhibitory Effect of Three Amino Acids Cysteine, Arginine and Proline as Green Inhibitors on Corrosion of Lead Alloy

One of the most effective and important ways to prevent metals corrosion is to use inhibitors. These compounds prevent corrosion of the metal surface by creating an impermeable barrier. Unfortunately, many inhibitors in aquatic environments are harmful to health. To solve this problem, in this study, the inhibitory effects of the three amino acids cysteine, arginine and proline on lead alloy coroosion in sulfuric acid medium were used. Amino acids are non-toxic compounds, inexpensive and can be prepared with a purity of more than ۹۹%. On the other hand, as we know, lead is one of the heavy elements that have adverse environmental effects and causes water and soil pollution, therefore it is necessary to study of its corrosion. In this study, electrochemical techniques including dynamic polarization and electrochemical impedance as well as non-electrochemical techniques including weight loss measurement and scanning electron microscopy have been used. The effects of temperature, sulfuric acid and amino acid concentrations on the behavior of inhibitors have been studied. Corrosion data including corrosion rate and corrosion potential are obtained from dynamic polarization curves. Charge transfer resistance has been calculated using electrochemical impedance method. Also, electron microscope images show that increasing the concentration of inhibitor has reduced the corrosion rate of the alloy surface. The inhibitory efficiency depends on the type of amino acid and its concentration. The inhibitory efficiency of more than ۹۹% has been measured in the presence of cysteine with a concentration of ۰.۱ M in a solution of ۱ M sulfuric acid.