Experimental studies of the inhibitory effect of thiamazole on copper corrosion in near neutral 3% sodium chloride solution

Abstract

As the unused drugs which are disgracefully arranged can contaminate the environment, a conceivable application of unused pharmaceutical compounds as corrosion inhibitors was successfully implemented, in this context thiamazole was assessed as a potential copper corrosion inhibitor in near neutral 3% sodium chloride solution. Electrochemical methods, surface and solution analysis are used to explore copper corrosion and its resistance. Corrosion of copper and its inhibition by thiamazole have been investigated in 3% NaCl solution using Potentiodynamic polarization, Electrochemical impedance spectroscopy, X-rays diffraction analysis, Scanning electron microscopy (SEM) along with Energy dispersive X-ray spectroscopy(EDX),contact angle measurements, Inductively Coupled Plasma (ICP) and Ion chromatography(IC).According to polarization measures, thiamazole works as a mixed type inhibitor. The values of polarization resistance and inhibition efficiency increase with thiamazole concentration increase, according to electrochemical impedance spectroscopy data. After 24 h immersion time of copper sheets in free amd containing thiamazole solution, it was revealed that thiamazole behave as mixed-type inhibitor with an efficiency of 97%. SEM/EDX investigations confirm that thiamazole forms a protective and hydrophobic layer on copper surface, this finding was assessed by contact angle (CA) tests; these results are further supported by XRD patterns that show the removal of crystalline corrosion products. The results of inductively coupled plasmasolution analysis and ionic chromatography demonstrate that in the presence of 10-4 M thiamazole in the investigated solution, the concentration of chloride increased while the concentration of copper (II) ions decreased.The outlined findings infer that the used molecule plays a role of an environmentally friendly corrosion inhibitor.