Investigation of the inhibitive effect of polyethylene glycol on corrosion of carbon steel in acid mixture solution HCl + H2SO4

摘要

The corrosion of steel is the most common form of corrosion, especially in acid and acid mixtures. It has practical importance, for example, in the acid pickling of iron and steel, chemical cleaning of the scale in metallurgy, oil recovery and petrochemical industry, and other electrochemical systems. Corrosion behaviors of different metals have been studied in industrial acid mixtures. According to inhibition effect of polyethylene glycols (PEG) on carbon steel corrosion in acidic media, they were mentioned as corrosion inhibitors in this study. The inhibition effect of PEG at two different mean molecular weight (200 and 6000 gmol-1) on carbon steel corrosion was studied in mixture of 1N hydrochloric acid + 1N sulphuric acid at different temperatures. This study was carried out by weight loss method, polarization and electrochemical impedance spectroscopy techniques and scanning electron microscopy. It was found that PEG has inhibition efficiency on carbon steel corrosion in the studied medium. The polyethylene glycol's inhibition efficiency increased with an increase in its molecular weight and concentration. The inhibitor adsorption was found to follow Langmuir adsorption isotherm. Thermodynamical parameters were also calculated for polymer adsorption on carbon steel and demonstrated a spontaneous substitution adsorption.