Potential of Tomato Pomace Extract as a Multifunction Inhibitor Corrosion of Mild Steel

Abstract The aim of this paper is to investigate tomato pomace extract (TPE) as multifunctional “green” vapor phase corrosion inhibitor for prevention of the atmospheric corrosion of mild steel and as corrosion inhibitor in neutral media of 0.5 M NaCl solution. The chemical profile of the TPE was analysed using gas chromatography mass spectrometry (GC-MS) and high performance liquid chromatography analysis (HPLC-DAD-MS). The major volatile constituents identified in tomato pomace extract were alcohols (12.5 %), fatty acids (23.78 %), aldehydes (41.6 %), ketones (8.65 %), and terpenoids (9.11 %). The predominant semi-volatile and high molecular weight chemical components in tomato pomace extract were phenolic acids and flavanols. The corrosion protection properties of the TPE as multifunctional corrosion inhibitor were studied using of accelerated corrosion tests (weight loss method) and electrochemical methods (polarization curves and linear polarization technique (LPR)). The mechanism of steel inhibition by TPE formulations was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM) observations. The analysis confirmed that the growth of inhibitory properties is prolonged and corrosion rate is reduced after 40–48 h of exposure. Quantum-chemical calculations were used to predict the adsorption/inhibition properties of some of the main compounds of the extract.