Comparison of corrosion inhibitor performance based on green corrosion inhibitor of extract leaf tobacco and commercial imidazoline inhibitor in a sweet environment at carbon steel AISI 1045 in NaCl 3.5% solution

Abstract

Organic inhibitor becomes alternative protection of corrosion because it is biodegradable, cheap, and also environmental friendly. This study evaluates the performance of imidazoline commercial inhibitor in a sweet environment. AISI 1045 carbon steel was chosen, with pH 5 and pH 7, flow rate 7.85 cm/s and 13.09 cm/s, and NaCl 3.5% solution. FTIR, XRD, Weight loss, Polarization, and Electrochemical Impedance Spectroscopy (EIS) tests were performed to obtain complete information regarding inhibitor’s performance. According to weight loss results at pH 5, the highest efficiency of inhibitor was 82.59% with 200 ppm inhibitor’s concentration, flow rate 7.85 cm/s, and corrosion rate of 0.104 mm/y. While at pH 7, the highest efficiency obtained was 92.697% in 100 ppm concentration of inhibitor, flow rate 7.85 cm/s, and corrosion rate 0.037 mm/y. XRD testing showed Fe24N10 compound formed as a result of reaction between Fe and the pyridine nitrogen atom. FTIR testing showed functional group of inhibitors precipitated on sample’s surface when immersed and EIS testing showed that the addition of the inhibitor concentration increased the value of polarization resistance of solution and the value of (constant phase element) decreased.