Optimization and Electrochemical Study on the Control of Mild Steel Corrosion in Hydrochloric Acid Solution with Bitter Kola Leaf Extract as Inhibitor

Abstract

Response surface methodology was applied to predict the optimum control of mild steel corrosion in acid medium with bitter kola leaf extract as inhibitor. The experiment was carried out to investigate the mutual interactions between the considered independent variables and the expected responses. Thermometric, gravimetric, potentiodynamics polarization and electrochemical impedance spectroscopy were used in the corrosion inhibition study. As a supplementary technique, infrared spectroscopy was used to analyze the pure extract and corrosion products and it was observed that some peaks shifted while some disappeared. Inhibition efficiencies of 88.24 %, 86.81 %, 90 %, 89.5 % and 85.3 % were obtained from optimization, thermometric, gravimetric, potentiodynamics polarization and electrochemical impedance spectroscopic techniques, respectively. The bitter kola leaf extract behaved as a mixed-mode inhibitor. Application of response surface methodology in this study was found to be good in predicting the optimum range for controlling of metal corrosion thereby reducing the number of experimental runs.

Electrochemical and quantum chemical parameters of (-)-(S)-9-flu¬oro-2,3-dihydro-3-methyl-10-(4-methyl-1-pipera-zinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acidas anti-corrosive agent for API 5L X-52 steel

“…Therefore, inhibitors with high dipole moment form strong dipole-dipole interactions with the metal, ensuring a strong adsorption on the surface of the metal and leading to higher inhibition efficiency. It was observed that the dipole moment value for Levaquin shown in Table 5 correlates with the experimental results reported elsewhere [32][33][34][35].…”

Experimental and theoretical study on the corrosion inhibitor potential of quinazoline derivative for mild steel in hydrochloric acid solution

“…This EEC is composed from few elements due to the solution resistance (Rs), charge-transfer resistance of the interfacial corrosion reaction (Rct) and the constant phase element (CPE) due to double-layer impedance. Impedance of CPE (ZCPE) is defined as [19,20,[32][33][34]:…”

Experimental, Statistical Modelling and Molecular Dynamics Simulation Concept of Sapium ellipticum Leaf Extract as Corrosion Inhibitor for Carbon Steel in Acid Environment

“…Weight loss method was performed at temperatures of 303 K, 318 K and 333 K, respectively. As previously expressed 10,16 the variation in the initial and final weight was studied for unprotected and protected test solution. At the end of corrosion study the coupons were removed, dipped in acetone, cleaned and finally re-weighed.…”

“…Further observation revealed that the activation energies increase as the concentration of SE molecules increases due to the spontaneous accumulation of SE molecules on steel surface which led to a considerable surface coverage and the film layer is seen to be higher than the destruction of the steel surface. 10…”

“…A series of investigations are available proving the fitness of plant extract as green and novel corrosion inhibitors. Among the various plants inhibitor studied such as ginkgo leaf extract gave efficiency of 92.5 % for mild steel in 1 M HCl at inhibitor concentration of 200 mg L -1 , 8 Rosmarinus officinalis extract gave efficiency of 93.26 % for low carbon steel in 1 M HCl at inhibitor concentration 3 %, 9 bitter kola leaf extract gave efficiency of 90 % for mild steel in 1.2 M HCl at inhibitor concentration of 0.9 g L -1 , 10 Mitracarpus hirtus extract gave efficiency of 89 % for mild steel in 1 M HCl at inhibitor concentration of 0.6 g L -1 , 11 Aegle marmelos extract gave efficiency of 83 % for mild steel in 0.5 M H 2 SO 4 at inhibitor concentration of 500 mg L -1 . 12 Bio-extracts are known to contain minute chemical constituents; in view of this it is cumbersome to isolate a definite constituent behind the inhibition process.…”