The Use of Citrullus Lanatusfor Corrosion Inhibition of A36 Steel in a CO2Saturated Saline Solution: A Thermodynamic and Kinetic Model Approach

Abstract

Citrullus lanatus was tested for its suitability as an Inhibitor on Mild Carbon Steel in a Carbon (IV) Oxide (CO2) saturated saline solution. The mechanism of corrosion was investigated with and without Inhibitor additive in order to compare the effectiveness of the Inhibitor. Thermodynamic computations namely Enthalpy, Entropy and Gibbs free energy were used to determine the Inhibitive property of the Citrullus lanatus Extract. In addition, four Kinetic Models namely; Langmuir, Temkin, Flory-Huggins and Frumkin were also used to fit the experimental data. Gas Chromatography-Mass Spectroscopy and Fourier Transfer Infrared Spectroscopy were used to characterize the Watermelon Seed Extract. Analysis of the results shows that Inhibitor efficiency decreases with increasing Temperature. The result also shows Inhibition efficiency within the range of 17.39%-71.79%. From the Result, the test sample without Inhibitor has the least Activation Energy in comparison with those with Inhibitor additives. The investigation also revealed that the Frumkin model at 50oC best fits the Experimental data with a Coefficient of determination, R2 of 99.9%, though; the other Models also fit the Experimental data.