Browsing by Author "Idema Osuani Fyneface"

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    Utilization of musa paradisiaca leaf extract-based inhibitor for corrosion protection of carbon steel in 3.5% NaCl
    (Federal University of Technology, Owerri, 2025-10) Idema Osuani Fyneface
    The utilization of musa paradisiaca leaves (MPL) extract-based inhibitor on carbon steel protection in marine environment has been studied using gas chromatography mass spectroscopy (GC-MS), Fourier transform infrared spectroscopy (FT-IR), gravimetric method (GM), Atomic force microscopy (AFM), Contact angle measurement (Ө), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), density functional theory (DFT) and molecular dynamics (MD) simulations. Firstly, the GCMS analysis showed the presence of compounds with heteroatoms in the MPL inhibitor. Likewise, the FT-IR analysis showed the presence of polar functional groups. The GM showed MPL extract-based inhibitor having optimum inhibition efficiency of 91% at a concentration of 100g/L and immersion time of 120 hours which led to a decrease in corrosion rate from 0.8817 mm/y to 0.0823 mm/y. Also, the weight loss experienced by the test specimen decreased from 0.0986g to 0.0091g. AFM morphology revealed thin film adhesion showing firm adsorption of Langmuir films on the metal/inhibitor interface, with root mean square roughness values for uninhibited and inhibited substrates 71.2722Rq and 33.6773Rq respectively. Likewise, contact angle measurement showed high contact angle of 152.42●with a hydrophobic metal/inhibitor interface for inhibited substrate hence not prone to corrosive species and low contact angle of 76.20● for the uninhibited substrate with hydrophilic surface which is prone to invasive corrosive species. The potentiodynamic polarization (PDP) via Tafel plots showed a cathodic slope capable of controlling both activation (oxidation) and diffusion (oxygen reduction) reactions. Also EIS via Nyquist, Bode plots and Phase angle showing high polarization resistance thereby reducing corrosion rate. Further, Density functional theory (DFT) analysis correlated the results by affirming the contributions of the isolated compounds of the MPL inhibitor molecule to the inhibition efficiency of 91%. In addition, MD results showed planer orientation of MPL inhibitor molecules over the surface of the substrate as such enhancing larger surface coverage, hence better inhibition effectiveness. Also, the high adsorption energy of -184.954cal/kJ is indicative of chemisorption. Radial distribution function (RDF) showed presence of short bond lengths of between 2.97-3.49 atom thick, confirming the presence of strong covalent bonding. Test of adsorption isotherms reveal conformance of the Langmuir model.