Browsing by Author "Adesina, A. S."

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    Corrosion Inhibition Behaviour for Mild Steel by Extracts of Musa sapientum Peels in HCl Solution: Kinetics and Thermodynamics Study
    (IOSR Journal of Applied Chemistry, 2012-11-01) Olasehinde, E.F.; Adesina, A. S.; Fehintola, E. O.; Badmus, B. M.; Aderibigbe, A. D.
    The inhibition of the corrosion of mild steel by acid extract of Musa sapientum peels in 1M HCl was investigated using weight loss method. The results showed that the corrosion rate of mild steel in 1M HCl decreases with increase in concentration of the extracts and the values were in the range 0.013021 - 0.002127 ghr-1 cm-2 . The inhibition efficiency increases progressively as the concentration of the extracts increases up to about 4% (v/v), above which, further increase in extract concentration did not cause any significant change in the inhibition efficiency. Effects of temperature on the inhibition efficiency of the extracts showed that inhibition efficiency decreases with increase in temperature. Activation energy (Ea) was found to be 61.60 Kjmol-1 for 1M HCl and increases to 66.72Kjmol-1 in the presence of Musa sapientum extract. The values for enthalpy of activation and entropy were all positive indicating the endothermic nature of the mild steel dissolution process. Calculated Gibbs free energy was in the range -9.43 to -8.99KJ. Kinetics of the reaction in the presence of the extracts revealed that it follows a first order reaction and the half-life increases as the concentration of the extracts increases suggesting that inhibition efficiency increases with increase in the concentration of the extracts. Preliminary investigation of the phytochemical constituents showed that Musa sapientumcontains tannin, flavonoid, terpenoid and some other compounds in trace constituents.
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    Inhibitory Action of Nicotiana tabacum Extracts on the Corrosion of Mild Steel in HCl: Adsorption and Thermodynamics Study
    (Science Pub, 2012-06) Olasehinde, Emmanuel F.; Olusegun, S. J.; Adesina, A. S.; Omogbehin, S. A.; Momoh, Yahayah H.
    The toxic effects of synthetic corrosion inhibitors have led to the search for naturally occurring substances which are not only readily available but are also environmentally friendly. Therefore, this study investigates the inhibition efficacy of acid extract of Nicotiana tabacum leaves on mild steel in 1M HCl using weight loss method. Experiments are performed by varying immersion period, concentration of the inhibitor and temperature. The inhibition efficiency is markedly higher on the addition of Nicotiana tabacum leaves extract in acidic medium compared with those in the absence of inhibitor. The inhibition efficiency increased with an increase in inhibitor concentration but decreased with rise in temperature and exposure time. Thermodynamic studies revealed that corrosion inhibition may be due to the spontaneous physical adsorption of the plant constituents on the surface of mild steel. Experimental data fitted with the Langmuir and Temkin adsorption isotherms. Kinetic treatment of the data followed a first order reaction. Calculated half-lives increase as the concentration of the extracts increases suggesting that inhibition efficiency increases with increase in the concentration of the extracts.Preliminary investigation of the phytochemical constituents showed that Nicotiana tabacum contains tannin,flavonoid, terpenoid and some other compounds in trace constituents. [Olasehinde, EF, Olusegun, SJ, Adesina, AS, Omogbehin, SA, Momoh-Yahayah, H. Inhibitory Action of Nicotiana tabacum Extracts on the Corrosion of Mild Steel in HCl: Adsorption and Thermodynamics Study