Ethanol extract of Terminalia catappa as a green inhibitor for the corrosion of mild steel in H2SO4
Ethanol extract of Terminalia catappa as a green inhibitor for the corrosion of mild steel in H2SO4
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Date
2008-12
Authors
Eddy, Nnabuk Okon
Ekwumemgbo, Patricia A.
Mamza, Paul A.P.
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Abstract
The inhibitive and adsorption properties of ethanol extract of Terminalia catappa for the corrosion of mild steel in H2SO4 were investigated using weight loss, hydrogen evolution, and infra red methods of monitoring corrosion. Ethanol extract of T. catappa is a good adsorption inhibitor for the corrosion of mild steel in H2SO4. The inhibition efficiency of the inhibitor increases with increasing concentration but decreases with increasing temperature. The inhibition potential of ethanol extract of T. catappa is attributed to the presence of saponnin, tannin, phlobatin, anthraquinone, cardiac glycosides, flavanoid, terpene, and alkaloid in the extract. The adsorption of the inhibitor on mild steel surface is exothermic, spontaneous and is best described by Langmuir adsorption model. From the calculated values of activation energy, free energy of adsorption and the trend in the variation of inhibition efficiency with temperature, the mechanism of adsorption of the inhibitor is physical adsorption.
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postprint journal article
Keywords
Ethanol extract,, Terminalia catappa,, green inhibitor,, corrosion,, mild steel,, H2SO4,