Browsing by Author "Onuchukwu, A. I."

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    Inhibition of mild steel corrosion in sulphuric acid using indigo dye and synergistic halide additive
    (Elsevier Ltd, 2004) Oguzie, E. E.; Unaegbu, C.; Ogukwe, C. N.; Okolue, B. N; Onuchukwu, A. I.
    Gravimetric method was used to study the inhibitory properties of indigo dye during corrosion of mild steel in aerated sulphuric acid solutions at 30–50°C. The effect of addition of halide salts KCl, KBr and KI was also investigated. The corrosion rates in all systems studied increased with rise in temperature. The inhibition efficiency of indigo dye increased with concentration and synergistically increased on addition of halide salts. Temperature studies revealed increased inhibition efficiency at higher temperatures, which is suggestive of chemisorption mechanism. The inhibitor adsorption characteristics were approximated by Frumkins isotherm and Flory–Huggins isotherm. Activation energy for Fe dissolution in sulphuric acid was observed to reduce from 54.6kJmol−1 in the uninhibited system to 34.9kJmol−1 in the inhibited system
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    Inhibitory mechanism of mild steel corrosion in 2M sulphuric acid solution by methylene blue dye
    (Elsevier Ltd, 2005) Oguzie, E. E.; Onuoha, G. N.; Onuchukwu, A. I.
    Methylene blue dye (MB) was investigated as a corrosion inhibitor for mild steel in 2M sulphuric acid solution using gravimetric and thermometric techniques. The inhibition efficiency of MB increased with concentration and synergistically increased in the presence of the halide additives, namely KCl, KBr and KI. The trend of inhibition efficiency with temperature suggests that inhibitor molecules are physically adsorbed on the corroding metal surface at lower concentration (0.01–0.5mM), and chemically adsorbed at higher concentration (1.0–5.0 mM). These results were further corroborated by kinetic and activation parameters for corrosion and adsorption processes evaluated from experimental data at the temperatures studied. MB was found to obey Langmuir and Frumkin adsorption isotherms in the concentration range investigated