ISSN 2305-6894

Corrosion studies of mild steel in sulphuric acid medium by acidimetric method

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1 Department of Chemistry, Benue State University, Makurdi, Nigeria
2 Centre for Food Technology and Research, Benue State University Makurdi, Nigeria

Abstract: Many corrosion monitoring techniques are available to study the behaviour of inhibitors in various media. Common among these techniques are weight loss, gasometric, thermometric, acidimetric, electrochemical impedance spectroscopy and a host of others. Each of these techniques has its strengths and weaknesses. While some of them are quite prone to errors, others require, extremely, expensive instrumentation. The acidimetric technique is, however, the least applied of among these techniques, in spite of its obvious advantages of simplicity, less prone to error and inexpensiveness. In this research work, we applied the acidimetric technique to the study of corrosion inhibition of mild steel in H2SO4 medium using urea, an organic molecule, as an inhibitor. The efficacy of the technique was then compared with an established and commonly applied corrosion monitoring technique; the weight loss technique. The two techniques were found out to give quite comparable results. However, the acidimetric technique was found to be faster, simpler, and yielded comparatively better results. The inhibition efficiency, %IE, which has the same trend for the two methods, decreased with increase in temperature, suggestive of physisorption. This was collaborated by values of activation energy, Ea, which are all below 80 kJ/mol. The adsorption mechanism of urea adsorption onto the metal surface was, therefore, resolved with the use of Adejo-Ekwenchi isotherm adsorption model to be physisorption, with the best fit adsorption isotherms being the Langmuir and El-Awady isotherm models.

Keywords: corrosion, acidimetric technique, weight loss technique, efficacy, adsorption isotherm

Int. J. Corros. Scale Inhib., , 8, no. 1, 50-61 PDF (703 K)
doi: 10.17675/2305-6894-2019-8-1-5

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