Abstract

UMOREN, S.A.; OBOT, I.B.; EBENSO, E.E.  and  OKAFOR, P.C.. Eco-friendly Inhibitors from Naturally Occurring Exudate Gums for Aluminium Corrosion Inhibition in Acidic Medium. Port. Electrochim. Acta [online]. 2008, vol.26, n.3, pp.267-282. ISSN 0872-1904.

Exudates gums from Pachylobus edulis (PE) and Raphia hookeri (RH) were evaluated as corrosion inhibitors for aluminium in HCl using weight loss and thermometric measurements at 30 - 60 ^oC. The exudates were found to retard corrosion rate of aluminium.  The inhibition efficiency (%1) increased with increase in concentration of the exudates. Increase in temperature increased the corrosion rate in the absence and presence of inhibitors but decreased the inhibition efficiency. Both PE and RH exudate gums were found to obey Temkin adsorption isotherm and Kinetic-Thermodynamic Model of El-Awady et al. at all the concentrations and temperatures studied. Phenomenon of physical adsorption is proposed from the activation parameters obtained. Thermodynamic parameters reveal that the adsorption process is spontaneous. Exudate gum from RH was found to be a better inhibitor than PE.

Keywords : corrosion inhibition; Pachylobus edulis; Raphia hookeri; adsorption isotherm; aluminium.

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