Corrosion Inhibition of Aluminium Using Exudate Gum fromPachylobus edulisin the Presence of Halide Ions in HCl

S A Umoren,E E Ebenso,I B Obot

doi:10.1155/2008/138407

S A Umoren, E E Ebenso + Show 1 more

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https://doi.org/10.1155/2008/138407

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Abstract

The anti-corrosive effect of Pachylobus edulis exudate gum in combination with halides ions (Cl–, Br–and I–) for aluminium corrosion in HCl was studied at temperature range of 30-60°C using weight loss method. Results obtained showed that the naturally occurring exudate gum acts as an inhibitor for aluminium corrosion in acidic environment. Inhibition efficiency (%I) increases with increase in concentration of the exudate gum and synergistically increased to a considerable extent on the addition of the halide ions. The increase in inhibition efficiency (%I) and surface coverage (θ) in the presence of the halides was found to be in the order I–> Br–> Cl–which indicates that the radii as well as electronegativity of the halide ions play a significant role in the adsorption process. Pachylobus edulis exudate gum obeys Temkin adsorption isotherm. Phenomenon of physical adsorption is proposed from the values of kinetic and thermodynamic parameters obtained. The values of synergism parameter (S1) obtained for the halides are greater than unity suggesting that the enhanced inhibition efficiency of the P. edulis caused by the addition of the halide ions is only due to synergistic effect.

Highlights

In order to mitigate aluminium corrosion, the main strategy is to effectively isolate the metal from corrosive agents by the use of corrosion inhibitors
The loss in weight of aluminium in 0.1M HCl in the absence and presence of P. edulis exudate gum, halides and exudate gum–halide mixtures after 168h of immersion was determined at temperature range of 30-60 oC
Inspection of the figure shows a decrease in weight loss of aluminium in the presence of halides, exudate gum and exudates gum-halide mixtures compared to the blank

Summary

Introduction

In order to mitigate aluminium corrosion, the main strategy is to effectively isolate the metal from corrosive agents by the use of corrosion inhibitors. As a contribution to the current interest on environmentally friendly, green, corrosion inhibitors, the present study investigates the inhibiting effect of exudates gum from Pachylobus edulis on aluminium corrosion in acidic solution using the weight loss technique at 30-60 oC. Synergistic effect of halide additives namely KCl, KBr and KI on the inhibition efficiency has been studied.

Results

Conclusion