Corrosion Inhibition Behaviour for Mild Steel by Extracts of Musa sapientum Peels in HCl Solution: Kinetics and Thermodynamics Study
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Date
2012-11-01
Journal Title
Journal ISSN
Volume Title
Publisher
IOSR Journal of Applied Chemistry
Abstract
The inhibition of the corrosion of mild steel by acid extract of Musa sapientum peels in 1M HCl was
investigated using weight loss method. The results showed that the corrosion rate of mild steel in 1M HCl
decreases with increase in concentration of the extracts and the values were in the range 0.013021 - 0.002127
ghr-1
cm-2
. The inhibition efficiency increases progressively as the concentration of the extracts increases up to
about 4% (v/v), above which, further increase in extract concentration did not cause any significant change in
the inhibition efficiency. Effects of temperature on the inhibition efficiency of the extracts showed that
inhibition efficiency decreases with increase in temperature. Activation energy (Ea) was found to be 61.60
Kjmol-1
for 1M HCl and increases to 66.72Kjmol-1
in the presence of Musa sapientum extract. The values for
enthalpy of activation and entropy were all positive indicating the endothermic nature of the mild steel
dissolution process. Calculated Gibbs free energy was in the range -9.43 to -8.99KJ. Kinetics of the reaction in
the presence of the extracts revealed that it follows a first order reaction and the half-life increases as the
concentration of the extracts increases suggesting that inhibition efficiency increases with increase in the
concentration of the extracts. Preliminary investigation of the phytochemical constituents showed that Musa
sapientumcontains tannin, flavonoid, terpenoid and some other compounds in trace constituents.
Description
Staff Publication
Keywords
Steel corrosion, inhibitor, Musa sapientum, Kinetics, Thermodynamics