Natural Polymer of Iraqi Apricot Tree Gum as a Novel Corrosion Inhibitor for Mild Steel in 1 M HCl Solution

I. M. Alwaan,Fouad Kadhim Mahdi

doi:10.1155/2016/5706432

I. M. Alwaan, Fouad Kadhim Mahdi

Open Access

https://doi.org/10.1155/2016/5706432

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Abstract

Corrosion inhibition of mild steel in 1 M hydrochloric acid using Iraqi apricot tree gum Arabic as natural polymer was studied. The weight loss method was used to predict the efficiency of the inhibitor on corrosion of mild steel in a temperature range of 17–40°C. The FTIR result of natural polymer revealed that the C=O and O-H groups were found in the structure of the natural polymer. The results of weight loss method showed that the inhibition efficiency (I%) increased with the increase in both the natural polymer concentration and the temperature; therefore, chemical adsorption mechanism was suggested in this system. The different mathematical models of the adsorption isotherms were studied and the results revealed that natural polymer was found to obey Temkin, Langmuir, and Freundlich adsorption isotherm. The activation energy of adsorption, enthalpy of adsorption, and entropy of adsorption were obtained for different concentrations of natural polymer (0, 0.1, 0.2, and 0.3 g/L) and the results showed that the thermodynamic properties decreased with the loading of a natural polymer. Gibbs free energy of adsorption results was a minus value that led to the conclusion of the spontaneous adsorption of the natural polymer in this system.

Highlights

Mild steel has been widely utilized in chemical industry equipment and the corrosive materials such as alkalis, acids, and salt solutions are contacted with mild steel materials
The corrosion rate of mild steel has been calculated for a 5-hour immersion period in different concentrations of the inhibitor and the weight loss method was dependent on calculating the corrosion rate (CR) as follows: CR
The spectrum of Fourier Transform Infrared (FTIR) shows clearly that natural polymer structure has C=O and O-H groups which lead to improving the adhesion of natural polymer on iron metal

Summary

Introduction

Mild steel has been widely utilized in chemical industry equipment and the corrosive materials such as alkalis, acids, and salt solutions are contacted with mild steel materials. Natural inhibitors substances are more attractive than synthesized organic inhibitors because they are environmentally friendly, nontoxic, cheap, and readily available and are a renewable source of materials. The natural products such as natural honey [8, 9], henna [10], opuntia extract [11], guar gum [12], jojoba oil [13], Artemisia oil [14], and Telfairia occidentalis extract [15] have been studied as corrosion inhibitors for iron and steel materials in acidic media. To the best of our knowledge, there has not been any systematic investigation on the influence of gum Arabic of Iraqi apricot tree on the corrosion of mild steel in 1 M HCl solution

Experimental

Results and Discussion

Mechanism of Corrosion Inhibition

Conclusion