Anticorrosive efficacy and adsorptive study of guar gum with mild steel in acidic medium

Anjali Peter,Sanjay K Sharma,Ime Bassey Obot

doi:10.1186/s40543-016-0108-3

Anjali Peter, Sanjay K Sharma + Show 1 more

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https://doi.org/10.1186/s40543-016-0108-3

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Abstract

Gums have been found to be good corrosion inhibitors due to their functional group; they form complexes with metal ions and on the metal surfaces. Most gums have -COOH functional groups, which can increase the contribution of electron or charge transfer and hence facilitate inhibition through adsorption. The corrosion and inhibition behaviors of mild steel in hydrochloric, sulphuric, and nitric acid in the presence of Cyamopsis tetragonoloba (guar gum) have been studied using the weight loss, gas chromatography mass spectrometry (GC-MS), and thermometric techniques. The temperature studies reflect that the percentage of inhibition efficiency is decreased with increase in temperature and that indicates the mechanism of physical adsorption. The calculated values of activation energy (Ea) also support the physiosorption process. The thermodynamic parameters such as heat of adsorption (Qads) and free energy of adsorption (ΔGads) suggested that the adsorption of inhibitor on the mild steel surface is exothermic and followed by spontaneous process. The formation of an adsorbed protective film of the inhibitor molecules on the mild steel surface is confirmed by scanning electron micrographs (SEM), which proves that the guar gum acts as good inhibitor at 1N acids concentration.

Highlights

Gums have been found to be good corrosion inhibitors due to their functional group; they form complexes with metal ions and on the metal surfaces
Most gums have -COOH functional groups, which can increase the contribution of electron or charge transfer and facilitate inhibition through adsorption
In persistence of our program for the corrosion inhibitor with high value and efficiency, the present paper explore the use of guar gum as effective corrosion inhibitor for mild steel corrosion in 1N HCl, H2SO4, and HNO3 solutions using weight loss method

Summary

Introduction

Gums have been found to be good corrosion inhibitors due to their functional group; they form complexes with metal ions and on the metal surfaces. Necessities occur to build up a different category of corrosion inhibitors with low poisonous effect, environment friendly and effective efficiency This new general approach, called green chemistry, was declared which aims for the reduction and replacement of hazardous materials in order to protect the environment and people. The oldest uses of plants were reported as corrosion inhibitor of Chelidonium majus (celandine) and other plants in 1930s (Raja and Sethuraman 2008). After this discovery, natural products drag the attention of scientists around the world for the research on plant extracts for corrosion inhibition. The presence of arbinogalactan, sucrose, oligosaccharides, polysaccharides, and glucoprotein confirms the presence of compounds containing oxygen and nitrogen atoms there, which are the active centers of adsorption (Gardner and Eikerts 1983; Bumgartner et al 1983; Shah and Walters 1984; Peter et al 2015)

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