Adsorption behaviour of gluten hydrolysate on mild steel in 1 M HCl and its role as a green corrosion inhibitor

The search for commercially available and low cost green corrosion inhibitors in combating metal corrosion has incited the investigation of the adsorption behavior and inhibition potentiality of gluten hydrolysate towards mild steel in 1 M HCl employing both electrochemical and weight loss techniques. Acting as a mixed-type inhibitor, gluten hydrolysate forms an inhibitive layer on the metal enhancing the polarization resistance. The thermodynamic and activation parameters for adsorption are explained following competitive physical and chemical adsorption models depending on concentration as well as temperature. FTIR data indicates the involvement of amide groups, as well as the side chains of amino acid residues during adsorption, while confirmatory evidence of enhanced corrosion resistance is obtained from SEM images.