1Department of Polymer and Textile Engineering, Federal University of Technology, P.M.B. 1526, Owerri, Nigeria
2Electrochemistry and Materials Science Research Laboratory, Department of Chemistry, Federal University of Technology, P.M.B. 1526, Owerri, Nigeria
*Corresponding author e-mail: innocent.arukalam@futo.edu.ng
Online published on 11 September, 2014.
The corrosion inhibition of mild steel in hydrochloric and sulphuric acid solutions by hydroxypropyl methylcellulose (HPMC) has been studied using weight loss, electrochemical impedance spectroscopy and potentiodynamic polarization techniques. Inhibition was found to increase with increasing concentration of the inhibitor. The activation energy as well as other thermodynamic parameters (Qads, ΔG, ΔH and ΔS) for the inhibition process was calculated. The results obtained show that the HPMC served as an effective inhibitor of the corrosion of mild steel in hydrochloric and sulphuric acid media. The inhibitor adsorption followed Langmuir isotherm. The local reactivity of the HPMC molecule was also analyzed theoretically using the density functional theory to explain the adsorption characteristics, while molecular dynamics simulations were performed to illustrate the adsorption configuration of HPMC at a molecular level. The theoretical predictions showed good agreement with experimental findings.
Acid corrosion, Adsorption, Cellulose derivative, Chemisorption, Corrosion inhibition, Electrochemical techniques, Langmuir isotherm, Weight loss
