Inhibitive Performance of Carboxymethyl Cellulose and Additives on Corrosion of Carbon Steel in Acidic and Alkaline Environments

The potential of the mixture of carboxymethyl cellulose (CMC) and additives (PVP, PAA and PVAc, respectively) as an eco-friendly corrosion inhibitor for carbon steel in 1 M HCl and 1 M KOH solutions, respectively, was studied using gravimetric and potentiodynamic polarization measurements and quantum chemical calculations. Gravimetric results revealed that CMC inhibited the corrosion of carbon steel in both environments even at low concentration, and the efficiency of inhibition slightly increased with an increase in concentration. Also, the mixture of CMC with additives (PVP, PAA and PVAc, respectively) increased the inhibition efficiency significantly. Temperature studies indicated that efficiency decreased with an increase in temperature. The calculated corrosion activation energies and heat of adsorption parameters supported the physical adsorption mechanism proposed. Freundlich and Langmuir isotherm models were used to approximate the adsorption characteristics of CMC at KOH and HCl, respectively. Polarization curves revealed that CMC adsorption affected both anodic and cathodic partial reactions and acted as a mixed-type inhibitor. Quantum chemical calculations were used to confirm the ability of CMC to adsorb on a carbon steel surface. © 2018, Springer International Publishing AG, part of Springer Nature.