Corrosion inhibition of curcuma and saffron on A106 Gr B carbon steel in 3% NaCl medium

Abstract

Purpose

Electrochemical measurements were used to characterize the inhibiting effectiveness of Curcuma and saffron, considered as green inhibitors in a corrosive environment 3% NaCl on A106 Gr B carbon steel.

Design/methodology/approach

This study/paper aims to polarization and potentiodynamic impedance spectroscopy techniques were performed on A106 Gr B carbon steel in the 3% NaCl environment only and containing various concentrations of Curcuma and Saffron (0.005, 0.01, 0.02, 0.04, g/L) after 30 min of immersion; these measures were taken at a temperature of (298 ± 1)K. A voltlab PGZ 301 assembled by A 106 Gr B carbon steel working electrode, a platinum counter electrode (CE) and a saturated calomel electrode as the reference electrode were used in the experiment. In this research, potentiodynamic polarization and electrochemical impedance spectroscopy were used.

Findings

The inhibition efficiencies increased with increase in the concentrations of the inhibitor but decreased with rise in temperature. The obtained results show an optimal efficiency with 0.04 g/L which are ordered of 78 and 96 per cent successively for the two inhibitors. Curcuma and saffron acts as a mixed type inhibitor. Adsorption of the inhibitor molecules corresponds to Langmuir adsorption isotherm. Mechanism of inhibition was also investigated by calculating the thermodynamic and activation parameters like (ΔG), (E_a), (ΔH_a) and (ΔS_a). The inhibitor molecules followed physical adsorption on the surface of carbon steel.

Originality/value

The present trend in research on environmental friendly corrosion inhibitors is concentrating on products of natural origin due principally to non-toxicity and eco-friendliness. Among these natural products are curcuma and saffron.

Citation

Dob, K., Zouaoui, E. and Zouied, D. (2018), "Corrosion inhibition of curcuma and saffron on A106 Gr B carbon steel in 3% NaCl medium", Anti-Corrosion Methods and Materials, Vol. 65 No. 3, pp. 225-233. https://doi.org/10.1108/ACMM-06-2017-1805