Sage Extract as a Natural Source of Corrosion Inhibitor for Tinplate in 3.0 % NaCl
1Faculty of Food Technology and Biotechnology University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
2Faculty of Chemistry and Chemical Engineering University of Maribor, Smetanova 17, 2000 Maribor, Slovenia
Received: 28 October 2020
Accepted: 2 September 2021
corrosion, green inhibitor, 3.0 % NaCl, sage, Salvia officinalis, tinplate
Research background. Due to the growing interest and attention of the world towards environmental problems and protection of environment, the worldwide demand for biodegradable and effective corrosion inhibitors for tinplate has grown. Considering the diversity of the structures of polyphenols that are present in sage extract, it represents a promising potential source of low-cost and biodegradable effective green corrosion inhibitors for tinplate in 3.0 % sodium chloride solution which is evaluated in this study.
Experimental approach. Tafel polarization and electrochemical impedance spectroscopy (EIS) at 25 °C has been used to evaluate the inhibition action of sage (Salvia officinalis, L.) extract as a green inhibitor for the corrosion protection for tinplate in 3.0 % sodium chloride solution.
Results and conclusions. Electrochemical impedance spectroscopy has been used to show that sage extract could serve as an effective inhibitor (90.2 %) for the corrosion of tinplate in 3.0 % NaCl at a concentration of 0.2 mg/L, and temperature of 25 °C. The results obtained from potentiodynamic polarization have revealed that the sage extract inhibitor acts as a mixed type, with inhibition efficiency up to 82.5 % and the inhibition efficiencies calculated from EIS are in close agreement with those results. FTIR results indicated that the inhibitory effect of the sage extract is due to the presence of a passivation layer on the tinplate surface, which consists of organic compounds such as polyphenols. It has been confirmed by these results that the sage extract is more efficient at inhibiting the corrosion of tinplate at a concentration of 0.2 mg/L than in higher concentrations. Also, it exhibits good inhibitive performance for tinplate in 3 % sodium chloride solution.
Novelty and scientific contribution. The exceptional corrosion potential of sage extract opens a door for its use and revalorization as a green corrosion inhibitor in the food industry.