Development and evaluation of a green corrosion inhibitor based on rice bran oil obtained from agro-industrial waste

In this study, agro-industrial waste was used to prepare a green corrosion inhibitor based on rice bran oil. Firstly, the rice-bran oil was recovered and filtered, and then a semi-refined process was applied to separate the waxes. The performance of the synthetized inhibitor was evaluated on a 1018 steel surface by means of different electrochemical techniques such as potentiodynamic polarization, open circuit, linear polarization resistance and electrochemical impedance spectroscopy (EIS). The present results have shown that the addition of 10 and 25 ppm of inhibitor improves the performance of the system, presenting efficiencies above 99%. Interestingly, the free-energy calculated for the rice bran oil (ΔGadsO = −53.80 kJ/mol) pointed out the good affinity of the inhibitor with respect to the steel surface. Moreover, the EIS spectra showed the formation of a protective layer caused by the adsorption of the inhibitor on the steel surface. This layer improved remarkably the charge-transfer resistance of the metallic material.