Evaluation of Fennel Seed Extract as a Green Corrosion Inhibitor for Pure Aluminum in Hydrochloric Acid: An Experimental and Computational Approach

Fennel seeds extract was investigated as a potential green corrosion inhibitor for pure Aluminum in 1M hydrochloric acid using gravimetric, galvanostatic polarization and electrochemical impedance techniques. The results from gravimetric measurements illustrate increase in inhibition efficiency with increment in extract concentration. Galvanostatic polarization curve revealed that the mode of inhibition was mixed type with predominance of cathodic inhibition. The results from impedance measurements revealed that with increase in concentration of inhibitor, charge transfer resistance increases while double layer capacitance value was deduced indicating adsorption of phytochemical constituents present in extract at metal/solution interface. The quantum chemical calculation facilitates the judgment that E-anethole pursues highest activity as a corrosion inhibitor in comparison with other molecules present in the extract.