Electrochemical Evaluation of Albendazole Drug as Corrosion Inhibitor for Aluminium in Acidic Medium
摘要
Pharmaceutical compounds are emerging as promising corrosion inhibitors due to their cost-effectiveness, low toxicity, and environmental compatibility. The present study investigates the anthelmintic drug albendazole as a corrosion inhibitor for aluminium in 0.5 M HCl using physicochemical and electrochemical techniques. Electrochemical impedance spectroscopy (EIS) confirmed an increase in charge transfer resistance (Rct) from 22.82 to 391.40 Ω, and a pronounced decrease in double-layer capacitance (Cdl) from 67.82 to 16.23 µF, supporting the formation of a protective film. The electrochemical test results confirmed that albendazole functions as a mixed-type inhibitor, influencing both anodic and cathodic processes, with a maximum inhibition efficiency of 94.17% from EIS and 63% from polarization in 0.5 M HCl at room temperature. Weight loss studies showed a reduction in corrosion rate from 31.36 to 1.84 mm yr−1, with 94.13% efficiency at 1000 ppm. The adsorption studies revealed that albendazole follows the Langmuir isotherm with negative ΔG°ads values, confirming a spontaneous mixed physisorption–chemisorption process. AFM, FE-SEM and Spectral Confocal Microscopy revealed smoother surfaces for inhibited samples, while UV–Visible spectra displayed a bathochromic shift, confirming complex formation between aluminium and the inhibitor. Overall, albendazole exhibits strong adsorption and forms a stable protective layer, effectively minimizing aluminium corrosion in acidic media.