Antimicrobial Activity and High Anticorrosion Efficiency of Carpobrotus acinaciformis L. Extracts Against C1020 Carbon Steel Corrosion in a Hydrochloric Acid Medium

M. Khelfaoui, D. Zouied, N. Bouzenad, A. Abdennouri, I. Boussouf, M. Damous, R. N. Boucetta, F. A. Merzeg, A. Djermoune and Y. Belhocine

Abstract
Corrosion causes significant damage to materials and equipment, prompting the search for effective inhibitors. This study investigates the use of Carpobrotus acinaciformis (CA) leaf extracts as alternative corrosion inhibitors for C1020 carbon steel in hydrochloric acid (HCl). Two extraction methods were employed: aqueous (denoted as CAW) and methanolic (denoted as CAM) extracts of Carpobrotus acinaciformis leaves. Electrochemical characterization, including polarization curves and electrochemical im pedance spectroscopy (EIS), was conducted to evaluate the corrosion inhibition efficiency of the extracts. Additionally, antimicrobial and antifungal activities were assessed against four bacterial strains and one yeast species. Surface and chemical analyses, performed using UV-vis spectroscopy, FTIR, and SEM, demonstrated that the inhibition efficiency (IE) increased with higher inhibitor concentrations. The CAM extract exhibit ed an inhibition efficiency (IE) of 96.36 % at 350 ppm, while the CAW extract achieved 94.73 % IE at 450 ppm. FTIR analysis identified key functional groups, such as hydroxyl and carbonyl, while SEM analysis confirmed the reduction in corrosion. These findings suggest that CAM and CAW extracts are effective, eco-friendly corrosion inhibitors and antimicrobial agents for C1020 carbon steel in an acidic environment.

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Keywords
antimicrobial activity, carbon steel, Carpobrotus acinaciformis, extraction, green inhibitor, surface characterization