Evaluation of the Potential of Daucus crinitus Extracts and Their Synthesized ZnO Nanoparticles in Inhibiting the Corrosion of Carbon Steel

This study explores Daucus crinitus extracts (DCE) and zinc oxide nanoparticles (ZnO-NPs) synthesized using the extracts as corrosion inhibitors for carbon steel (CS) in HCl medium. The synthesized ZnO-NPs were characterized via UV-vis spectroscopy, exhibiting a peak at approximately 375 nm. The study employed weight loss (WL) and electrochemical measurements, alongside spectrophotometric evaluation of corrosion products. Surface morphology was assessed via scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). Thermodynamic analysis revealed the physical adsorption of DCE on CS according to the Freundlich adsorption isotherm. Potentiodynamic polarization (PP) measurements indicated DCE as a mixed-type corrosion inhibitor. Electrochemical impedance spectroscopy (EIS) exhibited increased charge transfer resistance and reduced double-layer capacitance with inhibitory addition. The most effective inhibition was observed with butanol extract (BE) and improved more with its corresponding nanoparticles (BENPs), exhibiting inhibitory efficiencies of 80.20% and 91.20%, respectively, at 298 K with a concentration of 800 ppm. The evaluation of corrosion products using colorimetry revealed that the concentration of polyphenols decreased after the inhibitory process. Furthermore, the intensity of ferrous ions (Fe²⁺) decreased as the inhibitory concentration increased. In addition, SEM-EDS analysis confirmed the presence of ZnO-NPs, which enhanced the surface morphology and established a protective layer formed by the adsorbed inhibitors. The SEM-EDS analysis confirmed the presence of ZnO-NPs, the enhancement of surface morphology, and the establishment of a protective layer formed by the adsorbed inhibitors.