Combining Theoretical and Experimental Studies on the Effective Protection of Brass in 3% NaCl Medium by Loading Extracted Eugenol Corrosion Inhibitor into an Organoclay

The term “corrosion” refers to the real industrial scourge that results in significant financial losses when a material is exposed to corrosive conditions, such as sea water. To address this problem, a highly efficient and stable composite material (Eug-CTA-Clay) was developed using a simple method. A corrosion inhibitor (eugenol) extracted from cloves was encapsulated into a locally swelling clay (reservoir). Surface characterization techniques confirmed the success of the composite preparation, as evidenced by the shift of the characteristic reflexion related to the smectite mineral part from 4.66 to 6.29 Å in the X-ray diffraction diffractogram, while electrochemical tests demonstrated significant inhibition efficiency, reaching 83%. These findings are attributed to both the barrier effect of the clay fractions and the presence of additional heteroatoms in the eugenol molecule acting as a cathodic corrosion inhibitor. Theoretical approaches were used for additional evidence and to understand the relationship between the electronic properties of eugenol and the inhibition efficiency. Monte Carlo simulations and topological findings showed that eugenol adsorbs horizontally, through relatively strong interactions and Van der Waals bands, as reflected by the stronger interaction energy (− 92.81 kcal.mol⁻¹).