Anticorrosion and adsorption performance of expired antibacterial drugs on Sabic iron corrosion in HCl solution: Chemical, electrochemical and theoretical approach

Expired antibacterial drugs such as ampicillin (AMP) and Ceftriaxone (CRO) were used as anticorrosive for Sabic Fe corrosion in 1.0 M HCl solutions. Chemical and electrochemical methods were applied to confirm the performance of the inhibition of these drugs. The effectiveness of inhibition increases with an increased concentration of AMP and CRO drugs which also decreases with temperature. The inhibition performance of drugs owing to their adsorption on the Sabic iron surface through the Langmuir adsorption isotherm. Galvanostatic polarization demonstrated that the expired AMP and CRO act as mixed inhibitors. The thermodynamic function for activation and adsorption process was defined and interpreted. AMP and CRO drugs inhibit the pitting attack caused by the presence of chloride ions. Pitting potentials were transferred to more noble values that demonstrated that these drugs served as pitting corrosion inhibitors. All outcomes findings confirm that the AMP and CRO acted as excellent inhibitors for Sabic Fe corrosion in 1.0 M HCl solutions and the CRO is more efficient inhibitors than AMP at all the studied concentrations owing to its high molar mass. The quantum chemical calculations of the expired AMP and CRO drug molecules were done and discussed using density functional theory (DFT) method. The quantum chemical calculations and the results of the molecular dynamics simulation correlate well with experimental observations.