The continuous search for eco-friendly corrosion inhibitors due to differences in corrosive media remains an important point in corrosion control. The experimental studies on the corrosion inhibition of urea on mild steel in automotive gas oil (AGO) was conducted using gasometric techniques and scanning electron microscope (SEM). The theoretical approach on the density functional theory (DFT) on the urea molecule was carried out using Gaussian 09 software. The adsorption behavior of urea molecules on the surface of the mild steel was analyzed using Frumkin and Flory-Huggins adsorption isotherms models and Gibb’s free energy, respectively. The result of the experimental study shows a poor corrosion inhibitory effect of urea on mild steel in automobile gas oil (AGO) medium as the inhibition efficiency decreased from 69.30% in week 1 to 12% in week 11 at 200 ppm of inhibitor. The adsorption of urea on the mild steel surface obeys Frumkin’s adsorption isotherm model. Gibb’s free energy of adsorption of urea molecules onto mild steel surface revealed a physisorption mechanism. SEM results showed the non-inhibitive nature of urea on the studied mild steel. Quantum chemical parameters such as HOMO, LUMO, electron affinity, electronegativity, and the fraction of electrons transferred to the metal surface were calculated and interpreted to compare the experimental and theoretical results. The theoretical findings in the current investigation were not in agreement with the experimental result, thereby creating a need for further study using the electrochemical method.

Recently, nanoscale biotechnology has emerged as an essential field of contemporary science and a new era in the study of materials. It draws the attention of many scientists from all over the world due to its versatility in various fields. Many physical, chemical, and biological processes are used to create biomaterials. Among the materials of interest is magnesium oxide (MgO), which can be widely used in medical and biotechnological applications due to its non-toxicity and environmental friendliness. This review article discusses various methods for the synthesis of magnesium oxide nanoparticles (MgONPs), with particular emphasis on recent developments and applications of these nanomaterials.

The adsorption and inhibition performance of thiourea and lithium ion on aluminium corrosion in 3.5% NaCl were investigated using gravimetric measurement, scanning electron microscope (SEM) analysis and quantum chemical computational techniques respectively. Gravimetric analysis revealed that thiourea has a good inhibitory efficacy of 82% at 1 mM concentration of thiourea on the corrosion inhibition of aluminum under the conditions studied. Also, poor inhibitory effects were recorded with an increase in the concentration of inhibitor, and improvement in inhibition efficiency was observed with the addition of lithium ion. In addition, the effects of temperature (303–333K) on corrosion inhibition was investigated. The findings showed that the effectiveness of the inhibition rises with temperature. The adsorption of thiourea molecules onto an aluminium surface followed the Temkin adsorption isotherm, while the mixed inhibitor of thiourea and lithium ion followed the Langmuir adsorption isotherm model. SEM results confirmed that the inhibition mechanism is due to the formation of a protective thin film on the aluminium surfaces that prevents corrosion. Quantum chemical calculations based on the density functional theory (DFT) revealed that the presence of sulphur and nitrogen in the structure of thiourea molecules is responsible for the strong inhibitory performance due to possible adsorption with Al atoms on the metal surface. The computed experimental and theoretical parameters in this investigation are in good agreement.

The study aimed at evaluating the potential of Hibiscus sabdariffa leaf extract (HSLE) to retard the corrosion of aluminum in 0.1 M and 1 M HCl. Weight loss measurements and potentiodynamic polarization techniques were employed for the study. The mechanism of corrosion was also determined using Langmuir adsorption isotherm. Ethanolic extracts of Hibiscus sabdariffa leaves were obtained and used to prepare different concentrations ranging from 500 mg/L to 3000 mg/L and corrosion rate measurements were taken over time intervals of 24-120 hours for mild steel immersed in 0.1 M and 1 M HCl in the presence and absence of HSLE. The results showed that HSLE is a good inhibitor of aluminum corrosion under the studied conditions. Excellent inhibition efficiencies of 95.1 % and 96.2 % were obtained for 0.1 M and 1 M HCl respectively. The corrosion rate was retarded with an increase in concentration of HSLE and almost approached zero at 24 hours for 1 M HCl and at 96 and 120 hours for 0.1 M HCl. The mechanism of corrosion inhibition was physiosorption. Electrochemical result showed HSLE as a mixed-type inhibitor, retarding the corrosion potential and current density, and shifting the cathodic and anodic arms of the curve.