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In this study, Oregano (Origanum vulgare) leaf essential oil was studied as an environmental-friendly anticorrosion agent for carbon steel in aggressive hydrochloric acid. The corrosion inhibition of O. vulgare was characterized by surface morphology, electrochemical, weight loss, theoretical and computational methods. It was found that the highest inhibition performance of O. vulgare was 85.64% at 2 g/l in 1 M HCl. The results of Langmuir isotherm and adsorption thermodynamics investigation demonstrated that the O. vulgare inhibitor adsorbed on the metal surface by the formation of rigid covalent bonds. The adsorption and inhibition centers of the selected inhibitor were studied by the computational methods, resulting in that the hydroxyl functional groups and benzoyl rings are mainly responsible for the high inhibition efficiency.

Carbon nanocage structures such as fullerene, nanotubes, nanocapsules, nanopolyhedra, cones, cubes, and onions have been reported since the discovery of C60, and they offer tremendous promise for investigating materials of low dimensions in an isolated environment. Boron Nitride (BN) nanomaterials such a: nanotubes, nanocapsules, nanoparticles, and clusters have been described in several studies and are predicted to be useful as electronic devices, high heat-resistance semiconductors, nanocables, insulator lubricants, and gas storage materials. The interaction, and electronic of octahedral B12N12 nanocage cluster covalently modified from the attachment of alkyl and aryl radicals were analyzed using Density Functional Theory calculations. The work discusses for the first time to our knowledge the complete investigation of the impact of the grafted aryl and alkyl groups on the electronic, bang gap, and density of states on the B12N12. Furthermore, this is the first complete description of these radicals attaching to a surface of B12N12 nanocage cluster.

The anticorrosive performance of two acrylic polymers (PANa) and (PAA) on smild steel in the 0.1 M hydrochloric acid medium was investigated using numerous techniques, such as weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), Scanning electron spectroscopy (SEM), Energy-dispersive X-ray Analysis (EDAX), and DFT simulation. The obtained results through all tested methods are in good agreement. The polarization curves revealed that PANa and PAA belonged to mixed-type inhibitors. The influence of temperature on the corrosion of mild steel in 1.0 M HCl was also studied. The adsorption of PANa and PAA on mild steel surface in the studied medium follows the Langmuir isotherm. Scanning electron spectroscopy and Energy-dispersive X-ray analyses were carried out in order to study the mechanism which controls the corrosion inhibition of mild steel. Theoretical calculations realized using density functional theory (DFT), molecular dynamic (MD), and Monte Carlo (MC) simulations explored the most reactive sites of the investigated polymers.

Background Human and veterinary antibiotics are typically discharged as parent chemicals in urine or feces and are known to be released into the environment via wastewater treatment plants (WWTPs). Several research investigations have recently been conducted on the removal and bioremediation of pharmaceutical and personal care products (PPCPs) disposed of in wastewater. Results SiNP-Cu, a chelating matrix, was produced by delaying and slowing 1.5-dimethyl-1H-pyrazole-3-carbaldehyde on silica gel from functionalized with 3-aminopropyltrimethoxysilane. The prepared sorbent material was characterized using several techniques including BET surface area, FT-IR spectroscopy, Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and nitrogen adsorption–desorption isotherm. The pseudo-second-order model provided the best correlation due to the big match between the experimental and theoretical of different adsorption coefficients. The Langmuir and Freundlich adsorption models were used and the study showed a better match with the Freundlich model with a capacity of removal reached up to 420 mg g−1. The removal capacity was dependent on pH and increased by increasing pH. The removal percentage reached 91;5% at pH = 8. The adsorbent demonstrated a high percentage removal of TMP, reaching more than 94% when increased pH. The sample was simply regenerated by soaking it for a few minutes in 1 N HCl and drying it. The sorbent was repeated five times with no discernible decrease in removal capacity. The thermodynamic study also showed endothermic, increasing randomness and not spontaneous. The free energy was 2.71 kJ/mol at 320 K. The findings of the DFT B3LYP/6–31 + g (d, p) local reactivity descriptors revealed that nitrogen atoms and π-electrons of the benzene and pyrimidine rings in the TMP are responsible for the adsorption process with the SiNP surface. The negative values of the adsorption energies obtained by molecular dynamic simulation indicated the spontaneity of the adsorption process. Conclusion The global reactivity indices prove that TMP is stable and it can be removed from wastewater using SiNP surface. The results of the local reactivity indices concluded that the active centers for the adsorption process are the nitrogen atoms and the π-electrons of the pyrimidine and benzene rings. Furthermore, the positive value of the maximum charge transfer number (ΔN) proves that TMP has a great tendency to donate electrons to SiNP surface during the process of adsorption.

The novel hexafunctional epoxy polymer synthesized in our laboratory, namely hexaglycidyl trimethylene dianiline of ethylene (HGTMDAE), has been evaluated as corrosion inhibitor of E24 carbon steel (CS) in the aggressive environment (1.0 M HCl) by using a gravimetric measurements, electrochemical impedance spectroscopy (EIS) and molecular dynamic simulations (MD). However, to better understand information on the surface adsorption mechanism of the CS/HGTMDAE/1.0 M HCl medium, the corrosion protection was investigated by using the scanning electron microscopy. Furthermore, the gravimetric test results showed that the inhibition performance will increase with increasing in the concentration of HGTMDAE to reach a maximum of 90% at concentration 10−3 M. In addition, the EIS has a better inhibitory efficiency of 95% for the optimal concentration (10−3 M) of the epoxy polymer HGTMDAE. Moreover, the polarization results indicate that this macromolecular binder acts as a mixed inhibitor. The epoxy polymer formed protective layer on surface of the E24 CS by adsorption according to Langmuir model. The inhibitor adsorption phenomena have been tested through the estimation of kinetics thermodynamic parameters. MD simulations were used to describe the electronic and adsorption properties of epoxy polymer HGTMDAE.

The main objective of this study to develop an epoxy resin that is stable and does not homopolymerizes on storage. A series of di- and tetra-glycidyls of aromatic amines and alcohols were prepared. Diglycidyl of 4,4 '-dihydroxydiphenyl sulfone (DGEDDS) was prepared in a one step process by condensation with epichlorohydrin. The tetra-glycidyl of 4,4′-methylenedianiline (TGEDA) and 4,4′-(propane-2,2-diyl) diphenol, Tetraglycidyl 4-amino benzene sulfonamide (TGABSA) were obtained in satisfactory yields. The structures of the epoxy monomers were confirmed by FTIR, 1H NMR and 13C NMR spectroscopy. The viscosimetric study of the synthesized epoxy monomers showed that the bifunctional aromatic phenolic resins (DGEBA and DGEDDS) exhibited high thermostability making it possible to avoid homopolymerizing and self-crosslinking during storage. Unlike the tetra-glycidyl resins of aromatic amines (TGMDA, TGABSA and TGEDA) showed the disadvantage of self-crosslinking under the effect of temperature. The results indicate that the storage temperature for the tetra-glycidyl resins should not excess 5 °C. The bifunctional aromatic DGEDDS, should exceptional thermal stability and high fire resistance upon hardening it showed a Td of about 220 °C with a residual percentage of 40% at 500 °C. Hardened DGEBA which was used as a reference showed a Td of about 212 °C. The high thermal stability could be attributed to the presence of the sulfone group. The bifunctional aromatic amine resin TGEDA, when it is hardened with MDA it showed a Td equal of 296 °C. The increase in density of crosslinking in the case of bifunctional aromatic amine resin (TGEDA) cured with MDA enhanced the thermal resistance compared to those bifunctional aromatic phenolic resins and bifunctional aromatic amine resin (TGMDA and TGABSA). The Heteroskedasticity and autocorrelation Consistent Covariance, HAC was performed on the epoxy resins to explain the results of the thermal degradation of the examined epoxy resins as a function of the EHOMO and ELUMO, which are obtained from the optimized structure of the epoxy resins using the density functional theory. Consequently, the HAC model was validated by comparing the predicted theoretical results to experimental of thermal degradation of the studied epoxy monomers.

The structural properties and relative stabilities of the Na+Nen clusters, with n = 1–16, have been investigated by using pairwise and density functional theory (DFT) methods. The DFT calculations have been carried out using the M06-2X functional combined with the augmented aug-cc-pVTZ basis sets. For both methods, the high stability is obtained for Na+Ne12 cluster with an icosahedral structure, and the twelve Ne atoms complete the first solvation shell around the Na+ cation. Therefore, the icosahedral Na+Ne12 structure will be considered as the core for the larger sizes. The relative stabilities have been studied in terms of the binding energies, second-order difference of energies, fragmentation energies and HOMO–LUMO energy gaps. The Na–Ne interactions within the Na+Nen clusters in relation to the relative stabilities have been discussed through topological atom-in-molecules and reduced density gradient analyses. Finally, the relative stabilities of the Na+Nen clusters have been discussed topologically.

The present research focused on a coating formulation for aluminum surface 2024-T3 to protect it from corrosion. The formulation consisted of a polymeric epoxy resin-coated bisphenol A diglycidyl ether (DGEBA) cured with a polymeric polyaminoamide. The coated aluminum 2024-T3 was tested in a harsh environment of electrolyte solution (3 wt% NaCl solution) to simulate the harsh marine environment. The coated sample was evaluated by Electrochemical Impedance Spectroscopy (EIS). Under these conditions, a very high impedance (Z) value was obtained; even after exposure for a period longer than 4392 h, the performance was still acceptable. Surface morphological study of metallic specimens before and after exposures to the simulated marine environment (3 wt% NaCl) was carried out using scanning electron microscopy (SEM). The results indicate that the DGEBA-polyaminoamide (DGEBAAA) performed as an excellent barrier for Al surface. The results were combined by several modeling approaches involving molecular dynamics simulation (MD), Monte Carlo methods (MC), and the electronic density functional theory (DFT) computations to explore the adhesion forces between the DGEBAAA and the aluminum surface. The computational MD, MC, and DFT studies were executed in aqueous media. Computational results further evidenced the stronger DGEBA-aminoamide adhesion onto the aluminum 2024-T3 even in a wet environment.