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In the present study, we evaluated the effect of corrosion inhibition of ethanol extracts from Endostemon tereticaulis and Hyptis spicigera plants on mild steel in 1M HCl solution, using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). Also surface characterization techniques, namely scanning electron microscopy and X-ray energy dispersive spectroscopy (EDX), UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy were used. These plants extracts showed a good corrosion inhibitory efficiency. The inhibition efficiency increased with increasing of the concentration of the extracts. The potentiodynamic polarization studies showed that these extracts were mixed inhibitors, affecting both anodic and cathodic processes. Electrochemical impedance spectroscopy revealed that the corrosion phenomenon is controlled by the charge transfer process. The adsorption of organic molecules from these extracts onto the surface of mild steel followed the Langmuir isotherm. The study of the morphology of the steel surface before and after immersion showed the adsorption of the molecules of these extracts onto the surface of the steel. Analyses by UV-visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy confirmed the adsorption of these extracts by the formation of a protective film onto the steel surface.

The inhibition effectiveness of Punica granatum (also called Pomegranate) extract and the synergistic effect of potassium iodide (KI) against the degradation of mild steel in 1 M HCl was studied. Potentiodynamic polarization measurement (PDP) was used in order to investigate the performance of this compound. The presence of a mixture of iodide ions (KI) and inhibitor (PG) increased the degree of surface coverage. Also, the inhibition efficiency reaches 82% at 323 K when the concentration of P. granatum (PG) is 2 mg/L with 10 mM of KI. The synergistic effect between the inhibitor and KI could be explained by the reinforcement of the layer being adsorbed onto the steel surface. The adsorption of inhibitor onto the steel surface followed the Freundlich adsorption isotherm. Characterization techniques, such as scanning electronic microscopy coupled with energy dispersive X–ray spectroscopy (SEM/EDX), Raman, and ultra-violet-visible (UV-visible) spectroscopies, confirm the adsorption of inhibitor onto the surface morphology.

This work deals with the study of the inhibition activity of three thiazolidinones (prepared from monoterpenic ketones) on the deterioration of S300 steel in hydrochloric acid solution. The potenti...

Under the effect of acidic exposure, stainless steel structures of industrial equipment are constantly losing their corrosion resistance, and consequently leading to extensive damage. With the aim of protecting stainless steel equipment from the general corrosion in sulfuric acid, we investigate the inhibitory effect of Dittrichia viscosa extract and the main isolated sesquiterpenes. Potentiodynamic polarization and AC electrochemical impedance are used to demonstrate the efficiency of the tested inhibitors. For a better understanding of the molecular properties and the inhibitory potential of each sesquiterpene, quantum chemical calculations are performed using a hybrid method of B3LYP function with 6-31G (d, p) basis set. The present study provides comprehensive results proving the inhibitory effect of sesquiterpenes on the corrosion of stainless steel in sulfuric acid. The inhibition efficiency of tomentosin attains 95% at 7.5 × 10−5 mol/L. The adsorption data of tomentosin fit well the Langmuir isotherm, while the thermodynamic study substantiates its chemical adsorption. Quantum chemical calculations suggest the reactive sites of interaction and corroborate the experimental findings. The present work might help to understand the corrosion behaviour of stainless steel in sulfuric acid and the inhibitory potential of different sesquiterpenes.

Heavy metals became a great concern for scientists due to their harmful action on the environment and human life. EDTA and NTA chelation capacity were used to assess soil decontamination. The effect of pH, ligand, soil solution contact time with agitation, soil solution ratio, and particle size were investigated, in order to prioritize them, using the design of experiment methodology (Doe): pH was the most influential factor while the ratio mass of the soil by the volume of the solution and particle size were of equal importance. EDTA was more effective as a chelator than NTA in removing metals from the soil. The contact time was not a significant factor; a contact time of 10 minutes was sufficient to extract the two metals studied. An extraction efficiency of 45% was achieved for Pb and 85% for Cu without optimization process.

A new penta-substitued pyrrole derivative 1-(1-benzyl-4-(4-chlorophenyl)-2,5-dimethyl-1H-pyrrol-3-yl)ethanonewas synthesized in one pot four-component coupling reaction catalyzed by natural hydroxyapatite (Ca5(PO4)3OH). The structure of the title compound was studied using diverse spectroscopic techniques such as 1H and 13C NMR and FT-IR and confirmedby single-crystal X-ray diffraction. Computation studies using density functional theory (DFT) method at B3LYP/6-311 + G(d,p) in gas phase and polarizable continuum model have been performed to predict the spectral and geometrical data of the compound. Good correlations, higher than 99%, were found between the experimental and predicted spectroscopic data. Furthermore, the closest contacts between active atoms of the compound were obtained through Hirshfeld surface analysis along with the electrostatic potential surfaces (EPS) investigations. The electrochemical study showed a good inhibition efficiency of this compound on the steel S300 surface by blocking the active sites.

Stainless steel (SS) is a very corrosion-resistant alloy used in different industrial plants because of its chemical and mechanical properties. However, the high chloride concentration in sulfuric acid (H2SO4) may promote both general corrosion and pitting corrosion. The pitting corrosion susceptibility in SS in chlorinated H2SO4 and the effect of Euphorbia echinus extract (EEE) on both general corrosion and pitting corrosion have been studied using potentiodynamic polarization, electrochemical impedance spectroscopy, chronoamperometry, cyclic voltammetry, and scanning electron microscopy (SEM). The pitting potential has been found to shift slightly in the presence of chloride ions (Cl−) in H2SO4. Also, pitting corrosion initiation has been demonstrated in the recorded chronoamperograms as a linear straight line having a positive slope. EEE has reduced the general corrosion and the inhibitor adsorption was found to follow the Langmuir isotherm. SEM micrographs showed that the tested inhibitor has efficiently acted on pitting corrosion for different concentrations of Cl−. Also, the kinetic findings were in good agreement with the surface analysis data. Fourier transform infrared spectroscopy and ultraviolet-visible absorption spectrophotometric measurements provided more insights on the interaction between the chemical functional groups of the inhibitor and the SS surface.

The present work proposes the study of the extract of Senecio anteuphorbium (SA) as green corrosion inhibitor. This inhibitory effect of SA extract on the corrosion of S300 steel in hydrochloric acid 1 M has been evaluated by using the potentiodynamic polarization and electrochemical impedance spectroscopy. From the outcome of the polarization curves, SA extract acts as mixed-type inhibitor. The inhibition efficiency increased with the extract concentration increase to achieve a maximum of 91% at 30 mg/L. The adsorption of the inhibitor on the steel surface follows Langmuir isotherm and the values of activation energy suggested that the adsorption of inhibitor is a physical–chemical adsorption. Kinetic parameters such as enthalpy, activation energy and entropy were determined and discussed. The surface morphology of steel was observed before and after adding inhibitor by Fourier transform infrared spectroscopy. The changes in contact angles identified the formation of the protective film. Scanning electron microscopy and energy-dispersive X-ray revealed the adsorption of the same organic compounds of the extract on the interface metal/solution.

The effects of triterpene fraction (TF) on the corrosion behavior of AISI Type 321 stainless steel (SS) in sulfuric acid were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). This study shows that the inhibitor tested improve the overall corrosion resistance of stainless steel in sulfuric acid. Potentiodynamic polarization showed that TF acts as a mixed inhibitor. In addition, an adsorption model suitable for experimental data was discussed in depth. The Langmuir model gives the best fit, although all models show good agreement with the adsorption data. The effects of the inhibitor concentration and the temperature of the medium were thus evaluated. On the other hand, a hybrid method of B3LYP function and 6-31G (d, p) basis set was performed to correlate the TF molecular structure with the experimental data. In addition, a molecular electrostatic potential map was used to predict the chemical reactivity of tetracyclic triterpenes with the SS surface. The electrophilic and nucleophilic sites of adsorption were discussed, and the Fukui indices were determined. The findings obtained indicate that 8C and 9C are the most reactive sites in the tetracyclic system. Scanning electron spectroscopy confirmed the adsorption of TF on the stainless steel surface, thus supporting the experimental results.

Polysubstituted pyrroles have been synthesized in good yields via a four-component one-pot reaction of 1,3-dicarbonyl compounds, amines, aldehydes, and nitroalkanes using natural hydroxyapatite (HAp) as an efficient green catalyst. This strategy provides advantages such as simple experimental and work-up procedures, mild conditions, high selectivity, low cost, high atom economy, and environmental friendliness; it uses a green commercial catalyst and does not require a solvent. The electrochemical behavior of S300 steel in 1 M hydrochloric acidic was studied in the presence of these heterocyclic compounds. The results showed good inhibition efficiency for steel in acidic media.

A new complex N-(2-hydroxyethylamino)ethylsalicylaldiminato]-palladium(II) chloride [Pd(L)Cl] was synthesized by the reaction in ethanol of the Schiff base 2-(2-(2-hydroxyethylamino)ethylimino)methyl phenol (LH) and Li2PdCl4. The complex was characterized by 1H NMR, 13C NMR, FT-IR and UV–Vis spectroscopic techniques. The structure of the complex was confirmed by single-crystal X-ray structure analysis. The electrochemical properties of PdCl2 and [Pd(L)Cl] have been investigated by cyclic voltammetry. Additionally, the electronic structure, the solution spectrum and the redox property of [Pd(L)Cl] have been rationalized by DFT and TDDFT methods.

The inhibition efficiency of Atlas cedar essential oil (ACEO) as a green corrosion inhibitor on steel in 1 m hydrochloric acidic was studied. The effects of temperature and the concentration of the ACEO inhibitor on the inhibition efficiency were studied. Potentiodynamic polarization and electrochemical impedance spectroscopy were used to test the performance of the inhibitor. We found that the inhibition efficiency of ACEO exceeded 88% at 1 g/l at 298 K and increased with increasing concentration. The evaluation of activation and thermodynamic parameters reveals that the organic molecules of cedar essential oil and its fractions act by chemical adsorption on the metal surface. The adsorption of the inhibitor on the surface of steel is in a good agreement with the Langmuir adsorption isotherm. Increasing concentration of the corrosion inhibitor enhances the surface coverage and formation of a protective film.

The increased use of fertilizers from phosphates in agriculture generates water pollution by heavy metals contained in these phosphates at levels higher than the standards. In our study, we used a cadmium nitrate Cd(NO3)2 solution to simulate artificially polluted water, whose decontamination efficiency will be evaluated by an electrocoagulation/flotation process. During this work, we aimed to optimize the electrocoagulation process according to the following factors: initial pH of the solution, density of the electrolysis current, cell time, and nature of the supporting electrolyte and its concentration. The criteria adopted during the optimization of the process are relatively different from those used in similar studies. Indeed, we have tried to achieve maximum efficiency and also seeking to minimize costs and facilitate implementation. We achieved a 98% Cd removal efficiency from the solution at pH = 7, J = 6.25 A/m2, t = 10 min, and [K2SO4] = 0.01 M. In addition, during the characterization of the flocs obtained as a supernatant, we first highlighted the presence of Cd in this gelatinous body and then the relatively easy volatility of Cd as well as that of aluminum oxide (Al2O3).

The corrosion of stainless steel is one of the major industries’ issues that gained wide interest among researchers. It became necessary to develop and apply eco-friendly approaches to corrosion control. This work explores the inhibitory effect of a newly synthesized amino cadalene (ACM) on the corrosion of stainless steel type 321 in sulfuric acid 1M. Particularly, the experimental study consisting of electrochemical and surface analyses was conducted in conjunction with a theoretical approach. The electrochemical results showed that ACM acted as a mixed-type corrosion inhibitor and the inhibition efficiency attained 91% at 10−3M. EIS measurements revealed that both metal charge transfer and diffusion processes are involved in the interfacial metal/solution reactions. The interfacial mechanism is thoroughly investigated; the physisorption of the protonated molecules was preceded by the formation of a negative layer due to adsorption of the solution anionic species. The experimental insights are corroborated with the quantum chemical calculations.

In this study, a self-organized nanotubular titanium dioxide (TiO2) array was successfully produced by anodizing pure titanium in a mixture of glycerol, distilled water (8% vol.), and ammonium fluoride using a dual electrode system. The size control and distribution of the nanopores were performed in a DC voltage range varying from 30 V to 60 V. The diameter of TiO2 nanopores varies from 59 to 128 nm depending on the anodizing voltage. Energy-dispersive X-ray spectroscopy (EDX) analysis reveals that the as-prepared films are essentially composed of TiO2. According to the X-ray diffraction (XRD) and Raman spectroscopy analysis, the nanotubular arrays of TiO2 annealed at 600°C for 2 hours are composed of a phase mixture of anatase and rutile. Mott-Schottky analysis showed that the TiO2 nanotubes are consistent with an n-type semiconductor with a donor density of about 1017 cm-3. Preliminary results on the photocatalytic degradation of a pharmaceutical pollutant showed that the TiO2 nanotubes can be used as a promising material for application in wastewater treatment.

The anodization of the Ti-Cu (2%) alloy was carried out in a 5M H3PO4 solution for 2 minutes. The obtained layers are characterized by XPS, X-ray diffraction, and Raman spectroscopy. The results showed that the obtained films are composed of poorly crystallized TiO2 oxide. Electrochemical Impedance spectroscopy studies revealed that the thickness of the formed film increases with increasing anodization potential. Additionally, the resistance of charge transfer becomes higher when the anodization potential increases. Thus, the Mott Schottky model revealed that the formed film is an n-type semiconductor. The density of charge carriers is in good agreement with those found in the literature. Also, it is found that the flat-band potential increases with increasing treatment potential.

A single-crystal X-ray diffraction analysis of a pyrrole derivative namely 3-acetyl-2,5-dimethyl-1,4-diphenylpyrrole, that was synthesized by a multicomponent reaction, is described in this paper. The density functional theory (DFT) was performed using B3LYP functional with 6-31G(d, p) basis set for the determination of the molecular geometry and the electronic transitions of the studied compound. Moreover, calculations of the FT-IR vibrational frequencies, 1H and 13C NMR chemical shifts are in good agreement with the experimental values. Electrochemical tests were investigated by potentiodynamic polarization and AC impedance measurement to evaluate the anti-corrosion activity of the compound.

The effect of various families of Senecio anteuphorbium L. on the corrosion inhibition of steel S300 in hydrochloric acid was investigated using electrochemical techniques such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Segregation of various families present in Senecio anteuphorbium L. were extracted and evaluated on corrosion inhibition. The essential oil, represents the majority part and consists mainly of sesquiterpenes, especially γ-selinene, cyperene, γ-cadinene and α-cyperone, which show good inhibition efficiency as the alkaloids group. The inhibition efficiency for the tested groups achieves the values varying from 75 % to 90 % involving the synergistic effect. The excellent performance of these compounds due to the formation of the barrier film on the steel surface. The morphology of the steel surface was examined using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) spectroscopy to verify and evaluate the composition of the adsorbed film. The wettability behavior of the steel surface performed confirms the hydrophobic character of the formed film. The Fourier transform infrared spectroscopy (FTIR) and UV-Visible techniques provide powerful information's about the adsorption of inhibitor's molecules onto the steel surface.

The reaction of 1,3-dipolar cycloaddition of trans-anethole and three different diarylnitrilimines bearing different substituents X= {H, CH3, Cl} yield to the creation of three 1,3,4,5-tetrasubstituted pyrazoles. These reactions produce a single regioisomer. These compounds' structures were studied using diverse spectroscopic techniques such as 1H, 13C NMR, and HRMS. Afterwards, X-ray diffraction is performed at 5-(4-methoxyphenyl)-4-methyl-1,3-diphenyl-4,5-dihydro-1H-pyrazole. Also, Density Functional Theory (DFT) is performed to characterize these cycloadducts.Moreover, these synthesized compounds' molecular geometry and electronic structures have been studied using high-level ab initio calculations and DFT using the B3LYP functional. All geometries have been optimized at the B3LYP/6-311+G(d,p) basis set with different kinds of solvents. In the end, the protection against corrosion of copper surface is tested using these pyrazolines. As a result, the experimental analysis proved that the obtained cycloadducts belong to the pyrazoline family. Also, X-ray diffraction determined the stereochemistry of these compounds. DFT-based calculations revealed the existence of three stable conformations of each compound. The theoretical study and the experimental spectroscopic data showed perfect matching. The electrochemical investigation indicates that these pyrazoline compounds exhibit a good inhibition performance, preventing the degradation of copper in NaCl (3%) solution with a high inhibition efficiency of 80%.

Two dinuclear water-soluble oxovanadium (V) complexes [(L1H)VO(μ-O)]2 ( C1 ) and [(L2H)VO(μ-O)]2 ( C2 ) were prepared from VOSO4 and the corresponding tetradentate Schiff base ligands [N-(2-hydroxyethylamino)ethyl]-5-methoxysalicylaldimine (L1H) and 2-[(2-(2-hydroxyethylamino) ethylimino)methyl] phenol (L2H) in refluxing methanol. Their catalytic performance in the oxidation of olefins was explored in water as green solvent using different oxidant agents. Our results demonstrate the effectiveness and good yield of the catalysts by ensuring its effective reusability. The electrochemical behaviour of oxo-vanadium complexes were investigated using cyclic voltammetry (CV). The results showed that complexes exhibit one-electron transfer coupled with the electrochemical irreversibility of the process (ErCi mechanism) corresponding to the VOIV/VOV. The irreversibility behavior of the complexes was showed with the scan rate growing and deformation of peaks.

We have studied the inhibitory effect of some Monoterpenic Thiosemicarbazones on steel corrosion in 1 M HCl solution. The potentiodynamic polarization and electrochemical impedance spectroscopy were used. The Monoterpenic Thiosemicarbazones have inhibited significantly the dissolution of steel. The inhibition efficiency increased with increasing inhibitor concentration and also with the increase in temperature (293–323 K). Furthermore, the results obtained revealed that the adsorption of inhibitor on steel surface obeys Langmuir adsorption model and the thermodynamic parameters such as enthalpy and activation energy were determined. The scanning electron microscopy combined with dispersive X-ray spectroscopy examinations were used to see the shape of the surface morphology and to determine the elemental composition. Scanning electron microscope (SEM) images show that the surface damage decreases when the inhibitor is added. The quantum chemical calculations using density functional theory (DFT) were performed in order to provide some insights into the electronic density distribution as well as the nature of inhibitor-steel interaction.