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Steel surfaces treated with synthesized ionic liquid (ILs) namedly 4-methyl-1-(3-phenoxypropyl) pyridinium bromide (Pyr1), 4-(dimethylamino)-1-(2-phenoxyethyl) pyridinium bromide (Pyr2) and4-(dimethylamino)-1-(3-phenoxypropyl) pyridinium bromide (Pyr3) were investigated in HCl acid media (1 M) using several techniques. Surfaces were analyzed by SEM and FESEM microscopy and by XPS spectroscopy, while the inhibition process was studied by electrochemical impedance (EIS) measurements. The results obtained by EIS demonstrated a higher charge transfer resistance that led to a high inhibition performance. According to Langmuir isotherm model and the activation parameters, these ILs can be adsorbed onto the mild steel surface through physical and chemical bonds. This study was supported by DFT and Monte Carlo calculations approach which confirms the adsorption behavior of the studied ILs. [ABSTRACT FROM AUTHOR]

This research explored the efficiency of snail shells powder (SSP) for Cu(II) removal from aqueous solutions and the production of valuable compounds from the residual product. To confirm its chemical and mineral components, the material was characterized by different instrumental techniques. The effects of experimental parameters such as the pH of the solution, the effect of SSP dose, particle size, and initial concentration of Cu(II) on the removal process were studied. The removal of Cu(II) was reasonably fast to be completed within a time frame of 90 min. The kinetics following the pseudo-second-order model (R2 = 0.979) were better compared to the pseudo-first-order model (R2 = 0.896). The increase in pH values leads to an increase in the amount of Cu(II) adsorbed. Afterward, the adsorption capacity reaches stability at pH near 7. The maximum Cu(II) removal occurred with a mass of 8 g·L−1 and a particle size of 300 μm. This particle size presents approximately 44.5% of SSP particles, which is the largest proportion of the sample as shown by particle size analysis. The adsorption isotherm was well described by Langmuir and Freundlich equations. The thermodynamic parameters values showed that the Cu(II) adsorption was a spontaneous and exothermic process. Furthermore, with the presence of CaCO3, the precipitation of Cu(II) in the form of posnjakite occurred with a high Cu(II) removal rate close to 99%. The residual SSP was used for the production of valuable compounds through the thermal decomposition process at various temperatures. [ABSTRACT FROM AUTHOR]

• Imidazolium ionic liquids [Imid-3PE] Br and [Imid-4PE] br were showing a good performance as corrosion inhibitors for mild steel. • A stable passive layer was formed on the mild steel surface. • [Imid-3PE] Br and [Imid-4PE] Br showed a good inhibition performance during the immersing time. • Molecular dynamics simulations were performed involving the experimental conditions. • The theoretical part was confirmed by the experimental findings. The present paper was designed to investigate an original synthesized ionic liquid (ILs) named 1-phenethyl-3-(3-phenoxypropyl)-1H-imidazol-3-ium bromide [Imid-3PE] Br, and 1-phenethyl-3-(4-phenoxybutyl)-1H-imidazol-3-ium bromide [Imid-4PE] Br as corrosion inhibitors. These inhibitors were evaluated against mild steel corrosion in 1 M hydrochloric acid medium using electrochemical techniques. PDP experiments revealed that the [Imid-3PE] Br and [Imid-4PE] Br behaved as mixte type inhibitors. Electrochemical impedance spectroscopy (EIS) results indicated that the both compounds showed a good inhibition of the steel surface with an inhibition efficiency of 95.8% for [Imid-3PE] Br and 96.7% for [Imid-4PE] Br at the optimum concentration. According to Langmuir isotherm model and the activation parameters, these ILs can be adsorbed onto the mild steel surface through physical and chemical bonds. The theoretical approach confirms the adsorption behavior of the studied ILs based on DFT calculation and molecular dynamic simulation. [Display omitted] [ABSTRACT FROM AUTHOR]

• Two pyrazole derivatives were used for the creation of a thin solid film on the metal surface. • [Pyr-(CH 3) 2 ] and [Pyr-H 2 ] show 85 % and 78 % corrosion inhibition efficiency at 10−3 M, respectively. • SEM and AFM show their visible surface adsorption on the metal surface. • Electrochemical outcomes suggest its mixed type of inhibitor nature. • DFT and MD simulations agree with the experimental results. The adsorption performance of 4-((1H-pyrazol-1-yl)methyl)-4-methyl-2-phenyl-4,5-dihydrooxazole [Pyr-H 2 ] and 4-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)-4-methyl-2-phenyl-4,5-dihydrooxazole [Pyr-(CH 3) 2 ] was evaluated for mild steel in 1 M HCl solution. The current examination was carried out using weight loss measurements, electrochemical techniques (polarization curves and electrochemical impedance spectroscopy), surface morphology analysis, and theoretical approach. Before the experimental test, in-silico environmental toxicity was evaluated, indicating the eco-friendly behavior of the concentration used as corrosion inhibitors. The experimental findings showed that these chemicals acting as mixed-type inhibitors, preventing both anodic and cathodic reactions. Moreover, the mild steel surface was also examined using scanning electron microscopy coupled with EDX analysis. These chemicals adsorbed onto the mild steel surface following Langmuir isotherm. In addition, DFT calculations at B3LYP 6-311G (d,p) was used to estimate the reactivity of these molecules by linking their electronic characteristics with their experimental outcomes, whereas Monte Carlo simulation confirms the parallel approach of the studied pyrazole into the steel surface. Finally, it can be concluded that the existence of two methyl group in [Pyr-(CH 3) 2 ] inhibitor augmented the covered surface area compared to [Pyr-H 2 ] molecule. [Display omitted] [ABSTRACT FROM AUTHOR]

Three heterocyclic derivatives of 1,2,3-triazolyl-linked benzimidazolone, named Ph-TLB, OCH 3 Ph-TLB, and NO 2 Ph-TLB, were studied for their ability to inhibit corrosion of mild steel (MS) in a 1 M HCl solution using various techniques, including potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy dispersive x-ray (EDX) analysis. The results showed that all three derivatives were effective inhibitors of corrosion, with NO 2 Ph-TLB showing the highest inhibition effectiveness (96.6 %) and followed by Ph-TLB (95.2 %) and OCH 3 Ph-TLB (92.6 %) at an optimal concentration of 10−4 M and a temperature of 298 K. The PDP curves obtained in the presence of different organic compounds revealed that the inhibitors were of a mixed nature. The inhibitors were found to adsorb onto the surface of MS according to the Langmuir isotherm, and their adsorption and thermodynamic parameters were evaluated. SEM-EDX and X-ray diffraction (XRD) studies show the adsorption of studied compounds which forms a protective layer over the mils steel surface. Density Functional Theory (DFT) calculations and Monte Carlo (MC) simulations were applied to analyse the interactions of synthesized inhibitors with MS surface along with corrosive species as it happens in the corrosive environment. In addition, The Fukui indices were computed for the determination of the most plausible nucleophilic and electrophilic attack sites. [Display omitted] • Benzimidazolone derivatives are tested as corrosion inhibitors for MS in 1 M HCl. • Tafel polarization measurements indicated that Ph-TLB, OCH 3 Ph-TLB, and NO 2 Ph-TLB exhibit mixed-type inhibitory action. • Surface analysis by SEM-EDX and XRD confirms the protective effect of inhibitors. • MC simulation showed that the two inhibitors were adsorbed on parallel position to Fe (110). • DFT calculations are in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

• Toxicity results predicted that MF-PIT can be used with the concentration of 10−4 M without any problem. • DFT calculations predict high reactivity performance of MF-PIT. • MD simulation predict high interaction with Cu samples compared to MS and Al. • Electrochemical study was performed and confirmed the theoretically prediction results. • The surface characterization confirms the adsorption of MF-PIT. It is well known that the most practical approach to prevent metal from their degradation when it is in contact with aggressive solution is the application of inhibitors. The present work was designed to evaluate the inhibition behavior and the adsorption process of (E)‑1‑(5‑methylfuran‑2‑yl)‑3‑(6‑phenylimidazo[2,1‑b]thiazol‑5‑yl)prop‑2‑en‑1‑one (MF-PIT) for various metals (Copper (Cu), Mild steel (MS), and Aluminum (Al)) in 1 M HCl using electrochemical techniques, surface analysis characterization, and theoretical approaches. Firstly, DFT calculations and molecular dynamic simulation were executed to explore the reactivity of the studied inhibitor, and the adsorption configuration indicated in each metal. Before the experimental test, the environmental toxicity was evaluated and confirmed the safety of using the studied concentration. PDP results showed a good inhibition performance with inhibition efficiency of around 97.5% for copper, 95.9% for Mild steel, and 92.2% for Aluminum at the optimum concentration of 10−4 M. These results confirmed the EIS experiments and revealed that MF-PIT acted as a mixed-type inhibitor for the three metals. The adsorption of MFPIT obeyed the Langmuir isotherm model and form a strong bond with the studied metallic samples. The inhibition performance of MF-PIT showed a good correlation with the theoretical finding. [ABSTRACT FROM AUTHOR]

• Investigation of the corrosion inhibition of two pyrazole derivatives. • The adsorption of inhibitors obeys Langmuir adsorption isotherm and surface morphology was examined by SEM. • Potentiodynamic polarization curves reveal that tested inhibitors acts as a mixed type. • DFT, MC and MD simulations were performed. Corrosion inhibition is a vast area of research and its development is attracting increasing attention from researchers. Given the different biological activities that present these compounds, in the present work, we investigated two dimethyl-1 H -pyrazole derivatives namely: (E)- N ' -benzylidene-2-(3,5-dimethyl-1 H -pyrazol-1-yl)acetohydrazide (DPP) and E)- N ' -(4-chlorobenzylidene)-2-(3,5-dimethyl-1 H -pyrazol-1-yl)acetohydrazide (4-CP) as corrosion inhibitors for mild steel (MS) in 1 M HCl using weight loss (WL), electrochemical techniques [potentiodynamic (PP) polarization, electrochemical impedance spectroscopy (EIS)], surface examinations by scanning electron microscopy (SEM). Theoretical studies such as quantum chemical and molecular simulations studies were used to support the experimental findings. Analyses on mass loss (ML) and electrochemical properties confirmed adsorption of inhibitor as a protective layer on the surface of MS. The inhibition efficiency of DPP and 4-CP was enhanced as the concentration of inhibitors increased but decrease with rising temperature. The maximum inhibition efficiency for DPP and 4-CP at 10−3 M concentration has been obtained 80 % and 94 % respectively. Analysis of adsorption isotherms revealed that adsorption of DPP and 4-CP on MS surface follows Langmuir isotherm. Potentiodynamic polarization study confirmed that DPP and 4-CP are of mixed-kind inhibitors. EIS investigations displayed that the polarization resistance raised to 93.7 Ω cm2 and 287.7 for DPP and 4-CP , respectively at 10-3 M. Furthermore, to get detailed electronic/atomic-level findings regarding the dimethyl-1 H -pyrazole derivatives interactions over the MS substrate, theoretical investigations applying molecular dynamics (MD) and density functional theory (DFT) methods were conducted. The results extracted from these approaches affirmed the DPP and 4-CP adsorption on the MS adsorbent. [ABSTRACT FROM AUTHOR]