Corrosion inhibition properties of schiff base derivative against mild steel in HCl environment complemented with DFT investigations

There is growing interest in using corrosion inhibitors and protective treatments to limit the degradation of mild steel, leading to the development of numerous Schiff bases as cutting-edge inhibitors. In this study, the effectiveness of a Schiff base, 3-((5-mercapto-1,3,4-thiadiazol-2-yl)imino)indolin-2-one (MTIO), to prevent mild steel corrosion in HCl was investigated using weight loss measurements, potentiodynamic polarization measurements, electrochemical impedance spectroscopy techniques, and surface characterization. The experimental results showed that 0.5 mM MTIO exhibited a satisfactory inhibitor efficiency of 96.9% at 303 K. The MTIO molecules physically and chemically adsorbed onto the mild steel surface following the Langmuir model, forming a compact protective film attributed to the presence of a thiazole ring in the MTIO structure. Theoretical calculations were combined with experimental techniques to investigate the anticorrosion performance and mechanism of inhibition.

Performant removal of creatinine using few-layer-graphene/alginate beads as a kidney filter

Reduction of renal function, such as creatinine adsorption is one of the most common and dangerous diseases. Dedicated to this issue, developing high-performance, sustainable, and bio-compatible adsorbing materials is still challenging. Herein, barium alginate (BA) and BA containing few-layer graphene (FLG/BA) beads were synthesized in water from sodium alginate, also acting as bio-surfactant in in-situ exfoliation of graphite to FLG. The physicochemical characteristics of the beads demonstrated an excess of barium chloride used as a cross-linker. The efficiency and sorption capacity (Q_e) of creatinine removal increase with processing duration reaching 82.1, 99.5 %, and 68.4, 82.9 mg·g^-1 for BA and FLG/BA, respectively. The thermodynamic parameters detect the enthalpy change (ΔH°) of about -24.29 and -36.11 kJ·mol^-1 and the entropy change (ΔS°) of around -69.24 and -79.46 kJ·mol^-1 for BA and FLG/BA, respectively. During the reusability test, the removal efficiency decreases from the optimal first cycle to 69.1 and to 88.3 % in the sixth cycle for BA and FLG/BA, revealing superior stability of FLG/BA. The MD calculations confirm a higher adsorption capacity of FLG/BA composite compared to BA alone, clearly confirming a strong structure-property relation.

Interactions study of 1,2,4-triazole derivatives in acid medium using molecular dynamics

We investigated the interaction of some 1,2,4-triazoles derivatives: 4-amino-3-methylthio-5-phenyl-4H-1,2,4-triazole 1, 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol 2 A, 4-amino-5-phenyl-2H-1,2,4-triazole-3-thione 2B, and 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol 2 C (respectively MTE 1, TL 2 A, TN 2B and TL 2 C) using the molecular dynamics simulation. First, we employed this method to predict the total energies in vacuum and in solutions (water and acid media). Then, we calculated the MD parameters: interaction energies and angle parameters. We have also evaluated the conformations of these molecules in gas and in solutions. Next, we compared the calculated results in water with those in acid solution. Our simulated results prove that the presence of intermolecular hydrogen bond increases the interaction energies in the tautomer thione 2B. We confirm that the TN 2B reaches its high stable conformation state in the solution environment. The calculations confirm that the compound MTE 1 has a spatial conformation state and shows high interaction energy in acid medium. Our molecular dynamics results complete very well our quantum chemical calculations. Communicated by Ramaswamy H. Sarma.

The Role of Some Cationic Surfactants Based on Thiazine as Corrosion Inhibitors in Petroleum Applications: Experimental and Theoretical Approach

Two cationic surfactants based on thiazine, dodecyl thiazin bromide (DTB) and hexyl thiazin bromide (HTB), were synthesized, characterized, and investigated as corrosion inhibitors for API X-65 type steel in oil wells' formation water under an H₂S environment. Various spectroscopic techniques such as FTIR and ¹H NMR were used to confirm the DTB and HTB chemical structures. The corrosion inhibition efficiency of the selected compounds was investigated using both potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The innovation of the current study is the existence of a long chain in the inhibitor molecule, which leads to an increase in the performance of the surfactant as a corrosion inhibitor, due to the increase in the surface area per molecule. It was found that these surfactants act as mixed-type inhibitors, leading to suppression of both the cathodic and the anodic processes by its adsorption on the electrode surface according to the Langmuir adsorption isotherm. Carbon steel's inhibitory mechanism was studied using an analogous circuit. The scanning electron microscope technique was used as a suitable analysis tool to show the nature of the layer designed on carbon steel. Quantum chemical calculations and Monte Carlo simulation techniques were used to support the obtained experimental results. Finally, a suitable mechanism for the inhibition process was proposed and discussed.

Corrosion Inhibition Evaluation of Chitosan–CuO Nanocomposite for Carbon Steel in 5% HCl Solution and Effect of KI Addition

Chitosan–copper oxide (CHT–CuO) nanocomposite was made by an in-situ method utilizing olive leaf extract (OLE) as reductant. The OLE mediated CHT–CuO nanocomposite containing varying amount of chitosan (0.5, 1.0 and 2.0 g) was evaluated as corrosion inhibitor for X60 carbon steel in 5 wt% hydrochloric acid solution. The corrosion inhibitive performance was assessed utilizing weight loss and electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization techniques complemented with surface assessment of the corroded X60 carbon steel without and with the additives using scanning electron microscopy/energy dispersive X-ray spectroscopy and 3D optical profilometer. The effect of KI addition on the corrosion protection capacity of the nanocomposites was also examined. Corrosion inhibitive effect was observed to increase with increase in the nanocomposites dosage with the highest inhibition efficiency (IE) achieved at the optimum dosage of 0.5%. The order of corrosion inhibition performance followed the trend CHT1.0–CuO (90.35%) > CHT0.5–CuO (90.16%) > CHT2.0–CuO (89.52%) nanocomposite from impedance measurements. Also, IE was found to increase as the temperature was raised from 25 to 40 °C and afterwards a decline in IE was observed with further increase in temperature to 50 and 60 °C. The potentiodynamic polarization results suggest that the nanocomposites alone and in combination with KI inhibited the corrosion of X60 carbon steel by an active site blocking mechanism. Addition of KI upgrades the IE of the nanocomposites but is not attributable to synergistic influence. The lack of synergistic influence was confirmed from the computed synergism parameter (S1) which was found to be less than unity with values of 0.89, 0.74 and 0.75 for CHT0.5–CuO, CHT1.0–CuO and CHT2.0–CuO nanocomposites, respectively, at 60 °C. Furthermore, KI addition improved the IE with rise in temperature from 25 to 60 °C. Surface analysis results confirm the formation of a protective film which could be attributed to the adsorption of the nanocomposites on the carbon steel surface.

Multifunctional Aspects of the Synthesized Pyrazoline Derivatives for AP1 5L X60 Steel Protection Against MIC and Acidization: Electrochemical, In Silico, and SRB Insights

The inhibitory impact of low-cost synthesized pyrazoline derivatives named Pz series (Pz1 and Pz2) on the corrosion of API 5L X60 carbon steel in 5 M HCl was inspected to serve as corrosion inhibitors against such a solution for its usage in the oilfield well acidization process. Also, the same compounds were unitized as biocides for sulfate-reducing bacteria (SRBs) to inhibit the microbial-induced corrosion effect. This study was conducted via several electrochemical techniques, namely, electrochemical potentiodynamic polarization (EP) and electrochemical impedance spectroscopy (EIS), in addition to computational density functional theory (DFT). The inhibition efficiency (IE) of Pz series on the corrosion of 5L X60 carbon steel in 5 M HCl was found to increase whenever the Pz series molecule concentration was increased. EP measurements revealed that Pz1 and Pz2 have both cathodic and anodic features (mixed inhibitor) and their corrosion IEs were around 90%. The physicochemical properties of the Pz1 and Pz2 compounds were studied using Langmuir adsorption isotherms, where the equilibrium adsorption data were found to follow it accurately. EIS outputs were found to comply with the values obtained from EP. Scanning electron microscopy was used to examine the topographic anisotropy between the inhibited and uninhibited 5L X60 carbon steel samples to double-check the electrochemical findings. DFT calculations and Monte Carlo simulations were utilized to predict the behavior of inhibitors and to rationalize the experimental results. The serial dilution bioassay technique was used to assess the Pz series as potential biocides to counter the effect of SRBs in compliance with the TM0194-2014-SG standard test method, and the results showed the potency of Pz series in inhibiting such bacterial growth.

Green Corrosion Inhibition of Mild Steel by Hydrazone Derivatives in 1.0 M HCl

In the present study, the inhibition performance of two synthesized hydrazone derivatives (HDZs), namely, (E)-N′-(2,4-dimethoxybenzylidene)-2-(6-methoxynaphthalen-2-yl) propanehydrazide (HYD-1) and N′-cyclohexylidene-2-(6-methoxynaphthalen-2-yl) propanehydrazide (HYD-2) on mild steel (MS) in 1.0 M HCl was investigated using weight loss measurements, electrochemical techniques, and scanning electron microscope (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX). The experimental data suggested that the hydrazone derivatives exhibited a high inhibition performance, which increases with increasing their concentrations. HYD-1 and HYD-2 presented maximum inhibition efficiencies of 96% and 84%, respectively, at an optimal concentration of 5 × 10–3 M. The principal observations that resulted from electrochemical studies are that HYDs affected both anodic and cathodic reactions (mixed inhibitors). Their adsorption, which is a combination of chemisorption and physisorption, obeyed the Langmuir isotherm model. Furthermore, the temperature effect was carried out at various temperatures ranging from 303 to 333 K to verify the corrosion inhibition performance of HYD-1 at higher temperatures. Moreover, SEM-EDX analysis confirmed that HYDs can ensure remarkable prevention against corrosion through the adsorption onto the metal surface.

Galactomannan as a new bio-sourced corrosion inhibitor for iron in acidic media

The aim of this study is to evaluate the impact of a bio-sourced polymer as a corrosion inhibitor against iron corrosion in a 1 M HCl solution. Galactomannan was obtained from the carob plant (Ceratonia Siliqua L) and its structure was verified by infrared spectroscopy (FTIR) and elemental analysis. The inhibitor concentration effects and immersion time on the resistance of the iron surface against corrosion are evaluated using impedance and polarization electrochemical measurements, UV-visible analysis and theoretical study. The results show that the galactomannan is a mixed type inhibitor act by physisorption and chemisorption on the metal surface. In addition, the efficiency of these compounds increases with increasing the concentration of the inhibitor and reaches a value of 87.72% at a concentration of 1 g/l. The electrode surface was characterized by SEM surface analysis method coupled with EDS.

Adsorption characteristics and inhibition effect of two Schiff base compounds on corrosion of mild steel in 0.5 M HCl solution: experimental, DFT studies, and Monte Carlo simulation

In this work, we report the synthesis of two Schiff bases of substituted gallic acid derivatives via amidation reaction and their characterization using ¹H-NMR spectroscopy to study their inhibition performance on the aggressive attack of HCl on mild steel (MS). The inhibitive performance was examined using chemical (weight loss) and electrochemical (Tafel and EIS) test methods. The results indicate that these derivatives significantly suppress the dissolution rate of mild steel via adsorption phenomena, which correlates to the Langmuir adsorption model. Tafel data display the mixed-type properties of these compounds and EIS results show that increasing Schiff base concentration not only leads to delaying the charge transfer (R_ct) of iron from 26.4 ohm cm⁻² to 227.7 ohm cm⁻² but also decreases the capacitance of the adsorbed double layer (C_dl) from 8.58 (F cm⁻²) × 10⁻⁵ to 2.55 (F cm⁻²) × 10⁻⁵. The inhibition efficiency percentage reaches the peak (90%) at optimum concentration of 250 ppm. The Monte Carlo simulations confirm the adsorption ability of the as-prepared compounds on the Fe (1 1 0) crystal. The SEM/EDX results revealed the presence of a protective film on the mild steel sample.

Structures of the synthesized Schiff bases inhibitor.

New phosphonate based corrosion inhibitors for mild steel in hydrochloric acid useful for industrial pickling processes: experimental and theoretical approach

Phosphorus containing compounds have been evaluated by experimental and theoretical techniques and more than 96% corrosion inhibition efficiency was observed at 200 ppm concentration.

Evaluating corrosion inhibition property of some Schiff bases for mild steel in 1 M HCl: competitive effect of the heteroatom and stereochemical conformation of the molecule

Corrosion inhibition property due to the heteroatom present in organic Schiff bases and their stereochemical conformation is assessed. Three Schiff bases, namely 2-pyridyl-N-(2′-methylamino/methylthio/methoxy phenyl)methyleneimine are employed.

Green Schiff's bases as corrosion inhibitors for mild steel in 1 M HCl solution: experimental and theoretical approach

Three cysteine based Schiff bases were synthesized and their corrosion inhibition properties on mild steel in 1 M HCl solution were evaluated using weight loss and electrochemical studies and quantum chemical calculations.