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Propranolol is a pharmaceutical organic drug used for the treatment of high blood pressure, heart problems and anxiety diseases. The disposal of the expired drug threatens the environment, but still, it contains active components. The potentiality of the active components of the expired propranolol drug (EPD) has utilized to protect the mild steel corrosion in 1.0 M hydrochloric acid medium. Weight loss method, potentiodynamic polarization, ac-electrochemical impedance spectroscopy, scanning electron microscopy with energy disperse X-ray spectroscopy and atomic force microscopy (AFM) were used to investigate the expired propranolol drug's capacity to defend mild steel surfaces against corrosion in 1 M HCl medium. The outcomes of the studies demonstrate that expired propranolol drug efficiently inhibits the corrosion of mild steel in 1.0 M HCl medium at various temperatures and inhibitor concentrations. The maximum inhibition efficiency obtained by the weight loss method was 89.81% at 0.01 M EPD concentration at 303 K. EPD has been determined to follow the Temkin's adsorption isotherm model. The SEM–EDX and AFM images were indicated that the formation of protective layer on the surface of mild steel against the acid attack. Potentiodynamic polarization studies showed that the inhibition mechanism is mixed mode and predominantly cathodic control. The observed values of ∆G0ads, indicated that the inhibitive effect is exothermic and spontaneous. Furthermore, the determined thermodynamic parameters suggest that the adsorption process is spontaneous. [ABSTRACT FROM AUTHOR]

In the pursuit to find corrosion inhibitors of superior efficacy, N‐(pyrimidin‐2‐yl)‐4‐[(quinazoline‐4‐yl)amino]benzene‐1‐sulfonamide (PQS) and N‐(4‐methylpyrimidin‐2‐yl)‐4‐[(quinazoline‐4‐yl)amino]benzene‐1‐sulfonamide (MQS) are the two new sulfonamides employed, which have decelerating effect on mild steel (MS) corrosion in a medium 0.5 M HCl and were found to have an efficiency of 98.7 % and 96.8 % respectively (303 K for 40 ppm concentration) deliberated through the electrochemical techniques (PDP and EIS). The inhibitory efficacy relies on the temperature of the solution and inhibitor concentration. PQS had greater stability than MQS at higher temperatures which is indicative in the obtained experimental data. The relative adsorption process was in consonance with the Langmuir adsorption isotherm. The SEM, EDS, FT‐IR, and AFM analysis validated PQS and MQS to form a barrier on MS, opposing corrosion. The potential energy surfaces (PES) scan and a theoretical study for PQS and MQS were probed employing density functional theory (DFT) at B3LYP/6‐311+G(d, p) basis set level that explicated the formation of a complex between the sulfonamides and MS. The corrosion inhibition efficiency of PQS and MQS inferred from experimental and theoretical data comply, making them credible corrosion inhibitors. [ABSTRACT FROM AUTHOR]

In this work, we studied the corrosion of Cu metal in 0.5 mol L−1 HCl and the inhibition effect of the expired Cefazolin drug. The inhibition efficiency (IE) of Cefazolin varied according to its concentration in solution. As the Cefazolin concentration increased to 300 ppm, the IE increased to 87% at 298 K and decreased to 78% as the temperature increased to 318 K. The expired drug functioned as a mixed–type inhibitor. The adsorption of the drug on the copper surface followed Temkin's adsorption model. The magnitudes of the standard free energy change (ΔGoads) and adsorption equilibrium constant (Kads) indicated the spontaneous nature and exothermicity of the adsorption process. Energy dispersive X-ray (EDX) and scanning electron microscopy (SEM) techniques showed that the drug molecules were strongly attached to the Cu surface. The electrochemical frequency modulation (EFM), potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS) results were in good agreement with the results of the weight loss (WL) method. The density functional tight–binding (DFTB) and Monte Carlo (MC) simulation results indicated that the expired drug bound to the copper surface through the lone pair of electrons of the heteroatoms as well as the π-electrons of the tetrazole ring. The adsorption energy between the drug and copper metal was –459.38 kJ mol−1. [ABSTRACT FROM AUTHOR]

The corrosion inhibition properties of Cuscuta reflexa (Amerbel) leaf extract as a green inhibitor for iron corrosion in hydrochloric acid were investigated using gravimetric and surface techniques. Results show that the extract's inhibition efficiency varied with concentration and temperature. The Langmuir adsorption isotherm model was followed, and the adsorption was physical and spontaneous. The studies suggest that Cuscuta reflexa extract exhibits great potential as a mild steel corrosion inhibitor in HCl environments. [ABSTRACT FROM AUTHOR]

The inhibitory effects of extracts from Phaseolus vulgaris and Vicia faba beans, obtained from boiled beans, on the corrosion of EN Fe37-3FN mild steel in a 0.5 M hydrochloric acid medium were meticulously investigated utilizing electrochemical techniques and Electrochemical Impedance Spectroscopy (EIS). The corrosion rate was observed to decrease by 40% upon the introduction of 20 mg/L of the Phaseolus vulgaris extract, with a notable reduction of 70% when the concentration was increased to 2 g/L and beyond. The Vicia faba extract, however, displayed a slightly inferior inhibitory performance, with corrosion rates diminishing by 20% at 20 mg/L and 60% at concentrations of 2 g/L and above. The adsorption of extract constituents onto the steel surface was found to conform to the Langmuir adsorption isotherm model, thereby facilitating the calculation of the sorption equilibrium constant and revealing that the adsorption was primarily physical in nature. These extracts, which are typically discarded by-products of bean cooking, have emerged as cost-effective, readily accessible, and environmentally benign alternatives for mitigating steel corrosion in acidic environments. [ABSTRACT FROM AUTHOR]

The Uncaria Cordata as corrosion inhibitors for mild steel (MS) in a 1.0 M hydrochloric acid (HCl) solution. The EIS, polarization, and LPR measurements were used as experimental measurements to confirm the anti-corrosion performances of the Uncaria Cordata at room temperature. The corrosion inhibitors, even at a low dosage range, achieved inhibition efficiencies to a maximum of 97.0% for 400 ppm of Uncaria Cordata. Surface morphology via AFM and SEM/EDX was carried out to validate the presence of protected film and an optimum concentration of each extract above the metal's surface in the corrosive acidic solution. The ΔGoads value − 19.70 kJ/mol proved a spontaneous merge of physical and chemical adsorption by the extract compounds at the interface of MS and the HCl solution. DFT was governed to accommodate the elevated inhibition efficiency upshot obtained by the electrochemical tests and recommend a synergy mechanism for most of the adsorbed active compounds in Uncaria Cordata inhibitors with the MS surface. Monte Carlo simulation indicates three active compounds, namely 1, 2, and 8, found to have parallel adsorption on MS. This encourages the highest surface coverage and shields the MS surface from the intrusion of corrosive agents. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to prevent mild steel (MS) against corrosion in 0.5 M HCl solution, 2-amino-4-methoxy-6-methyl-1,3,5-triazine was used. The effectiveness of the compound as a corrosion inhibitor was studied via electrochemical, surface and theoretical calculation techniques. Design/methodology/approach: For concentrations ranging from 0.5 to 10.0 mM, almost similar polarization resistances were obtained from electrochemical impedance spectroscopy (EIS) and linear polarization resistance tests. It also investigated inhibitive activity of 2-amino-4-methoxy-6-methyl-1,3,5-triazine on the steel surface using scanning electron and atomic force microscope instruments. Langmuir adsorption is the best matched isotherm for the adsorption of the inhibitor to the steel surface. Findings: EIS method was used to determine inhibition efficiency, which was determined to be 95.7% for 10.0 mM inhibitor containing acid solution. Density functional theory's predictions for quantum chemistry agreed well with the other experimental results. Originality/value: The methods used in this study are effective and applicable; the used organic inhibitor is 2-amino-4-methoxy-6-methyl-1,3,5-triazine; and protective effectiveness is important, which is crucial for the task of MS corrosion prevention. [ABSTRACT FROM AUTHOR]

A new pyrazoline derivative, 1‐[5‐(4‐bromophenyl)‐3‐(6‐methoxypyridine‐3‐yl)‐4‐5‐dihydro‐1H‐pyrazol‐1‐yl]‐ethane‐1‐one (BMDP) was synthesised using chalcone derivative. The FTIR, 1HNMR, and mass spectral analysis were performed to validate the synthesised compound. The electrochemical impedance spectroscopy and potentiodynamic polarization techniques were performed to evaluate BMDP as a corrosion inhibitor for mild steel. The corrosion inhibition was observed to rise with an increase in BMDP concentration and decline with an increase in temperature. The maximum inhibition efficiency of 91.1 % was reported at 303 K in 40 ppm of BMDP concentration. Activation and adsorption parameters were found with statistical thermodynamic calculations. The surface investigation of the metal surface was performed by SEM, AFM and EDX techniques. UV‐visible spectroscopy was used to realise the inhibitor‐metal complex formation. The quantum chemical computations were performed by density functional theory using Gaussian 16 software, and the theoretical calculations confirm the outstanding anticorrosive property of BMDP at the diminutive level as analysed in electrochemical studies. [ABSTRACT FROM AUTHOR]

This study examines the utilization of the expired drug, namely ampicillin, as a mild steel corrosion inhibitor in an acidic environment. The inhibitor was evaluated using weight loss and electrochemical measurement accompanied with surface analytical techniques. The drug showed a potential inhibitory efficiency of > 95% at 55 °C. The inclusion of the inhibitor increased the charge transfer resistance at the steel-solution interface, according to impedance analyses. According to potentiodynamic polarisation measurements, expired ampicillin drug significantly decreased the corrosion current density and worked as a mixed-type corrosion inhibitor. The Langmuir adsorption isotherm was followed by the adsorption of ampicillin drug on the steel substrate, exhibiting an association of physical and chemical adsorption mechanisms. The surface study performed using contact angle and scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS) measurements supported the inhibitor adsorption on the steel substrate. [ABSTRACT FROM AUTHOR]

The study deals with the use of attapulgite as a corrosion inhibitor of two metals, namely aluminum and zinc, and their alloy (aluzinc), in a 0.5 M hydrochloric acid medium. The study was carried out by monitoring the free-corrosion potential and performing dynamic polarization measurements (Tafel curves) at different concentrations of inhibitor in solution. The measurements suggested that in a 0.5 M acidic medium, the surface of each of the three materials was attacked. The decrease in current density was very noticeable in aluminum and zinc at a level of 2 g-L-1. A weak tendency to passivity was noticed for zinc and aluzinc. The experimental results obtained showed a decrease in the current intensity in the presence of the corrosion inhibitor in the acidic medium. The maximum inhibitory efficiency rate reached for the metals and their alloy was higher than 99 %. This percentage was obtained for aluminum and zinc in the presence of 4 g-L-1 of attapulgite and 3 g-L-1 for aluzinc. [ABSTRACT FROM AUTHOR]

Undoubtedly, metal corrosion is one of the most challenging problems faced by industries. Introducing corrosion inhibitors is a reasonable approach to protecting the metal surface. Due to environmental concerns and the toxicity of industrial organic corrosion inhibitors, researchers are continually exploring acceptable replacements. The current study focused on the application of Falcaria Vulgaris (FV) leaves extract to mitigate mild steel (MS) corrosion in a 1 M HCl environment. The polarization findings demonstrated that the corrosion current density decreased from 264.0 µA/cm2 (for the sample submerged in the blank solution) to 20.4 µA/cm2 when the optimal concentration of 800 ppm of FV leaves extract was added to the acid solution. Electrochemical impedance spectroscopy (EIS) analysis revealed an inhibition efficiency of 91.3% at this concentration after 6 h of immersion. It was determined by analyzing several adsorption isotherms that this corrosion inhibitor obeys the Frumkin isotherm. AFM, FE-SEM, and GIXRD surface analyses also supported the findings that adding FV leaves extract can reduce metal damage by adsorption on the metal surface. [ABSTRACT FROM AUTHOR]

In this study, 1,5-diallyl-1H-pyrazolo [3,4-d] pyrimidin-4 (5H)-one (PPD) was evaluated as an anticorrosion agent for mild steel (MS) in 1 M HCl. The analysis was performed by weight loss (WL), potentiodynamic polarization measurement, and electrochemical impedance spectroscopy (EIS). The Tafel polarization showed that PPD is a mixed-type inhibitor and reaches 94% of the protective efficiency at 10−3 M. EIS results indicated that the resistance to charge transfer increases with increasing inhibitor concentration and the corrosion of MS is controlled by a charge transfer process. The inhibitor adsorption on the MS surface obeyed the Langmuir's adsorption isotherm. Thermodynamic parameters were calculated to elaborate the corrosion inhibition mechanism. The micrographic analysis revealed the existence of a barrier layer on the electrode surface with the presence of PPD. Theoretical examinations performed by electronic/atomic computer simulations confirmed that the obtained results were found to be consistent with experimental findings. [ABSTRACT FROM AUTHOR]

The corrosion inhibiting effect of three synthesised phosphonium containing ionic liquids of varying alkyl chain length, namely, butyltriphenyl phosphonium bromide (BTPPB), hexyltriphenyl phosphonium bromide (HTPPB) and hexadecyltriphenyl phosphonium bromide (HDTPPB) on mild steel, was evaluated in 1 M HCl medium. The corrosion inhibition performance was studied by gravimetric method, potentiodynamic polarization studies, electrochemical impedance spectroscopy and quantum chemical studies (DFT). However, the results of the SEM, AFM and contact angle tests confirmed that the protective layer formed on the mild steel. Furthermore, assessed the theoretical calculations for exploring the inhibition mechanism. A maximum of 95.77% inhibition efficiency was achieved using 250 ppm of HDTPPB. The obtained results showed that HDTPPB has greater inhibition ability than BTPPB and HTPPB. Adsorption studies obeyed the Langmuir adsorption isotherm. Moreover, the increased alkyl chain length of ionic liquids did increase their inhibition efficiency. [ABSTRACT FROM AUTHOR]

In this research work, N-hydroxypyrazine-2-carboxamide (NHP) is first introduced as a green, new and effective corrosion inhibitor to protect mild steel (MS) surface from corrosion destruction in a 1 M HCl aggressive solution. Experimental techniques such as gravimetric analysis and electron impedance spectroscopy (EIS) were used in the present analysis; the obtained results show that the inhibition efficiency for NHP was 93.51% at 200 ppm and 298K temperature. NHP molecules adsorbed on mild steel surface followed by Langmuir adsorption model. Similarly, the energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM) analyses were used to describe the changes in surface morphology and composition of MS surface, respectively. Quantum chemical analyses based on density functional theory (DFT) were also applied to calculate the frontier molecular orbitals, that is, EHOMO and ELUMO values for NHP inhibitor molecules; the DFT results are in good correlation with experimental results. Additionally, the studied inhibitor molecule does not produce any environmental threats and toxicity as it decomposed into amine and carbon dioxide and also pyrazine molecules are mainly used as drug precursors showing its green nature. [ABSTRACT FROM AUTHOR]

We report the green synthesis of novel ZrO2-Glycine nanocomposite referred to as ZrO2-Gly NC followed by its characterization using X-ray diffraction (XRD), Fourier transforms infrared (FT-IR) spectroscopy, SEM/EDX, and transmission electron microscopy (TEM) techniques. Further, the inhibition effect of the varying concentration of ZrO2-Gly NC on the corrosion of mild steel (MS) in 1 M HCl was investigated by weight loss and electrochemical measurements at 40–80 °C. The percentage inhibition efficacy of NC increased with the increase of concentration and temperature and reached about 81.01% at 500 ppm at 70 °C which decreased at 80 °C and exhibited 73.5% inhibition efficiencies. According to the polarization measurements, the investigated ZrO2-Gly NC works as a mixed-type inhibitor with predominantly inhibiting cathodic reaction. Also, the adsorption isotherm analysis indicated that the adsorption was spontaneous and followed the Langmuir adsorption isotherm. Furthermore, the contact angle measurement revealed the water-repelling property of the investigated inhibitor. The surface morphological study via SEM–EDS micrograph affirmed the appearance of a smooth surface in presence of inhibited media suggesting the formation of protective film by the adsorption of ZrO2-Gly NC on the surface of the MS even at higher temperature. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis and characterisation of an isatin Schiff base, namely 2-(2-oxoindolin-3-ylidene) hydrazinecarbothioamide (OHB). The chemical structure of OHB was elucidated through proton-nuclear magnetic resonance (1H-NMR), carbon-nuclear magnetic resonance (13C NMR), and Fourier-transform infrared (FT-IR) spectroscopic techniques. OHB was evaluated for its corrosion inhibition ability on mild steel specimens in 1 M HCl using gravimetrical methods and electrochemical measurements such as electrochemical impedance spectroscopy (EIS) and potentiodynamic techniques complemented with microscopic analysis. The results indicated that OHB is a mixed-type inhibitor and showed good corrosion inhibition, with a maximum corrosion inhibition efficiency of 96.7% at a concentration of 0.5 mM and 303 K. The inhibition performance increased with an increasing OHB concentration and decreased with increasing temperature. The inhibition efficiency was attributed to the formation of a protective film on the surface of the tested mild steel coupon. The electrochemical impedance studies also indicated that the charge transfer resistance increased with an increase in OHB concentration. The morphological analysis confirmed the inhibition performance of OHB and the protective barrier film conformed to Langmuir monolayer adsorption. The experimental and theoretical corrosion kinetics and thermodynamic parameters were in agreement and revealed that an adsorption film of Fe–N coordination bonds formed on the mild steel surface. [ABSTRACT FROM AUTHOR]

The treatment of low-carbon steel items with hydrochloric acid solutions is used in many industrial technologies. This process is accompanied not only by metal corrosion losses, but also by hydrogen absorption by the metal. In this study, the kinetics of hydrogen cathodic reduction on low-carbon steel in 2 M HCl containing corrosion inhibitors, namely, quaternary ammonium salts and a 3-substituted 1,2,4-triazole, have been studied. Adsorption isotherms of corrosion inhibitors on cathodically polarized steel surface have been obtained. XPS data provide valuable information on the composition and structure of protective layers formed on steel in HCl solutions containing inhibitors. The main rate constants of the stages of gaseous hydrogen evolution and incorporation of hydrogen atoms into the metal have been determined. The addition of quaternary ammonium salts or 3-substituted 1,2,4-triazole inhibits the cathodic reduction of hydrogen and its penetration into steel in the HCl solution. 3-substituted 1,2,4-triazole is the most efficient inhibitor of hydrogen absorption. The inhibitory effect of this compound is caused by a decrease in the ratio of the hydrogen concentration in the metal phase to the degree of surface coverage with hydrogen. The maximum decrease in hydrogen concentration in the metal bulk in the presence of the 3-substituted 1,2,4-triazole is 8.2-fold, which determines the preservation of the plastic properties of steel as it corrodes in HCl solutions. The high efficiency of the 3-substituted 1,2,4-triazole as an inhibitor of hydrogen cathodic reduction and absorption results from strong (chemical) adsorption of this compound on the steel surface and the formation of a polymolecular protective layer. [ABSTRACT FROM AUTHOR]

The author has focused on the corrosive effect of 0.14% carbon steel in the occurrence of several amounts of soluble Sulfonated Polystyrene (SPS) and was found to be best efficient on soft iron exterior at 100ppm concentration in 0.5M hydrochloric acid assortment at 298K heat during 3h of time in this paper. The examination was performed by studying the weight loss of mild steel by varying different parameters like mixture concentration, time, and solution temperature. The efficiency of SPS was observed to rise with an increase of 91.90% of an inhibitor in the acid solution. The mechanism of physical adsorption was studied to the initiation and permitted dynamics for the reaction of altitude and extracted taking place towards the exterior of the iron sample in endothermic, impulsive and dependable through the Langmuir isotherm adsorption. Anodic and cathodic both type of nature of soluble SPS was studied using the potentiodynamic polarization method. The AFM analysis was used to do the surface and protective film analysis and under varied settings, SPS polymer inhibitor proven to be more suited for iron metal exterior [ABSTRACT FROM AUTHOR]

Focused on the assessment of the diphenhydramine hydrochloride (DPH) capabilities as an alternative to conventional and harmful industrial corrosion inhibitors, electrochemical techniques were employed. The optimum concentration of 1000 ppm was determined by molecular simulation and validated through electrochemical experiments. The results acquired from the electrochemical impedance spectroscopy (EIS) study showed that DPH at a concentration of 1000 ppm has a corrosion efficiency of 91.43% after 6 h immersion. The DPH molecules' orientation on the surface was assessed based on EIS predicting horizontal adsorption on the surface. Molecular simulations were done to explore the adsorption mechanism of DPH. The DPH molecules' orientation on the surface was also assessed based on computational studies confirming the horizontal adsorption predicted by EIS. [ABSTRACT FROM AUTHOR]

Using traditional weight-loss tests, as well as different electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy), we investigated the corrosion-inhibition performance of 2,2′-(1,4-phenylenebis(methanylylidene)) bis(N-(3-methoxyphenyl) hydrazinecarbothioamide) (PMBMH) as an inhibitor for mild steel in a 1 M hydrochloric acid solution. The maximum protection efficacy of 0.0005 M of PMBMH was 95%. Due to the creation of a protective adsorption layer instead of the adsorbed H2O molecules and acidic chloride ions, the existence of the investigated inhibitor reduced the corrosion rate and increased the inhibitory efficacy. The inhibition efficiency increased as the inhibitor concentration increased, but it decreased as the temperature increased. The PMBMH adsorption mode followed the Langmuir adsorption isotherm, with high adsorption-inhibition activity. Furthermore, the value of the ∆ G a d s o   indicated that PMBMH contributed to the physical and chemical adsorption onto the mild-steel surface. Moreover, density functional theory (DFT) helped in the calculation of the quantum chemical parameters for finding the correlation between the inhibition activity and the molecular structure. The experimental and theoretical findings in this investigation are in good agreement. [ABSTRACT FROM AUTHOR]

The present paper aims to synthesize and examine the adsorption of a novel heterocyclic compound of xanthene derivatives, namely 3-oxo-3H-spiro[isobenzofuran-1,9'-xanthene]-3',6'-diylbis (3-methylbenzenesulfinate) (NAR1). This investigation was carried out by electrochemical techniques, scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM–EDX), and theoretical calculations. The electrochemical findings revealed that NAR1 achieved a high inhibition performance of 96% at a low concentration of 10−4 M, which decreases slightly with increasing temperature. In addition, NAR1 inhibitor obeys the Temkin isotherm forming a barrier film on the mild steel surface. Surface characterization analysis SEM/EDX confirmed the presence of a barrier layer covering the mild steel surface. DFT calculations and Monte Carlo simulation results confirm the inhibition behavior achieved experimentally. [ABSTRACT FROM AUTHOR]

An investigation into how Panthenol affects the corrosion of mild steel in 1 M hydrochloric acid was carried out, specifically its adsorption behaviour and the mechanism by which it inhibited corrosion and for this electrochemical analysis techniques, weight loss, scanning electron microscopy, atomic force microscopy, contact angle measurements has been used. Also, the theoretical study which includes study of global reactivity descriptors E HOMO , E LUMO , energy gap (∆E) etc. and molecular dynamics (MD) simulations in aqueous phase have been used to simulate the real situation. This study confirmed a high inhibition efficacy of 90 % at a concentration of 400 ppm. The electrochemical analysis demonstrated that as the concentration of Panthenol increased, there was an apparent reduction in the value of j corr and an upsurge in the value of R ct. In case of potentiodynamic polarization, the value of j corr came out to be 144 μA cm−2 and in electrochemical impedance spectroscopy, the value of R ct came out to be 125.32 Ω cm2 at 400 ppm. The surface morphological investigations revealed the deposition of an extensively protective coating on the mild steel surface. Calculated values of roughness (average and root mean square in nm) in the present study shows a reduction in roughness (in the acid the values were 401 nm, 518 nm respectively and acid with Panthenol, the values were 56.9 nm and 82.5 nm, respectively). In quantum chemical calculations, the calculated value of ΔE came out to be 5.098, validating the strong tendency of inhibitor to retard the corrosion. The investigation revealed that Panthenol is an effective and environmentally friendly inhibiting agent of corrosion for mild steel in a 1 M HCl solution. Additionally, the theoretical findings reiterated the experimental results obtained in this study. [Display omitted] [ABSTRACT FROM AUTHOR]

• The effect of synthesized BNP molecule on corrosion inhibition of the J55CS in hydrochloric acid is achieved using chemical and electrochemical method. • The adsorption of synthesized molecules follows the Temkin adsorption isotherm. • Polarization analysis revealed maximum 91.8% inhibition efficiency. • SEM, EDX, AFM and XPS analyses used and to demonstrate the adsorption mode of corrosion inhibition. • Quantum parameters and Monte Carlo simulation have shown strong adsorption configurations with high negative adsorption energies. The inhibitory efficacy of 2-(Benzoxazol-2-ylthio)-N-(4-phenyl-5-phenylazo-thiazol-2-yl)-acetamide (BNP) was systematically explored through weight loss measurements, potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS), in relation to the corrosion mitigation of J55 carbon steel (J55CS) within hydrochloric acid (HCl) environments. This research employs a combination of experimental techniques, including gravimetric analysis, electrochemical tests, and theoretical considerations. It has been determined that BNP has an inhibitory effect on the corrosion of J55CS in strong HCl, reaching 91.8% at 18 × 10−6 M at 298 K. The inhibitory efficiency displays a notable enhancement as the concentration of the BNP is elevated within the range of 3–18 × 10−6 M. Conversely, the IE% experiences a raised when the temperature is raised. This augmentation can be attributed to the inherent ability of BNP to facilitate the formation of inhibitory films on the surface of J55CS. An analysis of Tafel plots reveals that the BNP adheres to a mixed-type inhibitor. The adsorption of BNP obeyed the Temkin adsorption isotherm. The investigated isotherm plots revealed that the adsorption process for BNP on the metal surface was endothermic, spontaneous, and chemical adsorption. Theoretical modeling [density functional theory (DFT) and Monte Carlo (MC)] revealed the correlation between the BNP molecular chemical structure and its anticorrosive property. [ABSTRACT FROM AUTHOR]

The inhibition performance and adsorption behavior of an unsymmetrical tridentate Schiff base, 2-(((2-((2-nitrophenyl) thio) phenyl) imino) methyl)phenol (NOS) on mild steel in 2M hydrochloric acid solution has been studied using electrochemical and quantum chemical techniques. The electrochemical outcomes suggest that NOS works as an anodic-type inhibitor. The adsorption process of the NOS Schiff base obeys the Langmuir model. The theoretical evaluation has been performed using DFT calculations to investigate the correlation of effective corrosion inhibition with some NOS Schiff base structural parameters. The obtained results revealed that there was a good agreement between the theoretical and experimental results. [ABSTRACT FROM AUTHOR]

Natural gums due to availability, multifunctionality, and nontoxicity are multifaceted in application. In corrosion inhibition applications, their performance, in unmodified form is unsatisfactory because of high hydration rate, solubility issues, algal and microbial contamination, as well as thermal instability. This work attempts to enhance the inhibitive performance of Berlinia grandiflora (BEG) and cashew (CEG) exudate gums through various modification approaches. The potential of biogenic BEG and CEG gums−silver (Ag) nanocomposites (NCPs) for corrosion inhibition of mild steel in 1 M HCl is studied. The nanocomposites were characterized using the FTIR, UV–vis, and TEM techniques. The corrosion studies through the gravimetric and electrochemical (PDP, EIS, LPR, and EFM) analyses reveal moderate inhibition performance by the nanocomposites. Furthermore, the PDP results reveal that both inhibitors are mixed-type with maximum corrosion inhibition efficiencies (IE s) of 61.2 % and 54.2 % for BEG-Ag NCP and CEG-Ag NCP, respectively at an optimum concentration of 1.0 %. Modification of these inhibitors with iodide ion (KI) significantly increased the IE values to 90.1 % and 88.5 % for BEG-Ag NCP and CEG-Ag NCP at the same concentration. Surface observation of the uninhibited and inhibited steel samples using SEM/EDAX, 3D Surface profilometer, and AFM affirm that the modified nanocomposites are highly effective. [ABSTRACT FROM AUTHOR]

Plant extracts have been considered to be an effective corrosion inhibitor due to their high inhibition performance, huge amount, regeneration, and nature, as well as biological sources. However, several steps in the plant extract processes and extracted solvents are still questionable. Therefore, Papaya resin - extract (PRE) was recommended, produced, and characterized as a mixed-type inhibitor for corrosion of mild steel in 0.1 M hydrochloric acid medium. The results indicated that the 2000 ppm of PRE inhibitor has significant effects on the inhibition efficiency, reaching a remarkable value of 98.08% for mild steel in the investigated solution. The potentiodynamic polarization results showed that the PRE inhibitor acts as a mixed-type inhibitor with a dominant anodic inhibitor for mild steel. Moreover, electrochemical impedance spectroscopy and linear polarization resistance results demonstrated that PRE molecules can form protective film, and increase charge transfer and polarization resistances, suggesting the improved steel corrosion resistances. The scanning electron microscope results indicated less occurrence of corrosion on the steel surface exposed to the inhibitor system. Meanwhile, X-ray photoelectron spectroscopy results demonstrated that PRE's molecules were absorbed and created reactions with iron products to form a protective film on the steel surface. Furthermore, density functional theory (DFT) and molecular dynamics simulation were used to calculate, suggesting that the conjugation effect of two double bonds in PRE's molecules creates an electron-withdrawing effect on the reactive space around. Moreover, the results revealed the good adhesion and thermal stability of the absorbent protective layer, indicating an agreement with experimental characteristics. Therefore, this result suggests a contemporary design for developing the self-corrosion inhibitor based on natural products with less steps in the synthetic process. [Display omitted] • The use of Papaya resin – water extract (PRE) protected mild steel corrosion. • PRE acted as an effective mixed-type inhibitor with the dominant anodic inhibition. • High inhibition efficiency is due to film formation via adsorption processes. • Great adsorption is due to the appearance of active functional groups in PRE species. [ABSTRACT FROM AUTHOR]

• Inhibition efficiency of IPA increases by increasing its concentration. • Electrochemical measurements revealed mixed-type IPA inhibitor. • SEM/EDX and UV-Vis. analysis reveal the formation of a protective film on steel surface. • Computational outputs are in good agreement with experimental results. Mild steel protection activity in hydrochloric acid poses an important industrial challenge. In this study, an imidazole/pyridine derivative, i.e., 3-(imidazole [1,2-a]pyridine-2-yl)aniline (IPA), was synthesized, and its protectivity activity properties were evaluated using multifaceted comprehensive methods. Electrochemical measurements (PDP and EIS techniques) showed that IPA acted as a mixed-type protective agent with over 91 % efficiency at a 10−3 M concentration. Thermodynamic analysis via activation parameters and adsorption modelling revealed the formation of an adherent protective layer on metal surface. SEM-EDX and UV‒ Vis spectroscopy validated protective film formation through adsorption and metal complexation. DFT calculations identified key functional groups actively donating electrons to steel surfaces. Monte Carlo simulations provided atomic-level insights into IPA's superior adsorption behavior. A combined approach established IPA as a promising green protective agent for acidized mild steel, with the potential applications in industrial areas utilizing hydrochloric acid, such as in acid pickling. By unveiling protection mechanisms at experimental and theoretical levels, this study facilitates protective agent design with optimized protective properties. [ABSTRACT FROM AUTHOR]

Herein, a novel chitosan Schiff base (CS-FGA) as a sustainable corrosion inhibitor has been successfully synthesized via a simple amidation reaction by using an imidazolium zwitterion and chitosan (CS). The corrosion inhibition property of CS-FGA for mild steel (MS) in a 1.0 M HCl solution was studied by various electrochemical tests and physical characterization methods. The findings indicate that the maximum inhibition efficiency of CS-FGA as a mixed-type inhibitor for MS in 1.0 M HCl solution with 400 mg L−1 reaches 97.6 %, much much higher than the CS and the recently reported chitosan-based inhibitors. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and water contact angle (WCA) results reveal that the CS-FGA molecules firmly adsorb on the MS surface to form a protective layer. The adsorption of CS-FGA on the MS surface belongs to the Langmuir adsorption isotherm containing both the physisorption and chemisorption. According to the X-ray photoelectron spectroscopy (XPS) and UV–vis spectrum, Fe N bonds presented on the MS surface further prove the chemisorption between CS-FGA and Fe to generate the stable protective layer. Additionally, theoretical calculations from quantum chemical calculation (DFT) and molecular simulations (MD) were performed to reveal the inhibition mechanism of CS-FGA. [Display omitted] • A bio-inspired chitosan derivative (CS-FGA) inhibitor was synthesized. • Inhibition performance of CS-FGA was determined by various electrochemical measurements. • Inhibition efficiency of CS-FGA is significantly enhanced and reached ~97.6 %. • Comprehensive computational study further reveals inhibition mechanism of CS-FGA. [ABSTRACT FROM AUTHOR]

We report the green synthesis of novel ZrO2-Glycine nanocomposite referred to as ZrO2-Gly NC followed by its characterization using X-ray diffraction (XRD), Fourier transforms infrared (FT-IR) spectroscopy, SEM/EDX, and transmission electron microscopy (TEM) techniques. Further, the inhibition effect of the varying concentration of ZrO2-Gly NC on the corrosion of mild steel (MS) in 1 M HCl was investigated by weight loss and electrochemical measurements at 40–80 °C. The percentage inhibition efficacy of NC increased with the increase of concentration and temperature and reached about 81.01% at 500 ppm at 70 °C which decreased at 80 °C and exhibited 73.5% inhibition efficiencies. According to the polarization measurements, the investigated ZrO2-Gly NC works as a mixed-type inhibitor with predominantly inhibiting cathodic reaction. Also, the adsorption isotherm analysis indicated that the adsorption was spontaneous and followed the Langmuir adsorption isotherm. Furthermore, the contact angle measurement revealed the water-repelling property of the investigated inhibitor. The surface morphological study via SEM–EDS micrograph affirmed the appearance of a smooth surface in presence of inhibited media suggesting the formation of protective film by the adsorption of ZrO2-Gly NC on the surface of the MS even at higher temperature. [ABSTRACT FROM AUTHOR]

The corrosion performance of mild steel (MS) in 1M HCl solution was examined by weight loss (WL), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), and open circuit potential (OCP) measurements in the absence and presence of nonanedihydrazide. PDP measurements indicated that nonanedihydrazide acts as a mixed inhibitor due to its adsorption on the MS surface, exhibiting an inhibition efficiency of more than 97%. The surface morphology investigation of the protective layer on the MS surface confirmed that adsorption of nonanedihydrazide molecules occurred via chemical adsorption following Langmuir's isotherm model. The effect of temperature on the corrosion performance in the presence of nonanedihydrazide was investigated in the range of 303–333 K, showing that the inhibition efficiency increased with an increase in the inhibitor concentration and decreased with an increase in temperature. A new green corrosion inhibitor was synthesised and theoretical computations were conducted to completely understand the inhibition mechanism. Nonanedihydrazide molecules were investigated by DFT (density functional theory) using the B3LYP functional to evaluate the relationship of corrosion inhibition performance and the molecular structure. The computed theoretical parameters presented significant support for understanding the inhibitive mechanism revealed by the inhibitory molecules and are in good agreement with WL, PDP, EIS, (EFM), and OCP results. [ABSTRACT FROM AUTHOR]

The preventing effect of novel triphenyl imidazole based on 8-hydroxyquinoline (HDiPIQ) on the corrosion attack of mild steel in 1 M HCl solution was investigated. Electrochemical impedance and potentiodynamic polarization measurements have been realized. Inhibitor concentration increase leads to a considerable shift in mild steel oxidization rate in molar hydrochloric acid solution with inhibitive efficiency such as 89% at 10–3 M concentration of HDiPIQ. Tafel curves showed that HDiPIQ acted as a mixed-type inhibitor. Nyquist curve drawing showed that inhibitor concentration getting increased resulted in polarization resistance growth, that involves inhibition efficiency increase and double-layer capacitance decrease. The effect of temperature in the range 298–328 K at a concentration of 10–3 M HDiPIQ showed that inhibiting efficiency diminished slightly with temperature. HDiPIQ adsorption on steel surface has been found to comply with Langmuir's isotherm model, implying a mixed type of binding with predominance of chemical adsorption mechanism. Activation energy and thermodynamic results such as enthalpy, entropy and free energy have been determined and discussed. Surface characterization using scanning electron microscopy allowed the confirmation of HDiPIQ inhibiting effect on mild steel corrosion. UV–visible spectroscopy results have been analyzed and discussed. Quantum chemical factors such as the frontier molecular orbitals energies (EHOMO and ELUMO), the energy gap between ELUMO and EHOMO (ΔE), hardness (η), electronegativity (χ), and Fukui indexes have been calculated and discussed using density functional theory calculations and the Becke's three-parameter exchange functional with the Lee–Yang–Parr correlation function and the 6–311 + G(d,p) basis set. Monte Carlo simulation allowed elucidating inhibitor/mild steel interaction of the above-mentioned inhibitor molecule. [ABSTRACT FROM AUTHOR]

• Synthesized and evaluated two isoindigo derivatives as corrosion inhibitors. • Derivatives were effective corrosion inhibitors on carbon steel in acidic conditions. • Protective film is formed on the steel surface by the interaction of N and Fe atoms. • Offers new insights into inhibitors development and broadens the use of isoindigo. This investigation synthesized two isoindigo derivatives (IIDBr-NBr and IIDBr-MBr). These derivatives were then applied as green corrosion inhibitors for mild steel in a 1 mol L−1 HCl aqueous solution. The study investigated the corrosion inhibition performance of IIDBr-NBr and IIDBr-MBr through electrochemical and weight loss (WL) measurements, as well as surface analysis (SEM, AFM and XPS). The results showed that both IIDBr-NBr and IIDBr-MBr exhibited excellent corrosion inhibition performance (inhibition efficiency of 96.27 % for IIDBr-NBr and 96.46 % for IIDBr-MBr). Quantum chemical calculations based on density functional theory (DFT) and molecular dynamics (MD) were used to reveal the adsorption mechanisms of IIDBr-NBr and IIDBr-MBr at the steel/solution interface. [Display omitted] [ABSTRACT FROM AUTHOR]

Utilization of sunflower stalks to develop green and efficient corrosion inhibitors can further improve the added economic value of sunflower. In this work, sunflower (Helianthus annuus.) stalks extract (HASE) was prepared for the first time by ultrasonic extraction method. To investigate the inhibition effectiveness and mechanism of HASE on aluminium in HCl media, a variety of experimental techniques including weight loss, electrochemical tests and surface characterizations were utilized. The findings show that in 1.0 M HCl solution at 20 °C, 500 mg L−1 HASE has an inhibitory effectiveness of up to 93.3 %. HASE adsorption adheres to Langmuir isotherm model, which contains both chemisorption and physisorption in its adsorption behaviour on aluminium surface. HASE is a cathodic inhibitor that primarily slows down the cathodic hydrogen precipitation process. HASE greatly lowers the double layer capacitance and dramatically raising charge transfer resistance. The inhibitory action of HASE on aluminium in HCl medium is confirmed by corrosive solution testing and metal surface characterizations, which also provides evidence of inhibitor molecular adsorption. [Display omitted] • Helianthus annuus stalk extract (HASE) is a novel eco-friendly and efficient inhibitor for aluminum in HCl medium. • The adsorption of HASE on aluminum surface conforms to Langmuir isotherm. • HASE is a mixed-type inhibitor that drastically retards the cathodic reaction. • The adsorption and inhibition of HASE are confirmed by SEM-EDS, AFM, CLSM and XPS. • Qallic acid, tannin and rutin are the main effective components in HASE. [ABSTRACT FROM AUTHOR]

[Display omitted] An organotin(IV) dithiocarbamate compound namely bis(N -ethyl-isopropyl dithiocarbamate)chlorido butyltin(IV) [EIDTC 2 ClBuSn] was successfully synthesised and characterised, and showed good potentiality as a corrosion inhibitor on mild steel surfaces in 1 M hydrochloric acid (HCl). This organotin(IV) compound was synthesised using in situ method and characterised via physical and spectroscopic analysis. The physical analyses involved are melting point determination and elemental analysis. Meanwhile, the spectroscopy analyses involved are Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) and Nuclear Magnetic Resonance (NMR), specifically proton (1H), carbon (13C) and tin (119Sn) NMR. Corrosion inhibition efficiency for the synthesised complex was determined using the conventional method of weight loss and electrochemical measurements involving Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Polarisation (PDP) analysis. Surface analysis techniques such as Scanning Electron Microscopy with Energy Dispersive X-Ray (SEM-EDX) and Atomic Force Microscopy (AFM) were also employed. The inhibition efficiency was also found to increase with the concentration of inhibitor solution, and the highest percentage of inhibition efficiency (IE%) recorded was 91.78 %, 87.20 % and 98.27 % at 0.005 mM during weight loss, EIS and PDP analysis, respectively. The interaction between mild steel and the corrosion inhibitor is further described using theoretical studies involving the adsorption isotherm theory and thermodynamic calculation. The adsorption of EIDTC 2 ClBuSn onto the mild steel surface obeys the Langmuir isotherm, and the type of adsorption involved based on Gibbs Free Energy (ΔG ads) calculation is chemical adsorption. The neutral form of EIDTC 2 ClBuSn is subjected to the Density Functional Theory (DFT), revealing the predominant delocalisation of high-density electrons around the nitrogen and sulphur atoms. Despite ΔG ads suggesting chemical adsorption, the theoretical investigation indicates the potential protonation of EIDTC 2 ClBuSn through the nitrogen atom, as identified by the Mulliken population analysis in the DFT study. Consequently, this suggests that the compound is capable of adsorbing onto the mild steel surface through both initial physical adsorption and subsequent chemical adsorption. [ABSTRACT FROM AUTHOR]

[Display omitted] • The corrosion inhibition effect of Rosmarinus officinalis L. (ROL) essential oil tested for mild steel/1 M HCl system. • The phytochemicals of ROL were identified using GC–MS and UV–Vis techniques. • ROL inhibited more than 90 % efficiency at 1.5 g/L concentration and behaves as a cathodic-type inhibitor. • The adsorption mode of inhibition was reinforced by SEM/EDX and DFT/MC/MDS studies. • The coordination and complex forming ability of ROL was studied using UV–visible spectrophotometry. In this research, Rosmarinus officinalis L. (ROL) essential oil extracted from the plant was initially introduced as a green anti-corrosion agent for mild steel (MS) in a 1 M HCl solution. The components of the extract were identified using gas chromatography-mass spectrometry (GC–MS) and UV–Vis method. Gravimetric and electrochemical techniques (EIS and PDP) demonstrated that ROL inhibited steel corrosion by 90 % at a concentration of 1.5 g/l. The PDP experiment indicated that ROL essential oil acted as a mixed-type inhibitor with a cathodic predominance. The morphological and elemental characteristics of the metal surface were examined using SEM and EDX, revealing the formation of a corrosion-resistant film on the metal surface. The inhibited corrosive solutions were characterised before and after immersing MS using UV–visible spectrophotometry, indicating the possibility of iron-ROL complex formation. Finally, theoretical calculations using DFT, MC, and MD simulations were conducted and correlated with experimental results. [ABSTRACT FROM AUTHOR]

A rigid double Schiff base with a symmetrical plane, (1E,1′E)-N,N'-(1,4-phenylene)bis(pyrazin-2-yl)ethanimine) (PBPE), has been synthesized and characterized by 1H NMR and FTIR spectroscopies. The corrosion inhibition performance of PBPE for mild steel in 1.0 mol L−1 HCl solution was systematically measured by weight loss method, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization technique, field emission scanning electron microscopy (FE-SEM), energy dispersive spectrometer (EDS), atomic force microscope (AFM), and water contact angle measurement. The inhibition efficiency depends upon the PBPE concentration and the maximum inhibition efficiency by weight loss analysis is 93.10 % at 800 mg L−1 PBPE. The potentiodynamic polarization measurement revealed that PBPE behaves as a mixed-type inhibitor with a predominant anodic reaction. The thermodynamics adsorption analysis showed the adsorption of the PBPE molecules on the surface of mild steel obeys Langmuir adsorption isotherm, with both physisorption and chemisorption. In the corrosion reaction, the activation energy, activation enthalpy, and activation entropy all increased with increasing PBPE concentration. The surface morphology analysis such as SEM-EDS, AFM, and water contact angle further confirmed adsorption on the mild steel surface and resulted in the formation of protective film on the mild steel surface in PBPE solution. The quantum chemical parameters obtained such as global softness, electron transfer fraction, and energy gap together with Fukui indices can explain the good inhibition efficiency. Molecular dynamics simulations discovered that the PBPE molecules in a flat manner are adsorbed on the surface of mild steel, thus giving rise to a more effective adsorption and corrosion inhibition. [Display omitted] • PBPE can effectively inhibit mild steel corrosion in 1.0 mol L−1 HCl solution. • Adsorption behavior on mild steel surface was analyzed by morphology analysis. • DFT calculations study the predominant interaction between PBPE and metal surface. • MD simulations display that PBPE is flatly adsorbed on metal surface. [ABSTRACT FROM AUTHOR]

A novel series of 2‐(4‐substituted phenyl)‐6/8‐substituted‐ [1,3,4] oxadiazolo[2′,3′:2,3][1,3]thiazino[6,5‐b]quinolin‐11(3aH)‐ones were synthesized. Their structures have been characterized using standard spectroscopic techniques such as Infrared, Nuclear Magnetic Resonance, and Mass Spectroscopy. All the newly synthesized compounds were screened for their antibacterial and antifungal activities by the cup plate diffusion method. Antimicrobial studies revealed that compounds showed good to significant activity against tested strains. One of the compounds was evaluated for corrosion inhibition studies by potentiodynamic polarization and electrochemical impedance method in 0.1 M hydrochloric acid solution for mild steel. The tested compound had exhibited a good inhibitory action against corrosion of mild steel in the medium investigated. [ABSTRACT FROM AUTHOR]

Synergistic effect of KI on the corrosion inhibition efficiency of methylene bis [(2-hydroxy-5, 1-phenylene) bismethylene] tetraphosphonic acid (TPA) on corrosion of copper in 0.5 M HCl have been tested using weight loss, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The study show that copper is more efficiently inhibited by decreasing the concentration of TPA, and enhancement in inhibition efficiency was observed with an addition of 0.02 M potassium iodide due to synergism. The highest inhibition efficiency of 91% was observed for10−8 M TPA while an addition of 0.02 M KI to 10−8 M TPA improved the inhibition efficiency to 98%. Electrochemical test data prove that they are cathodic inhibitor and exhibit remarkable corrosion inhibition ability. The morphology confirms that the synergistic effect is due to coadsorption of iodide ions and TPA is co-operative in nature. Furthermore, the inhibition efficiency of (TPA + KI) does not depend on temperature. The adsorption of TPA alone or with iodide ions on the metal surface followed Frumkin adsorption isotherm. Thermodynamic parameters (Kads, ΔG°ads, ΔS°ads) were calculated using the adsorption isotherms from temperatures ranging from 25 to 55 °C. The experimental results were confirmed by density functional theory (DFT) and molecular dynamic simulation (MDS) calculation. [ABSTRACT FROM AUTHOR]

Abstract—The effects that indolizine derivatives, a tellurium organic compound, rhodanine, sodium diethyldithiocarbamate, and some of their mixtures have on corrosion of steel in 1 M hydrochloric acid are studied by gravimetric analysis, kinetic measurements at different temperatures, polarization measurements, and impedance spectroscopy. The listed compounds and their mixtures are found to be effective inhibitors of acidic corrosion of low-carbon steel. In the presence of inhibitors, the corrosion of steel in hydrochloric acid is shown to be kinetically controlled. The considered additives have different influences on partial reactions in the corrosion process. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of novel organic corrosion inhibitors based on poly(epichlorohydrin) (PECH) for mild steel immersed in 1 M HCl solution have been reported for the first time. In this way, the chlorine branches of poly(epichlorohydrin) (PECH) were substituted with 3-nitro-1,2,4-triazol-5-one (NTO) and Cl atoms in phosphoryl chloride (POCl3) were replaced by hydroxyl groups of poly(epichlorohydrin) containing NTO. UV-visible and Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) and elemental analyzer (CHN) and thermogravimetric analysis (TGA) were used to characterize the chemical composition of the synthesized organic compounds. Electrochemical impedance spectroscopy (EIS) and electrochemical polarization techniques were used to evaluate the corrosion inhibition performance of the organic inhibitors. Polarization results revealed that the corrosion inhibition efficiency in the inhibitor-containing samples was increased by increasing the concentration of the inhibitors in the corrosive electrolyte. In addition, it was found that the sample containing 200 ppm of the (PECH/NTO/PO(OH)2) organic inhibitor had the maximum inhibition efficiency of 99.5% after 24 h immersion in the HCl solution. [ABSTRACT FROM AUTHOR]

Plant extracts have gained a lot of attention due to their ecofriendly nature for corrosion inhibition. In this study, we examined the inhibition performance of grape seed extract as an eco-environmental inhibitor for mild steel in hydrochloric acid medium. Electrochemical impedance spectroscopy, potentiodynamic polarization, and electrochemical noise techniques were employed to study mild steel's electrochemical behavior in the hydrochloric acid solutions containing grape seed extract. Results depicted that grape seed extract could successfully inhibit the corrosion of mild steel. Besides, water droplet contact angle, field-emission scanning electron microscopy coupled with energy dispersive spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy were utilized to study the surface of mild steel specimens after dipping in acidic solutions. Electrochemical impedance results showed a corrosion efficiency of about 88% in 300 ppm of grape seed extract. Also, results revealed more compact corrosion products with improved integrity in the presence of grape seed, which confirmed electrochemical test results. [ABSTRACT FROM AUTHOR]

The investigation of the effect of Grass Jelly (Platostoma palustre) extract to the corrosion behavior of carbon steel had been carried out using electrochemical methods such potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Those experiments define corrosion rate, efficiency of inhibition and adsorptions isotherm values in 0.1 M hydrochloric acid solution. That extract was added gradually in acid solution up to 1,000 ppm. It found that the maximum of inhibition efficiency could reach 93% at 250 ppm concentration of extract. Typically, the efficiency of inhibition increased with increasing concentration of extract which tends to stable in the concentration range between 300 ppm and 1,000 ppm. The type of the extract is mixed inhibitor where it can inhibit the corrosion process in both anodic and cathodic sides. It presumed that the mechanism of adsorption on surface of metal corresponds to Langmuir adsorption isotherm. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate cimetidine as corrosion inhibitor of aluminium in hydrochloric acid medium. Design/methodology/approach: Cimetidine was characterized by gas chromatography mass spectrophotometer and Fourier transform infrared spectroscopy to determine its chemical composition and functional groups, respectively. Gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopic techniques were used in the corrosion inhibition process. Thermodynamic and adsorption parameters were evaluated. And response surface methodology was used to optimize the corrosion inhibition process. Findings: Analysis of the results revealed that major constituents of cimetidine include metronidazole, n-hexadecanoic acid cyclohexane and methyl ester. It has C-H stretch, C = N stretch, CH3C-H bend, ring C = C stretch, -C-O-O stretch, N-H bend, C-O stretch and C-H bend as predominant functional groups. Adsorption of molecules of the inhibitor on the aluminium surface was spontaneous, and it followed mechanism of physical adsorption. Response surface methodology revealed that quadratic model adequately described the inhibition efficiency of cimetidine as function of inhibitor concentration, temperature and time. Chemical and electrochemical results are in agreement that the cimetidine is a viable corrosion inhibitor. Cimetidine was revealed as mixed-type inhibitor because it controlled both cathodic and anodic reactions. Originality/value: Empirical and optimization studies of cimetidine drug as corrosion inhibitor of aluminium in hydrochloric acid medium were carried out. The research results can provide the basis for deploying drugs (with mucosal protective and antacid properties) for corrosion control of metallic structures. [ABSTRACT FROM AUTHOR]

The inhibition performance of sodium dodecyl sulfate (SDS) and 2‐mercaptopyridine (2MP) corrosion inhibitors on A3 steel in 0.5 M HCl increase with increasing of the inhibitor concentration (50–200 mg L−1). SDS and 2MP inhibitor follow Freundlich adsorption isotherm and Langmuir adsorption isotherm, respectively. These two inhibitors exhibit good synergistic inhibition effect on the corrosion of A3 steel in 0.5 M HCl solution when the mass ratio of SDS:2MP is 1:4. Gibbs free energy of the mixture is lower and the mixture exhibit good adsorption stability. 2MP molecule are adsorbed on metal surface through N atom and sulfhydryl group. SDS molecule interacts with metal through O atoms while the alkyl chain pointing to the test solution. This adsorption configuration is beneficial to the formation of the inhibitor film, the migration of the corrosive particles to the metal surface was hindered and thus the metal surface was protected. [ABSTRACT FROM AUTHOR]

The inhibition efficacy of N-(4,6-dimethylpyrimidin-2-yl)-4-[(quinazoline-4-yl)amino]benzene-1-sulfonamide (DMQS) as a new corrosion inhibitor on mild steel (MS) in 0.1 M HCl medium at varied temperature has been analysed and it has ensued 97.6% high efficiency at 4 × 10–5 M of DMQS. The electrochemical techniques employed were impedance spectroscopy and potentiodynamic polarization. Surface analysis of MS was carried out through scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS). Inhibitory effect of DMQS escalated with elevated concentration and declined with elevation in solution temperature. The adsorption of DMQS on MS has consent with the Langmuir adsorption isotherm. The computational study using density functional theory (DFT) with the B3LYP/3-21G basis set level for DMQS was investigated through the association between their molecular and electronic structure. The parameters involved in quantum chemical calculations were energy gap, EHOMO, ELUMO, absolute electronegativity, electrophilicity, softness, global hardness, energy gap, ionisation energy, electron affinity and dipole moment. DMQS shows EHOMO value of –6.256 eV, fortifying MS from corrosive attack and implicating it to be an effectual inhibitor. The results of the implemented studies show the corrosion inhibition efficiency of the DMQS is in good accord. [ABSTRACT FROM AUTHOR]