Synergistic inhibition effect of diolefinic dye and silver nanoparticles for carbon steel corrosion in hydrochloric acid solution.

The current work looks at the inhibitory effects of a diolefinic dye, namely 1,4-bis((E)-2-(3-methyl-2,3-dihydrobenzo[d]thiazol-2-yl) vinyl) benzene iodide salt, in relation to CS corrosion mitigation in hydrochloric acid (HCl) environment. This study uses a variety of experimental methodologies, including weight loss (WL) analysis, electrochemical tests, and theoretical considerations. The synergistic effect of diolefinic dye and AgNPs on the corrosion inhibition of CS in 1 M HCl was investigated. The inhibition efficiency (IE) displays a notable enhancement as the concentration of the dye is elevated and as the temperature raises the IE increases. The diolefinic dye exhibited % IE of 83% even at low concentration (1 × 10-4 M) whereas 90% in the presence of (2.26 × 10-10) AgNPs. Tafel graphs demonstrate that the dye follows a mixed type inhibitor. The adsorption of the dye on CS surface follows Langmuir model. Moreover, the influence of temperature and the activation parameters disclose that diolefinic dye is chemisorbed on the CS surface. The synergistic coefficient of the diolefinic dye and AgNPs under various concentration conditions was greater than unity. The surface morphology of CS sheets was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Density Functional Theory (DFT) calculations provide theoretical support for the inhibitory effects of the examined dye. Notably, there is a high agreement between the findings of practical studies and theoretical expectations.

Synthesis of new binary trimethoxyphenylfuran pyrimidinones as proficient and sustainable corrosion inhibitors for carbon steel in acidic medium: experimental, surface morphology analysis, and theoretical studies.

In this study, synthesis and assessment of the corrosion inhibition of four new binary heterocyclic pyrimidinones on CS in 1.0 M hydrochloric acid solutions at various temperatures (30-50 °C) were investigated. The synthesized molecules were designed and synthesized through Suzuki coupling reaction, the products were identified as 5-((5-(3,4,5-trimethoxyphenyl)furan-2-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-trione (HM-1221), 2-thioxo-5-((5-(3,4,5-trimethoxyphenyl)furan-2-yl)methylene)dihydropyrimidine-4,6(1H,5H)-dione (HM-1222), 1,3-diethyl-2-thioxo-5-((5-(3,4,5-trimethoxyphenyl)furan-2-yl)methylene)dihydropyrimidine-4,6(1H,5H)-dione (HM-1223) and 1,3-dimethyl-5-((5-(3,4,5-trimethoxyphenyl)furan-2-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-trione (HM-1224). The experiments include weight loss measurements (WL), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). From the measurements, it can be shown that the inhibition efficiency (η) of these organic derivatives increases with increasing the doses of inhibitors. The highest η recorded from EIS technique were 89.3%, 90.0%, 92.9% and 89.7% at a concentration of 11 × 10-6 M and 298 K for HM-1221, HM-1222, HM-1223, and HM-1224, respectively. The adsorption of the considered derivatives fit to the Langmuir adsorption isotherm. Since the ΔGoads values were found to be between - 20.1 and - 26.1 kJ mol-1, the analyzed isotherm plots demonstrated that the adsorption process for these derivatives on CS surface is a mixed-type inhibitors. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscope (AFM) and Fourier- transform infrared spectroscopy (FTIR) were utilized to study the surface morphology, whereby, quantum chemical analysis can support the mechanism of inhibition. DFT data and experimental findings were found in consistent agreement.

Application of lentil seed extract as an inhibitor to assess the corrosion properties of copper-nickel alloys in a NaCl environment.

Weight loss (WL), electrochemical, and surface analysis were used to explore the efficiency of lentil seed extract (LSE) in mitigating the electrochemical corrosion of Cu-10Ni and Cu-30Ni alloys in obviously aerated water. The adsorption of lentil seed extract (LSE) species to create a barrier layer improved the corrosion resistance of Cu-Ni alloys in a NaCl medium. It was shown that the temperature of the medium and the amount of extract used affected the enhanced inhibitory efficacy. Using the PDP approach, the Cu-10Ni alloy showed the maximum inhibition performance (IE) of about 98.58% and 8.53% with 300 ppm LSE, respectively. According to the findings, the studied extract had a good ability to slow down the step at which alloys corroded in a 3.5% NaCl solution. It was discovered that as the temperature rose, the rate of corrosion increased. The thermodynamic activation functions of the dissolution process were also calculated as a function of extract dose. PDP curve analysis reveals that LSE is a mixed-type inhibitor, and EIS findings demonstrates that increasing dose not only alters the charge transfer (R ct) of Cu-10Ni alloy from 1031 to 2984 Ω cm2 and for Cu-N30Ni alloy from 3093-6208 Ω cm2 but also changes the capacitance of the adsorbed double layer (C dl) for Cu-10Ni alloy from 728-678 µF cm2 and for Cu-30 Ni alloy from 726 to 701 µF cm2. The inhibitor's adsorption provides a good fit for the "Freundlich, Temkin, and Langmuir isotherm" models. Several methods are used to confirm that the alloy surface has a protective coating.

Verbena officinalis (VO) leaf extract as an anti-corrosion inhibitor for carbon steel in acidic environment.

In the present work, Verbena Officinalis (VO) leaf extract was used as potential corrosion inhibitor for the corrosion of carbon steel (CS) in 0.5 M H2SO4 medium. Further, the corrosion inhibiting nature of VO leaf extract towards the CS was evaluated using mass loss (ML), potentiodynamic polarization (PDP), electrical impedance spectroscopy (EIS) and surface morphological analyses using atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS) techniques. Calculation of activation energy E a ∗ using Arrhenius equation shows the increase in activation energy when adding the VO leaf extract in 0.5 M H2SO4 medium and the maximum activation energy ( E a ∗ = 49.9 kJ mol-1) was observed for 1000 mg L-1 VO leaf extract in acid medium. The negative free energy values suggested the spontaneous and the stability of the adsorbed layer of VO leaf extract on the CS surface. Using EIS measurements, high percent inhibitory effectiveness of 91.1% for 1000 ppm solutions was achieved. With an increase in VO leaf extract dose, the double layer capacitance (Cdl) values fall while the values of charge transfer (Rct) increase. This showed that a protective layer of VO leaf extract on CS surface was formed. The polarization curves showed that the VO leaf extract acts as a mixed-type inhibitor. It is discovered that the adsorption of VO leaf extract molecules adhering to the CS surface followed the Langmuir isotherm. The anti-corrosion action of VO leaf extract is fully demonstrated by some surface techniques.

Expression of concern: Experimental and surface morphological studies of corrosion inhibition on carbon steel in HCl solution using some new hydrazide derivatives.

Expression of concern for 'Experimental and surface morphological studies of corrosion inhibition on carbon steel in HCl solution using some new hydrazide derivatives' by Abd El-Aziz S. Fouda et al., RSC Adv., 2021, 11, 13497-13512, https://doi.org/10.1039/d1ra01405f.

Expression of concern: Effectiveness of some novel heterocyclic compounds as corrosion inhibitors for carbon steel in 1 M HCl using practical and theoretical methods.

Expression of concern for 'Effectiveness of some novel heterocyclic compounds as corrosion inhibitors for carbon steel in 1 M HCl using practical and theoretical methods' by Abd El-Aziz S. Fouda et al., RSC Adv., 2021, 11, 19294-19309, https://doi.org/10.1039/D1RA03083C.

Experimental and theoretical studies of the efficiency of metal-organic frameworks (MOFs) in preventing aluminum corrosion in hydrochloric acid solution.

Aluminum corrosion inhibitors "{[CuI (CN)2(phen) CuII (CN)2(phen)]5H2O},(MOF1) and {[CuI(CN)2(phen)CuII(CN)2(phen)]5H2O}@TiO2 (MOF1@TiO2) were studied in one molar HCl solution". The ML results for three different temperatures (25-45 °C) were compared with the results of PDP and EIS analyses. The adsorption of inhibitors on Al surfaces has been calculated and discussed by a Langmuir isotherm. The inhibitors that were created showed great effectiveness, with a noticeable increase in their inhibitory efficiency as the dosage was raised and the temperature was lowered. Inhibition efficiency each amounted to 88.6%, 84.5% at 400 ppm and 25 °C for MOF1@TiO2 and MOF1, respectively. Analyzing the polarization curves of synthesized inhibitors revealed that they were mixed-type inhibitors. Al was found to be surface inhibited when coated with a thin film of inhibitors, and "Al's surface morphology was assessed by different techniques such as scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and atomic force microscope (AFM)". "Theoretical models like quantum chemical and molecular dynamics simulation authenticated the experimental observation". The MOFs exhibit exceptional corrosion resistance against Al when exposed to acidic environments, according to several tests.

Synthesis and Characterization of New Polymeric Ionic Liquids as Corrosion Inhibitors for Carbon Steel in a Corrosive Medium: Experimental, Spectral, and Theoretical Studies.

A novel series of polymeric ionic liquids (ILs) based on benzimidazolium chloride derivatives, namely, 1,3-diheptyl-2-(2-phenyl-propyl)-3H-benzimidazol-1-ium chloride (IL1), 1,3-dioctyl-2-(2-phenyl-propyl)-3H-benzimidazol-1-ium chloride (IL2), and 1,3-Bis-decyl-2-(2-phenyl-propyl)-3H-benzoimidazol-1-ium chloride (IL3), were synthesized and chemically elucidated by Fourier transform infrared spectroscopy, 1H NMR, 13C NMR, and elemental analysis. Their influence as corrosion suppressors were investigated for C-steel corrosion in 1 M HCl, by weight loss (WL), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) methods, revealing that their exclusive addition decreased corrosion with mounting concentrations. These assays demonstrated that novel ILs are efficient inhibitors at relatively low dosages. The efficacy of the synthesized ILs reached 79.7, 92.2 and 96.9%, respectively, at 250 ppm and 303 K. Parameters for activation and adsorption were calculated and are discussed. The Tafel polarization results demonstrated that the investigated ILs support the suppression of both cathodic and anodic reactions, acting as mixed type inhibitors. Langmuir's adsorption isotherm was confirmed as the best fitted isotherm, describing the physical-chemical adsorption capability of used ILs on the C-steel surface with the change in the free energy of adsorption, ΔG°ads = 32.6-37.2 kJ mol-1. The efficacy of the synthesized ILs was improved by increasing the doses, and the temperature reached 86.6, 96.1, and 98.4%, respectively, at 318 K. Surface morphology was proved by Fourier Transform Infrared spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy (AFM), and then, changes in test solutions were checked by Ultraviolet-visible spectroscopy. Theoretical modeling (density functional theory and Monte Carlo) revealed the correlation between the IL's molecular chemical structure and its anticorrosive property.

Synthesis and Characterization of a Novel Quaternary Ammonium Salt as a Corrosion Inhibitor for Oil-Well Acidizing Processes.

A quaternary ammonium salt, 1,1'-(1,4-phenylenebis(methylene))bis(4-formylpyridin-1-ium) (PMBF), was synthesized, characterized, and investigated as an inhibitor for C1018 (type steel in oil wells) corrosion in 17.5% HCl solution. The chemical structure of PMBF was confirmed using altered techniques. Potentiodynamic polarization (PDP) was employed to investigate the corrosion inhibition effect of the synthesized compound in a 17.5% HCl solution for C1018. The corrosion protection was increased by improving the dose of the synthesized compound and reached 98.5% at 42.02 × 10-5 M and 313 K. On the other hand, it was decreased by increasing the temperature and reached 97.9% at the same concentration and 343 K. The parameters of activation and adsorption were calculated and debated. A polarization study revealed that PMBF functioned as a "mixed-kind inhibitor," i.e., affecting both cathodic and anodic processes through their adsorption onto the electrode surface. The adsorption was described by the Langmuir adsorption isotherm. Different techniques were employed as appropriate tools for analyzing the structure of the layer formed on C1018. Density functional theory (DFT) and Monte Carlo (MC) simulations were used to compare the results of the theoretical calculations with the experiments. Finally, an appropriate inhibition mechanism was suggested and discussed.

Experimental and computational approaches of methoxy naphthylbithiophene derivatives and their use as corrosion protection for carbon steel in acidic medium.

The inhibition efficiency and adsorption affinity were investigated for two novel compounds, namely: 6-methoxy-2-naphthyl-[2, 2'-bithiophene]-5-carboxamidine hydrochloride salt (MA-1440) and 5'-(4-chlorophenyl)-2, 2'-bifuran-5-carboxamidine hydrochloride salt (MA-1456). The inhibition study was conducted on carbon steel surface in 1.0 M HCl with different inhibitor doses and different temperature levels, to investigate the optimum dose and preferable temperature. The performed investigation included chemical, electrochemical, instrumental, and quantum computation techniques. A chemical technique was accomplished by using weight-loss measurements. Different factors were studied using weight-loss measurements in order to reach the maximum inhibition efficiency. The adsorption study revealed that the examined inhibitors obey the Langmuir adsorption isotherm and are chemically adsorbed on the steel surface. The electrochemical measurements were accomplished through the electrochemical impedance (EIS) and potentiodynamic polarization (PDP) techniques. Based on the electrochemical measurements, the examined compounds were categorized as mixed inhibitors. The instrumental examination using different techniques namely: scanning electron microscope (SEM), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) confirmed that the considered inhibitors are excellently adsorbed over the carbon steel surface. The extent of the adsorption affinity of these compounds on the carbon steel surface was studied theoretically using quantum computations and Monte Carlo simulation. The theoretical investigation results of quantum chemistry were validated with those obtained by chemical and electrochemical methodologies. All investigations prove that, the tested compounds were adsorbed chemically on the steel surface and achieved maximum inhibition efficiency of, 94.69% and 90.85% for M-1440 and MA-1456, respectively, at the optimum concentration 30 [Formula: see text] 10-6 mol L-1 and temperature 328 K.

Corrosion mitigation for steel in acid environment using novel p-phenylenediamine and benzidine coumarin derivatives: synthesis, electrochemical, computational and SRB biological resistivity.

Three novel p-phenylenediamine and benzidine coumarin derivatives were synthetized, namely: 4,4'-((((1,4-phenylenebis(azaneylylidene))bis(ethan-1-yl-1-ylidene))bis(2-oxo-2H-chromene-3,6-diyl))bis(diazene-2,1-diyl))dibenzenesulfonic acid (PhODB), 4,4'-(((-([1,1'-biphenyl]-4,4'-diylbis(azaneylylidene))bis(ethan-1-yl-1-ylidene))bis(2-oxo-2H-chromene-3,6-diyl))bis(diazene-2,1-diyl))dibenzenesulfonic acid (BODB) and 4,4'-(((-((3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-diyl)bis(azaneylylidene))bis(ethan-1-yl-1-ylidene))bis(2-oxo-2H-chromene-3,6-iyl))bis(diazene-2,1-diyl))dibenzenesulfonic acid (DODB). Their chemical structures were proved by performing Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance and mass spectrometry analysis. The synthesized p-phenylenediamine and benzidine coumarin derivatives were tested as corrosion inhibitors for mild steel (MS) in 1 M HCl solution using weight loss, electrochemical, morphological, and theoretical studies. The compound 3,3'-dimethoxy benzidine coumarin derivative (DODB) was proved to give the highest efficiency with 94.98% obtained from weight loss measurements. These compounds are mixed inhibitors, as seen by the polarization curves. Impedance diagrams showed that when the concentration of these derivatives rose, the double-layer capacitance fell and the charge transfer resistance increased. Calculated thermodynamic parameters were computed and the mechanism of adsorption was also studied for the synthesized p-phenylenediamine and benzidine coumarin derivatives. The ability of the synthesized derivatives to protect the surface against corrosion was investigated by scanning electron microscope (SEM), UV-visible spectroscopy and energy dispersive X-ray spectroscopy (EDX). Theoretical chemical calculations (DFT) and biological resistivity (SRB) were investigated.

Aizoon extract as an eco-friendly corrosion inhibitor for stainless steel 430 in HCl solution.

Aizoon extract is used as an eco-friendly anti-corrosive material for stainless steel 430 (SS430) in a 2 M hydrochloric acid solution. Many strategies were utilized to estimate the mitigation efficacy such as mass reduction (MR), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP). The inhibition percentage (%I) increases by increasing the concentration of Aizoon and reaches 95.8% at 300 ppm and 298 K, while it lowers by raising the temperature, reaching 85.6% at 318 K. Tafel curves demonstrated that Aizoon extract is a mixed type inhibitor with an excellent ability to inhibit the cathodic reaction. Adsorption of the Aizoon extract on an SS430 surface is regulated by the Langmuir adsorption model. The value is is -20.9 kJ mol-1 at 298 K indicating that the adsorption is of mixed type affecting both cathodic and anodic reactions. Thermodynamic factors for adsorption and activation processes were estimated and discussed. The adsorption of Aizoon extract on the SS430 surface was tested utilizing Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) techniques. The Nyquist curves confirmed that Aizoon extract prohibits the disintegration of SS430 in an acid medium without changing the dissolution reaction mechanism. The theoretical calculations showed that Aizoon extract is considered as an excellent corrosion inhibitor. The experimental data were supported by theoretical evaluations.

5-Arylidene-1,3-dialkylbarbituric acid derivatives as efficient corrosion inhibitors for carbon steel in molar hydrochloric acid solution.

The inhibiting impact of two ecofriendly 5-arylidene barbituric acid derivatives (5-ABA), namely 5-(3,4-dimethoxybenzylidene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione (inhibitor I, 3a) and 5-(3,4-dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (inhibitor II, 3b), in 1 M HCl on the corrosion of carbon steel has been examined via the weight loss (WL) method, potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) tests. In addition, DFT calculations and MC simulations were used to study the relationship between the inhibitor structure and its inhibition performance. The attained outcomes exhibit that the investigated compounds are excellent inhibitors and their inhibition efficiency (%IE) increases with the increase in the concentration and temperature. The adsorption of 5-arylidene barbituric acid on the C-steel surface was found to follow the Langmuir adsorption isotherm. The adsorption process of the investigated compounds is spontaneous and considered as the chemisorption type. The PP curves revealed that 5-arylidene barbituric acid derivatives are mixed-type inhibitors. Moreover, the EIS results confirmed the adsorption of 5-arylidene barbituric acid derivatives on the C-steel surface by increasing the charge transfer resistance (R ct) values. The %IE of the inhibitors (II & I) reached 92.8% and 86.6% at a concentration of 21 × 10-6 M, according to the WL method. The surface analysis of the C-steel surface was confirmed by scanning electron microscopy and energy dispersive X-ray techniques. Finally, the experimental and theoretical results are in good agreement.

Electrochemical and quantum chemical studies on the corrosion inhibition of 1037 carbon steel by different types of surfactants.

In this work, three different types of surfactants, namely, dodecyl trimethyl ammonium chloride (DTAC, C12H25N (CH3)3Cl)-, octyl phenol poly(ethylene glycol ether) x (TX-100, C34H62O11 for x = 10) and dioctyl sodium sulfosuccinate (AOT-100, C20H37O7NaS) with corrosion restraint were utilized as corrosion inhibitors for 1037 CS in 0.5 M HCl. The protection efficacy (% IE) was indicated by weight loss and electrochemical measurements. Polarization curves showed that the investigated compounds are mixed-type inhibitors. The protection efficacy (% IE) increases with the increase in the surfactant concentration and reached 64.42-86.46% at 8 × 10-4 M and 30 °C. Adsorption of these utilized surfactants (DTAC, TX-100, and AOT) onto the CS surface concurred with the Langmuir adsorption isotherm. Impedance data revealed that by increasing the surfactant concentration, the charge transfer resistance (R ct) increases and vice versa for the capacitance of double layer (C dl). Surface morphological investigations such as scanning electron microscopy (SEM) combined with EDX and atomic force microscopy (AFM) were used to further investigate the inhibitors' protective abilities. Monte Carlo simulations showed the great interaction between the tested surfactants and the metal surface of the CS. The theoretical results (density functional theory, DFT) were in good agreement with experimental measurements. The restraint efficiencies of anionic, neutral, and cationic surfactants regarded a certain dating to HSAB precept and Fukui indices.

Insights into the adsorption and corrosion inhibition properties of newly synthesized diazinyl derivatives for mild steel in hydrochloric acid: synthesis, electrochemical, SRB biological resistivity and quantum chemical calculations.

Two azo derivatives, 4-((4-hydroxy-3-((4-oxo-2-thioxothiazolidin-5-ylidene)methyl)phenyl) diazinyl) benzenesulfonic acid (TODB) and 4-((3-((4,4-dimethyl-2,6-dioxocyclohexylidene) methyl)-4-hydroxyphenyl)diazinyl) benzenesulfonic acid (DODB) were synthesized and characterized using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR) and mass spectral studies. Gravimetric methods, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM) techniques and inductive coupled plasma-optical emission spectroscopy were used to verify the above two compounds' ability to operate as mild steel (MS) corrosion inhibitors in 1 M HCl. Tafel data suggest that TODB and DODB have mixed-type characteristics, and EIS findings demonstrate that increasing their concentration not only alters the charge transfer (R ct) of mild steel from 6.88 Ω cm2 to 112.9 Ω cm2 but also changes the capacitance of the adsorbed double layer (C dl) from 225.36 to 348.36 µF cm-2. At 7.5 × 10-4 M concentration, the azo derivatives showed the highest corrosion inhibition of 94.9% and 93.6%. The inhibitory molecule adsorption on the metal substrate followed the Langmuir isotherm. The thermodynamic activation functions of the dissolution process were also calculated as a function of inhibitor concentration. UV-vis, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) techniques were used to confirm the adsorption phenomenon. The quantum chemical parameters, inductively coupled plasma atomic emission spectroscopy (ICPE) measurements, and the anti-bacterial effect of these new derivatives against sulfate-reducing bacteria (SRB) were also investigated. Taken together, the acquired results demonstrate that these compounds can create an appropriate preventing surface and regulate the corrosion rate.

Experimental and computational chemical studies on the corrosion inhibitive properties of carbonitrile compounds for carbon steel in aqueous solutions.

The present work aims to study 6-amino-4-aryl-2-oxo-1-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile derivatives namely: 6-Amino-2-oxo-1,4-diphenyl-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-H), 6-Amino-2-oxo-1-phenyl-4-(p-tolyl)-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-Me) and 6-Amino-4-(4-hydroxyphenyl)-2-oxo-1-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-OH) as corrosion inhibitors to provide protection for carbon steel in a molar hydrochloric acid medium. Chemical measurements such as (weight loss) and electrochemical techniques such as (Potentiodynamic polarization, electrochemical impedance spectroscopy, and Electron frequency modulation) were applied to characterize the inhibitory properties of the synthesized derivatives. The adsorption of these derivatives on the carbon steel surface was confirmed by Attenuated Total Refraction Infrared (ATR-IR), Atomic Force Microscope (AFM), and X-ray Photoelectron Spectroscopy (XPS). Our findings revealed that the tested derivatives have corrosion inhibition power, which increased significantly from 75.7 to 91.67% on the addition of KI (PdC-OH:KI = 1:1) to inhibited test solution with PdC-OH derivative at 25 °C. The adsorption process on the metal surface follows the Langmuir adsorption model. XPS analysis showed that the inhibitor layer consists of an iron oxide/hydroxide mixture in which the inhibitor molecules are incorporated. Computational chemical theories such as DFT calculations and Mont Carlo simulation have been performed to correlate the molecular properties of the investigated inhibitors with experimental efficiency. The theoretical speculation by Dmol3 corroborates with the results from the experimental findings.

Chemical, electrochemical and surface studies of new metal-organic frameworks (MOF) as corrosion inhibitors for carbon steel in sulfuric acid environment.

The effects of [Co2 (SCN) 4(hmt)2(H2O)6. H2O] (SC1) and [Co (CN)6 (Me3Sn)3(H2O). (qox)] (SCP2) MOF as corrosion inhibitors on C-steel in 0.5 M sulfuric acid solutions are illustrated utilizing mass reduction (MR), electrochemical [potentiodynamic polarization (PP), and AC electrochemical impedance (EIS)]. The experiments revealed that as the dose of these compounds rose, the inhibition efficacy (IE percent) of C-steel corrosion improved, reaching 80.7-93.1% at dose 25 × 10-6 M for SC1 and SCP2, respectively. IE percent, on the other hand, dropped as the temperature range grew. SC1was adsorbed physically and chemically (mixed adsorption) but SCP2 was adsorbed physically on the surface of C-steel and conformed to the Langmuir adsorption isotherm equation. The PP studies revealed that these compounds act as mixed kind inhibitors. To establish the morphology of the inhibited C-steel surface, scanning electron microscopy (SEM), energy transmitted X-ray (EDX), and atomic force microscopy (AFM) studies were used. All tested experiments were in good agreement.

Experimental and surface morphological studies of corrosion inhibition on carbon steel in HCl solution using some new hydrazide derivatives.

The corrosion inhibition of C-steel in 1 M HCl was assessed using three newly synthesized hydrazide derivatives (H1, H2 and H3) using weight loss (WL), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques. Also, the adsorption of these compounds was confirmed using several techniques such as atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). High inhibition efficiencies were obtained resulting from the constitution of the protective layer on the C-steel surface, which increased with increasing concentration and temperature and reached 91.7 to 96.5% as obtained from the chemical method at 20 × 10-6 M at 45 °C. The polarization curves refer to these derivatives belonging to mixed-type inhibitors. The adsorption of (H1, H2 and H3)on the CS surface follows the Temkin adsorption isotherm. Inhibition influence of hydrazide derivatives at the molecular level was greatly proven using quantum chemical calculations and Monte Carlo simulation methods. Furthermore, the molecular simulation results evidenced the adsorption of these derivatives on the carbon steel surface.

Effectiveness of some novel heterocyclic compounds as corrosion inhibitors for carbon steel in 1 M HCl using practical and theoretical methods.

Corrosion of carbon steel is a major problem that destroys assists of industries and world steel installations; the importance of this work is to introduce new heterocyclic compounds as effective and low-cost corrosion inhibitors. Three compounds of carbohydrazide derivatives, namely: 5-amino-N'-((2-methoxynaphthalen-1-yl)methylene)isoxazole-4-carbohydrazide (H4), 2,4-diamino-N'-((2-methoxy-naphthalene-1-yl)methylene) pyrimidine-5-carbohydrazide (H5) and N'-((2-methoxynaphthalen-1-yl)methylene)-7,7-dimethyl-2,5-dioxo-4a,5,6,7,8,8a-hexahydro-2H-chromene-3-carbohydrazide (H6) were used to examine the efficacy of corrosion of carbon steel in 1 M hydrochloric acid solution. This corrosion efficacy was detected by utilizing various methods including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), weight loss measurements (WL), surface morphology analyses by atomic force microscopy (AFM), quantum chemical computations based on density functional theory (DFT) and molecular dynamics (MD) simulation. The results indicated that these compounds act as mixed type inhibitors i.e. reduce the corrosion rate of carbon steel due to the formation of a stable protective film on the metal surface and reduce the cathodic hydrogen evolution reaction. As confirmed from impedance, carbohydrazide derivatives molecules are adsorbed physically on metal surface with higher corrosion efficacy reached to (81.5-95.2%) at 20 × 10-6 M concentration at room temperature. Temkin isotherm model is the most acceptable one to describe the carbohydrazide derivative molecules adsorption on the surface of carbon steel. Protection mechanism was supported by quantum chemical analyses and Monte Carlo modeling techniques. The theoretical calculations support the experimental results obtained. This proves the use of carbohydrazide derivatives as a very effective inhibitors against the corrosion of carbon steel in acidic media.