Inhibition effect of environmentally benign Karanj (Pongamia pinnata) seed extract on corrosion of mild steel in hydrochloric acid solution

The inhibition of the corrosion of mild steel in hydrochloric acid solution by the seed extract of Karanj (Pongamia pinnata) has been studied using weight loss, electrochemical impedance spectroscopy, potentiodynamic polarization, and linear polarization techniques. Inhibition was found to increase with increasing concentration of the extract. The effect of temperature, immersion time, and acid concentration on the corrosion behavior of mild steel in 1 M HCl with addition of extract was also studied. The adsorption of the extract on the mild steel surface obeyed the Langmuir adsorption isotherm. Values of inhibition efficiency calculated from weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy are in good agreement. Polarization curves showed that Karanj (P. pinnata) seed extract behaves as a mixed-type inhibitor in hydrochloric acid. The activation energy as well as other thermodynamic parameters for the inhibition process was calculated. The adsorbed film on mild steel surface containing Karanj (P. pinnata) seed extract inhibitor was also measured by Fourier transform infrared spectroscopy. The results obtained showed that the seed extract of Karanj (P. pinnata) could serve as an effective inhibitor of the corrosion of mild steel in hydrochloric acid media.     

甲基丙烯酸二甲氨基乙酯类离子液体 对Q235钢的缓蚀性能

以甲基丙烯酸二甲氨基乙酯为母体、 对氯甲基苯乙烯为季铵化试剂, 合成了一种具有疏水结构的甲基丙烯酸二甲氨基乙酯型离子液体(DEMA). 通过失重实验、 电化学分析、 原子力显微镜(AFM)、 接触角测试和量子化学计算等研究了DEMA在1 mol/L盐酸中对Q235钢的缓蚀性能, 并揭示了其在Q235钢表面的吸附行为和吸附机理. 失重实验结果表明, DEMA在盐酸中对Q235钢具有优异的缓蚀效果, 且在较高温度(60 ℃)下也能保持高效吸附; 电化学实验结果与失重测试结果一致; 接触角测试结果表明, DEMA可明显增强Q235钢表面的疏水性; 分析热力学参数可知, DEMA在Q235钢表面的吸附为自发、 放热过程, 符合Langmuir等温式, 且以化学吸附为主; 量子化学计算结果证实DEMA的结构中包含大量吸附活性位点.     

Adsorption Activity and Molecular Dynamics Study on Anti-corrosion Mechanism of Q235 Steel

The correlation between inhibition efficiency and molecular structures of the inhibitor during hydrochloric acid corrosion of Q235 steel was studied by quantum chemical calculations and molecular dynamics(MD) simulation. The proton affinity(PA) calculations demonstrated that 2-(quinolin-2-yl)quinazolin-4(3H)-one inhibitor has the tendency to be protonated in hydrochloric acid, which was in good agreement with experimental observations. Besides, quantum chemical parameters revealed that the protonated corrosion inhibitor molecules were more easily adsorbed on Q235 steel surface and improved the corrosion resistance of steel. MD simulations were implemented to search for the adsorption behavior of this molecule on Fe (110) surface, which might be used as a convenient tool for estimating the interaction mechanism between inhibitor and iron surface.     

Inhibition of CTAB on the Corrosion of Mild Steel in Hydrochloric Acid

The inhibition effect of cetyl trimethyl ammonium bromide (CTAB) on the corrosion of mild steel in 1.0 mol L^?1 hydrochloric acid (HCl) has been studied at different temperatures (25–60°C) by weight loss and potentiodynamic polarization methods. The results reveal that CTAB behaves as an effective inhibitor in 1.0 mol L^?1 HCl, and the inhibition efficiency increases with the inhibitor concentration. Polarization curves show that CTAB is a mixed-type inhibitor in hydrochloric acid. The results obtained from weight loss and polarizations are in good agreement. The effect of immersion time on corrosion inhibition has also been examined and is discussed. The adsorption of inhibitor on mild steel surface obeys the Langmuir adsorption isotherm equation. Thermodynamic parameters have been obtained by adsorption theory. The inhibition effect is satisfactorily explained by the parameters.     

Preparation of poly(naphthylamine-formaldehyde); Application as a new and an effective inhibitor of steel in hydrochloride acid solution

In this research, we first prepared poly (naphthylamine-formaldehyde) (PNAF) and then investigated its corrosion inhibition properties for polished steel specimens in 1 M HCl solution using chemical and electrochemical methods. Results showed that the PNAF could serve as an effective inhibitor of the corrosion of steel in hydrochloric acid media (the inhibition efficiency of this polymer at an optimum concentration of 100 mg L^–1 was 99.9 %). The effect of temperatures on the corrosion behavior of steel was studied in the temperature ranging from 303 to 333 K for 1 M HCl at an optimum concentration of PNAF. It has been demonstrated that the adsorption behavior of this polymer on steel in 1 M HCl was found to obey Langmuir adsorption isotherm. Also, potentiodynamic polarization measurements showed that PNAF was a mixed type inhibitor.     

Interactions and corrosion mitigation prospective of pyrazole derivative on mild steel in HCl environment

The effectiveness of 1H?pyrazole?3,5?dicarboxylic acid 5?benzyl ester 3?phenyl ester (PCBPE) as a preventer for deterioration of IS 513 Gr. D steel in 1 M HCl medium is evaluated via weight loss, electrochemical impedance, and polarization techniques. Kinetic and thermodynamic parameters assessed the feasibility of the adsorption process at diverse temperatures. The inhibition action on mild steel has been enhanced with increasing PCBPE concentration. It is found from the polarization studies that PCBPE behaves as mixed type inhibitor in HCl medium. The adsorption process of PCBPE on mild steel surface from acid environment is favoured Langmuir adsorption isotherm. The shielding efficiency of PCBPE has been enhanced at elevated concentrations, and it has been diminished at amplified temperatures. The Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM), and Energy Dispersive Spectrum (EDS) were used to establish a surface characterization of metal specimens. A quantum chemical analysis of electron density distributions in the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) demonstrated how the inhibitor undergoes adsorption on mild steel in 1 M HCl. All experimental findings substantiate the corrosion mitigation performance of PCBPE on mild steel in acidic environments.     

The effect of some triazole derivatives as inhibitors for the corrosion of mild steel in 5 % hydrochloric acid

Corrosion inhibition by triazole derivatives (n-MMT) on mild steel in 5 % hydrochloric acid (HCl) solutions has been investigated by weight loss and electrochemical methods. The results obtained revealed that these compounds performed excellently as corrosion inhibitors for mild steel in HCl solution. Potentiodynamic polarization studies showed that they suppressed both the anodic and cathodic processes and inhibited the corrosion of mild steel by blocking the active site of the metal. The effect of temperature on the corrosion behavior of mild steel in 5 % HCl with the addition of different concentrations of the inhibitors was studied in the temperature range from 303 to 333 K. The associated activation corrosion and free adsorption energies were determined. The adsorption of these compounds on the mild steel surface obeys the Langmuir adsorption isotherm. The effect of molecular structure on the inhibition efficiency has been investigated by quantum chemical calculations. The electronic properties of inhibitors were calculated and are discussed.     

Xanthione: A new and effective corrosion inhibitor for mild steel in sulphuric acid solution

The adsorption and inhibition effect of xanthione (XION) on mild steel in 0.5 M H₂SO₄ at 303–333 K were studied using gravimetric and UV–visible spectrophotometric methods. The results obtained show that XION acts as an effective corrosion inhibitor for mild steel in sulphuric acid and inhibition efficiency reaches 98.0% at a very low inhibitor concentration of 10 μM. Inhibition efficiency was found to increase with increase in XION concentration but decreased with temperature suggesting physical adsorption mechanism. Arrhenius law and its transition equation lead to estimate the activation parameters of the corrosion process. XION inhibits the corrosion of mild steel effectively at moderate temperature and adsorbs according to the Langmuir isotherm. Thermodynamic parameters governing the adsorption process have been calculated and discussed. The UV–visible absorption spectra of the solution containing the inhibitor after the immersion of mild steel specimen indicate the formation of a XEN–Fe complex. Attempt to correlate the molecular structure to quantum chemical indices was made using density functional theory (DFT).     

Tetrazolo[1,5‐a]quinoline‐4‐carbaldehyde and its Schiff base on mild steel as corrosion inhibitor in 1 M HCl solution: electrochemistry,theoretical and SEM surface analysis

The corrosion inhibition impact of two quinoline derivatives, viz tetrazolo [1,5‐a] quinoline‐4‐carbaldehyde ( TQC ) and (Z) ?5‐methyl‐N‐(tetrazolo [1,5‐a] quinolin‐4‐ylmethylene) thiazol‐2‐amine ( MTQT ), has been examined against mild steel in 1 M HCl solution using conventional weight loss, potentiodynamic polarization, linear polarization, electrochemical impedance spectroscopy, quantum chemical, and scanning electron microscopic studies. The experimental results have showed that TQC and MTQT revealed a good corrosion inhibition and that the inhibition efficiency increases with the increase of concentration of inhibitor to attain 94.54% for TQC and 99.25% for MTQT at 25 ppm. Polarization measurements suggest that TQC and MTQT act as a mixed‐type inhibitor. A synergism between inhibitors can be observed by polarization measurements. Electrochemical impedance spectroscopy measurements show an increase of the transfer resistance with the inhibitor concentration. Adsorption of TQC and MTQT on the mild steel surfaces in 1 N HCl solution follows the Langmuir adsorption isotherm model. Furthermore, quantum chemical calculations have been conducted using B3LYP functional and 6‐31G(d,p) basis set to complement the experimental evidences. Copyright © 2015 John Wiley & Sons, Ltd.     

Hydroclathrus clathratus marine alga as a green inhibitor of acid corrosion of mild steel

The corrosion inhibitive and adsorption behaviors of Hydroclathrus clathratus on mild steel in 1 M HCl and 1 M H₂SO₄ solutions at 303, 313 and 323 K were investigated by weight loss, electrochemical, and surface analysis techniques. The results show that H. clathratus acts as an inhibitor of corrosion of mild steel in acid media. The inhibition efficiency was found to increase with increase in inhibitor concentration but to decrease with rise in temperature, suggestive of physical adsorption. The adsorption of the inhibitor onto the mild steel surface was found to follow the Temkin adsorption isotherm. The inhibition mechanism was further corroborated by the results obtained from electrochemical methods. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses supported the inhibitive action of the alga against acid corrosion of mild steel.     

An experimental and theoretical investigation on adsorption properties of some diphenolic Schiff bases as corrosion inhibitors at acidic solution/mild steel interface

The effect of novel synthesized three Schiff bases, namely, 1,3-bis[2-(2-hydroxy benzylidenamino) phenoxy] propane (P1), 1,3-bis[2-(5-chloro-2-hydroxybenzylidenamino) phenoxy] propane (P2), and 1,3-bis[2-(5-bromo-2-hydroxybenzylidenamino) phenoxy] propane (P3), on the corrosion of mild steel in 0.1 M HCl was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy methods. Polarization measurements suggest that P1 acts as mixed type inhibitor while P2 and P3 behave as mainly cathodic inhibitors for acidic corrosion of steel. All electrochemical measurements show that inhibition efficiencies increase with increase in inhibitor concentration. This reveals that inhibitive actions of inhibitors were mainly due to adsorption on steel surface. Adsorption of these inhibitors follows Temkin adsorption isotherm. The correlation between the adsorption ability of inhibitors and their molecular structures has been investigated using quantum chemical parameters obtained by MNDO semi-empirical method. Calculated quantum chemical parameters indicate that Schiff bases adsorbed on steel surface by chemical mechanism.     

New anti-corrosion inhibitor (3ar,6ar)-3a,6a-di-p-tolyltetrahydroimidazo[4,5-d]imidazole-2,5(1 h,3h)-dithione for carbon steel in 1 M HCl medium: gravimetric,electrochemical, surface and quantum chemical analyses

The inhibition of (3ar,6ar)-3a,6a-di-p-tolyltetrahydroimidazo[4,5-d]imidazole-2,5(1 h,3h)-dithione (TTHIIDT) for carbon steel was full characterized in a 1 M hydrochloride acid environment at various inhibitor concentrations and temperatures by the gravimetric, electrochemical, surface and quantum chemical analyses. The obtained results confirmed that the inhibition efficiency of TTHIIDT was over 95–97% and nearly stable in the rise of temperature and concentration; TTHIIDT was mixed type inhibitor and effectively influenced both anodic and cathodic corrosion reactions; a protective hydrophobic thin layer of this inhibitor on the carbon steel surface is more stable and non soluble in 1 M HCl medium; this inhibitor adsorbed endothermically on the carbon steel surface by the chemical and physical adsorption processes. The quantum chemical calculations supported the experimental results and showed that the inhibition efficiency is depends on the structure of inhibitor.     

Experimental and theoretical studies on the inhibition potentials of some derivatives of cyclopenta‐1,3‐diene for the corrosion of mild steel in HCl solutions

The inhibition of the corrosion of mild steel in HCl by some cyclopentadiene‐1,3‐diene derivatives, namely, 1‐(thiophen‐2‐yl)ethanone (2APT), 1‐(1H‐pyrrol‐2‐yl)ethanone (2AP), and (E)‐2‐(1‐hydrazonoethyl)‐1H‐pyrrole (2APH)), was studied experimentally using weight loss and hydrogen gas evolution measurements. The theoretical aspect was studied using the density functional theory and quantitative structure activity relation (QSAR) methods. The results obtained indicated that the studied compounds are good inhibitors for the corrosion of mild steel in HCl. The adsorption of the inhibitor on mild steel surface was found to be spontaneous, exothermic, and obeyed the Langmuir adsorption isotherm model. A good correlation was found between experimental inhibition efficiencies and some calculated quantum chemical parameters and also with the theoretical inhibition efficiencies obtained from QSAR modeling. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Inhibition of Mild Steel Corrosion in 1 M Hydrochloric Acid Using (E)-(4-(4-methoxybenzylideneamino)-4H-1,2,4-triazole-3,5-diyl) Dimethanol (MBATD)

The inhibition of mild steel corrosion in 1 M HCl by (E)-(4-(4-methoxybenzylideneamino)-4H-1, 2,4-triazole-3,5-diyl) dimethanol (MBATD) was investigated by polarization, AC impedance, thermodynamic, molecular dynamics, and quantum chemical studies. Polarization studies revealed that MBATD act as mixed type inhibitor. Adsorption followed the Langmuir mode with a negative value of free energy, which indicates a stable and spontaneous inhibition process. To understand the energy changes associated with various thermodynamic and kinetic processes, different calculations were made. The correlation between inhibitive action and molecular structure is ascertained through quantum chemical calculations. The adsorption behavior of the inhibitor molecule on mild steel surface has been theoretically computed using molecular dynamics and density functional theory.     

The effect of 2-aminoquinoline-6-carboxylic acid on the corrosion behavior of mild steel in hydrochloric acid

The inhibitive effect of 2-aminoquinoline-6-carboxylic acid (AQC) against mild steel corrosion in 1?M HCl solutions was investigated using conventional weight loss, potentiodynamic polarization, linear polarization and electrochemical impedance spectroscopy methods. The weight loss results showed that AQC is an excellent corrosion inhibitor since its efficiency increased with the concentration to attain 91.8?% at 500?mg?l^?1. Electrochemical polarization measurements revealed that AQC acted as a mixed-type inhibitor and the results of electrochemical impedance spectroscopy have shown that the change in the impedance parameters, charge transfer resistance and double layer capacitance, with the change in concentration of the inhibitor is due to the adsorption of the molecule leading to the formation of a protective layer on the surface of mild steel. The adsorption was assumed to occur on the steel surface through the active centers of the molecule. The inhibition action of AQC was discussed in view of Langmuir adsorption isotherm. Density functional theory calculations of quantum parameters were used to explain efficiency in relation with molecular structure.     

Electrochemical studies of mild steel corrosion inhibition in sulfuric acid chloride by aniline

The corrosion behavior of mild steel in dilute hydrochloric acid under the inhibiting action of various concentrations of aniline was studied using the weight loss and linear polarization resistance technique. The efficiency of the inhibitor increased with the increase in the inhibitor concentration. The results obtained reveal that aniline performed effectively as a corrosion inhibitor. The adsorption mechanism indicates mixed molecular interaction from values of Gibbs free energy. The values of the inhibition efficiency calculated from the two techniques are in reasonably good agreement. The adsorption of the inhibiting compound was found to obey Langmuir, Frumkin and Freudlich adsorption isotherms. The mechanism of inhibition was discussed in the light of the chemical structure of the inhibiting compound and their adsorption on steel surfaces in relation to the potentiodynamic parameters.     

喹啉型双子季铵盐缓蚀剂的实验及理论分析

以喹啉为母体、 1,4-对二氯苄和顺-1,4-二氯-2-丁烯为联结基, 制备了2种具有疏水结构的水溶性双喹啉季铵盐(BQA-1和BQA-2). 通过失重实验、 电化学测试、 扫描电子显微镜(SEM)及量子化学计算等手段研究了BQA-1和BQA-2对1 mol/L盐酸中Q235钢的缓蚀性能, 并讨论了其在Q235钢表面的吸附机理. 失重结果显示, BQA-1和BQA-2对盐酸中的钢片均具有良好的缓蚀效果, 30 ℃下, 当浓度为0.5 g/L时, BQA-1和BQA-2的缓蚀率均超过94.59%; 升温导致BQA-2的脱附速率比BQA-1更快. 电化学测试结果显示, BQA-1和BQA-2是以抑制阴极为主的混合型缓蚀剂. 分析热力学参数可知, BQA-1和BQA-2在钢表面的吸附为自发、 放热过程, 符合Langmuir等温式, 且以化学吸附为主. 量子化学计算结果表明, BQA-1和BQA-2的吸附活性集中在喹啉环及杂原子上, 且BQA-1和BQA-2分子得电子与Fe作用的能力要强于供电子与Fe作用的能力.     

二硫代酰胺类化合物在盐酸中对碳钢的缓蚀性能(英文)

采用失重实验,动电位极化,交流阻抗,量子化学计算和拉曼光谱等方法研究了N,N′-二异丙氧基丙基二硫代二丙酰胺(DPDA)在1 mol.L-1盐酸溶液中对碳钢的缓蚀性能.失重实验结果表明,DPDA在盐酸溶液中能够有效地抑制碳钢的腐蚀,当缓蚀剂DPDA的浓度为1×10-3 mol.L-1时,其缓蚀效率达到90.2%.极化曲线表明DPDA为混合型缓蚀剂,单一的容抗弧变化表明碳钢电极表面的腐蚀过程主要由电荷转移步骤控制.由失重实验,动电位极化和电化学交流阻抗方法得到的DPDA缓蚀效率具有较好的相关性,均表现为缓蚀效率随着DPDA浓度的增大而增加.另外,DPDA在碳钢表面的吸附符合Langmuir吸附等温式.吸附过程的吉布斯自由能(ΔG0a0d0s)为-38.65 kJ.mol-1,这说明DPDA分子在碳钢表面形成共价键而发生了自发的化学吸附.拉曼光谱表明DPDA分子有效地吸附在碳钢表面,量子化学计算结果证明DPDA分子在碳钢表面的化学吸附活性中心集中在S原子上.     

Experimental and theoretical investigations of adsorption of fexofenadine at mild steel/hydrochloric acid interface as corrosion inhibitor

The present study examines the effect of fexofenadine, an antihistamine drug, on corrosion inhibition of mild steel in molar hydrochloric acid solution using different techniques under the influence of various experimental conditions. Results revealed that fexofenadine is an effective inhibitor and percent inhibition efficiency increased with its concentration; reaching a maximum value of 97% at a concentration of 3.0 × 10⁻⁴ M. Fourier-transform infrared spectroscopy (FTIR) observations of steel surface confirmed the protective role of the studied drug. Polarization studies showed that fexofenadine is a mixed-type inhibitor. The adsorption of the inhibitor on mild steel surface obeyed the Langmuir adsorption isotherm with free energy of adsorption (∆G°_ads) of −40 kJ mol⁻¹. Energy gaps for the interactions between mild steel surface and fexofenadine molecule were found to be close to each other showing that fexofenadine has the capacity to behave as both electron donor and electron acceptor. The results obtained from the different corrosion evaluation techniques are in good agreement.