Adsorption and inhibition properties of Tephrosia Purpurea as corrosion inhibitor for mild steel in sulphuric acid solution

Abstract

The present study investigated the adsorption and inhibition behavior of leaf extract of Tephrosia Purpurea (T. purpurea) on mild steel corrosion in 1?N H₂SO₄ solution using electrochemical and surface morphological methods. Techniques adopted for electrochemical studies were Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS) technique; and surface morphological studies were carried out using Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). The leaf extract of T. purpurea was characterized using UV-Visible spectroscopy (UV-Vis), Fourier-Transform Infrared Spectroscopy (FT-IR), Nuclear Magnetic Resonance Spectroscopy (NMR) and Gas Chromatography – Mass Spectrometry (GCMS). The results obtained from electrochemical studies exhibited the potential of T. purpurea as good corrosion inhibitor. And, it was found that, the inhibition efficiency (I.E in %) increases with increase in concentration of the inhibitor molecules, the optimum inhibitor concentration observed was 300?ppm and the inhibition efficiency of 93% was observed at this inhibitor concentration. Above 300?ppm, there was not much changes in inhibition efficiency. Polarization studies provided the information that the inhibition is of mixed type and EIS confirmed that the corrosion process is controlled by single charge transfer mechanism. And, it was obtained that, the adsorption of inhibitor molecules obeys Langmuir adsorption isotherm. The inhibition is mainly by the adsorption of inhibitor molecules on the mild steel electrode surface, which was confirmed by FT-IR, SEM and AFM studies. Through all the experimental results, it can be arrived that, the leaf extract of T. purpurea performed as a good corrosion inhibitor for mild steel in 1?N sulfuric acid medium.     

Inhibitive,adsorption and synergistic studies on ethanol extract of Gnetum Africana as green corrosion inhibitor for mild steel in H2SO4

Abstract

The inhibitive and adsorptive characteristics of ethanol extract of Gnetum Africana for the corrosion of mild steel in H₂SO₄ solutions have been studied using weight loss, gasometric, thermometric, and IR methods of monitoring corrosion. Ethanol extract of Gnetum Africana is a good adsorption inhibitor for the corrosion of mild steel in H₂SO₄. The inhibitive property of the extract is attributed to the presence of alkaloid, saponin, tannin, terpene, anthraquinone, cardiac glycoside, and alkaloid in the extract. The adsorption of the inhibitor on mild steel surface is exothermic, spontaneous and is consistent with the mechanism of physical adsorption. In addition, Langmuir and Temkin adsorption isotherms best described the adsorption characteristics of the inhibitor. Efforts to improve the adsorption of the inhibitor through synergistic combinations with halides indicated that only KCl may enhance the efficiency of the inhibitor. The study provides information on the use of ethanol extract of Gnetum Africana as a corrosion inhibitor for mild steel.     

Inhibition Effect of N-(Pyridin-2-yl-Carbamothioyl) Benzamide on the Corrosion of C-Steel in Sulfuric Acid Solutions

N-(Pyridin-2-yl-carbamothioyl)benzamide (PCMB) was newly synthesized and tested as a corrosion inhibitor for C-steel in 0.5 M H₂SO₄ using chemical and electrochemical techniques. Polarization measurements showed that the synthesized compound acted as a mixed inhibitor. The inhibition efficiencies obtained from the different methods were in good agreement. The inhibitive action of this compound is discussed in terms of blocking the electrode surface by adsorption of the inhibitor according to the Langmuir isotherm. The effect of temperature on the corrosion behavior in the absence and presence of 2.5 × 10^?5 M of PCMB was studied (283–308 K). The associated activation energies (E _a) and the thermodynamic parameters (ΔH*, ΔS*, K _ads, ΔG°_ads) for the adsorption process were determined. The ΔG°_ads value is ?36.55 kJ/mol, which indicated that the adsorption mechanism of PCMB on C-steel in 0.5 M H₂SO₄ solution was combined between physisorption and chemisorption processes.     

Effect of the alkyl chain of quaternary ammonium cationic surfactants on corrosion inhibition in hydrochloric acid solution

In this study, the effect of the alkyl chain of quaternary ammonium cationic surfactants on corrosion inhibition in hydrochloric acid (HCl) solution was investigated by using dodecyl trimethyl ammonium chloride (DTAC), tetradecyl trimethyl ammonium chloride (TTAC), cetyl trimethyl ammonium chloride (CTAC), and octadecyl trimethyl ammonium chloride (OTAC) as corrosion inhibitors to uncover their structure–efficiency relationships. The effect of the alkyl chain of quaternary ammonium cationic surfactants on corrosion inhibition in HCl solution was studied under different conditions, such as corrosion inhibitor concentration, temperature, and acidity, and this was done using the weightlessness method. The results obtained show that these inhibitors have high corrosion inhibition effect on A₃ steel, and the corrosion inhibition efficiency is dependent on the length of the alkyl chain. At the same concentration, the longer the alkyl chain, the weaker the corrosion inhibition effect. When the temperature was 50 °C and the concentration of corrosion inhibitor was 70 mg/L, the corrosion inhibition efficiency order of the four cationic surfactants was DTAC > TTAC > CTAC > OTAC. Besides, the experimental results obtained show that the adsorption of the inhibitor on the A₃ steel surface conforms to the Langmuir type isotherm, and then the corresponding adsorption thermodynamic parameters were obtained according to these parameters. It was observed that ΔH, ΔS, and E_a increased with increase in the length of the alkyl chain. The adsorption of the inhibitor on the steel surface is an exothermic, spontaneous, entropy process.     

Green approach to corrosion inhibition of mild steel in hydrochloric acid medium using extract of spirogyra algae

In the present investigation, a fresh water green algae spirogyra is used as an inexpensive and efficient mild steel corrosion inhibitor. The study is carried out in 0.5?M HCl solution using weight loss measurements, scanning electron microscopy–energy-dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transforms infrared (FT-IR) techniques. The maximum inhibition efficiency was found to be 93.03% at 2?g?L^?1. The adsorption of extract of spirogyra on mild steel surface obeys the Langmuir adsorption isotherm. Corrosion inhibition mechanisms were inferred from the temperature dependence of the inhibition efficiency as well as from calculation of thermodynamic and kinetic parameters which direct the process. FT-IR analysis of green algae spirogyra revealed the presence of hydroxyl, amino, and carbonyl groups, which are responsible for the adsorption on the mild steel surface. SEM analysis supported the inhibitive action of the spirogyra extract against the mild steel corrosion in acid solution.     

Corrosion inhibition and adsorption properties of Azadirachta indica mature leaves extract as green inhibitor for mild steel in HNO3

Abstract

The corrosion inhibition and adsorption properties of Neem (Azadirachta indica – AZI) mature leaves extract as a green inhibitor of mild steel (MS) corrosion in nitric acid (HNO₃) solutions have been studied using a gravimetric technique for experiments conducted at 30 and 60°C. The results disclose that the different concentrations of the AZI extract inhibit MS corrosion and that inhibition efficiency of the extract varies with concentration and temperature. For extract concentrations studied and ranging from 9.09 to 28.57 mg/L, the maximum inhibition efficiency was 80.5 and 80.07% both at 28.57 mg/L AZI at 30 and 60°C, respectively, in 2.0 N HNO₃. The adsorption of the inhibitor on the MS surface was exothermic and consistent with the physical adsorption mechanism, best described by the Frumkin adsorption isotherm.     

Applicability of winged bean extracts as organic corrosion inhibitors for reinforced steel in 0.5 ​M HCl electrolyte

Corrosion inhibition properties of winged bean (WB) extracts on reinforced steel in 0.5 ?M HCl solution was studied through experimental and theoretical calculation methods. The electrochemical studies suggested that inhibition efficiency increased with increasing concentration of WB extracts up to 95%. Nyquist diagrams revealed an increase in the charge transfer resistance values and a decrease in the constant phase element as the concentration of WB extracts were increased. The potentiodynamic polarization results revealed that WB extracts behave as mixed-type inhibitors, which physically adsorbed onto the reinforced steel surface. Effect of temperature study demonstrated that the corrosion resistance behaviour of WB extracts decreased with an increase in temperature, yielding a corrosion rate of 3.39 mmpy and 4.02 mmpy at 333 ?K with the incorporation of 1000 ?ppm WBW and WBE extracts, respectively. The thermodynamic study implied that the adsorption process follows the Langmuir isotherm with free energy adsorption of ΔG_ads WBW ?= ?-17.29 ?kJ ?mol^-1 and ΔG_ads WBE ?= ?-16.81 ?kJ ?mol^-1. Corresponding to the molecular modelling study, the semi-empirical method and molecular dynamics (MD) simulation investigated the correlation between the inhibitor compounds and the metal surface. One of the phenolic molecule constituents (gallic acid) was chosen to establish the structural and electronic parameters responsible for the high inhibition efficiency. A greater E_binding of 0.181 (a.u.) indicates that gallic acid in WB extracts can easily bind with the Fe surface, thus projecting a higher inhibitory performance. Surface morphology study affirmed the effective adsorption of WB extracts onto the surface of reinforced steel.     

The litchi (Litchi Chinensis) peels extract as a potential green inhibitor in prevention of corrosion of mild steel in 0.5 M H2SO4 solution

The corrosion inhibition of mild steel in 0.5 M H₂SO₄ solution by the extract of litchi peel (Litchi chinensis) was studied by weight loss method, potentiodynamics polarization and electrochemical impedance spectroscopy (EIS). The results show that the litchi peels extract acts as mixed-type inhibitor. The inhibition of corrosion is found to be due to adsorption of the extract on metal surface, which is in conformity with Langmuir’s adsorption isotherm. UV–Vis, Fourier transform infrared (FT-IR) spectroscopy and Scanning electron microscopy (SEM) studies confirm that the inhibition of corrosion of mild steel occurs through adsorption of the inhibitor molecules.     

Monte Carlo simulation and electrochemical performance corrosion inhibition whid benzimidazole derivative for XC48 steel in 0.5 M H2SO4 and 1.0 M HCl solutions

The inhibition of 1-(4-methoxybenzyl)-2-(4-methoxyphenyl)-1H-benzimidazole (MMB) on corrosion of XC48 steel in solutions 1.0 M HCl and 0.5 M H₂SO₄ were studied by potentiodynamic polarization and electrochemical impedance spectroscopy techniques (EIS). Potentiodynmic polarization curves revealed that MMB acts as a mixed-type inhibitor in both acidic media. The impedance results indicated that the corrosion process occurs under activation control. Furthermore, MMB shows a higher inhibition efficiency in HCl (97%) than in H₂SO₄ (92%) at 10^?4 M MMB. The values of ΔG°_ads, ΔH_a, E_a and ΔS_a in temperature range 293–323 K indicated that MMB strongly retarded the corrosion of XC48 steel in both solutions by a chemisorptions process. The adsorption of Benzimidazole (MMB) on carbon steel surface followed Langmuir adsorption isotherm. Scanning electron microscopy (SEM) analysis confirmed that there is an adsorbed film on the surface of XC48 steel. The results of Monte Carlo simulations studies confirmed the inhibition action of MMB.     

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.     

Aqueous extract of Acacia cyanophylla leaves as environmentally friendly inhibitor for mild steel corrosion in 1 M H2SO4 solution

The efficiency of Acacia cyanophylla leaves extract as an environmentally friendly inhibitor for mild steel in aerated aqueous 1 M H₂SO₄ solution has been investigated by potentiodynamic polarization measurements and electrochemical impedance spectroscopy techniques. Addition of inhibitor decreases the corrosion current whereas the corrosion potential values show slight shifts in positive directions. Inhibition efficiency was found to be about 93% (the maximum value was determined from the polarization curve). Efficiencies obtained from both electrochemical techniques are in good agreement. Adsorption of Acacia cyanophylla leaves extract on mild steel surface in 1 M H₂SO₄ solution obeys Langmuir adsorption isotherm. Polarization curves were also obtained at different temperatures in order to measure changes of corrosion rate. Corrosion current increases and inhibition efficiency decreases with temperature increasing in H₂SO₄ solutions with and without Acacia cyanophylla extract. Corrosion parameters also changed with exposure time. Copyright © 2010 John Wiley & Sons, Ltd.     

Inhibition of aluminium and mild steel corrosion in acidic medium using Gum Arabic

The corrosion behaviour of mild steel and aluminium exposed to H₂SO₄ solution and their inhibition in H₂SO₄ containing 0.1–0.5 g/L Gum Arabic (GA) used as inhibitor was studied at temperature range of 30–60 °C using weight loss and thermometric techniques. Corrosion rate increased both in the absence and presence of inhibitor with increase in temperature. Corrosion rate was also found to decrease in the presence of inhibitor compared to the free acid solution. Inhibition efficiency increases with increase in concentration of the inhibitor reaching a maximum of 37.88% at 60 °C for mild steel and 79.69% at 30 °C for aluminium at 0.5 g/L concentration of GA. The inhibitor, GA was found to obey Temkin and El-Awady et al. thermodynamic kinetic adsorption isotherm for mild steel and aluminium respectively from the fit of the experimental data at all concentrations and temperatures studied. The phenomenon of chemical adsorption is proposed for mild steel corrosion, while physical adsorption mechanism is proposed for aluminium corrosion. Results obtained for the kinetic/thermodynamic studies indicate that the adsorption of GA onto the metals surface was spontaneous. GA is a better corrosion inhibitor for aluminium than for mild steel.     

Some natural aqueous extracts of plants as green inhibitor for carbon steel corrosion in 0.5 M sulfuric acid

The inhibiting impact of natural aqueous extracts of some plants such as curcumin, parsley and cassia bark extracts for the corrosion of carbon steel (C-steel) in 0.5 M H₂SO₄ solution was inspected utilizing some techniques such as galvanostatic and potentiodynamic anodic polarization and weight loss measurements. Outcomes indicated that the percentage inhibition efficiency increases with increasing the concentration of the extract due to its horizontal adsorption on the C-steel surface. The process of adsorption is followed by the Temkin isotherm. These natural extracts acted as pitting corrosion inhibitors by shifting the pitting potential to more noble values. The sequence of inhibition efficiency of the natural extracts decreases in the following order: cassia bark extract > parsley extract > curcumin extract. This arrangement is related to the molecular size of the major components of the three natural extracts used.     

Corrosion inhibition of mild steel by highly stable polydentate schiff base derived from 1,3- propanediamine in aqueous acidic solution

Recently, the hydrolysis of Schiff bases under experimental conditions gives suspicion for their corrosion inhibition performance. The current study employs a stable Schiff base namely, 2,2′-{propane-1,3-diylbis[azanylylidene (E) methanylylidene]}bis(6-methoxyphenol) (LPD) as corrosion inhibitor for mild steel (MS) in 1 M HCl solution. The presence of the characteristic peak of the imine group in UV-visible spectra was taken as an indicator for LPD stability in acidic media. The inhibition action was examined using electrochemical techniques including potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) besides gravimetric measurement. The inhibition efficiency reached 95.93 % for 0.75 mM LPD after 24 h of immersion at 25 °C. This high efficiency is owing to the presence of the characteristic imine group and other heteroatoms and π- electrons of the aromatic benzene rings. The mechanism of inhibition depends on adsorption phenomena on mild steel surface which obeys Langmuir isotherm model. The calculated values of adsorption equilibrium constant (K_ads), adsorption free energy ΔG_ads, adsorption enthalpy ΔH_ads and adsorption entropy ΔS_ads indicated spontaneous exothermic adsorption process of both physical and chemical nature. By rising temperature, the inhibition efficiency of LPD was decreased. The calculated activation energy was increased as the concentration of LPD increased. LPD was considered as a mixed-type inhibitor as indicated from PDP measurements. The obtained surface morphology and composition analysis using SEM/EDS, AFM and FTIR techniques ensures the high efficiency of LPD as corrosion inhibitor.     

Inhibitive action of ethanol extracts from Nauclea latifolia on the corrosion of mild steel in H2SO4 solutions and their adsorption characteristics

The inhibitive action of ethanol extracts from leaves (LV), bark (BK) and roots (RT) of Nauclea latifolia on mild steel corrosion in H₂SO₄ solutions at 30–60 °C was studied using weight loss and gasometric techniques. The extracts were found to inhibit the corrosion of mild steel in H₂SO₄ solutions and the inhibition efficiencies of the extracts follow the trend: RT > LV > BK. The inhibition efficiency increased with the extracts concentration but decreased with temperature rise. Physical adsorption of the phytochemical components of the plant on the metal surface is proposed as the mechanism of inhibition. The adsorption characteristics of the inhibitor were approximated by the thermodynamic-kinetic model of El-Awady et al.     

向日葵盘果胶对碳钢的缓蚀性能研究

以向日葵盘为原料,利用纤维素酶制备果胶(SFP)。采用静态失重、极化曲线和交流阻抗技术研究SFP在1mol/L HCl及0.5mol/L H_2SO_4溶液中对碳钢的缓蚀性能,并探讨其在碳钢表面的吸附机理。结果表明,缓蚀效率随SFP浓度增大而增大,随温度升高而降低。在HCl和H_2SO_4溶液中,SFP的吸附方式分别服从Langmuir和Temkin等温式,属于物理吸附;极化曲线测试显示SFP是一种混合型缓蚀剂。本文的研究表明,向日葵盘果胶是碳钢的绿色高效缓蚀剂,且在HCl溶液中的缓蚀性能优于在H_2SO_4溶液中。     

Ficus carica extract as environmentally friendly inhibitor for the corrosion of L-80 carbon steel in 0.5 ​M ​H2SO4 media

We reported here, the corrosion inhibition of carbon steel (CS) in H₂SO₄ media by Ficus carica leaves extract as green sustainable inhibitor. This study was investigated using mass loss method (ML), potentiodynamic polarization (PDP), electrochemical frequency modulation (EFM) and electrochemical impedance spectroscopy (EIS). As well as the metal surface morphology was analyzed by Atomic Force Microscopy (AFM). In addition, the chemical characterization of green inhibitor is carried out by Fourier Transform Infrared (FTIR). EIS revealed that the Ficus carica extract formed a thin protective film on the metal surface and by using of 300 ​ppm of extract of Ficus carica allow reaches (92.7%) of corrosion inhibition efficiency (CIE). The PDP curves revealed that the Ficus carica extract act as a mixed-type inhibitor. It was demonstrated that %IE enhanced with rising the Ficus carica extract doses also increased with arises in temperature (95.7%). Kinetic parameters and thermodynamic adsorption of the system have also been measured and studied. The data obtained revealed that the adsorption of Ficus carica on metal surface followed the Temkin isotherm and according to the activation energy (Ea1) the Ficus carica extract acts by chemisorption process. The results from unlike measurements were in a well accord.     

Electroanalytical studies of the corrosion-protection properties of 4-amino-4H-1,2,4-triazole-3,5-dimethanol (ATD) on mild steel in 0.5?N sulfuric acid

Inhibition of the corrosion of mild steel in aerated 0.5?N H₂SO₄ solution by 4-amino-4H-1,2,4-triazole-3,5-dimethanol (ATD) was investigated by use of potentiodynamic polarization (Tafel), electrochemical impedance spectroscopy, adsorption, and surface morphological studies. The effects on the rate of corrosion of inhibitor concentration, temperature, extent of surface coverage, adsorption kinetics, and surface morphology were investigated. Inhibition efficiency increased markedly with increasing ATD concentration and decreased slightly with increasing temperature. The presence of ATD reduced the capacitance of the double layer and increased the charge-transfer resistance. Values of the activation energy (E _a) and of the thermodynamic data adsorption equilibrium constant (K _ads) and free energy of adsorption (??G _ads) were computed from the temperature dependence of the corrosion current. The inhibitor molecule first became adsorbed on the mild steel surface, obeying the Langmuir adsorption isotherm, and substantially reduced the rate of corrosion. Results of electroanalytical studies revealed that ATD acts as a mixed-type inhibitor.     

蛋氨酸衍生物的合成及其缓蚀性能研究

本文合成了一种新型蛋氨酸衍生物酸洗缓蚀剂,运用红外光谱及核磁共振氢谱对其结构进行了鉴定。采用失重法和电化学法研究了在0. 5mol·L~(-1)硫酸介质中其对碳钢试片的缓蚀性能,并通过吸附等温模型对缓蚀机理进行初步的探讨。结果表明,蛋氨酸衍生物的缓蚀效率约为90%,整体用量适中,是一种有望得到良好应用的绿色缓蚀剂。电化学分析表明,蛋氨酸衍生物为混合型缓蚀剂,其通过增大金属表面的电荷转移电阻而降低电化学腐蚀速率。     

Berberine isolated from Mahonia nepalensis as an eco-friendly and thermally stable corrosion inhibitor for mild steel in acid medium

BackgroundThe environmental and economic benefits have been the driving force in search of efficient corrosion inhibitors for iron/steel used in industrial acidic medium. This study reports on berberine isolated from methanol extract of high-altitude (1347 m) shrub Mahonia nepalensis as a highly efficient and thermally stable corrosion inhibitor for mild steel (MS) in 1.0 M H₂SO₄ simulating acid pickling condition.MethodsThe weight-loss and electrochemical methods revealed the fast adsorption of berberine.Significant Findings: It achieved above 91% inhibition efficiency (IE) in 0.25 h and reached 94% in 6 h for 1000 ppm berberine. The IE increased with concentration and temperature, giving an IE of 97.2% at 328 K, which makes it a promising candidate for industrial application. It behaved as a mixed type of inhibitor as revealed by open circuit potential and polarization curves. The results indicated suppression of the corrosion by effectively forming an adsorbed berberine layer on the MS surface. Adsorption of the berberine followed a Langmuir adsorption isotherm. The thermodynamic parameters such as activation energy (43.19 kJ/mol), free energy (−35.05 kJ/mol), enthalpy (40.55 kJ/mol), and entropy (−97.83 J/molK) of adsorption supported both physical and chemical interactions of berberine with MS surface. The obtained results also revealed that the adsorption process was endothermic and spontaneous in nature.