Hydrochloric Acid Environment Research Articles

Quantum chemical elucidation on corrosion inhibition efficiency of Schiff base: DFT investigations supported by weight loss and SEM techniques

AbstractThe corrosion inhibition of Schiff base, namely 2-((2-hydroxy-5-methoxybenzylidene)amino)pyridine (HMAP), for mild steel (MS) in a 1 M hydrochloric acid environment was investigated by means of weight loss and scanning electron microscopy techniques. Quantum chemical calculation based on density functional theory (DFT) was carried out on HMAP. Results illustrated that HMAP is a superior inhibitor for the corrosion of MS in 1.0M hydrochloric acid environment, and inhibition efficiency is higher than 90.0% at 0.5 g/L HMAP. Inhibition performance increases with regard to concentration increase and inhibition performance decreases when raising temperature. Adsorption of the inhibitor on the MS surface followed Langmuir adsorption isotherm and the value of the free energy of adsorption; ΔGads indicated that the adsorption of HMAP was a physisorption/chemisorption process. The DFT refers to perfect correlation with methodological inhibition performance.

Green corrosion inhibition and adsorption characteristics of Luffa cylindrica leaf extract on mild steel in hydrochloric acid environment

The corrosion inhibition of Luffa cylindrica Leaf Extract (LCLE) was investigated using gravimetric, depth of attack and surface analysis techniques. Effect of inhibitor concentrations (0.50–1.00 g/l), temperatures (30–60 °C) and immersion time (4–12 h) was studied on the Inhibition Efficiency (IE) of the extract on Mild Steel (MS) immersed in a 0.5 M HCl solution. The constituents of the proposed inhibitor were identified by using a GC-MS. The media solutions and adsorbed film on MS were characterized using FTIR Spectrophotometer. SEM microgram and surface tester were applied for studying surface morphology and depth of attack profile. The optimum IE of 87.89% was obtained. The LCLE adsorption on MS followed Langmuir isotherm and pseudo-second-order adsorption kinetics. Activation energy (28.71 kJ/mol), entropy (- 0.15 kJ/mol. K), average enthalpy (-28.00 kJ/mol) and Gibbs free energy (-11.43 kJ/mol) obtained at optimum condition indicate exothermic process and physical adsorption mechanism. The result obtained in this study compared well with many reported green inhibitors for MS corrosion.

A study on the inhibition of mild steel corrosion in hydrochloric acid environment by 4-methyl-2-(pyridin-3-yl)thiazole-5-carbohydrazide

A study on the inhibition of mild steel corrosion in hydrochloric acid environment by 4-methyl-2-(pyridin-3-yl)thiazole-5-carbohydrazide

Mechanical properties and creep behavior of fluoroelastomer under hydrochloric acid environments

Fluoroelastomers are commonly used as seal, gasket or membrane materials in many industrial applications. The temperature- and environment-dependent material property of rubbers will result in degradation and creep. In this study, the effects of both temperature and concentration of hydrochloric acid solution on mechanical properties and creep behavior of fluoroelastomer are investigated. The tensile test results demonstrate that the mechanical properties of rubber after acid treatment show a continual decrease as temperature or concentration increased. This degradation is attributed to the combination of both the swelling of rubber for the matrix which is penetrated by a number of acid solution molecules and the damage of chain networks where the acid–rubber reactions are generated inside. The tensile creep of the acid-treated rubbers is examined under controlled acidic environmental conditions. The creep rate and creep strain are both increased with increasing temperature or concentration. The creep curves are correctly fitted at long times by standard four-element model to evaluate the contributions from separate creep components. From fitting results, the change of viscoelastic strain component and viscous strain component suggests there are structural rearrangements within rubber chains and deformation of rubber matrix.

An effective corrosion inhibitor of N doped carbon dots for Q235 steel in 1 M HCl solution

N doped carbon dots (N-CDs) were prepared by hydrothermal method in methacrylic acid and n-butylamine precursors. The inhibition behavior of N-CDs on Q235 steel in hydrochloric acid environment was discussed via weight loss test, surface characterizations and electrochemistry measurements. Results showed that the as-prepared N-CDs could effectively protect Q235 steel and the inhibition efficiency reached up to 94.96% at 200 mg/L of N-CDs. In the meantime, the impedance modulus was greatly enhanced and the corrosion current density was reduced by one order of magnitude after the addition of N-CDs. Moreover, it could adhere to the steel surface by diffusion and agglomeration effect, resulting in the formation of adsorption film on steel surface. The adsorption mechanism of N-CDs almost complied with the Langmuir adsorption model, containing chemical and physical adsorptions.

6-Nitro-1,4-di(prop-2-yn-1-yl)quinoxaline-2,3(1H,4H)-dione (NQPr) – a novel corrosion inhibitor for mild steel in hydrochloric acid environment

6-Nitro-1,4-di(prop-2-yn-1-yl)quinoxaline-2,3(1H,4H)-dione (NQPr) – a novel corrosion inhibitor for mild steel in hydrochloric acid environment

A high-efficiency corrosion inhibitor of N-doped citric acid-based carbon dots for mild steel in hydrochloric acid environment

Novel N-doped carbon dots (CDs) were obtained through pyrolysis of ammonium citrate at 180 °C for 1, 2 and 3 h, and their corrosion inhibition effect on Q235 steel in 1 M HCl solution were evaluated through electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (Tafel), scanning vibrating electrode technique (SVET) analysis. The changes of corrosion current density and impedance modulus of Q235 steel in inhibitor solutions showed that the as-prepared carbon dots presented a valid protective effect on steel in 1 M HCl solution. Meanwhile, the inhibition efficiency of three carbon dots exceeded 90% at 200 mg/L and the highest inhibitive efficiency was found for the carbon dots prepared at the reaction time of 2 h. The adsorption mechanism of all as-prepared carbon dots complied with the Langmuir adsorption model, containing chemical and physical adsorptions, which was also confirmed by X-ray photoelectronic spectroscopy (XPS) analysis.

Evaluation of cathodic protection of mild steel with magnesium anodes in 0.5 M HCL

Abstract The performance of two different sizes of galvanic magnesium anodes on the cathodic protection of mild steel in 0.5 M hydrochloric acid was evaluated at room and elevated temperatures. The cathodic protection reactions process was observed by weight-loss method's corrosion rate calculation and potential and current measurement methods. The magnesium anodes were observed to be effective as sacrificial anode in the tested environments. The results obtained for the potential and current measurements bear close correlation with the corrosion rate method in the hydrochloric acid environment. The varying anode cross-sectional areas used showed the anode size effects. The varied percentage protection of magnesium anodes ranged between 5.88 and 59.81% (Mg 1); and, 16.80 and 48.65% (Mg 2) respectively at 27 °C. At 60 °C, the percent change ranged between 22.49 and 61.46 (Mg 1); and 21.7 and 68.95 for Mg anode 2.

Ekstraksi Daun Cocor Bebek Menggunakan Berbagai Pelarut Organik Sebagai Inhibitor Korosi Pada Lingkungan Asam Klorida

Telah dilakukan penelitian mengenai ekstraksi daun cocor bebek dengan menggunakan pelarut organik dengan berbagai tingkat kepolaran pelarut. Hal ini dilakukan untuk memperoleh pelarut mana yang mempunyai aktivitas inhibitor korosi pada lingkungan asam klorida, dimana diperoleh lima fraksi yaitu fraksi n-heksana, etil asetat, aseton, asam asetat, dan metanol. Berdasarkan analisis kuantitatif ekstrak daun cocor bebek dalam variasi sifat kepolaran pelarut menggunakan alat spektrofotometer dengan panjang gelombang 511nm. Kandungan flavanoid dalam ekstrak daun cocor bebek dihasilkan menggunakan pelarut aseton menunjukkan hasil paling tinggi. Laju korosi baja karbon dalam larutan HCl 0,1M; 0,05M; 0,01M dengan penambahan ekstrak daun cocor bebek mengalami penurunan seiring dengan peningkatan konsentrasi ekstrak dan mencapai penurunan terendah pada penambahan ekstrak dalam pelarut aseton sekitar 200 ppm dengan laju korosi 42,18 mpy dalam larutan HCl 0,1M dan pada peningkatan konsentrasi ekstrak terdapat penurunan laju tidak menunjukkan penurunan laju korosi yang signifikan. Untuk larutan HCl 0,05M dan 0,01m konsentrasi menunjukkan penurunan laju korosi sampai pada penambahan ekstrak 1500 ppm. Hasil ekstrak menggunakan pelarut aseton menunjukkan laju korosi baja karbon dalam larutan HCl 0,1M; 0,05M; dan 0,01M lebih rendah dibandingkan hasil ekstrak dengan pelarut lain (etil asetat, metanol, dan asam asetat 5%).

Flow-Accelerated Corrosion Inhibition of Steel in Hydrochloric Acid by Hexamethylenetetramine: Gravimetric, Density Functional Theory and Multiphysical Studies

In the present study, the flow-accelerated corrosion (FAC) behaviour of API 5L X65 steel was examined in hydrochloric acid environment in the presence of hexamethylenetetramine (HMT) as the organic inhibitor. Traditional experimentation was done through gravimetric method; density functional theory (DFT) was employed to explain the inhibitive tendency and reactive sites of the HMT as a corrosion inhibitor and computational fluid dynamics (CFD) simulation was used to study the hydrodynamics. The experimental results revealed that the optimum inhibition efficiency was achieved at 600 ppm inhibitor concentration with possible antagonism between the hydrodynamics and the inhibition process. The DFT study showed that HMT is a good organic inhibitor with the HOMO and HOMO-1 participating in the adsorption process while the CFD results revealed different flow fields around the surface of the specimen which are directly connected to the mass transfer rate.

Performance Evaluation of RAP Concrete in Aggressive Environment

AbstractIn this study, the feasibility of coarse (RC) and fine (RF) reclaimed asphalt pavement (RAP) inclusive concrete for sulfuric acid and hydrochloric acid environments is assessed. Moreover, t...

Corrosion inhibition studies of cashew nut (Anacardium occidentale) on carbon steel in 1.0 M hydrochloric acid environment

The corrosion inhibitive characteristics of the cashew nut (Anacardium occidentale) were studied as an eco-friendly green corrosion inhibitor at ambient temperature of 25 °C using weight loss analysis and adsorption isotherms. The effect of inhibitor concentration (4–12 g/l) at immersion time of 3–12 days was evaluated. The inhibitive ability of cashew nut shows a significant inhibition efficiency of 86% at 12 g/l concentration for 3-days and 72.9% at 12-days, which are undoubtedly as a result of the absorption of the inhibitor molecules on the metal surface which serve as a barrier against corrosion of carbon steel in acidic medium. The adsorption mechanism was found to fit Tempkin isotherms. The average optimum free energy of absorption was calculated to be −17.374 kJ mol–1 indicating that the process was exothermic and physisorption.

Anti-corrosion Properties of Areca Palm Leaf Extract on Aluminium in 0.5 M HCl Environment

The aluminium corrosion inhibition behaviour in the presence of Areca palm leaves (AL) extract in hydrochloric acid (0.5 M) medium was examined by chemical (mass loss), AC impedance spectroscopy, potentiodynamic polarization and surface (scanning electron microscopy) methods. Aluminium protection rates increased with an increase in the amount of AL extract to the 0.5M HCl system and decreased with increasing in the contact time of aluminium metal and temperature of 0.5M HCl solution. Arrhenius equation was applied in the determination of activation energy values. The other activation parameters such as activation entropy and enthalpy values were obtained from the transition state plot. The adsorption of AL extract species on the Al surface in 0.5M HCl solution follows the Langmuir adsorption mechanism. Tafel curves reflect the mixed (both anodic and cathodic) inhibition behaviour of green inhibitor (AL extract species) on electrode surface (Al) in 0.5M system. Impedance method indicates that the Al dissolution in hydrochloric acid environment was fully hindered by charge transfer process. The Al surface morphology was examined by applying scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Keywords: Aluminium, Areca palm leaves, weight loss, Arrhenius equation, Langmuir adsorption

Electrical conducting Xanthan Gum-graft-polyaniline as corrosion inhibitor for aluminum in hydrochloric acid environment

The work reports the preparation and characterization of Polyaniline (PANI) grafted on Xanthan Gum (XG) backbone as a conducting biopolymer. The grafting has been achieved by polymerization of aniline under acidic conditions employing microwave radiation. The formation of the graft copolymer has been confirmed by FTIR, UV-Vis and TGA data. The DC conductivity measurements indicated enhancement in conductivity of XG on grafting with PANI. The corrosion inhibitor property of XG and XG-g-PANI in aggressive acid environment was checked on aluminum surface by weight loss, potentiodynamic polarization, AC impedance and surface studies. Both the samples are found to be potential inhibitors, the effect being significantly higher for the grafted sample.

Red Arecanut Seed Extract as a Sustainable Corrosion Inhibitor for Aluminum Submerged in Acidic Corrodent: An Experimental Approach Towards Zero Environmental Impact

The effect of the red arecanut seed (RAS) extract on the corrosion of aluminum in 0.5 M hydrochloric acid environment is reported by weight loss, electrochemical (Tafel plot and impedance spectroscopy), scanning electron microscopy and atomic force microscopy studies. The weight loss study indicated that, protection efficiency of the red arecanut seed extract is directly proportional to its concentration and inversely proportional to solution temperature and aluminum contact time in the test solution. Langmuir adsorption isotherm is best fitted model explaining the adsorption of red arecanut seed extract constituents on aluminum surface in 0.5 M HCl system. The results obtained from Tafel curves indicated the mixed inhibition role of red arecanut seed extract. The impedance spectroscopy technique indicated that, red arecanut seed extract reduces the speed of aluminum corrosion by charge transfer process. The scanning electron microscopy and atomic force microscopy images of aluminum specimens clearly give clues about the adsorption of plant constituents on the surface of the aluminum metal.

Corrosion Inhibitive Behavior and Adsorption of Millet (Panicum miliaceum) Starch on Mild Steel in Hydrochloric Acid Environment

The performance of millet starch (MS) in controlling the corrosion of mild steel in 0.5 M HCl solution at 30 ± 1 °C was investigated using potentiodynamic polarization, gravimetric, thermometric and mathematical simulation technique. Data obtained from gravimetric and thermometric results revealed that MS inhibited corrosion of mild steel in the acid solution and increase in inhibition efficiency was concentration dependent for all the concentrations of MS investigated. The mode of adsorption of MS on the mild steel surface obeyed Langmuir adsorption isotherm. The potentiodynamic polarization result indicates that MS act as a mixed type inhibitor with absolute control on the cathodic partial reaction. The thermodynamic parameters (∆H ads, ∆S ads, ∆G ads and E a) for the inhibition process were calculated, and the results obtained supported the proposed physical adsorption mechanism. The mathematical simulation technique was used to evaluate the correlation between the inhibition efficiency of MS and its electronic molecular structure. The results show that there is a satisfactory agreement between mathematical simulation technique and experimental data.

Inhibition and Adsorption of Polyvinyl Acetate (PVAc) on the Corrosion of Aluminium in Sulphuric and Hydrochloric Acid Environment

The performance of PVAc as a safe inhibitor for corrosion of aluminium in 2 M H2SO4 and 0.5 M HCl solution at varying temperatures was investigated by weight loss, polarization measurement and computational technique. Weight loss measurements showed that PVAc exhibited excellent inhibitory character within the studied environment and efficiency of inhibition increased with increasing concentration of PVAc, but decreased with rise in temperature. Also, it is observed that aluminium displayed higher susceptibility to dissolution in the hydrochloric compared to sulphuric acid. Results of free energy of adsorption suggest physical adsorption. The adsorption of PVAc on the aluminium surface followed Langmuir adsorption isotherm, thus showing evidence of physisorption mechanism. Polarization results revealed that PVAc functions as a mixed-type inhibitor with absolute control of the anodic reaction. Results of computational technique showed the apparent correlation between corrosion inhibition efficiency and electronic molecular structure regarding frontier molecular orbital theory.

A novel imidazoline derivative as corrosion inhibitor for P110 carbon steel in hydrochloric acid environment

Abstract A novel imidazoline derivative, 2-methyl-4-phenyl-1-tosyl-4, 5-dihydro-1H-imidazole (IMI), was prepared and investigated as corrosion inhibitor for P110 carbon steel in 1.0 M HCl solution by weight loss measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests. The inhibition efficiency increased with the rising concentration of IMI inhibitor. The test results and fitting data indicated that the IMI behaved as a mixed-type inhibitor and obeys the Langmuir adsorption isotherm. Scanning electron microscopy (SEM) was carried out to investigate the surface of carbon steel specimens, showing great protection from aggressive solution. Finally, inhibition mechanism of IMI on metal surface was further discussed.

The polarity of metallic surfaces in the context of the corrosive and scuffing wear control

The concept of the metallic surfaces polarity in the context of scuffing performance is postulated and elucidated in the presented paper. The machining by grinding and surface treatment by burnishing is applied to control introducing changes in surface polarity and acid/base component of surface free energy is used for their quantitative determination. A clear relationship between the acid/base component of surface free energy and an activation of scuffing for the steel–cast iron friction pairs lubricated by oils with the surface-active sulphur-based additives is found. Obtained results are commented and clarified; thanks to the negative-ion concept of extreme pressure action of organo-sulphur compounds. Additionally, surface reactivity investigations are performed in order to determine the influence of acid/base component of surface free energy on the corrosion wear. It recognised a clear relationship between the acid/base component of surface free energy and the mass decrement of steel surfaces in the hydrochloric acid environment. On the basis of both parts of the investigations (scuffing and reactivity tests), an optimal surface polarity is determined for steel–cast iron friction pairs lubricated by lubricants with surface-active sulphur-based additives.

Adsorption Properties of Azadirachta indicia Extract on Corrosion of Aluminium in 1.85 M Hydrochloric Acid

The crude extract of Azadirachta indica was used in the corrosion inhibition study of aluminium metal coupons in 1.85 M hydrochloric acid environment by gasometric technique. The coupons were immersed in test solutions of uninhibited 1.85 M HCl and those containing extract concentrations of 10%, 20%, 30%, 40% and 50% (v/v) at room temperature. The rate of the reaction was captured by monitoring the volume of hydrogen gas evolved as a result of the interaction. The inhibition efficiency of the extracts and the adsorption isotherm of the process were calculated using Frumkin, Freundlich, Langmuir and Temkin adsorption theories and the surface morphology studied using Scanning Electron Microscopy (SEM). It was observed that the plant extract retarded the acid induced corrosion of aluminium and the volume of hydrogen gas evolved reduced with increasing extract concentration. The adsorption studies revealed that Langmuir isotherm is the best model for the adsorption of Azadirachta indica (R2 = 0.999) on aluminium surface. This implied that the Azadirachta indica extracts with aluminium metal undergoes chemisorption.