scholarly journals Acid Corrosion Inhibition and Adsorption Behaviour of Ethyl Hydroxyethyl Cellulose on Mild Steel Corrosion

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
I. O. Arukalam ◽  
I. O. Madu ◽  
N. T. Ijomah ◽  
C. M. Ewulonu ◽  
G. N. Onyeagoro
Keyword(s):  
Mild Steel ◽  
Molecular Orbital ◽  
Corrosion Inhibition ◽  
Density Functional ◽  
Inhibition Efficiency ◽  
Acid Corrosion ◽  
Hydroxyethyl Cellulose ◽  
Chemical Calculation ◽  
Free Energy Of Adsorption ◽  
Ethyl Hydroxyethyl Cellulose

The corrosion inhibition of mild steel in 1.0 M H2SO4 solution by ethyl hydroxyethyl cellulose has been studied in relation to the concentration of the additive using weight loss measurement, EIS, polarization, and quantum chemical calculation techniques. The results indicate that EHEC inhibited corrosion reaction in the acid medium and inhibition efficiency increased with EHEC concentration. Further increase in inhibition efficiency is observed in the presence of iodide ions, due to synergistic effect. Impedance results reveal that EHEC is adsorbed on the corroding metal surface. Adsorption followed a modified Langmuir isotherm, with very high negative values of the free energy of adsorption (ΔGads). The polarization data indicate that the inhibitor was of mixed type, with predominant effect on the cathodic partial reaction. The frontier molecular orbitals, HOMO (the highest occupied molecular orbital) and LUMO (the lowest unoccupied molecular orbital) as well as local reactivity of the EHEC molecule, were analyzed theoretically using the density functional theory to explain the adsorption characteristics at a molecular level. The theoretical predictions showed good agreement with experimental results.

scholarly journals A Computational Study of Quinoline Derivatives as Corrosion Inhibitors for Mild Steel in Acidic Medium

2019 ◽  
Vol 23 (10) ◽  
pp. 1819-1824
Author(s):  
E.A. Erazua ◽  
B.B. Adeleke
Keyword(s):  
Mild Steel ◽  
Molecular Orbital ◽  
Corrosion Inhibition ◽  
Density Functional ◽  
Inhibition Efficiency ◽  
Computational Study ◽  
Chemical Hardness ◽  
Chemical Calculation ◽  
Quinoline Derivatives ◽  
Donation Process

The corrosion inhibition efficiency of three quinoline derivatives namely; ethyl 2-(((8-hydroxyquinolin5-yl)methyl)amino)acetate (QN1), 5-((benzylamino)methyl)quinolin-8-ol (QN2) and 5-(azidomethyl)quinolin-8-ol (QN3) on the mild steel in 1 M HCl was studied using density functional theory (DFT) calculations and quantitative structural activity relationship (QSAR) approach. The experimental inhibition efficiency were discussed in relation with molecular descriptors such as such as EHOMO (energy of the highest occupied molecular orbital), ELUMO (energy of the lowest unoccupied molecular orbital), band gap (BG), dipole moment (DM), chemical hardness (η), softness (σ), electronegativity (χ), electrophilicity (ω), global nucleophilicity (ɛ), electrons transferred from inhibitors to metal surface (ΔN), initial molecule–metal interaction energy (∆ψ), the energy change during electronic back-donation process (ΔEb-d), Molecular weight (MW), and Volume (V). The result showed that EHOMO, σ , ω, ΔN, ∆Eb-d and ∆ψ increases as the percentage inhibition efficiency (%IE) increases. ELUMO, BG, η , DM, and e decreases with increasing% IE, while χ , MW and V did not show any correlation with %IE. The QSAR model developed reproduced the observed corrosion inhibition efficiencies of these compounds well with a cross validation (CV. R2 ) value of 0.9994 and adjusted squared correlation coefficient (R2 adj) value of 0.9988. The results obtained in the study are in good agreement with experimental inhibition efficiency results reported earlier in literature.Keywords: Corrosion Inhibition, Quantum Chemical Calculation, Quinoline Derivatives, QSAR

scholarly journals Corrosion Inhibition of Mild Steel in Acidic Media by N-[(3,4-Dimethoxyphenyl)Methyleneamino]-4-Hydroxy-Benzamide

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Kashmitha Muthamma ◽  
Preethi Kumari ◽  
M. Lavanya ◽  
Suma A. Rao
Keyword(s):  
Dft Calculations ◽  
Mild Steel ◽  
Corrosion Inhibition ◽  
Density Functional ◽  
Surface Characterization ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Low Carbon ◽  
Acid Media

Abstract Mild steel (a low carbon steel) is an affordable engineering material used for many purposes in various environments including mild acidic environment with some precautions. The corrosion behaviour of mild steel (MS) in 0.5 M H2SO4 and 0.5 M HCl, in the temperature range (303–323 K) without and with the inhibitor N-[(3,4-dimethoxyphenyl) methyleneamino]-4-hydroxy-benzamide (DMHB), was investigated using Potentiodynamic polarization and Electrochemical impedance spectroscopy (EIS) techniques supplementing with surface characterization study using scanning electron microscope (SEM) and atomic force spectroscopy (AFM). Experimental observations were found to be in agreement with Density functional theory (DFT) calculations. The inhibition efficiency increases with increase in DMHB concentration and showed maximum inhibition efficiency of 86% in 0.5 M H2SO4 and 81% in 0.5 M HCl, respectively, at concentration of 3 × 10─3 M at 303 K. The inhibition efficiency of DMHB obtained relatively at its lower concentration (3 × 10─3 M) compared to other reported related compounds confirms its potential towards corrosion inhibition. The variation in the kinetic and thermodynamic parameters indicated physisorption of DMHB on MS and its mixed type inhibitive action followed Langmuir’s isotherm model. DFT calculations go along with the experimental results, signifying the potential corrosion inhibition behaviour of DMHB for MS in both the acid media.

The experimental and quantum chemical investigation for two isomeric compounds as aminopyrazine and 2-amino-pyrimidine against mild steel corrosion

2016 ◽  
Vol 63 (5) ◽  
pp. 369-376 ◽  
Author(s):  
Basak Dogru Mert ◽  
Mehmet Erman Mert ◽  
Gülfeza Kardas ◽  
Birgül Yazici
Keyword(s):  
Mild Steel ◽  
Molecular Orbital ◽  
Density Functional ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Molecular Geometry ◽  
Orbital Energy ◽  
Content Type ◽  
Inhibition Effect ◽  
Amino Pyrimidine

Purpose The purpose of this paper is to investigate the adsorption and corrosion inhibition of two isomeric compounds (C4H5N3) as aminopyrazine (AP) and 2-amino-pyrimidine (2AP) on mild steel (MS) in 0.5 M HCl. The study was a trial to combine experimental and modelling studies and research effect of molecular geometry on inhibition effect of inhibitor molecules. Design/methodology/approach The thermodynamic, kinetic and quantum parameters were determined. The electrochemical impedance spectroscopy and anodic polarisation measurements were obtained. The scanning electron microscope was used for monitoring electrode surface. The highest occupied molecular orbital, energy of the lowest unoccupied molecular orbital, Mulliken and natural bonding orbital charges on the backbone atoms, absolute electronegativity, absolute hardness were calculated by density functional theory (DFT)/B3LYP/6-311G (++ d,p). Findings Results showed that AP and 2AP suppressed the corrosion rate of MS. The corrosion current values were 0.530, 0.050 and 0.016 mA cm-2 in HCl, AP and 2AP containing HCl solutions, respectively. It was illustrated with the blocked fraction of the MS surface by adsorption of inhibitors which obeyed the Langmuir isotherm. The inhibition efficiency follows the order: 2AP > AP which is in agreement with experimental and quantum results. Originality/value This paper provides lay a bridge on the molecular geometry and inhibition efficiency by electrochemical tests and modelling study. The inhibition effect of AP and 2AP has not been compared with each other, neither experimentally nor theoretically. This study put forward possible application of 2AP as corrosion inhibitor especially for closed-circuit systems.

scholarly journals Gravimetrical, theoretical, and surface morphological investigations of corrosion inhibition effect of 4-(benzoimidazole-2-yl) pyridine on mild steel in hydrochloric acid

2020 ◽  
Vol 64 (4) ◽  
pp. 122-130
Author(s):  
A.M. Resen ◽  
M. Hanoon ◽  
R.D. Salim ◽  
A.A. Al-Amiery ◽  
L.M. Shaker ◽  
...  
Keyword(s):  
Hydrochloric Acid ◽  
Mild Steel ◽  
Corrosion Inhibitor ◽  
Molecular Orbital ◽  
Corrosion Inhibition ◽  
Density Functional ◽  
Energy Gap ◽  
Mechanism Of Inhibition ◽  
Acid Environment ◽  
And Behavior

Abstract The corrosion inhibition efficiency of the novel pyridine namely, 4-(Benzoimidazole-2-yl)pyridine has been studied for mild steel in a 1 M hydrochloric acid environment by utilizing gravimetrical techniques. The synthesized inhibitor exhibits a significant inhibitive efficiency of 93.8% at 0.005 M. The adsorption isotherm of the investigated inhibitor on mild steel surface obeys the Langmuir isotherm. Surface morphology investigated by utilizing scanning electron microscopy (SEM) demonstrates a smooth metal surface with the addition of 4-(Benzoimidazole-2-yl)pyridine in a hydrochloric acid environment. Quantum chemical calculations using density functional theory (DFT) have been used to investigate the molecular structure and behavior of 4-(Benzoimidazole-2-yl) pyridine as a corrosion inhibitor. Different parameters have been calculated using DFT, such as energies of highest occupied molecular orbital and lowest occupied molecular orbital (EHOMO and ELUMO), energy gap (∆E), and dipole moment (μ). These parameters were important to elucidate the behavior of the investigated molecule as a corrosion inhibitor in acidic solution and also suggest the mechanism of inhibition.

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

2020 ◽  
Vol 15 (2) ◽  
pp. 202-209 ◽  
Author(s):  
Ahmed Al-Amiery ◽  
Taghried A Salman ◽  
Khalida F Alazawi ◽  
Lina M Shaker ◽  
Abdul Amir H Kadhum ◽  
...  
Keyword(s):  
Weight Loss ◽  
Schiff Base ◽  
Hydrochloric Acid ◽  
Corrosion Inhibition ◽  
Quantum Chemical ◽  
Density Functional ◽  
Inhibition Efficiency ◽  
Chemical Calculation ◽  
Acid Environment ◽  
Inhibition Performance

Abstract The 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.

scholarly journals Comparative Studies on the Corrosion Inhibition of Three Different Organic Heterocyclic Compounds as Corrosion Inhibitors for Mild Steel in Hydrochloric Acid

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Zineb Tribak ◽  
Mohammed Khalid Skalli ◽  
Omar Senhaji
Keyword(s):  
Hydrochloric Acid ◽  
Mild Steel ◽  
Corrosion Inhibition ◽  
Inhibition Efficiency ◽  
Charge Transfer Resistance ◽  
Protective Film ◽  
Free Energy Of Adsorption ◽  
Electron Microscopic ◽  
Transfer Resistance ◽  
Model Free

Abstract. Three organic inhibitors, based 5-Chloroisatin’s bases, namely, 1-allyl-5-chloro-indoline-2,3-dione (TZACI). 5-chloro-1-(2-(dimethylamino) ethyl) indoline-2,3-dione (TZCDI),5-chloro-1-octylindoline-2,3-dione (TZCOI) were influence on corrosion inhibition of mild steel in 1.0M hydrochloric acid solution. The inhibition efficiency increased with the increase of a compound concentration in the case of these three inhibitors, which have the mixed type behavior proposed by the polarization studies. Impedance measurements showed that after the addition of inhibitors, charge-transfer resistance increased and double-layer capacitance decreased, involving increased inhibition efficiency. The adsorption of three inhibitors on a steel surface obeyed Langmuir model. Free energy of adsorption showed that the type of adsorption was physical for TZACI and chemical for the TZCDI, TZCOI. Scanning electron microscopic analyses confirm the formation of the protective film on the surface.

scholarly journals Investigation of Anticorrosive Property of Carbazolecarbaldehyde Azine on Mild Steel Using Electrochemical, Morphological and Theoretical Studies

2020 ◽  
Vol 6 (4) ◽  
Author(s):  
Sneha Kagatikar ◽  
Dhanya Sunil ◽  
Preethi Kumari ◽  
Prakasha Shetty
Keyword(s):  
Mild Steel ◽  
Corrosion Inhibition ◽  
Density Functional ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Chemical Interaction ◽  
Kinetic And Thermodynamic Parameters ◽  
Industrial Sectors ◽  
Maximum Inhibition ◽  
Hcl Medium

Abstract Mild steel (MS) is one among the extensively utilized materials in several industrial sectors, but prone to deterioration when exposed to acidic environment. The main focus of this study is to examine the corrosion inhibitive efficacy of 9-ethyl-3-carbazolecarboxaldehyde azine (CCA) on MS immersed in 0.5 M HCl medium. The corrosion inhibition efficiency of CCA which was investigated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques improved with rise in temperature and inhibitor concentration. CCA showed a maximum inhibition efficiency of 92.4% at 323 K for 5 × 10–5 M concentration in 0.5 M HCl medium. The variation in the kinetic and thermodynamic parameters indicated chemisorption of CCA on MS, and its mixed-type inhibitive action followed Langmuir’s isotherm model. The infrared spectra provided evidences for the chemical interaction of CCA with MS specimen. Surface morphology evaluation using SEM and AFM in combination with elemental analysis using an energy dispersive X-ray analyser (EDX) indicated the creation of a protective adsorption layer of CCA on MS surface. The quantum chemical investigations performed using density functional theory (DFT) computations supplemented the experimental results, suggesting the potential corrosion inhibition behavior of CCA toward MS in aggressive HCl medium. Graphic Abstract

scholarly journals Corrosion Inhibition and Adsorption Characteristics of Tarivid on Mild Steel in H2SO4

2010 ◽  
Vol 7 (s1) ◽  
pp. S442-S448 ◽  
Author(s):  
N. O. Eddy ◽  
E. E. Ebenso
Keyword(s):  
Mild Steel ◽  
Corrosion Inhibition ◽  
Adsorption Mechanism ◽  
Inhibition Efficiency ◽  
Physical Adsorption ◽  
Free Energy Of Adsorption ◽  
Langmuir Adsorption ◽  
Adsorption Characteristics ◽  
Kinetic And Thermodynamic Parameters ◽  
Temperature Activation

The corrosion inhibition and adsorption characteristics of (+/-)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid (Tarivid) on the corrosion of mild steel has been studied using thermometric and gasometric methods. The study reveals that tarivid inhibits the corrosion of mild steel in H2SO4. The values of inhibition efficiency of tarivid were found to increase as its concentration increased but decreased with increase in temperature. Activation energies of the inhibited corrosion of mild steel ranged from 39.05 to 50.61 kJ/mol. Values of enthalpy change and free energy of adsorption were negative which indicated exothermic and spontaneous adsorption process. Physical adsorption mechanism is proposed from the obtained kinetic and thermodynamic parameters. Langmuir adsorption isotherm model is obeyed from the fit of the experimental data.

scholarly journals Insight into Anticorrosion Mechanism of Ampicillin on Mild Steel in Acidic Environment: A Combined Experimental and Theoretical Approach

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Tuan Dinh ◽  
Nguyen Minh Thong ◽  
Dinh Quy Huong ◽  
Trinh Le Huyen ◽  
Tran Duc Manh ◽  
...  
Keyword(s):  
Mild Steel ◽  
Molecular Orbital ◽  
Corrosion Inhibition ◽  
Inhibition Efficiency ◽  
Energy Gap ◽  
Electrochemical Impedance ◽  
Carbon Steels ◽  
Orbital Energy ◽  
Acidic Environment ◽  
Molecular Orbital Energy

The corrosion inhibition of mild carbon steels in an acidic environment by using ampicillin (AMP) has been evaluated based on experimental and quantum chemistry techniques. The experimental results indicate that the inhibition efficiency goes up at higher AMP concentration. The highest inhibition efficiency reaches 84.9% for polarization measurement and 90.1% for electrochemical impedance spectroscopy with the inhibitor of concentration 100 ppm at 298 K. The surface characteristics (SEM) also reconfirm the steel corrosion inhibition ability of AMP. Some important chemical factors such as EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy), ΔEL−H (energy gap), and Fukui functions were calculated based on the optimized configuration of AMP at the theoretical level of B3LYP/6-31+G(d,p). Moreover, Monte Carlo and molecular dynamics simulations were used to analyze the absorption behavior of inhibitor on the surface of Fe(110), which supplies the mechanism of inhibition corrosion processes. The obtained results showed that AMP is considered to be a potential corrosion inhibitor for mild steel in 1M HCl medium. Moreover, the protonated state of AMP plays an important role in the protection of Fe surface against the corrosive process.

scholarly journals Chemical Combination of 4-(4-Hydroxybut-2-ynyl) Pyridine and 3-Methylbenzenamine to Construct an Effective Inhibitor: Theoretical and Practical Investigation

2018 ◽  
Vol 3 (2) ◽  
Keyword(s):  
Theoretical Calculation ◽  
Corrosion Inhibition ◽  
Inhibition Efficiency ◽  
Acid Corrosion ◽  
Steel Corrosion ◽  
Md Simulations ◽  
Chemical Calculation ◽  
Pyridinium Bromide ◽  
Chemical Combination ◽  
Practical Investigation

A new inhibitor, N-m-benzylamine-4-(4-hydroxybut-2-ynyl) pyridinium bromide (designated as BAP) was designed and synthesized. Quantum chemical calculation and molecular dynamics (MD) simulations manifested that BAP, a compound by covalent combination of 4-(4-hydroxybut-2-ynyl) pyridine (HYP) and 3-methyl benzenamine (MBA), functioned better than did the two moieties (HYP and MBA) for X70 steel corrosion inhibition. The corrosion inhibition investigation revealed that the experiment outcome was in good consistency with the theoretical calculation. The inhibition efficiency of BAP was 95.72% for X70 steel in 5 M HCl at 90 0C. BAP adsorbed on X70 steel surface, obeyed Langmuir isotherm, retarded both the metal dissolution and the hydrogen evolution, and enhanced greatly the acid corrosion resistance of X70 steel. Comparative test demonstrated that the inhibition efficiency of BAP was about 10 times of that for MAB and 8 times of that for HYP albeit the concentration of BAP was tenth of that of HYP and MBA. The experimental investigation backs up the theoretical calculation and manifests intramolecular synergism of the structure moieties being beneficial to design of high effective inhibitors.

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