Mahendra Yadav

Corrosion inhibition effect of spiropyrimidinethiones on mild steel in 15% HCl solution: insight from electrochemical and quantum studies

The effect of synthesized spiropyrimidinethiones, namely, 6′-(4-methoxyphenyl)-1′-phenyl-2′-thioxo-2′,3′-dihydro-1′H-spiro[indoline-3,4′-pyrimidine]-2-one (MPTS) and 6′-(4-methoxyphenyl)-1′-phenyl-2′-thioxo-2′,3′-dihydro-1′H-spiro[indoline-3,4′-pyrimidine]-2-one (CPTS) on the corrosion of mild steel in 15% HCl solution was investigated by using weight loss and electrochemical methods. Both inhibitors act as mixed inhibitors and their adsorption on mild steel obeyed Langmuirs adsorption isotherm. The potential of zero charge (EPZC) for the mild steel was determined by electrochemical impedance spectroscopy methods. Scanning electron microscopy, energy dispersion X-ray spectroscopy, FTIR, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy were used to characterize the surface morphology of the uninhibited and inhibited mild steel specimens. Density Functional Theory (DFT) was employed for theoretical calculations.

Corrosion inhibition effect of pyrazole derivatives on mild steel in hydrochloric acid solution

Synthesized compounds, namely methyl 5-(4-Chlorobenzoyloxy)-1-phenyl-1H-pyrazole-3-carboxylate (MCPPC) and 5-(4-methoxyphenyl)-3-(4-methylphenyl)4,5-dihydro-1H-pyrazol-1-yl-(pyridin-4-yl)methanone (MMDPPM) were investigated as corrosion inhibitor for mild steel (MS) in 15% HCl solution using weight loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) methods. Inhibition efficiency was found concentration-dependent and increased by increasing the concentration of MCPPC and MMDPPM. Both of inhibitors were efficient even at a very low concentration of 25 ppm. The inhibitors MCPPC and MMDPPM showed inhibition efficiency of 67.1 and 76.8%, respectively, at 25 ppm, whereas it was 92.0 and 95.9%, respectively, at 250 ppm concentration at 303 K. The potentiodynamic polarization curves showed that MCPPC and MMDPPM act as mixed-type inhibitor in 15% HCl solution. The Nyquist plots showed that charge transfer resistance increased and double-layer capacitance decreased on increasing the concentration of studied inhibitors due to adsorption of inhibitor molecules on MS surface. The adsorption of each inhibitor on MS surface obeys Langmuir adsorption isotherm. On the basis of thermodynamic adsorption parameters, mixed-type adsorption (physisorption and chemisorption) for the studied inhibitors on MS surface was suggested. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and atomic force microscopy (AFM) analyses confirmed the existence of a protective film of the inhibitor on MS surface. The density functional theory was employed for theoretical calculations, and the obtained results were found to be consistent with the experimental findings.

Experimental and Quantum Chemical Studies on Corrosion Inhibition Performance of Thiazolidinedione Derivatives for Mild Steel in Hydrochloric Acid Solution

In the present investigation, two thiazolidinedione derivatives, 5-[(2-(3,4,5-trimethoxyphenyl)-6-phenylimidazo[2,1-b][1,3,4]thiadiazol-5-yl)methylidene]-1,3-thiazolidine-2,4-dione (Inh I) and 5-[2-(3,4,5-trimethoxyphenyl)-6-(4-methoxylphenyl)-imidazo[2,1-b][1,3,4]thiadiazol-5-yl)methylidene]-1,3-thiazolidine-2,4-dione (Inh II) were synthesized and investigated as inhibitors for mild steel corrosion in 15% HCl solution using the weight loss, electrochemical polarization, and electrochemical impedance spectroscopy (EIS) techniques. It was found that the inhibition efficiency of these inhibitors increased with increasing concentration. The effect of temperature on the corrosion rate was investigated, and some thermodynamic parameters were calculated. Polarization studies showed that both studied inhibitors were of mixed type in nature. The adsorption of inhibitors on the mild steel surface in acid solution was found to obey the Langmuir adsorption isotherm. Scanning electron microscopy (SEM) was performed on inhibited and uninhibited mild steel samples to characterize the surface. The semi-empirical AM1 method was employed for theoretical calculation of highest (E HOMO), and lowest unoccupied molecular orbital (E LUMO) energy levels, energy gap (E LUMO − E HOMO), dipole moment (μ), global hardness (γ), softness (σ), binding energy, molecular surface area, chemical potential (Pi), and the fraction of electrons transferred from the inhibitor molecule to the metal surface (ΔN). The results were found to be consistent with the experimental findings.

Experimental and theoretical study on amino acid derivatives as eco-friendly corrosion inhibitor on mild steel in hydrochloric acid solution

Amino acid derivatives, namely, 2-(2-oxo-2-phenothiazin-10-yl)ethylamino)-3-mercaptopropanoic acid (OPEM) and 2-(2-oxo-2-phenothiazin-10-yl)ethylamino)acetic acid (OPEA) were synthesized and investigated as inhibitors for mild steel corrosion in 15% HCl solution using the weight loss, polarization, and electrochemical impedance spectroscopy (EIS) techniques. The inhibition efficiency of both the inhibitors increased with increasing the temperature and concentration of inhibitor. The inhibitors OPEM and OPEA show corrosion inhibition efficiency of 97.5 and 95.8%, respectively, in 200 ppm concentration, at 333 K. Polarization studies showed that both studied inhibitors were of mixed type in nature. The adsorption of inhibitors on the mild steel surface obeys Langmuir adsorption isotherm and the surface of inhibited and uninhibited specimens were analyzed by scanning electron microscopy (SEM). The semiempirical AM1 method was employed for theoretical calculations and the obtained results were found to be consistent with the experimental findings.

Synthesized amino acid compounds as eco-friendly corrosion inhibitors for mild steel in hydrochloric acid solution: electrochemical and quantum studies

Corrosion inhibition performance of synthesized amino acid compounds, namely, (Z)-2-(2-oxoindolin-3-ylideneamino)acetic acid (OYAA) and 2-(2-oxoindolin-3-ylideneamino)-3-phenylpropanoic acid (OYPA) on mild steel in 15-% HCl solution was investigated by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Potentiodynamic polarization studies showed that both studied inhibitors were mixed types in nature. The adsorption of inhibitors on the mild steel surface obeyed Langmuirs adsorption isotherm. The potential of zero charge (EPZC) for the mild steel was determined via EIS to discuss the adsorption mechanism. Scanning electron microscopy, energy dispersion X-ray spectroscopy and atomic force microscopy were used to characterize the surface morphology of uninhibited and inhibited mild steel specimens. The density functional theory was employed for theoretical calculations.

Carbohydrate compounds as green corrosion inhibitors: electrochemical, XPS, DFT and molecular dynamics simulation studies

Corrosion inhibition and adsorption characteristics of synthesized carbohydrate compounds, namely, 5,6-bis(2-(1H-benzo[d]imidazol-2-yl)hydrazono)hexane-1,2,3,4-tetraol (BIHT) and 5,6-bis(2-(1-methyl-1H-imidazol-2-yl)hydrazono)hexane-1,2,3,4-tetraol (MIHT) on oil-field N80 steel in 15% HCl were measured by mass loss, polarization, EIS and PZC procedures. The compounds BIHT and MIHT are efficient corrosion inhibitors and they adsorb on the steel surface following the Langmuir adsorption isotherm. SEM, EDX, AFM and XPS were used for characterizing the surface of the steel samples after exposing them to 15% HCl without and with BIHT and MIHT. DFT and molecular dynamics simulation (MDS) were applied for theoretical studies.

Thiazole derivatives as efficient corrosion inhibitor for oil-well tubular steel in hydrochloric acid solution

The effect of 1-(benzo[d]thiazol-2-yl)-3-chloro-4-(3,5-dichlorophenyl)-4-methylazetidin-2-one (BDMA) and 3-(benzo[d]thiazol-2-yl)-2-(3,5-dichlorophenyl)-2,5-dimethylthiazolidin-4-one (BDMT) on the corrosion of oil well tubular steel (N80 steel) in 15% hydrochloric acid solution was investigated by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The surface morphology of the uninhibited and inhibited samples was studied with atomic force microscopy (AFM). The corrosion inhibition efficiency of both inhibitors increased with increasing inhibitors concentration. The adsorption of both inhibitor molecules on surface of N80 steel obeys Langmuir adsorption isotherm. Potentiodynamic polarization measurements indicated that both the studied inhibitors act as mixed type inhibitor. Quantum chemical calculations were carried out using density functional theory (DFT) to correlate the experimental results with the theoretical results.

Corrosion inhibitive properties of some new isatin derivatives on corrosion of N80 steel in 15% HCl

BackgroundThe inhibition effect of two synthesized isatin compounds, namely 1-morpholinomethyl-3(1-N-dithiooxamide)iminoisatin [MMTOI] and 1-diphenylaminomethyl-3(1-N-dithiooxamide)iminoisatin [PAMTOI], on the corrosion inhibition of N80 steel in 15% HCl solution was studied by polarization, alternating current impedance (electrochemical impedance spectroscopy), and weight loss measurements. The surface examination was carried out by scanning electron microscopy and Fourier transform infrared spectroscopy.ResultsThe compounds [PAMTOI] and [MMTOI] show the maximum of 91.2% and 84.3% inhibition efficiency, respectively, at 200-ppm concentration. Polarization curves revealed that the used inhibitors represent mixed-type inhibitors. Adsorption of used inhibitors led to a reduction in the double-layer capacitance and an increase in the charge transfer resistance.ConclusionsResults show that both inhibitors were effective inhibitors and their inhibition efficiency was significantly increased with increasing concentration. Adsorption of both compounds obeys the Langmuir adsorption isotherm.

Studies on Adsorption and Corrosion Inhibitive Properties of Indoline Compounds on N80 Steel in Hydrochloric Acid

Corrosion inhibition performance of synthesized indoline compounds, namely, 3′-(4-(1-acetyl-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-3-yl)phenyl)spiro[indoline-3,2′-thiazolidine]-2,4′-dione (MPIT) and 1-(4-(1-acetyl-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-3-yl)phenyl)spiro[imidazolidine-2,3′-indoline]-2′,5-dione (MPII) on N80 steel in 15% HCl solution was studied using weight loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. Polarization studies showed that both studied inhibitors were of mixed type in nature. The adsorption of inhibitors on the N80 steel surface obeys Langmuir adsorption isotherm. The potential of zero charge (EPZC) for the N80 steel was determined by EIS method. Scanning electron microscopy, energy-dispersive x-ray spectroscopy, and atomic force microscopy were used to characterize the surface morphology of uninhibited and inhibited N80 steel specimens. The density functional theory was employed for theoretical calculations.

Experimental and Theoretical Studies on Synthesized Compounds as Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution

Imidazole derivatives, namely, 1-((1-(piperazinomethyl)-1H-benzoimidazol-2-yl)methyl)-2-phenylhydrazine (PBIP), and 1-((1-(morpholinomethyl)-1H-benzoimidazol-2-yl)methyl)-2-phenylhydrazine (MBIP) were synthesized and investigated as inhibitors for mild steel corrosion in 15% HCl solution using weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. It was found that the inhibition efficiency of both the inhibitors increases with increase in concentration of inhibitors and decreases with increase in temperature. The inhibitors, PBIP and MBIP, show corrosion inhibition efficiency of 92.6% and 91.4% at 300 ppm concentration, respectively, at 303 K. Polarization studies showed that both the studied inhibitors were of mixed type in nature. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were performed for surface study of uninhibited and inhibited mild steel samples. The semi-empirical AM1 method was employed for theoretical calculations.