Abstract:Bitter leaves extract as inhibitive agent in HCl medium for the treatment of mild steel through pickling was studied. Thermometric, gravimetric and potentiodynamic polarization methods were employed in the corrosion inhibition study. The bitter leaves extract was analyzed using gas chromatography-mass spectrometer. The analysis of the extract revealed the presence of C6H8O (96 g/mole: 2,4-Hexadienal); C7H12 (96 g/mole: 3,4-Heptadiene; 1,3-Diethylallene) and C10H18O2 (170 g/mole: 2-Decenoic acid) as the predomi… Show more
“…The data obtained for the degree of surface coverage at various concentrations of the inhibitor were used to test Langmuir, Frumkin, Temkin and Flory–Huggins adsorption isotherms of equations (4) to (7), respectively (Li and Deng, 2012; Patel et al , 2013; Omotioma and Onukwuli, 2017; Onukwuli and Omotioma, 2019). The Gibb’s free energy of adsorption ( ΔG ads ) was calculated using equation (8): where C is the inhibitor concentration; K is the adsorption equilibrium constant; α is the lateral interaction term; “ a ” is the attractive parameter; θ is the degree of surface coverage; x is the size parameter; R is the gas constant; and T is the temperature.…”
Purpose
The purpose of this study was to investigate cimetidine as corrosion inhibitor of aluminium in hydrochloric acid medium.
Design/methodology/approach
Cimetidine was characterized by gas chromatography mass spectrophotometer and Fourier transform infrared spectroscopy to determine its chemical composition and functional groups, respectively. Gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopic techniques were used in the corrosion inhibition process. Thermodynamic and adsorption parameters were evaluated. And response surface methodology was used to optimize the corrosion inhibition process.
Findings
Analysis of the results revealed that major constituents of cimetidine include metronidazole, n-hexadecanoic acid cyclohexane and methyl ester. It has C-H stretch, C = N stretch, CH3C-H bend, ring C = C stretch, -C-O-O stretch, N-H bend, C-O stretch and C-H bend as predominant functional groups. Adsorption of molecules of the inhibitor on the aluminium surface was spontaneous, and it followed mechanism of physical adsorption. Response surface methodology revealed that quadratic model adequately described the inhibition efficiency of cimetidine as function of inhibitor concentration, temperature and time. Chemical and electrochemical results are in agreement that the cimetidine is a viable corrosion inhibitor. Cimetidine was revealed as mixed-type inhibitor because it controlled both cathodic and anodic reactions.
Originality/value
Empirical and optimization studies of cimetidine drug as corrosion inhibitor of aluminium in hydrochloric acid medium were carried out. The research results can provide the basis for deploying drugs (with mucosal protective and antacid properties) for corrosion control of metallic structures.
“…The data obtained for the degree of surface coverage at various concentrations of the inhibitor were used to test Langmuir, Frumkin, Temkin and Flory–Huggins adsorption isotherms of equations (4) to (7), respectively (Li and Deng, 2012; Patel et al , 2013; Omotioma and Onukwuli, 2017; Onukwuli and Omotioma, 2019). The Gibb’s free energy of adsorption ( ΔG ads ) was calculated using equation (8): where C is the inhibitor concentration; K is the adsorption equilibrium constant; α is the lateral interaction term; “ a ” is the attractive parameter; θ is the degree of surface coverage; x is the size parameter; R is the gas constant; and T is the temperature.…”
Purpose
The purpose of this study was to investigate cimetidine as corrosion inhibitor of aluminium in hydrochloric acid medium.
Design/methodology/approach
Cimetidine was characterized by gas chromatography mass spectrophotometer and Fourier transform infrared spectroscopy to determine its chemical composition and functional groups, respectively. Gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopic techniques were used in the corrosion inhibition process. Thermodynamic and adsorption parameters were evaluated. And response surface methodology was used to optimize the corrosion inhibition process.
Findings
Analysis of the results revealed that major constituents of cimetidine include metronidazole, n-hexadecanoic acid cyclohexane and methyl ester. It has C-H stretch, C = N stretch, CH3C-H bend, ring C = C stretch, -C-O-O stretch, N-H bend, C-O stretch and C-H bend as predominant functional groups. Adsorption of molecules of the inhibitor on the aluminium surface was spontaneous, and it followed mechanism of physical adsorption. Response surface methodology revealed that quadratic model adequately described the inhibition efficiency of cimetidine as function of inhibitor concentration, temperature and time. Chemical and electrochemical results are in agreement that the cimetidine is a viable corrosion inhibitor. Cimetidine was revealed as mixed-type inhibitor because it controlled both cathodic and anodic reactions.
Originality/value
Empirical and optimization studies of cimetidine drug as corrosion inhibitor of aluminium in hydrochloric acid medium were carried out. The research results can provide the basis for deploying drugs (with mucosal protective and antacid properties) for corrosion control of metallic structures.
“…2 ; a) methyl nicotinate (C 7 H 7 NO 2 ), and b) pyridine-4-carbohydrazide (C 12 H 10 N 4 O 5 S). Methyl nicotinate and pyridine-4-carbohydrazide of the castor oil leaf contain heteroatoms of O, N and S. Presence of the heteroatoms, antioxidants as well as lengthy hydrocarbon chain revealed that the material is highly suitable for corrosion control [ 6 , 16 , 18 , 21 , 24 ]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…Chemical constituent of the castor oil leaf extract was identified by gas chromatography-mass spectrometer (GCMS-QP2010 PLUS; SHIMADZU). The procedure used is similar to that of Onukwuli and Omotioma [ 21 ]. Features of gas chromatography (GC) and mass spectrometry (MS) were jointly applied to categorize different chemical constituents within the castor oil extract.…”
“…The chemical composition of the mango leaf extract are identified using instrumental analysis and gas chromatography-mass spectrophotometer (GCMS-QP2010 plus; Shimazu). The applied technique followed the technique used by previous research work [33]. Combined features of gas chromatography-mass spectrophotometer aided the categorization of the molecular constituents.…”
Section: Analysis Of the Chemical Composition Of Mango Leaf Extractmentioning
This study advanced the establishment of natural plant-based inhibitors for corrosion prevention procedures. It entails modelling the efficiency of leaf extract for mild steel corrosion control in HCl solution. The mango leaf extract are characterize to ascertain its molecules/molecular structures using gas chromatography-mass spectrophotometer (GCMS). The efficiency undergo modeling using response surface methodology (RSM) and artificial neural network (ANN). Critical phenomena of the inhibitor’s bio-molecules in the HCl solution and interfacial transition between the molecules and mild steel’s surface are examine using Langmuir, Frumkin, Temkin and Flory-Huggins adsorption isotherms. The results showed that 2-hydroxycyclopentadecanone (C15H28O2), 4-hepten-3-one (C8H14O), benzenemethanol (C9H12O), and 2,7-dimethyloct-7-en-5-yn-4-yl ester (C14H20O4 are the predominant molecular constituents (of higher inhibitive properties) in the mango leaf extract. The highest efficiency of 91.42% is obtain at an inhibition concentration of 0.6 g/L, temperature of 318 K and immersion time of 16 hours. Efficiency of the extract are model by optimization tools of RSM and ANN. Based on statistical analyses (correlation coefficient, RMSE and standard error of prediction), ANN performed better than RSM in the prediction of inhibition efficiency of the extract. Interfacial transition between the extract’s molecules and the mild steel surface established. The bio-molecular constituents inhibited the corrosion by process of adsorption.
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