scholarly journals Calcium D-Pantothenate as Green Corrosion Inhibitor on Mild Steel in 240 ppm NaCl Solution

Corrosion inhibition of mild steel in 240 ppm NaCl solution using Calcium D-Pantothenate (Vitamin B5 ) as corrosion inhibitor is studied using electrochemical impedance, potentiodynamic polarization and weight loss studies. From the potentiodynamic polarization studies, icorr (corrosion current density) decreases with increasing the concentration of vitamin B5 (VB5 ). The CR (corrosion rate) decreases and the IE (inhibition efficiency) of VB5 increases on increasing the concentration of VB5 .Surface investigation using SEM, EDX spectra, UV-Vis, FTIR, electrochemical impedance, potentiodynamic polarization and adsorption isotherm parameter of VB5 in 240 ppm NaCl solution shows that VB5 can act asworthy corrosion inhibitors. Quantum chemical data obtained from density functional theory (DFT) calculations also agreed with the experimental outcomes.

2019 ◽  
Vol 7 (4.14) ◽  
pp. 168
Author(s):  
N Z. Nor Hashim ◽  
K Kassim ◽  
F H. Zaidon

Two N-substituted thiosemicarbazone derivatives namely as 2-(4-chlorobenzylidene)-N-phenylhydrazinecarbothioamide and 2-benzylidene-N-phenylhydrazinecarbothioamide (L1 and L2, respectively) have been tested as corrosion inhibitors on mild steel in 1 M HCl. The ligands were synthesized and investigated using potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS).  The obtained results indicated that inhibition efficiency, (IE, %) L1 increased with increasing inhibitor concentrations which behaved as a good corrosion inhibitor compared to L2. The synthesized ligands were successfully characterized by melting point, elemental analysis (C, H, N, and S), Fourier-transform infrared spectroscopy (FT-IR) and NMR (1H and 13C) spectroscopy. The excellent inhibition effectiveness for both compounds on mild steel before and after immersion in 1 M HCl solution containing 40 ppm of L1 and L2 were also verified by scanning electron microscope (SEM). Based on potentiodynamic polarization results, it can be concluded that all investigated compounds are mixed-type inhibitors and obey the Langmuir adsorption isotherm. 


2018 ◽  
Vol 65 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Mohd Rashid ◽  
Umesh S. Waware ◽  
Afidah A. Rahim ◽  
A.M.S. Hamouda

Purpose The purpose of this study is to compare the inhibitive effect of polyaniline (PAni) and N-cetyl-N,N,N trimethyl ammonium bromide (CTAB)-stabilized PAni in a hydrochloric acid (HCl) medium. Design/methodology/approach PAni has been deposited potentiodynamically on mild steel in the presence of CTAB as a stabilizing agent to achieve high corrosion inhibition performance by the polymer deposition. The corrosion inhibition studies of CTAB-stabilized PAni inhibitor in 0.1 M HCl acidic solution was carried out by electrochemical methods, namely, open-circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy technique. Findings The results of electrochemical studies have shown that the CTAB-stabilized PAni inhibitor has higher corrosion efficiency than PAni on mild steel in 0.1 M HCl solution. The maximum per cent efficiency evaluated using the potentiodynamic polarization method is approximately 91.9. Originality/value CTAB-stabilized PAni has never been studied as a corrosion inhibitor for mild steel in an acidic medium. The investigations demonstrate relatively the better corrosion inhibition efficiency and high dispersion of the polymer in the acidic medium.


Author(s):  
Chinonso Blessing Adindu ◽  
Emeka Emmanuel Oguzie ◽  
Cynthia E. Ogukwe

The adsorption and corrosion inhibitive effect of the ethanol extract ofFuntumia elastica(FE) leaves on mild steel corrosion in 0.5 M H2SO4was studied using gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopic techniques. As well as Fourier transform infrared spectroscopy and computational methods. The gravimetric and electrochemical studies revealed that FE is an adsorption inhibitor. The potentiodynamic polarization result showed that the inhibitor is a mixed type corrosion inhibitor for mild steel in 0.5 M H2SO4, inhibiting both the cathodic and anodic partial reactions. Density functional theory calculations were performed to model the electronic structures of some selected extract constituents (conessine, and ascorbic acid) to confirm their inhibiting potential and established their individual contributions to the observed inhibiting effects.


2020 ◽  
Vol 2 (2) ◽  
pp. 40-41

The evaluation the anticorrosive performance of two macromolecular aromatic epoxy resins (ERs), namely, tetra glycidyl of ethylene dianiline (TGEDA), hexaglycidyl Tris (p-Ethylene Dianiline) Phosphoric Triamide (HGEDPAT), and their polymer composite reinforced with Zinc for copper corrosion in 3% NaCl by means of computational and experimental analyses. Anticorrosive property of the standards and composites was demonstrated using experimental and computational methods. Electrochemical results showed that HGEDAPT cured with methylene dianiline (MDA) showed better protection efficiency with optimum corrosion current density (icorr) value of 2.0 µcm-2 and the polarization resistance (Rp) value of 17,00 kΩ.cm2 than that of TGEDA-MDA having icorr value of 2.4 µcm-2 and the Rp value of 15.24 kΩ.cm2. The anticorrosive effect of TGEDA-MDA and HGEDAPT-MDA was evaluated in the presence of 5% zinc (Zn). Experimental results demonstrate that the presence of 5% of zinc in TGEDA-MDA and HGEDAPT-MDA formulations significantly enhanced their protection ability. The anticorrosive effect of different formulations followed the order: ER1 (TGEDA-MDA) (potentiodynamic polarization (PDP); 90% and electrochemical impedance spectroscopy (EIS) 92%) < ER2 (HGEDAPT-MDA) (PDP; 92% and EIS 93%) < ER3 (TGEDA-MDA-5%Zn) (PDP; 96% and EIS 97%) < ER4 (HGEDAPT-MDA-5%Zn) (PDP; 97% and EIS 98.5%). Density Functional Theory (DFT) study revealed that ER1 and ER2 interact with the metallic surface using donor-acceptor interactions in which electron-rich centers acted as the most favorable sites for the interactions. Molecular dynamics (MD) simulations studies suggest that ER1 and ER2 acquire flat or horizontal orientations, and their orientations on the metallic surface are largely influenced by the presence of zinc. Different experimental and computational studies are in good agreement.


RSC Advances ◽  
2015 ◽  
Vol 5 (36) ◽  
pp. 28743-28761 ◽  
Author(s):  
Lutendo C. Murulana ◽  
Mwadham M. Kabanda ◽  
Eno E. Ebenso

Corrosion inhibition studies of mild steel in aqueous HCl by some sulphonamides have been investigated using weight loss, potentiodynamic polarization (PDP), Electrochemical Impedance Spectroscopy (EIS) and Density Functional Theory (DFT).


2019 ◽  
Vol 9 (21) ◽  
pp. 4684 ◽  
Author(s):  
Sihem Lahrour ◽  
Abderrahim Benmoussat ◽  
Brahim Bouras ◽  
Asma Mansri ◽  
Lahcene Tannouga ◽  
...  

C-Mn steels, commonly employed in structural applications, are often exposed to near-neutral aerated environments and hence subjected to general corrosion. In broader contexts, for example during pickling, acidizing treatments, or acid-releasing processes, where steel comes in contact with more aggressive solutions, the use of corrosion inhibitors is a supplementary strategy to cathodic protection and/or coating. This work focuses on the C-Mn steel corrosion protection in the presence of HCl, either as process fluid or by product. In order to avoid the toxicological issues related to conventional synthetic products, a bio-copolymer containing glycerin-grafted starch, synthesized by modification of maize starch, was studied as a “green” corrosion inhibitor by the weight loss method and electrochemical techniques (open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy). Corrosion-related parameters, such as inhibitor concentration and temperature, were varied and optimized to characterize the corrosion process. Results showed that inhibition efficiency increases with increasing bio-copolymer concentration, reaching a maximum of 94%at the concentration of 300 mg L−1. The kinetic and thermodynamic parameters were determined and discussed. The obtained values of corrosion potential and corrosion current density, Ecorr and icorr, obtained by potentiodynamic polarization, are in agreement with the weight loss method. The corrosion current densities decrease when the concentration of the inhibitor increases.


2021 ◽  
Author(s):  
Lutendo C. Murulana ◽  
Tshimangadzo Nesane ◽  
Mwadham M. Kabanda ◽  
Lukman O. Olasunkanmi ◽  
Eno E. Ebenso

Abstract The anticorrosive properties of six (6) selected sulphonamide derivatives on the aluminium surface were investigated in order to reveal their mechanism and mode of adsorption on Al/HCl interface, as well as the strength of the interactions between the inhibitor and Al surface. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) techniques were utilised to evaluate the inhibition efficiencies of the selected compounds, while scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy techniques were utilised to understand the surface morphology of Al and adsorption sites of the sulphonamides. Density functional theory (DFT) calculations were utilised to investigate the strength of interactions between the inhibitor molecules and Al. Corrosive electrolyte of 1 M hydrochloric acid was employed in the study. All the studied sulphonamides showed excellent corrosion inhibition efficiencies with maximum values of up to 95%-97% at the optimum concentrations (4 × 10-5 M - 4 × 10-5 M), based on EIS measurements. The EIS parameters further revealed adsorbed film of the sulphonamides on the Al surface with capacitive-inductive characters. All the six sulphonamides reduced the corrosion current densities for both anodic and cathodic half-reactions and shifted the corrosion potentials to some anodically nobler values as revealed by the PDP data. Adsorption of the sulphonamides at the Al/HCl interface was described by the Langmuir isotherm model. Surface protection properties of the sulphonamides were further confirmed by SEM plates that showed less damaged surface of Al for the inhibited process compared to the uninhibited one. DFT results suggest that the binding energy for the inhibitors on the Al surface results in an energy that is less than 30 kJ/mol, which is an indication that the interactions are van der Waal type of interaction, suggesting physisorption mechanism.


Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3679
Author(s):  
Ismat H. Ali

This study aimed to examine the extract of barks of Tamarix aphylla as a corrosion inhibitor. The methodology briefly includes plant sample collection, extraction of the corrosion inhibitor, gravimetric analysis, plotting potentiodynamic polarization plots, electrochemical impedance spectroscopic measurements, optimization of conditions, and preparation of the inhibitor products. The results show that the values of inhibition efficiency (IE%) increased as the concentrations of the inhibitor increased, with a maximum achievable inhibition efficiency of 85.0%. Potentiodynamic polarization (PP) tests revealed that the extract acts as a dual-type inhibitor. The results obtained from electrochemical impedance spectroscopy (EIS) measurements indicate an increase in polarisation resistance, confirming the inhibitive capacity of the tested inhibitor. The adsorption of the inhibitor on the steel surface follows the Langmuir adsorption isotherm model and involves competitive physio-sorption and chemisorption mechanisms. The EIS technique was utilized to investigate the effect of temperature on corrosion inhibition within the 298–328 K temperature range. Results confirm that the inhibition efficiency (IE%) of the inhibitor decreased slightly as the temperature increased. Lastly, the thermodynamic parameters for the inhibitor were calculated.


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