Cephalexin as Efficient Corrosion Inhibitor for Mild Steel in Acidic Media Chemical, Electrochemical and Thermodynamic Studies

Posted on Thursday, March 31, 2016 by Prof. Dr. A. S. Fouda

Prof. Dr. A. S. Fouda
Fig. 13: The optimized molecular structures, HOMO, LUMO
Tab. 9: The calculated quantum chemical parameters for Cephalexin compound using PM3.
Tab. 8: Electrochemical kinetic parameters obtained by EFM technique for mild steel in 0.5 M H2SO4 solutions with different concentration of investigated drug
Fig. 12: Intermodulation spectrum for mild steel in 0.5 M H2SO4 solutions with 600 ppm of investigated compound at 25 ºC
Fig. 11: Intermodulation spectrum for mild steel in 0.5 M H2SO4 solutions without investigated compound at 25 ºC.
Fig. 1: Molecular structure of Cephalexin Molecular formula: C16H17N3O4S, Molecular weight: 347.39
Fig. 9: The bode plot for mild steel in 0.5 M H2SO4 solution in the absence and presence of different concentrations of the investigated drug

The corrosion inhibition of mild steel in 0.5 M H₂SO₄solution by pharmaceutical antibacterial drug named Cephalexin has been investigated by using weight loss, potentiodynamic polarization, electrochemical frequency modulation technique (EFM) and electrochemical impedance spectroscopy (EIS) measurements. The polarization data showed that this drug is mixed-type inhibitor. The percentage inhibition efficiency was found to increase with increasing the concentration of the drug and with decreasing temperature. The Langmuir`s isotherm was found to provide an accurate description of adsorption behavior of this drug. Some thermodynamic parameters were computed and discussed. The correlations between advanced quantum chemical concepts and inhibition efficiency was found and discussed. The data obtained from different methods are in good agreement.

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Corrosion protection of 6061 Al-15 Vol. Pct. SiC_(p) composite using a biopolymer- An electrochemical approach

Posted on Tuesday, February 16, 2016 by Prof. Dr. R. Padmalatha

Fig. 6: Bode magnitude plots for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl at 35 °C in the presence of various concentration of inhibitor
Fig. 5: Bode phase plots for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl at 35 °C in the presence of various concentration of inhibitors
Fig. 4a: Equivalent circuit used to simulate for the obtained impedance values
Fig. 4b: Impedance data obtained for 6061 Al-15 vol. pct. SiC(P) composite corrosion in 0.05M HCl at 35 °C
Fig. 3: Impedance plot for corrosion control of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl at 35 °C
Fig. 2: Potentiodynamic polarization curves for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl containing various [starch] at 35 °C
Fig. 1: FTIR spectrum of starch
Fig. 14(a): XRD spectrum for corroded 6061 Al-15 vol. pct. SiC(P) composite
Fig. 14(b): XRD spectrum for 6061 Al-15 vol. pct. SiC(P) composite immersed in inhibited solution
Fig. 13a
Fig. 13b
Fig. 13c
Fig. 12a
Fig. 12b
Fig. 12c /// Fig. 12: SEM image of 6061 Al-15 vol. pct. SiC(P) composite material of a) freshly polished surface, b) immersed in 0.05 M HCl medium, c) immersed in 0.05 M HCl medium + 800ppm starch at 30℃
Fig. 11(b): Structure of amylopectin
Fig. 11(a): Structure of amylose
Fig. 10: ΔG0 ads vs T plot
Fig. 9: Langmuir adsorption isotherm for the adsorption of starch on 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl at different temperature
Fig. 8: Plots of ln(CR/T) vs 1/T for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl containing different concentration of inhibitors
Fig.7: Plots of ln(CR) verses 1/T for corrosion inhibition of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl containing different concentration of inhibitors
Tab. 2: Results of Potentiodynamic polarization studies for corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl containing various [starch]
Tab. 3: Impedance values obtained for the corrosion 6061 Al-15 vol. pct. SiC(P) composite in 0.05 M HCl in the absence and presence of various concentrations of starch
Tab. 4: Activation parameters for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl containing different concentrations of inhibitor
Tab. 5: Thermodynamic parameters for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl
Tab. 6: EDX data obtained for 6061 Al-15 vol. pct. SiC(P) composite surface analysis
Tab. 7: AFM data obtained for 6061 Al-15 vol. pct. SiC(P) composite surface analysis

The influence of biopolymer starch as corrosion inhibitor on 6061 Al-15 vol. pct. SiC_(p)composite in 0.05M hydrochloric acid was studied by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) technique. The surface morphology was studied using SEM, EDX, AFM and XRD techniques. The results showed that the inhibition efficiency of starch increased with increasing inhibitor concentrations and also with increase in temperatures. Starch acted as a mixed inhibitor and underwent chemical adsorption following Langmuir adsorption isotherm.

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Prof. Isabel Díaz Tang – New member of the Advisory Board

Posted on Tuesday, November 24, 2015 by Leuze Verlag

Prof. Isabel Díaz Tang Pontificia Universidad Católica del Perú Instituto de Corrosión y Protección (ICP-PUCP) Av. Universitaria 1801 San Miguel, Lima 32, Perú

A few days ago we had introduced to you Dr. Saeid Kakooei as an new member of our Advisory Board. Today I have the great pleasure to welcome Prof. Isabel Díaz Tang too. Continue reading… →

Dr. Saeid Kakooei - New member of the Advisory Board

Posted on Monday, November 23, 2015 by Leuze Verlag

Dr. Saeid Kakooei Dr. Saeid Kakooei Mechanical Engineering Department Centre for Corrosion Research Universiti Teknologi PETRONAS Malaysia

Today we want to introduce Dr. Saeid Kakooei to you. He is a new member of our Advisory Board. Working as a lecturer he is teaching Corrosion Engineering, Engineering Materials and Thermodynamic courses in Universiti Teknologi Petronas (UTP) to Undergraduate students of Mechanical Engineering Department, he has a lot of experience. Continue reading… →

Malonic Acid as Corrosion Inhibitor for Carbon Steel in 1 M Hydrochloric Acid Solutions

Posted on Thursday, October 8, 2015 by Prof. Dr. A. S. Fouda

Fig. 10: SEM micrographs of carbon steel surface (a) before of immersion in 1 M HCl, (b) after 3 h of immersion in 1 M HCl and (c) after 3 h of immersion in 1 M HCl + 300 ppm of malonic acid at 25°C
Tab. 1: Data of mass loss measurements for carbon steel in 1M HCl solution in the absence and presence of various concentrations of malonic acid 25°C
Tab. 2: Potentiodynamic data of carbon steel in 1 M HCl and in the presence of various concentrations of malonic acid at 250C
Tab. 3: EIS data of carbon steel in 1 M HCl and in the presence of various concentrations of malonic acid at 25°C
Tab. 4: Electrochemical kinetic parameters obtained by EFM technique for carbon steel in the absence and presence of various concentrations of malonic acid in 1 M HCl at 25ºC
Tab. 5: Activation parameters for dissolution of carbon steel the absence and presence of various concentrations of malonic acid in 1 M HCl
Tab.: 6 Surface composition (wt %) of carbon steel before and after immersion in 1 M HCl without and with 300 ppm of malonic acid at 25°C

The protection effect of malonic acid on carbon steel corrosion was studied in aerated stagnant 1M HCl solutions at 25⁰C. Measurements were conducted under different experimental conditions using weight loss, Tafel polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. malonic acid was found to be good inhibitor of carbon steel corrosion in1 M HCl. The adsorption of this inhibitor is found to obey the Langmuir adsorption isotherm. The calculated activation energies proposed that the inhibitor molecules being physically adsorbed onto the metal surface. Polarization data revealed that this compound behave as mixed type inhibitor.

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JEPT – Journal for Electrochemistry and Plating Technology

Edited by: DGO-Fachausschuss Forschung – Hilden / Germany

Cephalexin as Efficient Corrosion Inhibitor for Mild Steel in Acidic Media Chemical, Electrochemical and Thermodynamic Studies

Corrosion protection of 6061 Al-15 Vol. Pct. SiC_(p) composite using a biopolymer- An electrochemical approach

Prof. Isabel Díaz Tang – New member of the Advisory Board

Dr. Saeid Kakooei - New member of the Advisory Board

Malonic Acid as Corrosion Inhibitor for Carbon Steel in 1 M Hydrochloric Acid Solutions