Research
Expired Cidamex Drug as Corrosion Inhibitor for Aluminum in Acidic Solution
The inhibitive effect of expired Cidamex drug on aluminum in 1M HCl solution was studied using weight loss, hydrogen evolution, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. The results indicate that Cidamex is good inhibitor and inhibition efficiency improved with concentration and reached 99.6% at 300 ppm. Thermodynamic activation parameters that govern the process were deduced from the temperature dependence. Potentiodynamic polarization curves indicated that this drug behaves as mixed-type inhibitor. This drug was adsorbed on aluminium surface follows Langmuir adsorption isotherm. The results obtained from all investigated techniques are in good agreement.
Chemical and Electrochemical Study on the Effectively of Melilotus Officinalis Extract as save Corrosion Inhibitor for Aluminium in 1 M Hydrochloric Acid Solutions
Melilotus officinalis Extract (MOE), was investigated as a green corrosion inhibitor for aluminium in 1 M HCl solution using weight loss, hydrogen evolution, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. Surface morphology was tested using scanning electron microscope (SEM). The effect of the temperature on corrosion behavior with addition of different concentrations was studied in the temperature range of 25-45 ºC by weight loss method. Polarization curves reveal that the investigated extract is a mixed type inhibitor. The inhibition efficiency was found to increase with increase in the investigated extract concentration and increase with increase in solution temperature. The adsorption of the inhibitor on aluminium surface was found to obey the Temkin‘s adsorption isotherm. The activation and adsorption parameters were calculated and discussed. The results obtained from chemical and electrochemical techniques are in good agreement.
Corrosion Inhibition of Mild Steel in Aqueous Solutions using Nonionic Surfactants
The inhibiting effect of nonionic surfactant of Tween- 20 and 60 on the corrosion of mild steel in 0.5 M HCl was studied by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM).techniques The results show that inhibition efficiency increases with increasing the inhibitor concentration, while it decreases with increasing the temperature. The adsorption of Tweens on the mild steel surface obeys the Langmuir adsorption isotherm. The effect of temperature on the corrosion behavior of mild steel was also studied at four temperatures ranging from 25 to 55ºC the thermodynamic parameters were calculated and discussed. The values of free energy of adsorption for investigated Tweens were calculated. It was found the adsorption process is spontaneous and increases, in the same direction as inhibition efficiency. Polarization curves show that Tween-20 and 60 is mixed-type inhibitors but the cathode is more polarized than the anode. The results obtained from chemical and electrochemical techniques are in good agreement.
Streptoquin and Septazole: Antibiotic Drugs as Corrosion Inhibitors for Copper in Aqueous Solutions
The inhibiting effect of streptoquin and septazole towards the corrosion of the copper in 0.1M of HCl solution has been studied by potentiodynamic polarization measurements, electrochemical impedance spectroscopy (EIS) and Electrochemical frequency modulation technique (EFM). Potentiodynamic polarization curves indicted that these compounds behave as mixed-type inhibitors. These drugs were adsorbed on copper surface follow Langmuir adsorption isotherm. The results obtained from EIS and EFM are in good agreement with potentiodynamic polarization measurements. Some quantum chemical parameters were calculated and compared with the experimental data.
