Electrochemical Behavior of Magnetite on a Carbon Steel Electrode in Hydrochloric Acid-Disodium Citrate Buffer Solutions

CORROSION ◽  
1991 ◽  
Vol 47 (11) ◽  
pp. 840-851 ◽  
Author(s):  
I. H. Plonski
2018 ◽  
Vol 10 (1) ◽  
pp. 102-115
Author(s):  
Cinthia E. B. Maia ◽  
Gilberto A. Romeiro ◽  
Márcia C. C. Veloso ◽  
Mariane F. dos Santos ◽  
Marcos V. da Silva Santana ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3535
Author(s):  
Naba Jasim Mohammed ◽  
Norinsan Kamil Othman ◽  
Mohamad Fariz Mohamad Taib ◽  
Mohd Hazrie Samat ◽  
Solhan Yahya

Extracts from plant materials have great potential as alternatives to inorganic corrosion inhibitors, which typically have harmful consequences. Experimental and theoretical methodologies studied the effectiveness of agricultural waste, namely, date palm seed extract as a green anti-corrosive agent in 0.5 M hydrochloric acid. Experimental results showed that immersion time and temperature are closely related to the effectivity of date palm seed as a corrosion inhibitor. The inhibition efficiency reduced from 95% to 91% at 1400 ppm when the immersion time was increased from 72 h to 168 h. The experimental results also indicated that the inhibition efficiency decreased as the temperature increased. The presence of a protective layer of organic matter was corroborated by scanning electron microscopy. The adsorption studies indicated that date palm seed obeyed Langmuir adsorption isotherm on the carbon steel surface, and Gibbs free energy values were in the range of −33.45 to −38.41 kJ·mol−1. These results suggested that the date palm seed molecules interacted with the carbon steel surface through mixture adsorption. Theoretical calculations using density functional theory showed that the capability to donate and accept electrons between the alloy surface and the date palm seed inhibitor molecules is critical for adsorption effectiveness. The HOMO and LUMO result indicated that the carboxyl (COOH) group and C=C bond were the most active sites for the electron donation-acceptance type of interaction and most auxiliary to the adsorption process over the Fe surface.


1959 ◽  
Vol 37 (11) ◽  
pp. 1859-1869 ◽  
Author(s):  
R. J. Abraham ◽  
E. Bullock ◽  
S. S. Mitra

The structures of the ions formed by several alkyl pyrroles in hydrochloric acid are deduced from proton resonance spectra. Basicity values for three alkyl pyrroles are determined from ultraviolet spectra of their salts in buffer solutions. An attempt is made to estimate the basicity of other pyrroles from the variation of the—OD stretching frequency of methanol-d in solution in the pyrroles. Variations of the free and bonded NH frequencies of alkyl pyrroles are shown to be a simple function of the positions and number of the substituents.


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