Electrochemical, Spectrochemical and Quantum Chemical Studies on Dimedone as Corrosion Inhibitor for Copper in Acetonitrile | Chapter 09 | Advances in Applied Science and Technology Vol. 3
A number of techniques have been
applied in the investigation of inhibition abilities of dimedone (DMD) for
copper in acetonitrile at 25°C. By potentiodynamic polarization and
electrochemical impedance spectroscopy (EIS), the corrosion resistance was found
to be increased with inhibitor concentration up to 93.68% inhibition efficiency
at 3.00 mM, indicating that DMD molecules can cumulatively adsorb on the copper
surface and finally form a protective film on copper-solution interface. This
is also supported by the decreasing of copper oxidation in cyclic voltammogram.
Polarization curves revealed that DMD is of mixed type inhibitor.
The adsorption of DMD on copper surface
obeys the Langmuir isotherm and the adsorption mechanism is of physisorption
type. The values of standard energy of adsorption (∆Goads)
were found to be in good agreement for both polarization and impedance
techniques to be -8.17 and -8.43 kJmol-1 respectively. Fourier
Transform Infrared spectroscopy (FT-IR) confirmed the interaction of copper
with oxygen on DMD. The mole ratio method suggested that the complexation ratio
of copper-DMD is 1:2. Scanning electron microscopy (SEM) of copper surface
after immersion in DMD solution indicates the presence of a protective layer on
the electrode surface. The frontier molecular orbital energy EHOMO
(highest occupied molecular orbital), ELUMO (lowest unoccupied
molecular orbital) and the Mulliken charge distribution obtained from Quantum
chemical calculations revealed (∆E) for DMD 0.2091 hartree, reflecting strong
adsorption of the molecules on copper surface. The enhanced corrosion
inhibition is possibly due to the compact film structure blocking electron
transfer at the electrode surface. This provides a typical example in understanding
the system as well as interpretation of the data by both traditional and
advanced technology to support the newly coming technology which would make
science much more fruitful.
Author(s) Details
Pipat Chooto
Analytical Chemistry
Division, Department of Chemistry, Faculty of Science, Prince of Songkla
University, Hatyai, Songkhla 90112, Thailand.
Sontaya Manaboot
Analytical Chemistry
Division, Department of Chemistry, Faculty of Science, Prince of Songkla University,
Hatyai, Songkhla 90112, Thailand.
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