{Electrochemical and quantum chemical parameters of (-)-(S)-9-flu¬oro-2,3-dihydro-3-methyl-10-(4-methyl-1-pipera-zinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acidas anti-corrosive agent for API 5L X-52 steel}
http://dx.doi.org/10.5599/jese.744 235
J. Electrochem. Sci. Eng. 10(3) (2020) 235-244; http://dx.doi.org/10.5599/jese.744
Open Access: ISSN 1847-9286
www.jESE-online.org
Original scientific paper
Electrochemical and quantum chemical parameters of
(-)-(S)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-pipera-
zinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic
acidas anti-corrosive agent for API 5L X-52 steel
Fidelis E. Abeng1,2,, Magdalene E. Ikpi2, Victor E. Okpashi3, Onumashi A. Ushie4 and
Mbang E. Obeten1
1Material and Electrochemistry Research Group, Department of Chemistry, Cross River University of
Technology, Calabar, P. M. B 1123 Calabar, Nigeria
2Corrosion and Electrochemistry Research Laboratory, Department of Pure and Applied Chemistry,
University of Calabar, P.M.B. 1115 Calabar, Nigeria
3Department of Biochemistry, Cross River University of Technology, P. M. B.1123 Calabar, Nigeria
4Department of Chemical Science, Federal University Wukari, Nigeria
Corresponding author: fidelisabeng@yahoo.com
Received: November 1, 2019; Revised: January 5, 2020; Accepted: January 6, 2020
Abstract
The inhibitive action of (-)-(S)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-
-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid (Levaquin) on API 5L X-52 steel
in 2 M HCl solution was investigated using potentiodynamic polarization method and
quantum chemical study. Levaquin drug showed good inhibition efficiency of 88 and 95 %
at 303 and 323 K, respectively. The results of experimental measurements revealed that
Levaquin drug works as a mixed type inhibitor. Langmuir thermodynamic model was tested
to describe the mode of inhibitor adsorption on the steel surface. The quantum chemical
calculations confirmed the efficacy of Levaquin drug as a corrosion inhibitor.
Keywords
Corrosion; density functional theory; potentiodynamic polarization; organic inhibitor; adsorption.
Introduction
Corrosion is a destructive attack on a material caused by its reaction with environment. The
severe consequence of corrosion has become a problem to the society. Corrosion causes waste of
valuable resources, loss or contamination of products, and reduction in efficiency of the cost
maintenance. Corrosion destroys the safety of metal structures and reduces technological progress.
http://dx.doi.org/10.5599/jese.744
http://dx.doi.org/10.5599/jese.744
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mailto:fidelisabeng@yahoo.com
J. Electrochem. Sci. Eng. 10(3) (2020) 235-244 LEVAQUIN AS ANTI-CORROSIVE AGENT
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Therefore, some control measures are needed to be implemented in order to inhibit corrosion,
thereby prolonging the life span of metal structures. Use of organic corrosion inhibitors is the most
efficient and economical approach among all anticorrosive methods. These inhibitors, however,
cannot be used for large scale corrosion inhibition because of the growing ecological awareness
about their high hazardous environmental implication [1]. Thus, some non- or low-toxic alternatives
must be developed to replace traditional hazardous inhibitors. In recent years, some pharmaceutical
drugs were recommended for such a purpose such as azithromycin [2], amoxicillin [3], cefixime [4],
ciprofloxacin [5], amlodipine[6], oxytetracycline [7], doxycycline [8], norfloxacin [9], enrofloxacin
[10], amifloxacin [11], pefloxacin [12], penicillin V [13], ampicillin [14], cloxacillin [15] and
flucloxacillin [16]. All these pharmaceutical compounds are rich in heteroatoms like nitrogen,
sulphur and oxygen, bonds and/or aromatic rings, which are major adsorption centres in good
corrosion inhibitors.
One of the most widely used metals is carbon steel, i.e. an alloy of iron and carbon which corrodes
in the form of rusting. Rusting is the process of oxidation in which iron combines with water and oxy-
gen to form corrosion products (rust). The present study aims to investigate (-)-(S)-9-fluoro-2,3-di-
hydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic
acid (Levaquin) as corrosion inhibitor for API 5L X-5 carbon steel in 2 M HCl solution, using poten-
tiodynamic polarization method and density functional theory (DFT) for the calculation of quantum
chemical parameters.
Experimental
Acid-inhibitor solution preparation
Levaquin is an antibiotic drug used to treat several bacterial infections. It belongs to the class of
fluoroquinolones and has molecular formula C18H20FN3O4 and molecular weight of 361.368 g/mol. The
tablets of Levaquin were supplied from Peace land Pharmaceutical shop in Calabar-Nigeria. 500 mg of
the drug was ground and dissolved in one liter of prepared 2 M HCl solution. The resultant solution was
filtered to obtain the stock solution of concentration 500 ppm. Solutions of concentrations 50, 100, 200
and 300 ppm were prepared from this stock solution using serial dilution method [17,18].
Sample preparation
API 5L X-52 steel specimen with chemical composition shown in Table 1 was obtained from a
cylindrical pipeline. The steel specimen was mechanically press cut into coupons of dimensions
111 cm. The coupons were polished using different grades of emery paper to obtain mirror
polished surfaces. Copper wires were soldered to the coupons and mounted in epoxy resin to
produce the working electrode. Prior to running electrochemical experiments, the coupons were
once again polished, rinsed in distilled water, degreased in acetone and air dried.
Table 1. Chemical composition of API 5L X-52 steel
Element C Mn P S Si V Cr Ni Mo Al Nb Ti Fe
Content, %wt 0.22 1.40 0.025 0.015 0.45 0.15 0.20 0.20 0.08 0.03 0.15 0.04 97.04
Electrochemical experiments
Potentiodynamic polarization experiments were carried out using a conventional three-electrode
electrochemical cell assembly. Steel coupons with an exposed surface area of 1 cm2 was used as the
working electrode, saturated calomel electrode (SCE) as the reference electrode and platinum plate
F. E. Abeng et al. J. Electrochem. Sci. Eng. 10(3) (2020) 235-244
http://dx.doi.org/10.5599/jese.744 237
as the counter electrode. The polarization measurements at 303 and 323 K, as well as estimations
of corresponding polarization resistance values were performed using Gamry electrochemical
analyzer. Potentiodynamic current-potential curves were recorded by changing the electrode
potential automatically at the scan rate of 0.5 mV s-1, from 0.25 V below to 0.60 V above the
corrosion potential (Ecorr). Before each run, the working electrode was immersed in the test solution
for 30 minutes to attain steady state. The corrosion rate (CR) of the metal was examined through
the corrosion current density (jcorr) using the equation
corrEWCR=
Kj
d
(1a)
where K is conversion factor (3272 mm A-1 cm-1 y-1), EW is equivalent weight of corroding metal in g
equivalent, and d is density of the metal in g cm-3. The inhibition efficiency (IE) was evaluated from
jcorr values using the following equation [19-21]
corr(blank) corr(inh)
corr(blank)
IE 100
j j
j
−
= (1b)
where jcorr(blank) and jcorr(inh) are corrosion current densities measured in the blank solution and
solution containing inhibitor, respectively.
Quantum chemical study
The density functional theory (DFT) was used for the quantum chemical calculations. Materials
Studio 4.0 software with a basis set of 6.311 G and hybrid functional of B3LYP were used to treat
the exchange-correlation interaction of electrons.
Results and discussion
Potentiodynamic polarization measurements
Polarization plots forAPI 5L X-52 steel coupons measured in 2 M HCl solution in the absence and
presence of different concentrations of Levaquin (50, 100, 200, 300 and 500 ppm) and at two tem-
peratures (303 and 323 K) are presented in Figures 1 and 2.
j / A cm-2
Figure 1. Potentiodynamic polarization curves for carbon steel in 2 M HCl in the absence and
presence of denoted concentrations of Levaquin at 303 K
E
/
V
v
s.
S
C
E
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In both cases, cathodic and anodic branches of Tafel polarization curves in the presence of
Levaquin are shifted towards lower current density values, which may be a result of the adsorbed
inhibitor molecules [10]. It can also be deduced from the plots in Figures 1 and 2 that the studied
molecules inhibit corrosion by controlling both cathodic and anodic reactions, i.e. as mixed type
inhibitor [19]. In other words, addition of inhibitor reduces anodic dissolution of API 5L X-52 steel
and also retards the cathodic reaction. Electrochemical parameters deduced from the polarization
curves measured at two temperatures are listed in Table 2.
j / A cm-2
Figure 2. Potentiodynamic polarization curves for carbon steel in 2 M HCl in the absence and
presence of denoted concentrations of Levaquin at 323 K
Table 2. Electrochemical parameters obtained from Tafel plots
T / K c / ppm a / mVdec-1 c /mV dec-1 Ecorr/ mV jcorr / μAcm
-2 CR, mm y-1 Rp / Ω cm2 IE, %
303
Blank 102 454 -446 560 6.498 10633 -- --
50 72 84 -412 98 1.137 22357 0.83 83
100 71 84 -422 92 1.067 23137 0.84 84
200 71 79 -417 80 0.928 24053 0.86 86
300 64 90 -408 71 0.824 29029 0.87 87
500 61 111 -402 65 0.754 41503 0.88 88
323
Blank 116 217 -442 3560 41.307 5433 -- --
50 76 391 -333 3370 39.102. 9469 0.05 5
100 61 249 -333 2040 23.670 5284 0.43 43
200 53 541 -326 1770 20.537 22229 0.50 50
300 74 100 -405 622 7.217 4752 0.83 83
500 56 87 -425 188 2.181 8524 0.95 95
It can be observed from data in Table 2 that increase in the concentration of inhibitor results in
decreased corrosion current density and corrosion rate, respectively. Simultaneous increase of
inhibition efficiency (IE) or degree of surface coverage ( ), as well as polarization resistance (Rp)
suggest that the studied compound blocked the available surface area of steel [19-23]. Note that
the values of listed in Table 2 were determined using Equation (1b) divided by 100.
Effect of temperature
Temperature dependence gives some insight into the mechanism of inhibitor adsorption,
because increase of inhibition efficiency of an inhibitor with increase in temperature predicts
E
/
V
v
s.
S
C
E
F. E. Abeng et al. J. Electrochem. Sci. Eng. 10(3) (2020) 235-244
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chemical adsorption mechanism. At the other side, physical adsorption mechanism is feasible for
decreasing inhibition efficiency at increasing temperature [3]. Hence lower inhibition efficiency at
higher temperature (Table 2) suggests that a physical adsorption mechanism is generally operative
in inhibition of steel corrosion by Levaquin, except at its highest concentration. Activation energy
has also been used to predict the mechanism of adsorption as it depends on temperature. Generally,
when the activation energy of an inhibitor is higher than that of the blank solution, physical
adsorption mechanism is implied, whereas when the activation energy is lower than that of
uninhibited solution, chemical adsorption is probable adsorption mechanism. Therefore, increase
of the inhibition efficiency with increase in temperature corresponds to decrease of corrosion acti-
vation energy in the presence of inhibitor, suggesting thus the chemisorption mechanism. In rever-
se, decrease of inhibition efficiency with increase of temperature corresponds to increase in cor-
rosion activation energy in the presence of inhibitor, suggests physical adsorption mechanism [23].
The apparent activation energies (Ea) for dissolution of API 5L X-52 steel in 2 M HCl in the absence
and presence of the inhibitor were calculated from the condensed Arrhenius equation [24]:
a2
1 1 2
CR 1 1
log =
CR 2.303
E
R T T
−
(2)
where R is gas constant, while CR1 and CR2 are corrosion rates at temperatures T1 and T2,
respectively. The calculated Ea values are listed in Table 3, showing generally higher values in
presence of inhibitor than in blank solution, except for the highest concentration of Levaquin. In
agreement with previous observations on IE temperature changes, it seems that physisorption
mechanism is operating at lower concentration of Levaquin. Heat of adsorption (Qads) was evaluated
using the following equation:
2 1 1 2
ads
2 1 2 1
2.303 log log
1 1
T T
Q R
T T
= −
− − −
(3)
where 1 and 2 are degree sof surface coverage at temperatures T1 and T2, respectively. The
estimated values of Qads are also listed in Table 3. The negative values of Qads are consistent with an
inhibitor that is physically adsorbed on the metal surface [23,25].
Table 3. Calculated values of activation energy (Ea) and heat of adsorption (Qads)
c / ppm Ea / kJ mol-1 Qads / kJmol-1 1 2
Blank 73.33 -- -- --
50 140.71 -57.71 0.83 0.05
100 122.57 -78.11 0.84 0.43
200 123.14 -72.53 0.86 0.50
300 86.42 -15.34 0.87 0.83
500 43.03 -35.07 0.88 0.95
Adsorption isotherm
A possible way of discussing the mechanism of corrosion inhibition is through consideration of
adsorption of organic compounds. The adsorbed compounds block the surface of the metal from
corrosive agents, reducing thus the corrosion process. Adsorption provides information about
interaction among adsorbed molecules, as well as their interaction with the metal surface.
Adsorption isotherm is very important in proposing the mechanism of heterogeneous organo-
electrochemical reaction on solid surfaces [26]. Different adsorption isotherm models were fitted
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240
to the experimental data, and it was found that Langmuir adsorption isotherm fitted well to the
experimental data (Figure 3). Langmuir adsorption isotherm is defined as
2 ads
1c
c
K
= + (4)
where c is bulk concentration of adsorbed (inhibitor) species, while Kads is equilibrium adsorption
constant (L mol-1), equal to the reciprocal of the intercept of straight line in Figure 3.
Figure 3. Langmuir adsorption isotherm plot for the adsorption of Levaquin on API 5L X-52steel in 2 M HCl
As shown in Table 4, the values of slopes and correlation coefficient (R2) illustrate that at both
temperatures, the experimental data agree very well with linear relationships. The thermodynamic
adsorption parameter known as free energy of adsorption (ΔGads) was calculated at different
temperatures using the equation
ΔGads= -2.303RT log 55.5 Kads (5)
where 55.5 is concentration of water in mol L-1, R is gas constant and T is absolute temperature
Table 4. Calculated values of free energy of adsorption
T / K Kads Slope ΔGads / kJ mol-1 R2
303 0.183 1.126 -18.41 0.995
323 0.0062 0.717 -66.87 1
The negative signs of ΔGads in Table 4 indicate that adsorption of Levaquin on the surface of
API 5L X-52 steel is spontaneous. Generally, the values of ΔGads higher than -40 kJ mol-1 reflect
chemisorption which involves charge sharing or transfer from inhibitor molecules to the metal
surface to form a coordinate bond type, while values of ΔGads below -40 kJ mol-1 suggest electrostatic
interaction between metal surface and charged organic molecules in the bulk of the solution
identified as physisorption [23]. The calculated ΔGads values presented in Table 4 are between -18.41
and -66.87 kJ mol-1, indicating that the adsorption mechanism of Levaquin on API 5L X-52 steel in 2
M HCl solution is physical adsorption at 303 K and chemical adsorption at 323 K.
Quantum chemical calculations
Quantum chemical calculations were employed to gain insight into the inhibition mechanism of
Levaquin drug by examining the structure-reactivity correlation of the compound [1,19]. Figure 4
shows a complete geometric optimization of the studied molecule, while Figure 5 displays the
frontier molecular orbitals namely, the highest occupied molecular orbital (HOMO) and the lowest
y = 1.1266 x + 5.4727
R² = 1
y = 0.7174 x + 160.79
R² = 0.9953
0
100
200
300
400
500
600
0 200 400 600
(c
/
)
/
p
p
m
c / ppm
303 K
323 K
F. E. Abeng et al. J. Electrochem. Sci. Eng. 10(3) (2020) 235-244
http://dx.doi.org/10.5599/jese.744 241
unoccupied molecular orbital (LUMO), present in studied compound. The calculated quantum
chemical parameters obtained according to [16-24] are listed in Table 5.
Figure 4. Optimized structure of Levaquin molecule
HOMO LUMO
Figure 5. Frontier molecular orbital (HOMO and LUMO) structures of Levaquin
Table 5. Calculated quantum chemical parameters for Levaquin
EHOMO /eV ELUMO /eV ΔE / eV IP, eV EA, eV /eV / eV μ / D ΔN /e
-6.817 -3.315 3.502 6.817 3.315 3.066 1.751 0.571 12.28 7.327 0.501
Frontier molecular orbital calculations
The values of energy of the highest occupied molecular orbital (EHOMO) and energy of the lowest
unoccupied molecular orbital (ELUMO) were obtained from DFT analysis. EHOMO is often connected
with the electron donating ability of a molecule, while ELUMO shows its electron accepting ability.
According to the results presented in Table 5, higher energy value of EHOMO reveals the ability of the
studied molecule to donate electron to an empty molecular orbital. Thus, increase in EHOMO value
facilitates adsorption of inhibitor [26-27], while the energy of LUMO shows the potential of the
molecule to accept electrons.
Energy gap
Energy gap can also be used to predict inhibition efficiency of a compound or to develop a
theoretical model for explaining the structure and confirmation barrier in many molecular systems.
Energy gap (ΔE) is calculated using the following equation [28-29];
ΔE = ELUMO- EHOMO (6)
From our study the value of ΔE in Table 5 is within the range of values of good corrosion
inhibitors [29].
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Ionization potential and electron affinity
Ionization potential (IP) is the maximum energy necessary to remove an electron from many
electron atoms in a gas phase, whereas electron affinity (EA) is the energy released when an electron
attaches to a gas phase atom. According to the following equations
IP = -EHOMO (7)
EA = -ELUMO (8)
IP is related to EHOMO while EA is related to ELUMO. The calculated values of IP and EA are listed in
Table 5 [30-31].
Electronegativity
Electronegativity reflects the power of an electron or group of atoms to attract electrons towards
itself. The Koopman’s theorem was used to estimate the electronegativity () of the studied
compound using the following equation
χ = ½(EHOMO + ELUMO) (9)
The higher the value of χ, the more effective is the inhibitor and vice versa. Data in Table 5 shows
that χ value is within the range of effective inhibitors. These results agree with the experimental
results of other studies [24,31].
Global hardness and softness
Global hardness (ƞ) measures the resistance of an atom to charge transfer, whereas global
softness (σ) describes the capacity of an atom or group of atoms to receive electrons [3,25]. The
expressions for ƞ and σ are given as follows
ƞ = ½(EHOMO – ELUMO) (10)
= 1/ƞ (11)
A hard molecule requires a large ΔE and a soft molecule requires a small ΔE. Soft molecules could
therefore easily offer electrons to an acceptor system that make them more reactive than hard
molecules. Furthermore, adsorption may occur at the point of a molecule where absolute softness
is high [26,32]. Table 5 shows that the values of global hardness and global softness are within the
range of effective corrosion inhibitors.
Dipole moment
The dipole moment (μ) is another index that is often used for the prediction of corrosion
inhibition process. It is the measure of polarity in a bond, related to the distribution of electrons in
a molecule. Therefore, inhibitors with high dipole moment form strong dipole-dipole interactions
with the metal, ensuring a strong adsorption on the surface of the metal and leading to higher
inhibition efficiency. It was observed that the dipole moment value for Levaquin shown in Table 5
correlates with the experimental results reported elsewhere [32-35].
Global electrophilicity index
Global electrophilicity index () is estimated by combining the electrophilicity and chemical
hardness parameters according to the following relation;
2
2
χ
ω
η
= (12)
A high value of electrophilicity index describes a good electrophile while a small value describes
a good nucleophile [25-32]. The results presented in Table 5 show good correlations with the
F. E. Abeng et al. J. Electrochem. Sci. Eng. 10(3) (2020) 235-244
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experimental result of the study. The fraction of transferred electrons (ΔN) can be evaluated using
the following equation:
( )
inh
Fe inh
Δ
2
W χ
N
η η
−
=
−
(13)
where W is work function, χinh is electronegativity of inhibitor, while ƞFe and ƞinh are the global hardness
of Fe and inhibitor, respectively. The electronegativity χ was calculated using eq. (9), the value of ƞFe
was taken as 0 eV mol-1, while ƞinh was calculated using eq. (10). To calculate N, the work function
with the value of W = 4.82 for Fe (110) surface was applied. For the value of ΔN > 0, the electron
transfer takes place between an inhibitor molecule and the metal surface, while for ΔN< 3.6, the
electron donating ability of an inhibitor molecule is increased. All the calculated values of this study
are within the range of values already reported for some excellent corrosion inhibitors [27-28,36].
Conclusions
(-)-(S)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-
benzoxazine-6-carboxylic acid was tested as corrosion inhibitor process on API 5L X-52 steel in 2 M HCl
solution, using potentiodynamic polarization and quantum chemical calculations. The following
conclusions can be derived from the present study.
1. Inhibition efficiency of Levaquin increases with increase in its concentration.
2. Adsorption behaviour of Levaquin follows Langmuir adsorption isotherm and depending on
temperature, reflects either physical or chemical adsorption mechanism. Levaquin is good
corrosion inhibitor which acts as a mixed type inhibitor.
3. Results of calculations of quantum chemical parameters carried out in this study are in good
agreement with experimental results.
References
[1] Y. Qiang, S. Zhang, B. Tan, S. Chen, Corrosion Science 133 (2018) 6-16.
[2] O. A. Abdullatef, Journal of Advances in Chemistry 11 (2015) 3642-3655.
[3] A. A. Siaka, N. O. Eddy, S. O. Idris, L. Magaji, Z. N. Garba, I. S. Shabanda, International Journal of Modern
Chemistry 4 (2013) 1-10.
[4] I. Naqvi, A. R. Saleemi, S.Naveed, International Journal of Electrochemical Science 6 (2011) 146-161.
[5] I. A. Akpan, N. O. Offiong, International Journal of Chemistry and Materials Research 2 (2014) 23-29.
[6] I. A. Akpan, N. O. Offiong, Chemical and Process Engineering Research 26 (2014) 20-23.
[7] J. A. Von Fraunhofer, S. H. Stidhan, Journal of Biomedical Engineering 13 (1991) 424- 428.
[8] S. K. Shukla, M. A. Quraishi, Corrosion Science 52 (2010) 314-322.
[9] X. Pang, X. Ran, F. Kuang, J. Xie, B. Hou, Chinese Journal of Chemical Engineering 18 (2010) 337-345.
[10] S. Acharya, S. N. Upadhyay, Transition Indian Institute of Metal 57 (2004) 297-306.
[11] G. Gece, Corrosion Science 53 (2011) 3873-3898.
[12] A. S. Fouda, H. A. Mostafa, H. M. El-Abbasy, Journal of Applied Electrochemistry, 40 (2010) 163-173.
[13] N. O. Eddy, S. A. Odoemelam, Advanced Natural and Applied Science 2 (2008) 225-232.
[14] M. Abdallah, Corrosion Science 46 (2004) 1981-1996.
[15] A. S. Fouda, A. A. Al-Sarawy, F. S. Ahmed, H. M. El-Abbasy, Corrosion Science 51 (2009) 439-702.
[16] X. H. Pang, W. J. Guo, W. H. Li, J. D. Xie, B. R. Hou, Science of China Series B Chemistry 51 (2008) 928-936.
[17] P. O. Ameh, P. Ukoha, P. Ejikeme, N.O. Eddy, Industrial Chemistry 2 (2016) 2469-9764.
[18] S. Kumar, H. Vashisht, L. O.Olasunkanmi, I. Bahadur, H. Verma, G. Singh, I .B. Obot, E. E. Ebenso,
Scientific Reports 6 (2016) 30937-30949
[19] J. Bhawsar, P.K. Jain, S. P. Jain, Alexandria Engineering Journal 54 (2015) 769-775.
[20] P. C. Okafor, E. E. Ebenso, U. J. Ekpe, International Journal of Electrochemical Science 5 (2010) 978-993.
[21] A. S. Fouda, G. E. Bekheit, M. W. El-Sherbari, Journal of Bio and Tribo-Corrosion 11 (2016) 1-16.
[22] N. O. Eddy, S. R. Stoyanov, E. E. Ebenso, International Journal of Electrochemical Science 5 (2010) 1127-1150.
http://dx.doi.org/10.5599/jese.744
J. Electrochem. Sci. Eng. 10(3) (2020) 235-244 LEVAQUIN AS ANTI-CORROSIVE AGENT
244
[23] M. M. Kabanda, L. C. Murulana, M. Ozcan, F. Karadag, I. Dehri, I. B. Obot, E. E. Ebenso, International
Journal of Electrochemical Science 7 (2012) 5035-5056.
[24] H. Elmsellem, H. Nacer, F. Halaimia, A. Aouniti, I. Lakehal, A. Chetouani, S. S. Al-Deyab, I. Warad, R.
Touzani, B. Hammouti, International Journal of Electrochemical Science 9 (2014)5329-5351.
[25] G. H. Koch, M. P. H. Brongers, N. G. Thompson, Y. P. Virmani, J. H. Payer, Corrosion cost and preventive
strategies, NACE, Houston TX, United States, (2002) 773.
[26] P. O. Ameh, P.U. Koha, N. O. Eddy, Chemical Sciences Journal 6 (2015)
doi: 10.4172/2150-3494.1000100
[27] M. Y. Habibat, N. O. Eddy, J. F. Iyum, C. E. Gimba, E. E. Oguzie, Chemical Material Research 2 (2012) 1-12.
[28] R. Chami, M. Boudalia, S. Echihi, M. ElFal,A. Bellaouchou, A. Guenbour, M. Tabyaoui, E. M.Essassi, A.
Zarrouk, Y. Ramli, Journal of Materials and Environmental Sciences 8 (2017) 4182-4192.
[29] G. Raja, K. Saravanan, S. Sivakumar, Rasayan Journal of Chemistry 8 (2015) 8-12.
[30] M. E. Mohammed, K. K. Taha, S. A. Khalil, S. A. Talab, International Letters of Chemistry, Physics and
Astronomy 14 (2013) 87-102.
[31] M. Lebrini, M. Traisnel, M. Lagrenée, B. Mernari, F. Bentiss, Corrosion Science 50 (2008) 473-479.
[32] B. Tan, S. Zhang, W. Li, X. Zuo, Y. Qiang, L. Xu, J. Hao, S. Chen. Journal of Industrial and Engineering
Chemistry 77 (2019) 449-460.
[33] A. A. Khadom, A. N. Abd, N. A. Ahmed, South African Journal of Chemical Engineering 25 (2018) 13-21.
[34] V. C. Anadebe, O. D. Onukwuli, M. Omotioma, N. A. Okafor, South African Journal of Chemistry 71
(2018) 51-61.
[35] T. He, W. Emori, R. H. Zhang, P. C. Okafor, M. Yang C. R. Cheng Bioelectrochemistry, 130 (2019) 107332-
107342
[36] M. Ramezanzadeh, G. Bahlakeh, B. Ramezanzadeh, Journal of Molecular Liquids 292 (2019) 111387-
111396.
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