Synthesis, surface properties and inhibition behavior of novel cationic gemini surfactant for corrosion of carbon steel tubes in acidic solution

Article abstract of DOI:10.1016/j.molliq.2015.06.051

In the present investigation a novel gemini surfactant namely N,N-((oxalylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-1-aminium bromide) was synthesized, characterized, and tested as a corrosion inhibitor for carbon steel in 1 M HCl solution. The corrosion inhibition efficiency was determined by using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and weight loss methods. From the results, it was clear that the synthesized inhibitor is a good inhibitor for carbon steel in 1 M HCl solution. The inhibition efficiency increases by increasing the concentration of the inhibitor. Thermodynamic and activation parameters were discussed. The synthesized inhibitor's adsorption was found to follow the Langmuir's adsorption isotherm.

Full text of DOI:10.1016/j.molliq.2015.06.051

Journal of Molecular Liquids 211 (2015) 126–134
Contents lists available at ScienceDirect
Journal of Molecular Liquids
journal homepage: www.elsevier.com/locate/molliq
Synthesis, surface properties and inhibition behavior of novel cationic
gemini surfactant for corrosion of carbon steel tubes in acidic solution
b
b
b
M.A. Hegazy a, , S.M. Rashwan , M.M. Kamel , M.S. El Kotb
⁎
a
Egyptian Petroleum Research Institute (EPRI), Nasr City, Cairo 11727, Egypt
Department of Chemistry, Faculty of Science, Suez Canal University, Ismailia 41522, Egypt
b
a r t i c l e i n f o
a b s t r a c t
Article history:
In the present investigation a novel gemini surfactant namely N,N՝-((oxalylbis(oxy))bis(ethane-2,1-
diyl))bis(N,N-dimethyldodecan-1-aminium bromide) was synthesized, characterized, and tested as a corrosion
inhibitor for carbon steel in 1 M HCl solution. The corrosion inhibition efficiency was determined by using elec-
trochemical impedance spectroscopy (EIS), potentiodynamic polarization, and weight loss methods. From the re-
sults, it was clear that the synthesized inhibitor is a good inhibitor for carbon steel in 1 M HCl solution. The
inhibition efficiency increases by increasing the concentration of the inhibitor. Thermodynamic and activation
parameters were discussed. The synthesized inhibitor's adsorption was found to follow the Langmuir's adsorp-
tion isotherm.
Received 13 April 2015
Received in revised form 11 June 2015
Accepted 16 June 2015
Available online xxxx
Keywords:
Cationic surfactants
Synthesis
© 2015 Elsevier B.V. All rights reserved.
Surface activity
Corrosion inhibition
1. Introduction
1 M HCl solution using electrochemical impedance spectroscopy (EIS),
potentiodynamic polarization and weight loss methods. In addition,
Corrosion process plays an important role in the field of economics
and safety. Various types of steel including carbon steel are used in dif-
ferent industries (chemical and electrochemical industries, nuclear,
power, petroleum, and food industry), and also in daily life. However,
carbon steel suffers from a certain type of corrosion within some envi-
ronments. For this cause, the electrochemical properties of carbon
steel are the subject of many studies. Hydrochloric acid is widely used
as aggressive solution to remove unwanted scale and rust in many in-
dustrial processes. Due to the aggressiveness of acids, corrosion can be
minimized by addition of corrosion inhibitors in small concentrations
[1–7]. Surfactants are among those organic compounds which can be
used as corrosion inhibitors in acid solutions [8–10]. The ability of a sur-
factant to physical (electrostatic) adsorption or chemisorption onto the
metal surface was found to be responsible for the corrosion inhibition of
the metal surface [11]. Gemini surfactants are a new generation of sur-
factants that have been paid considerable attention. A gemini surfactant
is consists of two hydrophilic groups and two hydrophobic groups that
are joined together by a rigid and flexible aromatic or an aliphatic spacer
in a molecular structure [12–16]. They are more surface-active and have
much lower critical micelle concentration (CMC) values than their
monomeric counterparts. Because of their unique physical–chemical
properties, gemini surfactants continue to gain widespread interest for
various applications [17]. The aim of this work is to study the effect of
the prepared surfactant on the corrosion inhibition of carbon steel in
the surface properties of the new gemini surfactant were determined.
2. Experimental methods and materials
2.1. Synthesis of inhibitor
The inhibitor that was used in this work was prepared through
two steps. In the first step, we react (4.457 g, 0.05 mol) 2-
dimethylaminoethanol with (12.462 g, 0.05 mol) dodecyl bromide.
The reactants were allowed to reflux in ethanol at 80 °C for 24 h,
and then the reaction mixture was left to cool to room temperature.
After that the mixture was washed with diethyl ether and was
filtrated by using a filter paper to separate the white precipitate
(N-(2-hydroxyethyl)-N,N-dimethyldodecan-1-aminium bromide).
In the second step, the gemini surfactant compound was synthesized
by a condensation reaction between (6.7674 g, 0.02 mol) N-(2-
hydroxyethyl)-N,N-dimethyldodecan-1-aminium bromide and
(0.9003 g, 0.01 mol) oxalic acid in toluene as a solvent and p-
toluene sulfonic acid as a dehydrating agent at 140 °C for 8 h. The
reaction was completed when the water (0.36 g, 0.02 mol) was
removed from the reaction system. Furthermore, the reaction
mixture was distilled under vacuum to completely remove the sol-
vent. The produced compound was recrystallized twice from etha-
nol. The chemical structure of the synthesized novel cationic
gemini surfactant (Fig. 1), N,N′-((oxalylbis(oxy))bis(ethane-2,1-
diyl))bis(N,N-dimethyldodecan-1-aminium bromide) was charac-
terized by FTIR, 1H NMR and Mass spectroscopic analysis.
⁎
Corresponding author.
E-mail address: mohamed_hgazy@yahoo.com (M.A. Hegazy).
http://dx.doi.org/10.1016/j.molliq.2015.06.051
0167-7322/© 2015 Elsevier B.V. All rights reserved.

M.A. Hegazy et al. / Journal of Molecular Liquids 211 (2015) 126–134
127
Fig. 1. The chemical structure of the synthesized cationic gemini surfactant.
2.2. Carbon steel sample
3. Results and discussion
The chemical composition of the working electrode, a steel electrode
(API 5L line pipe), was determined using the spectrolab quantometer, as
represented in Table 1. The steel electrode was mounted in polyester. It
was mechanically ground with 320, 400, 600, 800, 1000 and 1200
emery paper, washed by acetone and bidistilled water, then dried and
inserted into the cell.
3.1. Confirmation of chemical structure of the prepared inhibitor
The chemical structure of the synthesized cationic gemini surfactant
was confirmed by FTIR, 1H NMR and Mass spectroscopy.
3.1.1. FTIR spectra
FTIR spectrum of the synthesized compound showed the following
absorption bands at 2923.56 cm−1 (C–H stretching), 1738.51 cm−1
(C_O stretching), 1464.67 cm−1 (C–H bending), 1198.54 cm−1 (C–O
stretching), 1083.8 cm−1 (C–N+), and 515.865 cm−1 (C–Br). The FTIR
spectrum confirmed the expected functional groups in the synthesized
cationic gemini surfactant as shown in Fig. 2.
2.3. Weight loss technique
Steel specimens with dimensions of 3 cm × 6 cm × 0.5 cm were
immersed in 1 M HCl in a closed beaker with and without the addition
of different concentrations of inhibitor for 24 h at 25–60 °C. Triplicate
specimens were exposed for each condition and the average weight
losses were reported.
3.1.2. 1H NMR spectra
The 1H NMR spectra of the synthesized compound showed different
bands at δ = 0.8487–0.8762 ppm (t, 6H, NCH2CH2(CH2)nCH3); δ =
1.1697–1.3271 ppm (m, 36H, NCH2CH2(CH2)nCH3); δ = 1.7276 ppm
(m, 4H, NCH2CH2(CH2)nCH3); δ = 3.2698 ppm (s, 12H, NCH3); δ =
3.4609 ppm (t, 4H, NCH2CH2(CH2)nCH3); δ = 3.6473–3.7207 ppm (m,
4H, OCH2CH2NCH2CH2(CH2)nCH3); δ = 4.5766–4.8151 ppm (m, 4H,
OCH2CH2NCH2CH2(CH2)nCH3). The data of 1H NMR spectrum
confirmed the expected hydrogen proton distribution in the synthe-
sized cationic gemini surfactant as shown in Fig. 3.
2.4. Electrochemical technique
For electrochemical measurements, a classical three-electrode glass
cell with a platinum counter electrode and a saturated calomel
electrode (SCE) as a reference was used. Carbon steel rod as a working
electrode was pressure fitted into a polytetrafluoroethylene (PTFE)
holder exposing only a 0.7 cm2 surface to the solution. The exposure
surface was abraded with different grades of emery paper, degreased
with acetone, washed with bidistilled water and then dried. The exper-
iments were done at a constant temperature (within 1 °C). EIS mea-
surements were carried out in a frequency range of 100 kHz to
30 MHz with a 10 mV sine wave as the excitation signal at open circuit
potential. The potentiodynamic current-potential curves were recorded
by changing the electrode potential automatically with a scan rate of
0.2 mV s−1 from −0.8 to −0.3 V versus SCE. Before each run, the work-
ing electrode was immersed in the test solution for 30 min to reach
steady state. All potentials were measured against SCE. Measurements
were obtained using a Voltalab 40 Potentiostat PGZ 301 combined
with corrosion program (Voltamaster 4) [18].
3.1.3. Mass spectra
The mass spectrum of the synthesized compound showed that a mo-
lecular ion peak m/z 730.05 (4.57%), base peak at m/z 58.04 (100%)
C2H2O2 and other significant peaks are shown at m/z 73.52 (9.27%)
C4H11N, 88.06 (69.04%) C4H10NO or [C5H14N]+, 93.92 (7.78%) CH3Br,
212.17 (83.60%) [C14H30N]+, 244.26 (12.56%) C11H22N2O4, 382.28
(3.29%) C21H38N2O4, 570.91 (3.07%) [C34H70N2O4]2+. The data of Mass
spectrum confirmed the chemical structure of the synthesized cationic
gemini surfactant as shown in Fig. 4.
3.2. Weight loss measurements
The corrosion rate (k) was calculated from the following
equation [19]:
2.5. Surface tension technique
ΔW
St
k ¼
ð1Þ
Surface tension was measured with a Du NouyTensiometer (Kruss
Type 6) for different concentrations of the synthesized cationic gemini
surfactant. Doubly distilled water with a surface tension equal
72 mN m−1 at 25 °C was used.
where ΔW is the average weight loss of three parallel steel sheets, S is
the total area of the specimen and t is the immersion time. The corrosion
Table 1
Chemical composition of carbon steel sample
Element
C
Si
Mn
P
S
Ni
Cr
Al
V
Ti
Cu
Fe
Weight (%)
0.19
0.05
0.94
0.009
0.004
0.014
0.009
0.034
0.016
0.003
0.022
Rest

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M.A. Hegazy et al. / Journal of Molecular Liquids 211 (2015) 126–134
Fig. 2. FTIR spectrum of N,N՝-((oxalylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-1-aminium bromide).
inhibition efficiencies,η, were calculated according to the following
equation [20]:
molecules from the metal surface at higher temperatures. The standard
deviation average of three replicate experiments is 0.78.
Wo−W
Wo
η ¼
ꢀ 100
ð2Þ
3.3. Potentiodynamic polarization curve results
where Wo and W are the weight loss of carbon steel in the absence and
presence of the inhibitor, respectively.
Both anodic and cathodic polarization curves for carbon steel in 1 M
HCl at different concentrations of the prepared cationic gemini surfac-
tant are shown in Fig. 5. It is clear that the presence of the inhibitor
causes a marked decrease in the corrosion rate, i.e., shifts the anodic
curves toward more positive potentials and the cathodic curves toward
more negative potentials. This may be due to adsorption of the inhibitor
on the corroded surface [21]. The values of the corrosion current
densities (icorr), corrosion potentials (Ecorr), cathodic Tafel slopes (βc)
and anodic Tafel slopes (βa) were calculated from Fig. 5 and are listed
in Table 3. From these results, it is clear that the corrosion current
decreases with the increase in the inhibitor concentration. The anodic
Weight loss data of carbon steel in 1 M HCl in the absence and
presence of various concentrations of inhibitor are listed in Table 2.
Data show that, the corrosion inhibition efficiency for the synthesized
inhibitor increases with increasing the inhibitor concentration. The
influence of solution temperature on the inhibition efficiency was
studied at 25, 40 and 60 °C and the values were listed in Table 2. It
was observed that the inhibition efficiency decreases with increasing
temperature from 25 to 60 °C. The reduction in inhibition efficiency
with temperature may be attributed to desorption of the inhibitor
Fig. 3. 1H NMR spectrum of N,N՝-((oxalylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-1-aminium bromide).

M.A. Hegazy et al. / Journal of Molecular Liquids 211 (2015) 126–134
129
Fig. 4. Mass spectrum of N,N՝-((oxalylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-1-aminium bromide).
and cathodic Tafel slopes change with the increase of the inhibitor con-
centration. Therefore, the prepared cationic gemini surfactant can be
classified as a mixed-type inhibitor in 1 M HCl. The standard deviation
average of three replicate experiments is 0.71. These results are in a
good agreement with the results obtained for weight loss technique.
concentration of the inhibitor in the test solution indicates excellent in-
hibitive behavior due to adsorption of more inhibitor molecules on the
metal surface at higher concentrations. Furthermore, the reduction of
phase angle at relaxation frequency takes place with decreasing inhibi-
tor concentrations, which indicates the decrease of capacitive response
with the decrease of inhibitor concentration.
3.4. Electrochemical impedance spectroscopy
The equivalent circuit used to fit the experimental data is shown in
Fig. 8. The equivalent circuit obtained consists of a constant phase ele-
ment (CPE) Q in parallel with a resistor Rct. One constant phase element
(CPE) is substituted for the capacitive element to give a more accurate
fit, as most capacitive loops are depressed semi-circles rather than reg-
ular semi-circles. For each set of experimental data the parameters Yo, n,
Rs and Rct were evaluated using ZSimpWin program. The impedance
parameters and inhibition efficiencies are listed in Table 4. The CPE
type impedance, ZCPE, was calculated from the following equation [23]:
Fig. 6 shows the Nyquist plots for carbon steel in 1 M HCl in the
absence and presence of different concentrations of the prepared inhib-
itor. The Nyquist plots were regarded as one part of a semicircle. The
charge transfer resistance values (Rct) were calculated from the differ-
ence in impedance at lower and higher frequencies [22]. Fig. 7 shows
Bode and phase angle plots for carbon steel electrode immersed in
1 M HCl in the absence and presence of different inhibitor concentra-
tions. In Bode plots, it was observed that in the intermediate frequency
region, a linear relationship between log|Z| vs. log f with a slope near −1
and the phase angle approaching −60° has been observed. This indi-
cates the capacitive behavior at intermediate frequencies. It was report-
ed that an ideal capacitive behavior will be obtained if the slope of Bode
impedance plot value is −1 and a phase angle value is −90° at interme-
diate frequencies. In the present study Bode impedance plot slope at in-
termediate frequencies, S, and the maximum phase angles, α°, deviate
from the values of −1 and 90° respectively. At the beginning of the im-
mersion, S and α° values are close to the ideal capacitive values which
may be related to a decrease of the dissolution rate with time. Values
of S and α° in inhibited solutions are higher than those obtained in un-
inhibited solution which reflects the inhibitive action of the tested in-
hibitor in the carbon steel dissolution process. Fig. 7 shows the phase
angle plots of the synthesized inhibitor. As we can see increasing the
1
ZCPE
¼
ð2Þ
n
YoðjωÞ
where the exponent n is the phase shift, which gives information
about the degree of non-ideality in capacitive behavior, and Yo is a
proportional factor, and J2 = −1, ω = 2πf. For n = 0, ZCPE represents
a resistance with R ¼ Yo−1, for n = 1 a capacitance with C = Yo, for
n = 0.5 a Warburg impedance with W = Yo and for n = −1 an induc-
−1
tive with L ¼ Yo
.
The double layer capacitance, Cdl, for a circuit including a CPE was
calculated from the following equation [24]:
n−1
Cdl ¼ Yoðωmax
Þ
ð3Þ
Table 2
Weight loss data of carbon steel corrosion in 1 M HCl in the absence and presence of different concentrations of the synthesized inhibitor at different temperatures
Conc. of
25 °C
40 °C
60 °C
inhibitor (M)
k (mg cm−2 h−1
)
θ
ηw (%)
k (mg cm−2 h−1
)
θ
ηw (%)
k (mg cm−2 h−1
)
θ
ηw (%)
0.00
0.78
0.14
0.11
0.07
0.05
0.04
–
–
1.77
0.40
0.31
0.22
0.15
0.13
–
–
4.28
1.20
0.98
0.80
0.60
0.47
–
–
5 × 10−5
1 × 10−4
5 × 10−4
1 × 10−3
5 × 10−3
0.82
0.87
0.91
0.93
0.95
81.98
86.52
90.55
93.19
94.81
0.77
0.82
0.88
0.91
0.93
77.31
82.47
87.85
91.39
92.86
0.72
0.77
0.81
0.86
0.89
72.06
77.07
81.19
86.03
89.02

130
M.A. Hegazy et al. / Journal of Molecular Liquids 211 (2015) 126–134
Fig. 6. Nyquist plots for carbon steel in 1 M HCl in the absence and presence of different
concentrations of N,N՝-((oxalylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-
1-aminium bromide) at 25 °C.
water molecules by inhibitor molecules at the surface of the
electrode. Also, the inhibitor molecules may reduce the capacitance
by increasing the double layer thickness according to the Helmholtz
model [10]:
Fig. 5. Potentiodynamic polarization curves for carbon steel in 1 M HCl in the absence and
presence of different concentrations of N,N՝-((oxalylbis(oxy))bis(ethane-2,1-
diyl))bis(N,N-dimethyldodecan-1-aminium bromide) at 25 °C, (B)
1 M HCl,
(1) 5 × 10−5 M, (2) 1 × 10−4 M, (3) 5 × 10−4 M, (4) 1 × 10−3 M and (5) 5 × 10−3 M.
ꢁ
εε A
δorg
¼
ð5Þ
where ωmax = 2πfmax and fmax is the frequency at which the imaginary
component of the impedance is maximal.
Cdl
In the case of the electrochemical impedance spectroscopy, the
inhibition efficiency was determined using charge transfer resistance
according to the following equation [25,26]:
where ε is the dielectric constant of the medium, εo is the vacuum
permittivity, A is the electrode surface area and δorg is the thick-
ness of the protective layer. The value of Cdl is always smaller in
the presence of the inhibitor than in its absence, which may be
resulting from the effective adsorption of the synthesized inhibi-
tor. The standard deviation average of three replicate experi-
ments is 0.53.
Ro −Rct
ct
Roct
ηI ¼
ꢀ 100
ð4Þ
where Rct and R°ct are the charge transfer resistance values in the
absence and presence of the inhibitor, respectively.
The electrochemical impedance parameters derived from the
Nyquist plots and the inhibition efficiency, ηI, are listed in Table 4. It
was clear that:
3.5. Adsorption isotherm and thermodynamic consideration
The adsorption isotherm can provide basic information on the
interaction of inhibitor and metal surface. The values of surface coverage
(θ) were calculated from the following equation [27] and obtained from
weight loss measurements at 25, 40 and 60 °C:
1. The values of charge transfer resistance, Rct, in the presence of the
inhibitor are always greater than their values in the absence of the
inhibitor, indicating a reduction in the corrosion rate of carbon steel.
2. The values of charge transfer resistance, Rct, increase with increasing
the concentration of the inhibitor.
ꢀ
ꢁ
Wo−W
Wo
θ ¼
ð6Þ
3. The double layer capacitance, Cdl, values decrease in the presence of
the inhibitor. This is mainly due to a decrease in local dielectric
constant and/or an increase in the thickness of the electrical double
layer, assuming that the inhibitor molecules acted by adsorption at
the metal/solution interface. Addition of synthesized inhibitor
provides lower Cdl values, as a consequence of the replacement of
where Wo and W are the weight loss in the absence and presence of
inhibitor, respectively.
The plot of C/θ versus C (Fig. 9) gave a straight line with correlation
coefficient of 0.9999 and a slope close to 1, providing that the adsorption
of the prepared surfactant in hydrochloric acid solution on the carbon
Table 3
Potentiodynamic polarization parameters for carbon steel corrosion in
1
M
HCl in the absence and presence of different concentrations of the synthesized N,N՝-
((oxalylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-1-aminium bromide) at 25 °C
Conc. of inhibitor (M)
Ecorr (mV(SCE))
icorr (mA cm−2
)
β
a (mV dec−1
)
β
c (mV dec−1
)
ηp (%)
0.00
−524.5
−525.4
−526.0
−526.3
−527.6
−529.1
0.797
0.147
0.109
0.077
0.055
0.041
139.0
166.6
143.4
179.1
160.6
144.9
−149.2
−179.1
−145.0
−210.1
−177.8
−175.0
–
5 × 10−5
1 × 10−4
5 × 10−4
1 × 10−3
5 × 10−3
81.60
86.33
90.32
93.09
94.84

M.A. Hegazy et al. / Journal of Molecular Liquids 211 (2015) 126–134
131
Fig. 7. Bode and phase plots for carbon steel in 1 M HCl in the absence and presence of different concentrations of N,N՝-((oxalylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-1-
aminium bromide) at 25 °C.
steel surface obeys Langmuir adsorption isotherm, which is presented
by Eq. (7) [28,29]:
−20 kJ mol−1 or higher are associated with an electrostatic interaction
between charged molecules and charged metal surface, physisorption;
those of −40 kJ mol−1 or lower involve charge sharing or transferring
from the inhibitor molecules to the metal surface to form a coordinate
covalent bond, chemisorption [31]. The values of ΔG°ads were ranged
from −37.30 to −39.76 kJ mol−1 as shown in Table 5. This indicated
that the adsorption of investigated inhibitor on carbon steel surface is
neither typical physisorption nor typical chemisorptions, but it is
mixed physisorption and chemisorption.
C
θ
1
Kads
¼
þ C
ð7Þ
where C is the inhibitor concentration, θ the degree of surface coverage
and Kads is the equilibrium constant for adsorption–desorption process.
The values of Kads calculated from the reciprocal of intercept of
isotherm lines for carbon steel at different concentrations and tempera-
tures are listed in Table 5. It was found that the synthesized inhibitor is
easily and strongly adsorbed on the carbon steel surface at lower
temperature. On the other hand, the values of the equilibrium constant
decrease with increasing the temperature due to the increase in desorp-
tion of the inhibitor. The standard free energy of adsorption (ΔG°ads) is
related to adsorption constant (Kads) with the following equation [30]:
The adsorption heat, ΔH°ads, can be calculated according to the Van't
Hoff equation [24]:
ꢀ
ꢁ
−ΔHoads
RT
lnKads
¼
þ constant:
ð9Þ
The value of ΔH°ads is calculated from the slope of the relation
between ln Kads vs. 1/T which is equal to –ΔH°ads/R. The value of
ΔH°ads is negative, suggesting that the adsorption of inhibitor is an
ΔGoads ¼ −RT lnð55:5 Kads
Þ
ð8Þ
exothermic process [32]. Entropy of the inhibitor adsorption (ΔS°ads
)
where ΔG°ads is the free energy of adsorption, Kads is the equilibrium
constant for adsorption–desorption process, R is the gas constant, T is
the absolute temperature and 55.5 is the molar concentration of water.
It was observed that the values of ΔG°ads for synthesized compound
are negative (Table 5) and these values are consistent with the
spontaneity of the adsorption process and the stability of the adsorbed
layer on the carbon steel surface. Generally, ΔG°ads values of
was calculated using the following equation:
ΔGoads ¼ ΔHoads−TΔSaods
:
ð10Þ
The obtained ΔS°ads values are listed in Table 5. The positive values of
ΔS°ads are attributed to the increase of disorder due to the adsorption of
only one molecule of inhibitor by desorption of more water molecules.
Fig. 8. The suggested equivalent circuit model for the studied system.

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M.A. Hegazy et al. / Journal of Molecular Liquids 211 (2015) 126–134
Table 4
EIS parameters for corrosion of carbon steel in 1 M HCl in the absence and presence of different concentrations of the synthesized N,N՝-((oxalylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-
dimethyldodecan-1-aminium bromide) at 25 °C
Conc. of inhibitor (M)
Rs (Ω cm2)
Yo (Ω−1 sn cm−2
)
n
Error of n (%)
Rct (Ω cm2)
Cdl (μF cm−2
)
ɳI (%)
0.00
1.53
1.84
1.58
1.56
1.88
1.83
0.0001703
0.0001376
0.0001127
0.0000828
0.0000627
0.0000523
0.88
0.84
0.79
0.79
0.78
0.78
0.80
0.69
0.70
0.58
0.74
0.63
37.85
210.3
275.7
365.8
501.7
641.2
84.37
16.28
12.64
9.13
6.65
5.12
–
5 × 10−5
1 × 10−4
5 × 10−4
1 × 10−3
5 × 10−3
82.00
86.27
89.65
92.46
94.10
3.6.3. Surface excess (Γcmc
)
Maximum surface excess of a surfactant (Γcmc) at the air/solution in-
terface is calculated from the maximal slope ((dγ/d log C)) in the γ vs.
logC plot. In the absence of electrolyte, it is calculated by Gibbs adsorp-
tion equation [34]:
ꢀ
ꢁꢀ
ꢁ
−1
nRT
dγ
d logC
Γmax
¼
ð12Þ
where dγ/d log C is the surface pressure, T is the absolute temperature, R
is the gas constant and value of n is taken as 3 for a dimeric surfactant
made up of a divalent surfactant ion and two univalent counter ions in
the absence of a swamping electrolyte. The value of Γmax was calculated
and listed in Table 6.
3.6.4. The area per molecule (Amin
)
The minimal surface area per adsorbed molecule, Amin (nm2), is
obtained as follows [34]:
Fig. 9. Langmuir adsorption plots for carbon steel in 1 M HCl in the presence of different
concentrations of the synthesized cationic gemini surfactant at various temperatures.
1014
NAΓmax
Amin
¼
ð13Þ
where NA is the Avogadro's number and Γmax is the maximal surface
excess of adsorbed surfactant molecules at the interface. The value of
the area per molecule was calculated and listed in Table 6.
3.6. Surface active properties
3.6.1. Surface tension (γ)
Fig. 10 shows the relationship between the surface tension and the
logarithm of the concentration of the surfactant. Sharp decrease in the
surface tension values is observed as the concentration increases until
Ccmc is attained, and then continue to decrease slowly as the concentra-
tion increases. This common behavior, shown by surfactant in solution,
was used to determine its purity and Ccmc. The critical micelle
concentration (Ccmc) was determined from the intersection points in
the γ–log C curves and listed in Table 6.
3.7. Comparison between the inhibition efficiency of the synthesized gemini
surfactant with those of the previously published ordinary cationic
surfactant at the same conditions
The inhibition efficiency of the synthesized gemini surfactant, for
carbon steel corrosion in 1 M HCl solution, was comparatively and
even better than ordinary cationic surfactant at the same
conditions [35–37] (see Table 7). In general, surfactant is amphiphilic
compound that contains hydrophilic group (head) and hydrophobic
group (tail) [38]. Moreover, surfactant molecules are lowering the
surface tension (or interfacial tension) between corrosive medium and
steel surface and also act as dispersants [10,20]. Furthermore, surfac-
tants up to critical micelle concentration (Ccmc) will diffuse out of the
bulk water phase and are adsorbed at the interfaces between carbon
steel and corrosive medium [10,20]. Ordinary cationic surfactant
contains one hydrophobic group and one hydrophilic group while gem-
ini surfactant contains two hydrophobic groups and two hydrophilic
groups. This is due to the fact that the Ccmc of gemini surfactant is small-
er than cationic surfactant. Therefore, migration of gemini surfactant is
faster than ordinary cationic surfactant thus concentration of gemini
3.6.2. Effectiveness (πcmc
)
The maximum surface pressure (πcmc) can be defined as the effec-
tiveness of a surfactant in lowering surface tension [33]. It is calculated
from the following equation:
πcmc ¼ γο−γcmc
ð11Þ
where γο is the surface tension measured for pure water at the
appropriate temperature and γcmc is the surface tension at a critical
micelle concentration. πcmc value of the synthesized surfactant is listed
in Table 6. The synthesized surfactant is considered as a strong surface
active agent at air/water interface.
Table 5
Standard thermodynamic parameters of the adsorption on carbon steel surface in 1 M HCl containing different concentrations of the synthesized inhibitor at various temperatures
Temperature (°C)
Kads × 10-4 (M−1
)
ΔG°ads (kJ mol−1
)
ΔH°ads (kJ mol−1
−16.52
)
ΔS°ads (J mol−1 K−1
)
25
40
60
6.22
5.20
3.11
−37.30
−38.71
−39.76
69.74
70.90
69.81

M.A. Hegazy et al. / Journal of Molecular Liquids 211 (2015) 126–134
133
negative sign of the ΔG°ads and ΔH°ads indicates that the adsorption
process is spontaneous and exothermic.
References
[1] L.T. Popoola, A.S. Grema, G.K. Latinwo, B. Gutti, A.S. Balogun, Corrosion problems during oil
and gas production and its mitigation, Int. J. Ind. Chem. 4 (2013) 35–49.
[2] W. Aperador, E. Delgado, A. Mejía, Electrochemical characterization of copper coatings on
low carbon steel from industrial waste, Int. J. Electrochem. Sci. 8 (2013) 12154–12162.
[3] K. Ting, Y. Pang Ma, The evaluation of erosion:corrosion problems of carbon steel piping in
Taiwan PWR nuclear power plant, Nucl. Eng. Des. 191 (1999) 231–243.
[4] E.M. Esparza Zúñiga, M.A. Veloz Rodríguez, J. Uruchurtu Chavarín, V.E. Reyes Cruz, Corro-
sion of carbon steel in sour water from the oil industry: the effect of temperature, Int. J.
Electrochem. Sci. 6 (2011) 5016–5030.
[5] S.K. Oladele, H.K. Okoro, Investigation of corrosion effect of mild steel on orange juice, Afr.
J. Biotechnol. 10 (2011) 3152–3156.
[6] C. Kamal, M.G. Sethuraman, S. Platensis, A novel green inhibitor for acid corrosion of mild
steel, Arab. J. Chem. 5 (2012) 155–161.
[7] F.E. Heakal, A.S. Fouda, S.S. Zahran, Environmentally safe protection of carbon steel corro-
sion in sulfuric acid by thiouracil compounds, Int. J. Electrochem. Sci. 10 (2015)
1595–1615.
[8] A. Khamis, M.M. Saleh, M.I. Awad, Synergistic inhibitor effect of cetylpyridinium chloride
and other halides on the corrosion of mild steel in 0.5 M H2SO4, Corros. Sci. 66 (2013)
343–349.
[9] M.A. Hegazy, A.S. El-Tabei, Synthesis, surface properties, synergism parameter and inhibi-
tive performance of novel cationic gemini surfactant on carbon steel corrosion in 1 M HCl
solution, J. Surfactant Deterg. 16 (2013) 221–232.
[10] M.A. Hegazy, S.S. El Rehim, A.M. Badawi, M.Y. Ahmed, Studying the corrosion inhibition of
carbon steel in hydrochloric acid solution by 1-dodecyl-methyl-1H-benzo[d][1, 2, 3]
triazole-1-ium bromide, RSC Adv. 5 (2015) 49070–49079.
Fig. 10. Variation of the surface tension with concentration of N,N՝-
((oxalylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-1-aminium bromide)
in bidistilled water at 25 °C.
surfactant at interface between steel surface and corrosive solution is
higher than cationic surfactant at the same concentration.
[11] M. Motamedi, A.R. Tehrani-Bagha, M. Mahdavian, Effect of aging time on corrosion inhibi-
tion of cationic surfactant on mild steel in sulfamic acid cleaning solution, Corros. Sci. 70
(2013) 46–54.
4. Conclusions
[12] L.G. Qiu, Y. Wu, Y.M. Wang, X. Jiang, Synergistic effect between cationic gemini surfactant
and chloride ion for the corrosion inhibition of steel in sulphuric acid, Corros. Sci. 50
(2008) 576–582.
[13] Q. Zhang, Z. Gao, F. Xu, X. Zou, Adsorption and corrosion inhibitive properties of gemini
surfactants in the series of hexanediyl-1,6-bis-(diethyl alkyl ammonium bromide) on alu-
minium in hydrochloric acid solution, Colloids Surf. A Physicochem. Eng. Asp. 380 (2011)
191–200.
[14] Y. Wang, E.F. Marques, Non-ideal behavior of mixed micelles of cationic gemini surfactants
with varying spacer length and anionic surfactants: a conductimetric study, J. Mol. Liq. 142
(2008) 136–142.
[15] X. Wang, H. Yang, F. Wang, Inhibition performance of a gemini surfactant and its co-
adsorption effect with halides on mild steel in 0.25 M H2SO4 solution, Corros. Sci. 55
(2012) 145–152.
The corrosion inhibition efficiencies of the synthesized cationic
gemini surfactant were studied using series of techniques. The following
points can be emphasized:
1. Novel cationic gemini surfactant shows good inhibitor for corrosion
of carbon steel in 1 M HCl.
2. The chemical structure of synthesized cationic surfactant was
confirmed by FTIR and 1H NMR spectroscopy.
3. The inhibition efficiency increases with increasing the concentration
of the synthesized inhibitor but it tends to decrease with tempera-
ture increasing.
4. The high inhibition efficiency of the synthesized cationic gemini
surfactant was related to the adherently adsorption of inhibitor mol-
ecules on the carbon steel surface, and formation of a protective film.
5. The synthesized inhibitor is an effective inhibitor. The results obtained
from the weight loss measurements were in a good agreement with
those obtained from the potentiodynamic polarization and EIS
methods.
[16] D. Asefi, M. Arami, N.M. Mahmoodi, Electrochemical effect of cationic gemini surfactant
and halide salts on corrosion inhibition of low carbon steel in acid medium, Corros. Sci.
52 (2010) 794–800.
[17] P. Patial, A. Shaheen, I. Ahmad, Gemini pyridinium surfactants: synthesis and their surface
active properties, J. Surfactant Deterg. 17 (2014) 929–935.
[18] M.A. Migahed, M.A. Hegazy, A.M. Al-Sabagh, Synergistic inhibition effect between Cu2+
and cationic gemini surfactant on the corrosion of downhole tubing steel during second-
ary oil recovery of old wells, Corros. Sci. 61 (2012) 10–18.
[19] Mohamed H.M. Hussein, Mohamed F. El-Hady, Hassan A.H. Shehata, M.A. Hegazy, Hassan
H.H. Hefni, Preparation of some eco-friendly corrosion inhibitors having antibacterial ac-
tivity from sea food waste, J. Surfactant Deterg. 16 (2013) 233–242.
[20] M.A. Hegazy, Novel cationic surfactant based on triazole as a corrosion inhibitor for carbon
steel in phosphoric acid produced by dihydrate wet process, J. Mol. Liq. 208 (2015)
227–236.
[21] X. Li, S. Deng, G. Muc, H. Fu, F. Yang, Inhibition effect of nonionic surfactant on the corro-
sion of cold rolled steel in hydrochloric acid, Corros. Sci. 50 (2008) 420–430.
[22] M.A. Hegazy, A.S. El-Tabei, H.M. Ahmed, ynthesis of nonionic surfactants and their inhibi-
tive action on carbon steel in hydrochloric acid, Corros. Sci. 64 (2012) 115–125.
6. The adsorption of the synthesized cationic gemini surfactant molecules
on the metal surface obeys Langmuir adsorption isotherm. The values
of adsorption equilibrium constant suggested that the synthesized
surfactant is strongly adsorbed on the carbon steel surface. The
Table 6
Critical micelle concentration (Ccmc), effectiveness (πcmc), maximum surface excess (Γmax), and minimum area (Amin) values of the synthesized cationic gemini surfactant
Ccmc × 103 (mol dm−3
)
γ
cmc (mN m−1
24.9
)
π
cmc (mN m−1
47.1
)
Γ
max × 1010 (mol cm−2
1.33
)
Amin (nm2)
3.24
1.25
Table 7
Comparison of inhibition efficiency of the synthesized gemini surfactant with those of previously published ordinary cationic surfactant at the same conditions
Inhibitor name
Inhibition efficiency (%)
Reference
N-(3-((3,4-dimethoxybenzylidene)amino)propyl)-N,N-dimethyldecane-1-ammonium bromide
N-(3-((3,4-dimethoxybenzylidene)amino)propyl)-N,N-dimethyldodecane-1-ammonium bromide
N-(3-((3,4-dimethoxybenzylidene)amino)propyl)-N,N-dimethylhexadecane-1-ammonium bromide
N,N-bis(2-hydroxyethyl)-N-octylbenzo[d]thiazol-2-ammonium bromide
N,N-bis(2-hydroxyethyl)-N-decylbenzo[d]thiazol-2-ammonium bromide
Decyldimethylisopropylammonium hydroxide
85
88
90
87
91
90
91
95
[35]
[35]
[35]
[36]
[36]
[37]
[37]
Dodecyldimethylisopropylammonium hydroxide
N,N՝-((oxalylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-1-aminium bromide)
The present study

134
M.A. Hegazy et al. / Journal of Molecular Liquids 211 (2015) 126–134
[23] R. Solmaz, Investigation of adsorption and corrosion inhibition of mild steel in hydrochlo-
ric acid solution by 5-(4-Dimethylaminobenzylidene)rhodanine, Corros. Sci. 79 (2014)
169–176.
[31] A. Doner, R. Solmaz, M. Ozcan, G. Kardas, Experimental and theoretical studies of thiazoles
as corrosion inhibitors for mild steel in sulphuric acid solution, Corros. Sci. 53 (2011)
2902–2913.
[24] A.S. El-Tabei, M.A. Hegazy, A.H. Bedair, M.A. Sadeq, Synthesis and inhibition effect of a
novel Tri-cationic surfactant on carbon steel corrosion in 0.5 M H2SO4 solution, J. Surfac-
tant Deterg. 17 (2014) 341–352.
[32] M.R. Noor El-Din, A.M. Al-Sabagh, M.A. Hegazy, Study of the inhibition efficiency for some
novel surfactants on the carbon steel (Type H-11) pipelines in 0.5 M HCl solution by po-
tentiodynamic technique, J. Dispers. Sci. Technol. 33 (2012) 1444–1451.
[33] A.S. El-Tabei, M.A. Hegazy, Synthesis and characterization of a novel nonionic gemini sur-
factant as corrosion inhibitor for carbon steel in acidic solution, Chem. Eng. Commun. 7
(2015) 851–863.
[34] A. Labena, M.A. Hegazy, H. Horn, E. Müller, The biocidal effect of a novel synthesized gem-
ini surfactant on environmental sulfidogenic bacteria: planktonic cells and biofilms, Mater.
Sci. Eng. C 47 (2015) 367–375.
[25] X. Wang, H. Yang, F. Wang, A cationic gemini-surfactant as effective inhibitor for mild steel
in HCl solutions, Corros. Sci. 52 (2010) 1268–1276.
[26] A.H. Kadhum, A.B. Mohamad, L.A. Hammed, A.A. Al-Amiery, N.H. San, A.Y. Musa, Inhibition
of mild steel corrosion in hydrochloric acid solution by new coumarin, Materials 7 (2014)
4335–4348.
[27] G.E. Badr, The role of some thiosemicarbazide derivatives as corrosion inhibitors for C-
steel in acidic media, Corros. Sci. 51 (2009) 2529–2536.
[35] S.M. Shaban, I.A. Aiad, M.M. El-Sukkary, E.A. Soliman, M.Y. El-Awady, Evaluation of some
cationic surfactants based on dimethylaminopropylamine as corrosion inhibitors, J. Ind.
Eng. Chem. 21 (2014) 1029–1038.
[28] M. Dahmani, A. Et-Touhami, S.S. Al-Deyab, B. Hammouti, A. Bouyanzer, Corrosion inhibi-
tion of C38 steel in 1 M HCl: a comparative study of black pepper extract and its isolated
piperine, Int. J. Electrochem. Sci. 5 (2010) 1060–1069.
[36] E.A. Badr, Inhibition effect of synthesized cationic surfactant on the corrosion of carbon
[29] A.S. El-Tabei, M.A. Hegazy, Application of the synthesized novel 3,6,9,12,15,18,21-
heptaoxatricosane-1,23-diyl bis(4-((4-(dimethylamino)benzylidene)amino)benzoate) as
a corrosion inhibitor for carbon steel in acidic media, J. Dispers. Sci. Technol. 35 (2014)
1289–1299.
[30] R. Yıldız, A. Doner, T. Dogan, I. Dehri, Experimental studies of 2-pyridinecarbonitrile as cor-
rosion inhibitor for mild steel in hydrochloric acid solution, Corros. Sci. 82 (2014)
125–132.
steel in 1 M HCl, J. Ind. Eng. Chem. 20 (2014) 3361–3366.
[37] A.M. Badawi, M.A. Hegazy, A.A. El-Sawy, H.M. Ahmed, W.M. Kamel, Novel quaternary am-
monium hydroxide cationic surfactants as corrosion inhibitors for carbon steel and as bio-
cides for sulfate reducing bacteria (SRB), Mater. Chem. Phys. 124 (2010) 458–465.
[38] M.J. Rosen, J.T. Kunjappu, Surfactants and Interfacial Phenomena, 4th ed. John Wiley &
Sons, Hoboken, New Jersey, 2012. 1.