Synthesis and evaluation of some Triazole derivatives as corrosion inhibitors and biocides

Article abstract of DOI:10.1007/s11743-013-1547-0

Three compounds namely; 5-(phenyl)-4H-1,2,4-triazole-3-thiol, 3-(decylthio)-5-phenyl-1H-1,2,4-triazole and 3-(benzylthio)-5-phenyl-1H-1,2,4- triazole) were synthesized. The chemical structure of the prepared compounds was confirmed using FTIR and ¹H-NMR analysis. The compounds were tested as corrosion inhibitors against the corrosion of carbon steel in 1 M HCl using weight loss, polarization and electrochemical impedance methods. The results revealed that these compounds have significant inhibiting effects on the corrosion of carbon steel. Polarization studies showed that the compounds act as mixed-type inhibitors which retard the anodic and the cathodic reactions with a predominant effect towards the cathodic reaction. The prepared compounds were evaluated as antimicrobial agents against sulfate-reducing bacteria using the serial dilution method, which showed good biocidal action.

Full text of DOI:10.1007/s11743-013-1547-0

J Surfact Deterg
DOI 10.1007/s11743-013-1547-0
ORIGINAL ARTICLE
Synthesis and Evaluation of Some Triazole Derivatives
as Corrosion Inhibitors and Biocides
•
Ali A. Abd-Elaal Ismail Aiad Samy M. Shaban
•
•
•
Salah M. Tawfik Atef Sayed
Received: 24 July 2013 / Accepted: 4 November 2013
Ó AOCS 2013
Abstract Three compounds namely; 5-(phenyl)-4H-1,2,4-
triazole-3-thiol, 3-(decylthio)-5-phenyl-1H-1,2,4-triazole
and 3-(benzylthio)-5-phenyl-1H-1,2,4-triazole) were syn-
thesized. The chemical structure of the prepared compounds
was confirmed using FTIR and 1H-NMR analysis. The
compounds were tested as corrosion inhibitors against the
corrosion of carbon steel in 1 M HCl using weight loss,
polarization and electrochemical impedance methods. The
results revealed that these compounds have significant
inhibiting effects on the corrosion of carbon steel. Polariza-
tion studies showed that the compounds act as mixed-type
inhibitors which retard the anodic and the cathodic reactions
with a predominant effect towards the cathodic reaction. The
prepared compounds were evaluated as antimicrobial agents
against sulfate-reducing bacteria using the serial dilution
method, which showed good biocidal action.
metal dissolution and acid consumption during these pro-
cesses, Inhibitors are often used [3–5]. The organic com-
pounds containing O, S and/or N atoms act as effective
inhibitors [6–8] throughout the adsorption on the metal sur-
faces and then decrease the corrosion process [9–12]. Triazole
and triazole-type compounds containing sulfur, and hetero-
cyclic species have attracted more attention because of their
excellent corrosion inhibition performance [13–19]. Zhang
et al. [20] studied the inhibiting action of oxadiazole–triazole
derivatives against the corrosion of mild steel in sulfuric acid
solution. The results indicatedthat the compounds are acted as
efficient corrosion inhibitors in the acidic solution.
The strategies to control the effects of microbiologically
influenced corrosion (MIC) in oil field companies include
the reduction of the sulfate-reducing bacteria (SRB) using
biocides; in order to: kill the organisms which enter the
system, and reduce the growth rate of microorganisms
within the biofilm. Microbiologically influenced souring
(MIS) is the production of H2S through the metabolic
activities of the sulfate-reducing bacteria. A better chance
of mitigating MIS in some down-hole environments is
using biocides [21]. The objective of this work is to syn-
thesize three triazole derivatives and to study their corro-
sion inhibition effect on carbon steel dissolution in acidic
medium, and their biocidal activity against SRB.
Keywords Triazole derivatives ꢀ Corrosion
inhibition ꢀ Antimicrobial activity
Introduction
Hydrochloric acid solution is commonly used for the removal
of undesirable scale and rust in metalworking processes,
cleaning of boilers, and heat exchangers [1, 2]. To prevent the
Electronic supplementary material The online version of this
article (doi:10.1007/s11743-013-1547-0) contains supplementary
material, which is available to authorized users.
Materials and Methods
Synthesis of 5-(phenyl)-4H-1,2,4-triazole-3-thiol (I)
A. A. Abd-Elaal (&) ꢀ I. Aiad ꢀ S. M. Shaban ꢀ
S. M. Tawfik ꢀ A. Sayed
A mixture of benzoic acid (12.2 g, 0.1 mol) and thiosem-
icarbazide (91.1 g, 0.1 mol) was heated under reflux at
140 °C in the presence of xylene as a solvent and p-toluene
sulfonic acid as a dehydrating agent until the theoretical
Applied Surfactant Laboratory, Petrochemicals Department,
Egyptian Petroleum Research Institute, El-Zhoor, Nasr City,
Cairo 11727, Egypt
e-mail: ali_ashour5@yahoo.com
123

J Surfact Deterg
amount of water was collected in the dean stark trap [22].
The mixture was cooled and the product was filtered to
obtain 1-(benzoyl)-thiosemicarbazide, which was refluxed
for 3 h in 200 ml of NaOH solution (2 N), then cooled and
acidified to pH 4. The precipitate was filtered off and re-
crystallized from methanol to yield 5-(phenyl)-4H-1,2,4-
triazole-3-thiol (I) as shown in Scheme 1 [23].
spectroscopy. FTIR spectra showed the following bands: at
940 cm-1 (I), 926 cm-1 (II), 924 cm-1 (III) for (N–C–S),
1,299 cm-1 (I), 1,312 cm-1 (II), 1,309 cm-1 (III) for (N–
N–C), 3,365 cm-1 (I), 3,432 cm-1 (II), 3,395 cm-1 (III)
for (N–H), 681 cm-1 (I), 682 cm-1 (II), 682 cm-1 (III)
(C–S), 3,060 cm-1 (I), 3,059 cm-1 (II), 3,059 cm-1 (III)
for (Ar CH), 1,452 cm-1 (I), 1,422 cm-1 (II), 1,418 cm-1
(III) for (C–N), 2,056 cm-1 (I) for (SH), 2,924 cm-1 (II),
2,935 cm-1 (III) and 2,853 cm-1 (II), 2,825 cm-1 (III) for
(CH2 asym and sym). 1H-NMR spectra of (I, II, III) showed
peaks at: d = 7.75 ppm (m, 5H, Ar–H), d = 3.25 ppm (s,
1H, S–H) for compound (I); d = 7.84 ppm (m, 5H, Ar–H),
d = 3.38 ppm (t, 2H, S–CH2), d = 1.45 ppm (m, 16H,
CH2), d = 0.81 ppm (t, 3H, CH3) for compound (II);
d = 7.86 ppm, 7.24 ppm (m, 10H, Ar–H), d = 3.86 ppm
(t, 2H, S–CH2) for compound (III).
Synthesis of 3-(decylthio)-5-phenyl-1H-1,2,4-triazole
(II)
A mixture of 5-(phenyl)-4H-1,2,4-triazole-3-thiol (1.77 g,
0.1 mol) and 1-bromodecane (2.22 g, 0.01 mol) was
refluxed in ethanolic alkali (0.08 g KOH in 20 ml ethanol)
for 2 h and then cooled to precipitate compound (II) which
was recrystallized from ethanol [24].
Synthesis of 3-(benzylthio)-5-phenyl-1H-1,2,4-triazole
Corrosion Measurements
(III)
Weight Loss Measurements
A mixture of 5-(phenyl)-4H-1,2,4-triazole-3-thiol (1.77 g,
0.01 mol) and benzyl chloride (1.26 g, 0.01 mol) was
refluxed in ethanolic alkali (0.08 g KOH in 20 ml ethanol)
for 2 h, and then cooled to precipitate compound (III)
which was recrystallized from ethanol [24].
The weight loss experiments were performed with carbon
steel specimens having a composition of: 0.21 C, 0.025
Mn, 0.082 P and the remainder is Fe. The carbon steel
sheet dimensions were 6 cm 9 3.0 cm 9 0.6 cm, the test
was done according to ASTM G31-72 (re-approved 2004).
The steel coupons were immersed in 1 M HCl with and
without the inhibitors I, II and III at concentrations of 100,
200, 400, 600 ppm by weight for 24 h at different tem-
peratures (25, 45 and 65 °C). Then coupons were washed,
Analyses
The chemical structures of the synthesized compounds
(I, II, III) were confirmed by FTIR and 1H-NMR
S
O
H
S
2N NaOH
N
Xylene
N
NH2
H2N
+
H
NH2
N
OH
O
Reflux 6 hr
H
benzoic acid
1-(benzoyl)-thiosemicarbazide
thiosemicarbazide
H
N
N
S
N
e
N
N
3-(decylthio)-5-phenyl-1H-1,2,4-triazole
n
a
c
e
d
mo
o
r
(II)
SH
B
1
N
H
E
H
t
-
O
N
N
5-(phenyl)-4H-1,2,4-triazole-3-thiol
H
/
N
S
a
O
(I)
H
N
3-(benzylthio)-5-phenyl-1H-1,2,4-triazole
(III)
Scheme 1 Illustrated the chemical structure of the synthesized triazole derivatives
123

J Surfact Deterg
dried and weighed accurately [25]. The test was repeated
three times and the weight loss was their average. The
corrosion rate (R) and the inhibition efficiency (g %) were
calculated using Eqs. (1–2):
was incubated with a contact time of 3.0 h; each system
was cultured in SRB specific media for 21 days at
37–40 °C.
Biodegradation Test
R ¼ W=At
g % ¼ ½ðR0ꢁRÞ=R0ꢂ ꢃ 100
ð1Þ
ð2Þ
The biodegradability test in river water of the synthe-
sized inhibitors I, II, and III was carried out using the
surface tension method (Du-Nou¨y tensiometer, Kru¨ss
type K6, Germany) using a platinum ring [30, 31] at
1 % inhibitor concentration. Each inhibitor was dissolved
in river water to a concentration of 100 ppm and incu-
bated at 38 °C. A sample was withdrawn daily (for
7 days), filtered and the surface tension value was
measured. The biodegradation percentage (D %) was
calculated using Eq. (4):
where W is the average weight loss of three parallel carbon
steel sheets, A is the total surface area of the specimen, t is
the immersion time, R and R0 are the corrosion rate with
and without the inhibitor, respectively [26, 27].
Polarization Measurements
The polarization measurements were carried out using a
potentiostat (Volta lab 40 PGZ 301 in a conventional three
electrode cell system, France). The working electrode was
immersed in the test solution for 30 min until the open
circuit potential (OCP) is reached. The working electrode
was polarized in cathodic and anodic directions. The cor-
rosion current densities (Icorr) were calculated by extrapo-
lation of Tafel lines to pre-determine the OCP [28]. A
standard ASTM electrochemical glass cell was used and a
platinum electrode was used as an auxiliary electrode. All
potentials were measured against a saturated calomel
electrode (SCE) as a reference electrode. The potential was
increased with a rate of 30 mV/min started from 1,000 to
200 mV. The inhibition efficiency (g %) was calculated
using Eq. (3):
D % ¼ ðct ꢁ coÞ=ðcbt ꢁ coÞ ꢃ 100
ð4Þ
where: ct is the surface tension at time t, co is the surface
tension at time 0 (initial surface tension) and cbt is the
surface tension of river water without addition of inhibitor
at time t.
Results and Discussion
Weight Loss Technique
Effect of Inhibitor Concentration
g % ¼ ½ðI0ꢁIÞ=I0ꢂ ꢃ 100
where the I and I0 are the current density values with and
ð3Þ
In a steel/water system, the steel surface is covered with a
layer of FeOOH through which the interaction of surfactant
molecules takes place. The OH groups on the solid surface
are the most important sites for surface interactions; these
groups can act as acids or bases. The adsorption process is
highly dependent on various parameters such as pH and
electrolyte content [32].
without inhibitors.
Electrochemical Impedance Technique
The Electrochemical Impedance Spectroscopy (EIS) mea-
surements were carried out using alternating current (AC)
signals of amplitude 10 mV peak to peak at the OCP in the
The corrosion inhibiting efficiencies (g) of the synthe-
sized compounds of the carbon steel corrosion in 1 N HCl
were measured. The test was done at different temperatures
30–60 °C. Different inhibitor concentrations (100, 200,
400, 600 ppm by weight) were used. The results were
illustrated in Fig. (1), (Figs. 1–2, supplementary file) and
listed in Table 1. It was found that the efficiency of syn-
thesized triazole derivatives decreases the corrosion rates
of the steel in testing solutions and its inhibition efficien-
cies are dependent on its concentration in the tested solu-
tion. Also, it is clear that gradual increasing the inhibitor
concentration from 100 to 600 ppm decreases the steel
corrosion rate. The increase of efficiency, g with increasing
the inhibitor concentration is attributed to the adsorption of
the inhibitor molecules on the steel surface and thus
increases the metal surface coverage [33].
frequency range of 100 kHz to 30 MHz using
potentiostat.
a
Antimicrobial Activity Measurements
The growth inhibition of the three prepared compounds on
the SRB was measured using the serial dilution method.
SRB-contaminated water was supplied from Qarun Petro-
leum Co. (Western Desert, Egypt). This water was used for
the microbial inhibition test. The test was conducted
according to ASTM D4412-84 [29]. The tested water was
subjected to growth of about 1,000,000 bacteria cells/ml.
The prepared compounds were tested as a biocide for the
SRB by doses of (50, 100, 200 and 400 ppm). The system
123

J Surfact Deterg
100
90
80
70
60
higher temperatures, the physical adsorption was less. The
time gap between the process of adsorption and desorption
of inhibitor molecules over the metal surface becomes
shorter with an increase in the temperature. Hence, the
metal surface remains exposed to the acid environment for
a longer period, therefore the inhibition efficiency falls at
elevated temperatures [33]. A slight increase or constancy
in g with the increase in temperature at higher concentra-
tions for (II, III) may be due to the chemical adsorption
alone or due to the combination of physical and chemical
adsorption [34]. The mass loss experiment showed a rapid
increase in weight loss at elevated temperature in the
absence of inhibitor. This shows that the tested inhibitor
molecules are good corrosion inhibitors for steel in 1 N
HCl in the range of temperatures studied.
100 ppm
200 ppm
400 ppm
600 ppm
25
30
35
40
45
50
55
60
65
Temperature (OC)
Fig. 1 Variation of g % against temperatures for inhibitor II
A visual examination was carried out after the weight
loss measurements were over. It can be noted that, in the
absence of inhibitor, a uniform corrosion attack was
observed, while on the other hand in the presence of
inhibitors, such an attack was not observed: therefore, the
surface area was bright and did not present any corrosion
form, which is indicative that no attack was occurring on
the surface area.
Apparent Activation Energy (Ea) and Pre-exponential
Factor (A)
The activation parameters for the corrosion process were
calculated from the Arrhenius Eq. (5), and transition state
Eq. (6).
ꢀ
ꢁ
ꢁEa
ln K ¼
þ ln A
ð5Þ
ð6Þ
RT
Effect of Temperature
ꢀ ꢁ ꢀ ꢀ
ꢁ
ꢀ
ꢁꢁ
K
R
DSꢄ
DHꢄ
ln
¼
ln
þ
ꢁ
RT
To examine the action of inhibitors at elevated tempera-
tures, mass loss experiments were carried out at different
temperatures (30–60 °C). The results indicate that effi-
ciency shows different trends for the testing compounds. It
was noticed that at a lower concentration (100 ppm by
weight) all compounds show a decrease in efficiency with
increasing solution-temperature of all the testing com-
pounds I, II and III. The same trend was obtained for higher
concentrations of compound I. Meanwhile at higher con-
centrations of the solutions (200 to 600 ppm by weight) of
compounds II and III, the efficiency increases with
increasing the temperature from 30 to 60 °C [33]. At any
temperature, the inhibition efficiency of compound (I) was
found to decreases in efficiency with the increases in
temperature. This is attributed to physical adsorption. At
T
NAh
R
where: k is the corrosion rate, A is the pre-exponential
factor (Arrhenius constant), R is the gas constant and T is
the absolute temperature. h is the Plank constant, NA is the
Avogadro number, DS is the entropy of activation, DH is
the enthalpy of activation.
The activation corrosion energy (Ea) for different con-
centration of compounds (I, II and III) was calculated by
linear regression between ln (K) and 1,000/T as shown in
Fig. 2, (Fig. 3, supplementary file) and the results are shown
in Table 2. Inspection of Table 2 shows that values of Ea
obtained in solutions containing triazole derivative com-
pounds (II and III) are lower than those in the inhibitor-free
acid solutions at high concentrations (400–600 ppm by
Table 1 Weight loss, corrosion rate, surface coverage and corrosion inhibition efficiency in the absence and presence of 600 (ppm by weight) of
compounds I, II and III at different temperatures
Inhibitor name
Blank
I
II
III
Temp. (°C)
Weight loss (mg)
Corrosion rate (mg/cm2 h)
30
45
60
30
45
60
30
45
60
30
45
60
344.6
0.306
–
1,013.2
2,400
2.136
–
58.2
0.051
0.831
83.1
233.8
0.208
0.769
76.9
661.3
0.588
0.724
72.4
27.1
0.024
0.921
92.1
38.6
0.034
0.961
96.1
50.5
0.044
0.978
97.8
27.5
0.024
0.921
92.1
42.1
0.037
0.95
95.8
55.2
0.049
0.977
97.7
0.902
h
–
–
gw (%)
–
–
123

J Surfact Deterg
0
1
2
3
4
5
6
7
1M HCl
100 PPM
200 PPM
400 PPM
600 PPM
Fig. 2 Arrhenius plots of ln (K) versus 1,000/T in the absence and
presence of different concentrations of inhibitor I
1100
900
700
potential (mV)
500
300
100
Fig. 3 Anodic and cathodic polarization curves obtained at 30 °C in
1 M HCl at different concentrations of inhibitor I
weight). The lower values of the apparent activation energy
obtained in the presence of triazole derivatives compounds
(II and III) compared with those obtained in its absence. This
means that this can be attributed to its chemisorption on the
steel surface [35]. The inhibition efficiency also increased as
the temperature increased (Table 2). The fact that g (%)
increased with temperature was explained by Bouyanzer and
Hammouti [36] and de Souza and Spinelli [37], as the likely
specific interaction between the steel surface and the inhib-
itor. Ivanov [38] considers the increase in g (%) with tem-
perature increases as the change in the nature of the
adsorption mode. The inhibitor is being physically adsorbed
at lower temperatures, while chemisorption is favored as the
temperature increases. Noor and Al-Moubaraki [39]
suggested that with an increase in temperature, some
chemical changes occur in the inhibitor molecules, leading to
an increase in the electron density at the adsorption centers of
the molecule, which causes an improvement in inhibition
efficiency. Al-Sabagh et al. [40] explained that, steel corro-
sion occurs at the uncovered part of the surface. Thus
adsorption of inhibitors was assumed to occur at the higher
energy sites. The presence of inhibitor compounds which
result in the blocking of the active sites must be associated
with an increase in the activation energy (Ea) of steel in the
inhibited sites. The relationships between the temperature
dependence of the percentage IE of an inhibitor and the Ea
can be classified into three groups according to temperature
effects [40, 41].
Table 2 Activation parameter values in the absence and presence of
different concentrations of the synthesized triazole derivatives (I, II,
III)
(i) IE decreases with an increase in temperature, Ea
(inhibited solution) [ Ea (uninhibited solution);
(ii) IE increases with an increase in temperature, Ea
(inhibited solution) \ Ea (uninhibited solution);
(iii) IE does not change with temperature, Ea (inhibited
solution) = Ea (uninhibited solution).
Inhibitor
Inhibitor Ea
conc.
DH*
DS*
(kJ mol-1
)
(kJ mol-1
)
(J mol-1 K-1
)
(ppm by
weight)
Blank 1 M 0.00
54.37689
79.78114
78.15991
76.26598
68.12575
77.34182
27.10031
22.00716
19.06317
76.69000
59.73858
27.57255
19.55536
51.73636
77.14062
75.50027
73.62546
65.48605
74.70129
24.46062
19.36663
14.80557
74.0503
-84.0373
-8.62097
-16.5359
-25.3487
-53.3254
-24.1432
-190.609
-211.154
-227.097
-23.8772
-99.1355
-191.231
-219.928
I
100
200
400
600
100
200
400
600
100
200
400
600
Potentiodynamic Polarization
II
III
The polarization curves for carbon steel in 1 N HCl with
the studied inhibitors, I, II and III at different concentra-
tions at 30 °C are shown in Fig. 3 and (Figs. 4,5, supple-
mentary file). The electrochemical corrosion kinetic
parameters, i.e., anodic and cathodic Tafel slopes (ba, bc),
corrosion current density (Icorr) and inhibition efficiency
(gp %) are listed in Table 3. The surface coverage area h
was calculated using Eq. (7):
57.09806
24.93202
16.91566
h ¼ 1 ꢁ ðIinh=Icorr
Þ
ð7Þ
* Standard value
123

J Surfact Deterg
double layer capacitance (Cdl), values were calculated
where Icorr and Iinh are the uninhibited and inhibited cor-
rosion current densities, respectively.
using Eq. (9) [48].
The inhibition efficiency (gp %) of this inhibitor was
obtained from Eq. (8):
fðꢁZmaxÞ ¼ ð2pCdlRctÞꢁ1
ð9Þ
gp % ¼ h ꢃ 100
ð8Þ
where f(-Zmax) is the frequency of maximum imaginary
components of the impedance. The inhibition efficiency
was calculated using charge transfer resistance using Eq.
(10):
It is clear from the polarization curves that the increases
in the inhibitor concentrations of I, II and III decrease the
corrosion current density (Icorr
) which consequently
g % ¼ ððRctꢁRoctÞ=RctÞ ꢃ 100
ð10Þ
increases the surface coverage values (Table 3). These
inhibitors cause changes in the anodic and cathodic Tafel
slopes and no definite trend was observed in the shift of
Ecorr values in the presence of different concentrations of
the synthesized inhibitors, suggesting that these
compounds behave as mixed-type inhibitors mainly anodic.
The results show that the most effective compound is II
which has the hydrocarbon chain length C10. The maxi-
mum inhibition efficiencies were 83, 91 and 93 %, for
compound I, III, and II, respectively [42–45].
where Rct and Roct are the charge transfer resistance values
with and without inhibitor for carbon steel in 1 N HCl,
respectively. The electrochemical impedance parameters
derived from the Nyquist plots and the inhibition efficiency
are listed in Table 4. It was clear that, Rct values in the pre-
sence of the inhibitor were always greater than their values in
the absence of the inhibitor and also increase with increasing
inhibitor concentration, which indicates a reduction in the
steel corrosion rate. The capacitance, Cdl, values were lower
due to a decrease in the local dielectric constant and/or an
increase in the thickness of the electrical double layer, sug-
gesting that the inhibitor molecules acted by adsorption at the
metal/solution interface [49]. The inhibiting efficiency was
in the following order: II [ III [ I.
Electrochemical Impedance Spectroscopy (EIS)
Results obtained from EIS can be interpreted in terms of
the equivalent circuit of the electrical double layer shown
in Fig. 6 in the supplementary file [46].
Figure 4 and (Figs. 7–8 supplementary file) show the
Nyquist plots for carbon steel in 1 M HCl solution with and
without different concentrations of the synthesized triazole
compounds (I, II, and III) at 30 °C. The Nyquist plots were
regarded as one part of a semicircle. The charge transfer
resistance values (Rct) were calculated from the difference
in impedance at lower and higher frequencies [47]. The
Antimicrobial Activity Against Sulfate-Reducing Bacteria
(SRB)
The antimicrobial activity of the three synthesized com-
pounds (I, II, III) against SRB was determined by the serial
dilution method at doses of 50, 100, 200 and 400 ppm and
the results are listed in Table 5. The three synthesized
Table 3 Potentiodynamic polarization parameters of different concentrations of synthesized triazole derivatives (I, II, III) at 30 °C at a scanning
rate of 2 mV s-1
Inhibitor
I
Inhibitor conc. (ppm by weight)
Ecorr [mV (SCE)]
Icorr (mA cm-2
)
ba (mV dec-1
)
bc (mV dec-1
)
h
g %
0.00
100
200
400
600
100
200
400
600
100
200
400
600
-558.4
-522.7
-560.1
-541.2
-560
0.266
0.096
0.066
0.053
0.042
0.049
0.046
0.023
0.018
0.056
0.046
0.024
0.021
318.2
158
-174.
–
–
-152.7
-152.3
-104.5
-140.7
-140.5
-206.3
-310.5
-293.7
-132
0.637
0.749
0.800
0.839
0.814
0.824
0.913
0.931
0.789
0.827
0.908
0.919
63.7
74.9
80.0
83.9
81.4
82.4
91.3
93.1
78.9
82.7
90.8
91.9
209.2
147
260
II
-494.5
-488.3
-511.2
-503.2
-544.2
-520.4
-510.7
-508.4
100.3
152.9
118.5
102.6
192
III
142.9
81.7
-290.3
-209.3
-300
126.5
123

J Surfact Deterg
400
350
300
250
200
150
100
50
Table 5 The bacterial count (cell/ml) of different doses of the syn-
thesized compounds (I, II, III)
Dose (ppm)
50
100
200
400
Cpd (I)
1,000
1,000
100
100
10
10
Nil
Nil
Nil
Cpd (II)
Cpd (III)
Nil
Nil
10
Biodegradability
The biodegradability of I, II and III was evaluated using
the Die-away test as described in Ref. [50]. The results
of the biodegradation using surface tension measure-
ments for 7 days (Fig. 5) showed a gradual increase in
the biodegradation extent of the different inhibitor
solutions by increasing the time. The extent of the bio-
degradation values of the inhibitor solutions in the river
water reached a maximum after 7 days. The gradual
increase in biodegradation is ascribed to the loss of the
surface activity of the inhibitors dissolved in the river
water. The loss of surface activity may be due to the
disruption of the inhibitor molecules [51]. The biodeg-
radation products in the start of the test period (i.e.,
1–3 days) have surface active characters, which retain
the surface activity of the solutions. However, at the end
of the test period (4–7 days), the products lose their
surface activity due to the severe degradation. The
biodegradation ratios of the inhibitor (Table 6) range
between 35 and 53.8 % after 7 days. The biodegradation
values of these inhibitors specified them as biodegrad-
able compounds [52].
0
0
200
400
600
800
1000
Zi [ ohm.cm²]
1M HCl
100 PPM
400 PPM
200 ppm
600 PPM
Fig. 4 Nyquist plots for carbon steel in 1 M HCl in the absence and
presence of different concentrations of inhibitor I
compounds showed impressive results due to their rela-
tively high efficiency against this type of bacteria. The
results indicate that the three synthesized compounds have
high antimicrobial activity against the SRB at relatively
high doses (200–400 ppm), and that the three synthesized
compounds were inactive at the lowest concentration
(50–100 ppm). On the other hand, it was capable to killing
all the bacteria within 3 h (as contact time) at the highest
concentration. To decrease the effect of the microbial
induced corrosion, the biocides should be used to inhibit
SRB growth and other acid producing bacteria in the oil
field.
Table 4 EIS parameters in the absence and presence of different concentrations of synthesized triazole derivatives (I, II, III) at 30 °C
Inhibitor
Inhibitor conc. (ppm)
Rs (ohm cm2)
Rct (ohm cm2)
Cdl (lF cm-2
)
h
g %
0.00
100
200
400
600
100
200
400
600
100
200
400
600
4.9
160.7
463.9
707.1
829.5
939.7
873
221.8
24.42
22.5
–
–
I
28.21
12.22
1.96
5.6
0.653
0.772
0.806
0.828
0.815
0.867
0.906
0.943
0.789
0.828
0.879
0.891
65.3
77.2
80.6
82.8
81.5
86.7
90.6
94.3
78.9
82.8
87.9
89.1
15.34
15.16
14.58
8.288
6.56
II
15
13
1,213
1,726
2,842
762.7
936.2
1,330
1,479
8
1.72
2.33
-7
5.59
III
9.34
6.02
5.69
8.779
5.9
4.81
123

J Surfact Deterg
inhibitor for corrosion of pure iron in molar sulphuric acid. Prog
Org Coat 46:312–316
6. Bouklah M, Benchat N, Aouniti A, Hammouti B, Benkaddour M,
60
50
40
30
20
10
0
I
II
III
´
Lagrenee M, Vezine H, Bentiss F (2004) Effect of the substitution
of an oxygen atom by sulphur in a pyridazinic molecule towards
inhibition of corrosion of steel in 0.5 M H2SO4 medium. Prog
Org Coat 51:118–124
7. Chetouani A, Hammouti B, Aouniti A, Benchat N, Benhadda T
(2002) New synthesised pyridazine derivatives as effective
inhibitors for the corrosion of pure iron in HCl medium. Prog Org
Coat 45:373–378
8. Morad MS (1999) Influence of propargyl alcohol on the corrosion
behaviour of mild steel in H3PO4 solutions. Mater Chem Phys
60:188–195
9. Bilgic¸ S (2002) The inhibition effects of benzoic acid and sali-
cylic acid on the corrosion of steel in sulfuric acid medium. Mater
Chem Phys 76:52–58
0
1
2
3
4
5
6
7
8
Time, day
Fig. 5 Dependence of biodegradation (%) on the time for the
synthesized inhibitors
´
10. Bentiss F, Traisnel M, Lagrenee M (2000) The substituted 1,3,4-
oxadiazoles: a new class of corrosion inhibitors of mild steel in
acidic media. Corros Sci 42:127–146
11. Quraishi MA, Khan MAW, Ajmal M, Muraidharan S, Iyer SV
(1997) Influence of heterocyclic anils on corrosion inhibition and
hydrogen permeation through mild steel in acid chloride envi-
ronments. Corrosion 53:475–480
Table 6 Biodegradation (%) of the synthesized inhibitors
Inhibitors
Biodegradation (%)
12. Khamis E (1990) The effect of temperature on the acidic disso-
lution of steel in the presence of inhibitors. Corrosion 46:476–484
13. Qafsaoui W, Takenouti H (2010) Corrosion protection of
Cpd (I)
35.3
42.1
53.2
Cpd (II)
Cpd (III)
2024-T3 aluminium alloy by electro-polymerized 3-amino 1,2,4-
triazole in sulphate solution containing chloride. Corros Sci
52:3667–3676
14. Finsgar M, Milosev I (2010) Inhibition of copper corrosion by
1,2,3-benzotriazole: a review. Corros Sci 52:2737–2749
15. Zheludkevich ML, Yasakau KA, Poznyak SK, Ferreira MGS
(2005) Triazole and thiazole derivatives as corrosion inhibitors
for AA2024 aluminium alloy. Corros Sci 47:3368–3383
16. Bentiss F, Traisnel M, Gengembre L, Lagren0ee M (2000) Inhi-
bition of acidic corrosion of mild steel by 3,5-diphenyl-4H-1,2,4-
triazole. App Surf Sci 161:194–202
17. Gopi D, Govindaraju KM, Collins ArunPrakash V, Angeline
Sakila DM, Kavitha L (2009) A study on new benzotriazole
derivatives as inhibitors on copper corrosion in ground water.
Corros Sci 51:2259–2265
18. Wang L (2006) Inhibition of mild steel corrosion in phosphoric
acid solution by triazole derivatives. Corros Sci 48:608–616
19. Quraishi MA, Jamal D (2001) Corrosion inhibition of N-80 steel
and mild steel in 15% boiling hydrochloric acid by a triazole
compound—SAHMT. Mater Chem Phys 68:283–287
20. Zhang S, Tao Z, Liao S, Wu F (2010) Substitutional adsorption
isotherms and corrosion inhibitive properties of some oxadiaz-
ole–triazole derivative in acidic solution. Corros Sci
52:3126–3132
Conclusions
From the above results it may be concluded that
1. The synthesized triazole derivative compounds dem-
onstrate good inhibition of the corrosion process of
mild steel in 1 N HCl and they have a high capability
to prevent SRB growth.
2. The prepared compounds act as a mixed-type inhibitor
in 1 N HCl. The weight loss and polarization curves
are in good agreement.
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Author Biographies
Ali A. Abd-Elaal received his B.Sc. (2004) and his M.Sc. in organic
chemistry (2010) from the chemistry department in the Faculty of
Science, Zagazig University. He worked as a research assistant from
2007 and as an associate researcher since 2010 in the Petrochemicals
Department, Egyptian Petroleum Research Institute, Cairo, Egypt. He
is interested in the synthesis of organic compounds and their
application.
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inhibitor for mild steel. Corros Sci 51:642–649
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Metallurgy, Moscow
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metal corrosion and inhibitor adsorption processes in mild steel/
1-methyl-4[40(-X)-styryl pyridinium iodides/hydrochloric acid
systems. Mater Chem Phys 110:145–154
Ismail Aiad received his Ph.D. in physical chemistry from the
Faculty of Science, Zagazig University 1998 where he is the vice
head of the Petrochemical Department. He is a member of the board
of the Chemical Services and Development Center for Oil Field
Chemicals, and he is a professor at the Egyptian Petroleum Research
Institute Surfactants Laboratory, Cairo, Egypt. He has been working
on the synthesis and applications of surfactants materials.
40. Al-Sabagh AM, Kandil NGh, Ramadan O, Amer NM, Mansour
R, Khamis EA (2011) Novel cationic surfactants from fatty acids
and their corrosion inhibition efficiency for carbon steel pipelines
in 1 M HCl. Egypt J Petrol 20:47–57
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ment of novel acidizing inhibitors for carbon steel corrosion in
15% boiling hydrochloric acid. Corrosion 64:541–552
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of 4-amino-5-hydrocarbon-2,4-dihydro-3H-1,2,4-triazole-3-thi-
one Schiff bases. Chem J Chin Univ 19:1617–1619
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Kalkhambkar RG (2008) Inhibition effects of some Schiff’s bases
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Corros Sci 50:3356–3362
Samy M. Shaban received his M.Sc. from Zagazig University in
2009. He is an assistant researcher in the surfactants laboratory at the
Egyptian Petroleum Research Institute, and he is a member in board
of the Chemical Services and Development Center for Oil Field
Chemicals.
Salah M. Tawfik is an assistant researcher in the petrochemicals
department of the Egyptian Petroleum Research Institute. He earned
his M.Sc. in organic chemistry in 2010 from Helwan University. He is
interested in the synthesis and application of novel surfactants
containing heterocyclic rings and their application as corrosion
inhibitors and biocides.
Atef Sayed is a specialist in microbiology in the Petrochemicals
Department, Egyptian Petroleum Research Institute, Cairo, Egypt. He
is a currently an M. Sc. Student at Helwan University. He is interested
in the effect of sulfate-reducing bacteria on the corrosion rates of
metals.
123