10A STUDY OF CORROSION INHIBITON EFFECT OF THIOSEMICARBAZIDE BASED SCHIFF
BASE ON ALUMINIUM METAL IN ACIDIC MEDIUM
Sanjay Kumar1, Amarchand Kumawat2 and V. K. Swami3
1

Research Laboratory, Govt. Lohia P. G. College, Churu (Raj.) India
2,3
S. B. D. Govt. P. G.College, Sardarshahar, Churu, India
Corresponding Author: sanjaysnkp@gmail.com

How to cite this paper:
Sanjay Kumar; Kumawat,
Amarchand and Swami, V. K.
(2022) A Study of Corrosion
Inhibiton
EffectofThiosemicarbazide
based
Schiff base on Aluminium
metal in Acidic Medium,
Journal of Global Resources,
Vol. 08 (01)DOI:
10.46587/JGR.2022.v08i01.010

Received: 15 Oct. 2021
Reviewed: 30 Oct. 2021
Revised: 09 Dec. 2021
Final Accepted: 11 Dec. 2021

Abstract: Corrosion is the destruction of metal surface by thereaction with its environment (humidity, gases, acid, alkalineetc.). In this process metal convert in to the more stable form
such as sulphide oxide etc. Corrosion of materials andstructures is a hindrance to the development of society as it
causes significant loss to the economy, leads to pollution, andleads to serious disasters, hence its prevention and control isof great benefit for the humanity. Addition of corrosion
inhibitors is one of the practical and easy methods to protect
metals and alloys against attack of corrosion in many industrial
environments. In this chapter thiosemicarbazide based Schiffbase 2-[(3,4-dihydroxy-5-nitrophenyl)methylidene]hydrazine1-carbothioamide (DHNPMHC) was synthesized andcharacterized using elemental analysis, FT-IR and UV–Vis
methods. The inhibition efficiency of Schiff base DHNPMHC
against aluminium corrosion in 0.5 M HCl was examined usingmass loss measurement and scanning electron microscopy(SEM). Results showed that DHNPMHC is an effective
inhibitor for aluminium corrosion in 0.5 M HCl solution. The
inhibition efficiency also increased with concentration of
inhibitor increased. Maximum percentage inhibition eﬃciency
92.6 % (at 4-hour immersion time) is shown at highest
concentration of inhibitor 5% (5X10-5M). Adsorption of theinhibitor on the aluminium surface followed Langmuiradsorption isotherm. SEM study of aluminium surface inpresence of inhibitor and in absence of inhibitor also supports
the inhibition of corrosion in acidic medium. All results showthat the Schiff base of thiosemicarbazide (DHNPMHC) is
excellent corrosion inhibitor for aluminium in 0.5 M HCl.
Key words: DHNPMHC, Corrosion, Inhibition Efficiency,
Aluminium, Mass Loss Measurement, SEM.

Journal of Global Resources, January 2022, Volume 08 (01) Sanjay Kumar, A. Kumawat and V. K. Swami Page | 91

Introduction
Nature providing us valuable resources likes air, water, materials etc. on the earth. In nature
different phenomenon happened continuously likes rain, combustion, volcanic eruption, corrosionof materials etc. Our material resources such as copper, iron, aluminium, chromium, manganese,
etc., are vanishing day by day. If it continues like this, soon we will be facing acute shortage ofmaterials. The upcoming metal crisis is harsh reality rather than just a possibility. In metallurgy
pure metal like Fe, Cu, Al etc. extracted from their ores by different chemical and physicalmethods. In corrosion process metal reacts with its environment (humidity, gases, acid, alkalineetc.) and convert into the more stable form such as sulphide oxide etc. Due to corrosion
mechanical properties of metals become changed, hence causes materials failure in nature [1-5].
Corrosion of materials and structures is a hindrance to the development of society as it causes
significant loss to the economy, leads to pollution, and leads to serious disasters, hence its
prevention and control is of great benefit for the humanity. The economic cost of corrosion all over
the world is enormous and goes into billions of dollars. According to a report of National
Metallurgical Laboratory (NML), Jamshedpur, the figure of Rs 1.07 lakh crore given by National
Association of Corrosion Engineers (NACE) recently excluded corrosion losses being incurred by
the country's small & medium enterprises (SMEs) engaged both in manufacturing and utility
services sectors.
According to NACE international impact report 2013 on corrosion of metals “The global
cost of corrosion is estimated to be US $ 2.5 trillion, which is equivalent to 3.4% of the global
gross domestic product (GDP)” [6]. Corrosion process in industries and engineering structures is
the main dangerous problem of materials failure and loss of lives. In last decades, there areseveral cases of engineering structure failure and aircraft accidents happened where hundreds
live lost. In these accidents corrosion of materials is directly or indirectly responsible [7-9].
Aluminum is one of the world’s most commonly used metal. The aluminium is a soft, nonmagnetic, nontoxic, ductile, low density, highly electrical conductive and highly corrosion resistantelement. Due to these properties it has wide range of applications such as: in structural materials(in aircraft, ships, cars, and heat exchangers), in buildings, in packaging (in cans, foil, frame etc.),
for cooking utensils, to make electrical power cables etc. Aluminium forms a diversity of alloys
which have a wide range of properties and applications. It is also easy to form and recycle [1011]. HCl is commonly used for acid cleaning, acid de-scaling, chemical and electrochemical
etching in many industries where in aluminium and its alloys are used [12-14]. Due to use of HClaluminium easily gets corroded. Corrosion of metals is a continuous process and difficult toeliminate completely. Addition of corrosion inhibitors is one of the practical and easy methods toprotect metals and alloys against attack of corrosion in many industrial environments. Different
corrosion protection is in practice present time. The use of organic corrosion inhibitors is also
practical and easiest method for protection of corrosion of metals in acidic medium [15-16].
Compounds containing hetero atoms such as sulfur, nitrogen, phosphorus, or oxygen are often
found to be good corrosion inhibitors for metal corrosion. The corrosion inhibition efficiency oforganic inhibitor is depending on the structural properties of the compound like functional groups(methoxy, amino, hydroxy etc.), electron density at the donor atom and the presence ofaromaticity the molecule [17-18]. Synthetic inhibitors that are in practice have createdenvironmental problems due to its toxicity properties. They also changed the properties of metals.
Thus it is important and necessary to develop low cost and ecofriendly organic corrosion inhibitors[19-20].
In last decades, the efficiency of Schiff bases as organic corrosion inhibitors for metals
corrosion in acidic medium has been widely reported [21-26]. The Schiff base ofthiosemicarbazide (DHNPMHC) is nontoxic and soluble in aqueous media in presence of
Journal of Global Resources, January 2022, Volume 08 (01) Sanjay Kumar, A. Kumawat and V. K. Swami Page | 92

Dimethyl sulphoxide (DMSO). It is relatively cheap and easy to produce with high yield. These
properties would justify the use of Schiff base of thiosemicarbazide as corrosion inhibitor towards
metal corrosion in acidic medium. The object of this study to examined anticorrosive properties ofthiosemicarbazide based Schiff base 2-[(3,4-dihydroxy-5-nitrophenyl)methylidene]hydrazine-1carbothio amide (DHNPMHC) on aluminium corrosion in 0.5 M HCl.
Synthesis and characterization of 2-[(3,4-dihydroxy-5-nitrophenyl) methylidene]
hydrazine-1-carbothio amide (DHNPMHC):
Synthesis of (DHNPMHC):
The entire chemical used to synthesize the organic inhibitor DHNPMHC were analytical grade.
The organic inhibitor DHNPMHC has been synthesized and characterized on the basis ofprevious reported research studies [27-31]
The Schiff base 2-[(3,4-dihydroxy-5-nitrophenyl)methylidene]hydrazine-1-carbothio amide(DHNPMHC) was synthesized from the condensation of 3,4-dihydroxcy-5-nitrobenzaldehyde(2gm) and thiosemicarbazide (2gm) in ethanol (20ml) in presence of glacial acetic acid(2ml). The
content was refluxed about 6-7 hours at 70oC in round bottom flask. On cooling the contents theshining yellow colored solid (M.P.175-180 oC) separated out. The yield of (DHNPMHC) is 3.35gm(81.25%). The method of synthesis is summarized in Figure 01.
Figure 01: Reaction Scheme

Characterization of DHNPMHC:
The structure of compound was characterized by elemental analysis, IR and electronic studies.
IR studies support the synthesis of DHNPMHC. In the IR spectrum of the compound presence ofυ(C=N) band at 1695-1650 cm-1 confirm the condensation between aldehyde group of 3,4dihydroxcy-5-nitro-benzaldehyde and amino group of thiosemicarbzide. In the UV- Visible
spectrum of DHNPMHC 𝑛 → 𝜋 ∗ absorption peak of azomethine group were observed at 352,
366.5, 390, 391,416 nm.
Experimental
Mass Loss Measurement:
It is a most convenient and easiest method for measuring different corrosion parameters of metal
corrosion. In this study mass loss in absence of inhibitor and in presence of inhibitor in corrosive
media (0.5 M HCl) were measured at different time interval (4 hours to 72 hours). For the massloss study rectangular aluminium specimens of size 3.0cm x 3.0cm x 0.1 cm were used. Test
solutions with given concentration of the inhibitor in the acid was prepared by properly diluting thebulk solution of the inhibitor (.01N). In this study inhibitor concentrations range was used varied
from1.0% to 5.0%. The corrosion parameters mass loss, inhibition efficiency, surface coverageand corrosion rate were incorporate in table 01.
The percentage inhibition efficiency () of metal has been determined by using the given formula: =[ΔMu − ΔMi
] × 100 ……. (1)ΔMu

Journal of Global Resources, January 2022, Volume 08 (01) Sanjay Kumar, A. Kumawat and V. K. Swami Page | 93

Where,ΔMu= Mass loss of metal only in presence of corrosive solution
ΔMi= Mass loss of metal in presence of inhibitor
The degree of Surface coverage (𝜃) of metal coupon by inhibitor was calculated as:
ΔMu − ΔMi
𝜃 = ΔMu ……….. (2)The corrosion rate (CR) of corrosion process in millimeter per year can be calculated as:
Mass loss ×87.6
CR (mm / yr) =……….. (3)𝑑𝐴𝑇
Where,
d= density of aluminium
A= surface area of metal coupon
T= immersion time in HCl
Surface Morphological Studies:
Scanning electron microscopy (SEM) is an important electron microscopy technique that is used
to take visual image of a particle with high quality and spatial resolution. SEM is largely employed
to observe the surface phenomenon of the materials. In this chapter Scanning Electron
Microscope (TESCAN, MODEL: VEGA3XMU) is used to study the corrosive surface of aluminium
in presence of inhibitors and absence of inhibitors. The surface morphology of the aluminium
surface after its immersion in the acidic medium in the absence and in the presence of the
DHNPMHC (at 5% concentrations) was carried out by scanning electron microscope (SEM) at
25.0 kv and 10 𝜇𝑚 resolution.
Adsorption Isotherms:
The corrosion inhibitors generally adsorb on the metal surface and protect the surface fromexternal corrosive environment. An adsorption isotherm is the mathematical expression, which
relates the bulk concentration of adsorbing species to its surface concentration at constanttemperature. An adsorption isotherm gives the relationship between the surface coverage of asurface with an adsorbed species and the concentration of the species in solution. Most of theorganic inhibitors obey Langmuir adsorption isotherm. According to Langmuir adsorption isotherm
the plot between log θ/(1 – θ) v/s log C show linearity.
Result and Discussion
In this study corrosion inhibition behavior of thiosemicarbazide based Schiff base DHNPMHC
towards aluminium corrosion in 0.5 M HCl has been studied. In this study effects of immersion
time and inhibitor concentration on inhibition efficiency were examined. Result of mass loss
measurement shows that inhibition efficiency of DHNPMHC decreases with increasing immersion
time. Corrosion rate of metal corrosion in 0.5 M HCl slow down by using inhibitor. It decreases
with increasing the concentration of inhibitor. The inhibition efficiency increases with increasing
the concentration of inhibitor and maximum percentage Inhibition eﬃciency 92.6 % shown at 5%(5X10-5M) inhibitor concentration at 4-hour time interval (Figure 02.a). The above statements it isclear that the inhibitor adsorbed on the aluminium surface and forms a protecting layer. The plotlog (𝜃/1-𝜃) versus logC (mol/L) shows linearity which indicate the adsorption of Schiff base ofthiosemicarbazide on aluminium surface obey Langmuir adsorption pattern (Figure 02.b).
The SEM images of aluminum (fresh aluminium, in 0.5 M HCl and with inhibitors for aperiod of 4 hour ) are shown in Figure 04a-c. On comparison of SEM images it is clear that themetal surface was smooth when inhibitor used, whereas the surface is damaged in the case ofaluminium immersed in 0.5 M HCl without inhibitor.

Journal of Global Resources, January 2022, Volume 08 (01) Sanjay Kumar, A. Kumawat and V. K. Swami Page | 94

Table 01: Concentration of inhibitor (COI), mass loss, inhibition efficiency (), surface coverage(𝜽) and corrosion rate for aluminium metal in presence of DHNPMHC at different time interval
C
O
I(%)

ΔM
(mg)

(%)

blank
1
2
3
5

.82
.38
.26
.12
.06

….
53.6
68.2
85.3
92.6

4 hours



𝜃

….
.53
.68
.85
.92

CR
(m
m/
yr.)
7.3
3.4
2.3
1.0
.54

ΔM
(mg)

24 hours
𝜃

(%)

2.0
.98
.53
.40
.17

…
51
73
80
91

…
.51
.73
.80
.91

CR
(m
m/y
r)
3.0
1.4
.79
.60
.25

ΔM
(mg)

48 hours
𝜃

(%)

2.2
.92
.64
.35
.23

…
58
71
84
89

…
.58
.71
.84
.89

CR
(m
m/y
r)
1.6
.69
.48
.26
.17

ΔM
(mg)

72 hours
𝜃

(%)

2.7
1.2
0.8
.47
.29

…
55.55
70.37
82.59
89.25

…
.55
.70
.82
.89

CR
(m
m/y
r)
1.3
.60
.40
.23
.14

100
90
80
70
60
50
40
30
20
10
0

1.2
1
4 hours
24 hours

48 hourslog (𝜃/1-𝜃)Inhibition Efficiency (%)

Figure 02: (a) The graph inhibition efficiency v/s concentration of inhibitor (b) Langmuiradsorption isotherm plot

0.8
72 hours

0.6

48 hours

0.4

24 hours

0.2

72 hours

4 hours

0

1

2

3

5

Concentration of inhibitor (%)

logC(mol/L)

(a)

(b)
Figure 03: IR spectrum of DHNPMHC

Figure 04: (a) Fresh Aluminum surface. SEM image for 4 hr time duration (b) Al + 0.5M HCl (c) )Al +0.5M HCl+5% DHNPMHC

(a)

(b)

(c)

Conclusion
The eﬃciency of synthesized Schiff base of thiosemicarbazide (DHNPMHC) as corrosion
inhibition for aluminium in 0.5 M HCl have been studies. Results obtained from mass loss
Journal of Global Resources, January 2022, Volume 08 (01) Sanjay Kumar, A. Kumawat and V. K. Swami Page | 95

measurements indicate that Schiff base of thiosemicarbazide (DHNPMHC) has good corrosion
protection properties towards aluminium metal corrosion in 0.5 HCl solutions. The surface
coverage increases with increasing concentration of inhibitor increases. The graph between
inhibition efficiency and concentration shows linearity. Adsorption of inhibitor on the surface ofaluminium obey Langmuir adsorption isotherm pattern. It means linear plot observed between log(𝜃/1-𝜃) versus logC (mol/L). Scanning electron microscopy (SEM) images of aluminium inpresence of inhibitor and in absence of inhibitor in acidic medium also supports the inhibition of
corrosion. All results of study shows that excellent corrosion protection property of the Schiff baseof thiosemicarbazide (DHNPMHC).
Acknowledgement: Special thanks to department of chemistry Dungar College, Bikaner and
the Principal, Govt. Lohia (PG) College, Churu provided facility of Research Laboratory. Also a
special thanks to Dr. N. K. Soni, NTPC, Noida for providing SEM facility.
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