Lupine Publishers | An archive of organic and inorganic chemical sciences
Abstract
We reported the synthesis of Cu4O3
nanoparticles fabricated by Camellia Sinensis (green tea) leaves extract as
reducing and stabilizing agent and studied the azo dyes removal efficiency. The
formation of copper oxide nanoparticles was confirmed after change in solution
of salt and plant extract from green to pale yellow. Subsequently, the above
said nanoparticles were characterized by SEM, XRD, FTIR, and UV
spectrophotometer for size and morphology. The average particle size of copper
oxide nanoparticle was found to be 17.26nm by XRD shrerrer equation, average
grain diameter by SEM was calculated 8.5×10-2mm with spherical and oval shaped.
UV spectroscopy range was between 200-400nm. These copper oxide nanoparticles
were applied as azo dyes (Congo red and malachite green) degradation. Effect of
reaction parameters were studied for optimum conditions. Kinetic models like
Langmuir, Freundlich and elovich models were applied. Finally, concluded that
these particles are effective degradation potential of azo dyes at about 70-75%
from aqueous solution.
Keywords: Green Tea; Cu4O3; Green synthesis; XRD; Congored; Malachite
Green
Background
With elevating improvement in
technology, the Scientific developments are approaching to new horizons [1].
Besides supplementary needs, the stipulation of industrial wastewater has
increased swiftly, supervened in the huge amount of wastewater including azo
dyes. Azo dyes are the foremost group of commercial pollutants [2]. Azo dyes
are class of synthetic dyes with a complex aromatic structure and contain two
adjacent nitrogen bond (N=N), that can accompany color to materials [3].
Furthermore, the aromatic structures of dyes form them sturdy and not-
biodegrade [4]. Textile consume prodigious quantities of hazardous chemicals
particularly in dyeing operations. This work is constructed on malachite green
and congored azo dyes. The toxic Habit of the azo dyes can be elaborated by
fact that upon decomposition it breaks up into hazardous products [5]. The MG
and CR azo dyes toxic dye which has been removed from water samples through the
physical, chemical and biological methods. Azo dyes are toxic, probably cause
aesthetic problems and mutagenic and carcinogenic effects on human health, so
must be degraded [6]. Therefore, the adsorption method by using copper oxide
metal nanoparticles for wastewater treatment comprised with azo dyes. Cu4O3
nanoparticle were applied as an adsorbent for the degradation of MG and CR dyes
and its kinetic and isotherm studies. Biogenic technology is regarded an emerging
advancement of the current time which has been utilized to synthesize
nanoparticles of a desired shape and size by using plant extract [7].
Consequently, the synthesized nanoparticles using innovative techniques which
is used as cost-friendly reagent and less reactive. The work symbolizes
application of conventional physical and also chemical methods for
decolorization of azo dyes. physical method includes osmosis, filtration,
adsorption and flocculation. the chemical method (oxidation, electrolysis) and
biological method (microorganism, enzymes) are also applicable [8]. Green
technology deals with the manipulation of matter at size typically b/w 1-100nm
range. Nanoparticles having high surface to volume ratio responsible for
enhanced properties [9]. Specific area is appropriate for adsorption property
and other relevant properties such as dye removal [10].
Azo dye normally has aromatic
structure and N=N bond that’s why they are hardly biodegradable [11,12]. These
dyes have also mutagenic and carcinogenic effect. Normally, conventional
methods have considerably less potential of degradation. Copper oxide
nanoparticles have efficient power of dyes removal [12-17]. Most probably,
copper oxide are low cost and novel adsorbent of azodyes. Copper oxide nanoparticle
has efficiency of azo dyes removal from wastewater [12]. Malachite green dye
(C23H25N2 with molar mass364.911g/mol) is organic in nature. Its lethal dose is
80mg/kg the structure of malachite green dye is in Figure 1 below. Congo red an
azo dye is sodium salt of 3,3′-bis structure. Congo red dye is water soluble,
its solubility is enhanced in organic solvents. Its molecular formula is
C32H22N6Na2O6S2 with molar mass of 696.665 g/mol [13- 14]. The structure is
given below Figure 2. The Camellia synesis is evergreen small tree. The
Camellia synesis leaves act as capping and reducing agent during the synthesis
of metal nanoparticle. There are certain properties of green tea extract such
as antitumor, antioxidant, anticoagulant, antiviral, blood pressure and
lowering activity [18-22] (Figure 3). Plant extract has some chemicals like
phenols, acid, vitamins, responsible for reduction of metal [23]. Camellia
synesis leaves have polyphenols, catechins (ECG), OH groups which cause copper
metal reduction (Table 1). Copper oxide Cu4O3 is known as paramelaconite
material in tetragonal shape. Plants contain a wide range of secondary
metabolites included phenolics help a vital role in the reduction of copper
metal ions yielding nanoparticles [24]. Thus, ideally be used for the
biosynthesis of nanoparticles. Copper oxide Cu4O3 is known as paramelaconite
material in tetragonal shape. Copper nanoparticles synthesis by using green tea
has Nano range particle size confirmed by characterization [25-28]. This is
One-step processes in which no surfactants and other capping agents used.
Aims of Study
The main aim of the study was
To extract copper nanoparticles using camellia sinensis leaves
a) To characterize the copper NPs
b) To study its potential to degrade azodyes
c) To find out the effect of different experimental parameters on
%degradation.
d) Kinetic study of adsorption of congored and malachite green dye
Method
Material and Method
The material used for the preparation of copper nanoparticles Cu4O3 includes
copper sulfate (CuSO4.5H2O from Sigma Aldrich) and camellia sinensis leaves
(from botanical garden of institute) for the preparation of green tea extract.
All chemicals used were of analytical grade and pure (Figure 4).
Preparation of Green Tea Extract
Green tea leaves of 30g were taken and then washed with distilled water.
further, the leaves were dried and then ground. The powder of green tea was
used in the formation of extract [29]. The 100ml of deionized water was used.
Later, the solution was boiled for 10 minutes and subsequently kept at low
temperature after filtration.
Preparation of Cu4O3 Nanoparticles
A copper sulfate soln. of 50ml was added into 5ml of green tea extract.
Magnetic stirrer was used for stirring. The color changed from green to pale
yellow and finally dark brown confirmed the formation of nanoparticles. After
the formation of nanoparticles, solution was centrifuged at the speed of
1000rpm for 20 mins. After the removal of supernatant copper oxide
nanoparticles were dried and washed with ethanol. At the end calcination was
performed at 500 degree for one hour and resultantly black colored particles
were collected for characterization [27-29].
Results
Characterization of Cu4O3 Nanoparticles
UV spectrophotometer, X-ray diffractometer (XRD), Fourier transform infrared
spectrophotometer (FTIR) and Scanning electron microscope (SEM) were used in
order to characterize the size, shape, chemical and structural composition of
Cu4O3 nanoparticles [30]. During the study, the green color soln. transformed
into dark brown which confirm the formation of copper oxide nanoparticles.
X-Ray Diffraction Studies
The X-ray diffraction pattern of copper oxide nanoparticles were examined by
x-ray diffractometer. To determine the intensity of copper oxide nanoparticles,
the powder was added in the XRD cubes for analysis. The resultant pattern of
the copper oxide nanoparticles was matched with JCPDS card number (033-0480),
the peaks at 2θ intensity 28.09, 30.61, 36.14 and 44.14 and have 112, 103, 202
and 213 patterns respectively. However, average crystal size calculated by the
Scherrer equation keeping lemda at 0.154 and FWHM value calculated 0.5 found
was 17.2nm. The shapes of the particles of Cu4O3 nanoparticles in XRD was
tetragonal [31-33].
Name and Formula
Reference code: 00-033-0480
Mineral name: Paramelaconite
Compound name: Copper OxideEmpirical formula: Cu4O3
Chemical formula: Cu4O3
Ultraviolet Spectroscopy:
The range at which copper oxide nanoparticles appeared was
200-400nm. The maximum absorption peak was confirmed at 280nm which confirmed
the copper oxide nanoparticles (Figure 6).
FTIR Analysis:
In the current study, FTIR spectrum was examined to determine the copper
nanoparticles functional group peaks. The overall peak was observed in ranged
from 400 to 4000cm-1. The spectrum at peak 3310.7cm and 1611.2cm revealing the
(Figure 7) presence of alcoholic group. The bands at 3310.7cm- 1, and 2850cm-1
another functional group present are listed in table below (Table 2).
SEM Analysis:
The average particle size of copper nanoparticle was
analyzed by SEM model (JSM-6480). The range of grain of copper oxide
nanoparticle was calculated about 8.5 ×10-2mm by SEM micrograph. The prepared
copper oxide nanoparticles were well dispersed. It was observed that particles
were smooth with a tetragonal shape (Figure 8).
Removal of Malachite Green and Congo Red Azo Dye by Cu4o3 Nanoparticles
Preparation of Standard Solution: In 1-liter distilled water, the dye
was dissolved to prepare 1000ppm solution of malachite green and Congo red.
From stock solution different concentrations of dyes were prepared. After
dilution from 1000ppm solution to 100ppm solution was prepared. From that 150,
200, 250-ppm solution were prepared. Efficiency of Color removal was calculated
by percentage degradation formula
% decolorization of dye= A-B /A×100.
Where A and B are absorbance of dye solution without nanoparticles and with particles
respectively.
Mechanism of Azodye Degradation
50 microliter of the hydrogen peroxide H2O2 was added as the oxidizing agent
to yield hydroxyl radical. Catalytic activity process mainly depends on the
formation of superoxide anion radical and hydroxyl radical. The concentration
of CR and MG dyes in aqueous solutions were measured by UV–vis
spectrophotometer. A reducing agent H2O2 was added with adsorbent to check the
adsorption capacity.
Effect of Experimental Parameters On % Degradation of Dye Removal
Time effect: Effect of time on percentage degradation of azo dyes was
also studied by UV spectrophotometer. The samples of copper oxide NPs
synthesized by green tea C-1, C-2(GT) were calculated. The time required for
removal of above said dye was between (40-45min) and percentage removal was
observed for all samples between 70-75%. The result of graphs clearly shows the
time effect on color degradation of azo dye malachite green-MG and acid red
28-CR by using adsorbent copper oxides nanoparticles. The experimental
conditions during experiment were kept constant just like temperature 308
kelvin and initial concentration of adsorbent was within ranges from 20-
250mg/l. Samples C-1, C-2 are samples codes synthesized by camellia sinensis
leaves extract at different temperatures. In figure below C-1 sample is dye+
adsorbent +H202 and C-2 sample without reducing agent. It was concluded from
graphs %degradation enhanced in presence of reducing agents. Figure 9 Effect of
time by copper oxide nanoparticles samples C-1, C-2(Green tea mediated) on
malachite green dye and Congo red dye calculated by ultraviolet
spectrophotometer DB-20.
Adsorption Kinetics Studies: The kinetics of azo dye adsorption was
carried under selecting optimum operating conditions. The kinetic parameters
are helpful for the estimation of adsorption rate. A solution prepared by
dissolving 20mg of adsorbent in 50ml of 10ppm dyes and continuously stirred.
Adsorption Kinetic Studies of Copper Oxide NPs: The
pseudo-second-order model was found to explain the adsorption kinetics most
effectively. The results indicated a significant potential of nanoparticles as
an adsorbent for azo dye removal. The straight line shows that nanoparticles
follow pseudo-second-order kinetics rather than first orde
Adsorption Reaction Isotherm Models
Langmuir Isotherm Model: The Langmuir isotherm is applicable for
adsorption of a solute as monolayer adsorption on a surface having few numbers
of identical sites. Langmuir isotherm model provide energies of adsorption onto
the plain. That’s why, the Langmuir isotherm model is selected for adsorption
capacity relating to monolayer surface of adsorbent. Adsorption process fits
the Langmuir and pseudo-second-order models. Langmuir isotherm or single
crystal surfaces describes well adsorption at low medium coverage, adsorption
into multilayer is ruled out. Parameters of different models studied in this
research are listed below in Table 3.
Freundlich Isotherm Model: The Freundlich isotherm model is suitable
for the adsorption of dye on the adsorbent. Freundlich equation is stated below
In qe = Kf qm+ 1/n InCe
qe is the amount used of azo dye in unit of mg/g, Ce is the equilibrium
concentration of the azo dye and Kf and n are constants factors affecting the
capacity of adsorption and adsorption speed. The graph between lnqe versus ln
Ce shows linearity. The adsorption reaction isotherms are fitted to models by
linear square method. The result shows in this study that Langmuir model fit
better than the Freundlich model. The adsorption activity of copper oxide
nanoparticle samples prepared by green source were observed against the
degradation of malachite green and congored azodyes (Figure15).
Discussion
In present we reported an eco-friendly and cost-efficient preparation of copper
oxide nanoparticles by leaf extract of camellia sinensis. the characterization
of particles were performed by SEM, UV, XRD, FTIR analysis. UV spectroscopy
peak was observed at 280nm and a broadband observed which confirmed
nanoparticles existence. The particle size was calculated by Scherrer equation
was 17.26nm. The SEM results confirmed tetragonal shape of cu403 particles with
grain average diameter 8.5×10-2nm, and FTIR spectra indicated the peaks of OH,
C=C, C-H functional groups, which is due to thin coating of extract on
nanoparticles. The calculated surface area of nanoparticles was 65m2/g. The
%degradation of azo dyes malachite green and congored range were b/w70-75% at
maximum 0.2g/l and 20mg/l dosage of adsorbent and dye. The optimum time was b/w
30-40mint, PH 3-4, temperature 70-80 Co for maximum degradation. The effect of
different experimental parameters was studied on percentage degradation of
dyes. The azo dyes congored and malachite green dyes adsorption isotherm models
were studied. The reaction kinetics followed pseudo second order for both dyes
rather than first order. The Langmuir model fit better with linearity rather
than Freundlich, which confirmed by graph having r2 0.98,0.99and0.95 values for
models. The elovich model also linear fit. In conclusion, copper oxide
nanoparticles keep excellent azo dyes degradation potential.
Conclusion
In present we reported an eco-friendly and cost-efficient preparation of
copper oxide nanoparticles by leaf extract of camellia Sinensis. According to
kinetic study it proved that Cu4O3 NPs keep excellent adsorption capability for
MG and CR azo dyes.
https://lupinepublishers.com/chemistry-journal/pdf/AOICS.MS.ID.000174.pdf
https://lupinepublishers.com/chemistry-journal/fulltext/kinetic-isotherm-studies-of-azo-dyes-by-metallic-oxide-nanoparticles-adsorbent.ID.000174.php
For more Lupine Publishers Open Access Journals Please visit our
website: https://lupinepublishersgroup.com/
For more Open Access
Journal on Chemistry articles Please Click Here:
https://lupinepublishers.com/chemistry-journal/
To Know More About Open Access Publishers Please Click on Lupine
Publishers
Follow on Linkedin : https://www.linkedin.com/company/lupinepublishers
Follow on Twitter : https://twitter.com/lupine_online
No comments:
Post a Comment