Kinetic Isotherm Studies of Azo Dyes by Metallic Oxide Nanoparticles Adsorbent

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.


Research Article 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. Cu 4 O 3 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
Copper oxide nanoparticle has efficiency of azo dyes removal from wastewater [12]. Malachite green dye (C 23 H 25 N 2 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 C 32 H 22 N 6 Na 2 O 6 S 2 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.
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][26][27][28]. This is One-step processes in which no surfactants and other capping agents used.    Vitamin C, D 10

Aims of Study
The main aim of the study was To extract copper nanoparticles using camellia sinensis leaves

Material and Method
The material used for the preparation of copper nanoparticles Cu4O3 includes copper sulfate (CuSO 4 .5H 2 O 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 Cu 4 O 3 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][28][29].

Characterization of Cu 4 O 3 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 Cu 4 O 3 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

Name and Formula
Reference code: 00-033-0480 Mineral name: Paramelaconite   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).   (Figure 8).     Temperature Effect: The temperature effects on percentage degradation effectively. The observed results indicate that after increasing temperature from 35-80 degree the percentage removal potential of copper oxides NPs samples C-1, C-2 (green synthesized by Green tea) increases. The graphical representation of temperature effect of is shown below in Figure 11. Effect of temperature by copper oxide nanoparticles samples C-1, C-2 (synthesized by green tea) on malachite green dye and congored dye calculated by ultraviolet spectrophotometer DB-20.   Parameters of different models studied in this research are listed below in Table 3.
In the equation qm is adsorption capacity in unit mg/g.

Discussion
In present we reported an eco-friendly and cost-efficient

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.

Authors Contribution
All data analysis experimental and graphical. Author conduct and drafted research.