Laplap purpureus (Dolichos Bean) plant stems used as biosorbent for the removal of  Bismark Brown R dye from aqueous solution

 

G. Bharathidasan^*, N. Mani, G. Vishnuvardhanaraj, K. Mohamed Faizal

PG and Research Department of Chemistry, A.V.V.M. Sri Pushpam College (Autonomous), Poondi, Thanjavur (Dt), Tamil Nadu, India.

*Corresponding Author E-mail: gpdasangee@gmail.com

Adsorption of dyes using Biosorbent is an alternative method to remove dye from wastewater. Biosorbent prepared from Laplap Purpureus stem powder(LPSP) has been used as an adsorbent for the removal of Bismark Brown R dye from the aqueous solution. The biosorbent material was analysed by scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The batch adsorption studies are carried out by absorbing the effect of experimental parameters such as pH, adsorbent dosage, equilibrium time and initial dye concentration. The values obtained from the experimental data were analyzed by Langmuir and Freundlich isotherm model equation. The adsorption kinetic studies werealso analyzed by pseudo first order and pseudo second order models. From the analyzes of the data, it is observed that the biosorbent had a good capacity to remove the Bismark Brown R dye from the aqueous solution.

 

 

 

1. INTRODUCTION:

In developing countries, environmental pollution caused due to the discharge of industrial waste water is a major concern. Usually, untreated or partially treated industrial effluents are being discharged into the natural ecosystem. These industrial effluents act as major water pollutants. The dyes, an important class of pollutants are the compounds which are organic in nature and present in the industrial effluents discharged from textiles, paper, rubber, plastics, leather, cosmetics, pharmaceutical and food industries. Synthetic dyes are being produced on large scale than that of the natural dyes and are frequently being used in industries. Due to their extensive applications, the synthetic dyes can cause considerable environmental pollution and serious health risks.

 

The presence of dyes in water bodies is toxic to aquatic as well as human lives, due to the presence of an aromatic structure; in some cases, metals in their structure. The dye-contaminated water is mutagenic, carcinogenic and causes many health problems such as nausea, hemorrhage, ulceration of skin and mucous membrane etc.^1,2. The methods of dye removal from industrial effluents include biological treatment, coagulation, floatation, adsorption, oxidation and membrane filtration. Amongst the treatment options, adsorption method appears to have considerable potential for the removal of dye from industrial effluents³. Adsorption method is superior in simplicity of design, initial cost, easy to operation and insensitivity to toxic substance. A large number of suitable adsorbents such as activated carbon, polymeric resins or various low cost adsorbents (non modified or modified cellulose biomass, chitin, bacterial biomass, etc.) have been studied. Identification of a potential dye adsorbent must be in good agreement with its dye binding capacity, its requirements and limitations with respect to environmental condition. The valorization of agricultural wastes into valuable materials without generating pollutants is a big challenge and recommended for an industrial sustainable development in order to protect the environment ⁴. Therefore, biosorption is a promising method for pollutant removal from their solutions. The materials of biological origin are used as sorbents in order to remove dyes from the solutions. These ‘biosorbents’ contain a variety of functional groups which can complex with dyes. Research in the field of biosorption suggests a number of advantages over other techniques such as the material can be found easily as waste or by products, materials can be recycled, no need of costly growth media, methods are simple, and requires less investment. Moreover, the process is ecofriendly, rapid, easy to operate and independent of the physiological constraints of living cells⁵. In recent years a large number of biosorbents have been studied to removal of dyes, such as carrot leaves and their stem⁶, potato plant waste⁷, Cucumis sativus fruit peel ⁸, coconut coir dust⁹, wood apple shell¹⁰, Casuarina equisetfolia needle¹¹,  Bengal gram seed husk¹²,peanut husk ¹³. The efficiency of adsorption process mainly depends on the cost and removal capacity of adsorbents used. Nowadays agricultural waste materials are receiving much more attention as adsorbents for the removal of dyes from industrial effluents due to its low cost and easy availability. The objectives of present study were to examine the sorption characteristics of Laplap purpureus stem powdered (LPSP), under optimum conditions, for the removal of dye from aqueous solution so as to facilitate comparison with other adsorbents.

 

2. MATERIALS AND METHODS:

2.1 Preparation of adsorbent:

The Laplap purpureus plant stems was collectedfrom local home garden after harvest at Sevvaypatti village, Karambakudi (T.K), Pudukkottai (D.T), Tamil Nadu -614 614, India. The stems were cut into small segments, thoroughly washed with tap water to remove dirt and then dried in sun light for five days. The driedLaplap purpureus plant stems were then ground as fine powder in a domestic grinder and screened to separate the particles of <90 µm by usingmanual (Jayant Test Sieves) sieves. These separated (LPSP)particles were kept in air tight plastic bottle for use in adsorption studies.

 

2.2 Preparation of Adsorbate:

Bismark Brown R having molecular formula C₂₁H₂₆Cl₂ N₈was chosen as the adsorbate.The Bismark Brown R dye used is Himedia grade. The dye stock solution was prepared by dissolving accurately weighed Bismark Brown R dye in double distilled water to the concentration of 1g/L. The experimental solutionwas obtained by diluting the stock solution in accurate proportions to requiredinitial concentrations. The IUPAC name of the Bismark brown R is 4-[5- (2, 4-Diamino-5-methylphenyl) diazenyl-2-methylphenyl] diazenyl-6-methylbenzol-1, 3-diamine^14,15.

 

Batch Experiment:

Dye solution adsorption experiments were performed by taking50 mL of stock solution of dye (200 mg/L) and treated with500mg of adsorbent dose. The various studies were performed like pH, adsorbent dose, agitation time and initial dye concentration. After the desired times of treatment, samples were filtered to remove the adsorbent and progress of adsorption was determined by using lambda 35 UV-visible Spectrophotometer at the wave length for maximum absorbance λ_max which at 420 nm for Bismark Brown R dye.

 

3. RESULT AND DISCUSSION:

3.1 Effect of pH of dye solution on adsorption:

The pH of the aqueous solution is clearly on important parameter that controlled the adsorption process. The experiments were done with pH range (2 to 12), temperature (30̊ C), contact time (50 minutes), agitation speed (360 rpm), initial concentration 200 mg/Land the adsorbent dose is 300mg. The experimental results are shown in the table-1. The graph was plotted between pH and dye uptake shown in the figure-1. The figure shows that the biosorbent consists of polymers with many functional groups, so that the net charge on the biosorbent is also pH dependent¹⁶. When the pH of the system increases the number of negatively charged sites on the biosorbent also increase, due to increase in the hydroxyl ion concentration where as the number of positively charged sites decrease¹⁷. Therefore at higher pH, the surface of the adsorbent gets more negatively charged by losing protons and thus favors the uptake of positively charged (cationic) dyes due to increased electrostatic force of attraction ¹⁸. Hence, dye uptake decrease at lower pH due to less number of negatively charges site at the LPS surface. The lower sorption of BBR at lower pH was probably due to the presence of the excess H⁺ ions competing with the cationic groups on the dye for sorption sites ¹⁹. The maximum sorption of the BBR (cationic or positively charged dye) dye was observed at pH 8. The decrease in the biosorption of BBR dye after pH was insignificant.

 

 

 

 

 

 

 

 

 

Table 1Effect of pH on dye uptake, Time 50 min, Adsorbent dose 300 mg, Volume of the solution 50 mL, Initial dyeconcentration200 mg/L and Temperature 30 ̊̊ C.

Initial dye concentration ( ppm)	pH	Removal Efficiency in percentage
200	2	61.53
200	3	65.55
200	4	67.04
200	5	68.23
200	6	71.60
200	7	74.66
200	8	77.94
200	9	75.38
200	10	75.00

 

 

 

 

Figure 1 Effect of pH on dye uptake, Time 50 min, Adsorbent dose 300 mg, Volume of the solution 50 mL, Initial dye concentration  200 mg/L and Temperature 30 ̊̊ C.

 

 

3.2 Effect of biosorbent dose on adsorption:

The effect of adsorbent dose was also investigated for the removal of dye from aqueous solution. The experiments were carried out with adsorbent dose varied from (100 to 500mg) with keeping other parameter constant such as pH 8, initial dye concentration 200 mg/L, temperature (30̊ C ), contact time (50 minutes), agitation speed (360 rpm). The experimental results are shown in table -2. The influence of biosorbent dose in removal of dye is shown in figure -2. The figure indicating that adsorption was almost complete with biosorbent from 100 to300mg. The increase in adsorption with adsorbent dosage can be attributed to an increase in the adsorption surface and availability of more adsorption sites²⁰. Further increase in biosorbent dose, did not show significant for the removal of dye, therefore, 300 mg biosorbent dose was chosen for successive experiments.

 

 

 

Table 2Effect of adsorbent dose on dye uptake, Time 50 min, pH 8, Volume of Solution 50 mL, Initial dye concentration 200 mg/L and Temperature 30 ̊̊ C.

Initial dye concentration (ppm)	Adsorbent dose (mg)	Removal Efficiency in percentage
200	100	72.52
200	200	75.82
200	300	78.02
200	400	77.62
200	500	77.42

 

 

Figure 2Effect of adsorbent dose on dye uptake, Time 50 min, pH 8, Volume of Solution 50 mL, Initial dye concentration 200 mg/L and Temperature 30 ̊̊ C.

 

3.3 Effect of contact time on adsorption:

The contact time is one of the most important factors in batch adsorption process. In this study all of the parameter other than contact time 10 to 70 minutes, including temperature (30̊ C), adsorbent dose (300mg), pH 8, initial dye concentration 200 mg/L, agitation speed (360 rpm) were kept constant. The experimental data are shown in the table -3 and the effect of contact time on dye adsorption efficiency showed in the figure -3. The time variation plot indicates that the removal of dye is rapid in initial stages but when it attains equilibrium, it slows down gradually. This may be due to the availability of vacant surface sites during the preliminary stage of adsorption, and after a certain time period the vacant sites get occupied by dye molecules which lead to create a repulsive force between the adsorbate on the adsorbent surface and in bulk phase. The attainment of equilibrium takes place after agitating the solution containing the adsorbent up to 50 minutes and once equilibrium was attained, the percentage of adsorption of dye did not show any appreciable change with respect to time. This suggests that after equilibrium is attained, further treatment does not provide more removal²¹. In batch adsorption, the rate of removal of the adsorbate from aqueous solutions is controlled mainly by the transport of dye molecules from the surrounding sites to the interior sites of the adsorbent particles²². The figure showed that a contact time of 50 minutes was sufficient to achieve equilibrium and the adsorption does not change with further increasing contact time, therefore the contact time has been chosen as 50 minutes for the continuous experiment.

 

Table 3Effect of contact time on dye uptake, pH 8,volume of solution 50 mL, Adsorbent dose300 mg, Initial dye concentration 200 mg/L, Temperature 30 ̊̊ C

Initial dye concentration (ppm)	Time (min)	Removal Efficiency in percentage
200	10	70.32
200	20	72.52
200	30	75.82
200	40	76.92
200	50	77.47
200	60	77.47
200	70	77.47

 

Figure 3Effect of contact time on dye uptake, pH 8,volume of Solution 50 mL, Adsorbent dose 300 mg, Initial dye concentration 200 mg/L, Temperature 30 ̊̊ C.

 

3.4 Effect of Initial dye concentration on adsorption:

The rate of adsorption is highly dependent on the initial amount of dye concentration. The experiment were done with various concentration ( 100 to 1000 mg/L) and constant temperature (30̊ C), adsorbent dose (300mg), pH 8, contact time (50 minutes), agitation speed (360 rpm). The experimental data are shown in table -4 and the graphs are plotted between dye uptake and initial dye concentrations are shown in figure -4. The figure shows that the effect of initial dye concentration factor depends on the immediate relation between the dye concentration and the available binding sites on an adsorbent surface⁹. Generally the percentage of dye removal decreases with increase in initial dye concentration, which may be due to the saturation of adsorption sites on the adsorbent surface²³ and the adsorption capacity increased with an increase in the initial concentration of the dye. At low concentration there will be unoccupied active sites on the adsorption surface, and when the initial dye concentration increases, the active sites required for adsorption of the dye molecules will not be available ²⁴.

 

Table 4 Effect of Initial dye concentration on dye uptake, Time 50 min, pH 8, Volume of Solution 50 mL, Adsorbent dose 300mg  and Temperature 30 ̊̊ C

Initial dye concentration (ppm)	Removal Efficiency in percentage
100	79.31
200	78.02
300	76.59
400	76.28
500	75.75
600	75.49
700	75.23
800	73.83
900	72.47
1000	71.81

 

 

Figure4 Effect of Initial dye concentration on dye uptake, Time 50 min, pH 8, Volume of Solution 50 mL, Adsorbent dose 300 mg and Temperature 30 ̊̊ C.

 

3.5 Adsorption Isotherm:

Adsorption isotherm provides important models in the description of adsorption behavior. It describes thathow the adsorbate interacts with the adsorbent and so it is important in optimizing the use of adsorbent. Two common isotherm equations namely, Langmuir and Freundlich models were tested.

 

Langmuir Isotherm:

Langmuir isotherm takes assumption that the sorption occurs at specific homogeneous sites within the adsorbent. The general term for Langmuir equation is,

q_e  = bq_maxCe/1+bCe

The linear form of isotherm equation can be written as,

1/q_e = ( 1/bq_max) (1/Ce) + (1/q_max)

q_max = Maximum dye uptake corresponding to the saturation capacity of the adsorbent,  b = Energy of adsorption variable C_e andq_e respectively.

 

The constant q_max and bare the characteristics of the Langmuir isotherm and can be determined from the above equation. Therefore a plot of 1/q_e Vs 1/C_e gives a straight line of a slope (1/q_max) and intercepts 1/q_max. So the data fit with Langmuir isotherm. The linearity of the plot indicates application of Langmuir equation supporting monolayer formation on the surface of the adsorption.

 

 

Figure 5 Langmuir isotherm plot of Bismark Brown R dye usingLaplap purpureus plant stem powder.

 

 

Freundlich Isotherm:

Freundlich isotherm is an empirical equation based on a heterogeneous surface.The general form of Freundlich equation is,

q_e = k_fC_e^l/n

 

and the linearized form is, log q_e = log k_f + l/n log C_e where the intercept log k_f is a measure of adsorption capacity and slope l/n is the intensity of adsorption. The variable q_e and C_e are dye adsorbed and the equal dye concentration in solution. Langmuir and Freundlich plots were arrived using the tables – 5 and their plots were shown in figure – 5 and figure – 6 respectively. It appears that Langmuir and Freundlich model both best fit the experimental range with good correlation coefficient.

Figure 6 Freundlich isotherm plot of Bismark Brown R dye using Laplap purpureus plant stem powder.

 

 

Table:5 Langmuir and Freundlich model parameters

Temperature	Langmuir model			Freundlich model
30o C	qm (mg/g)	b (L/mg)	r2	Kf (mg1-n g-1 Ln)	n(mg1-n g-1 Ln)	r2
	17.66	0.0187	0.9766	2.5386	1.0369	0.9719

 

3.6 Kinetic models:

Kinetic models have been used to test the experiment data to investigate about mechanism of adsorption and potential rate controlling step such as mass transfer and chemical reaction process. The transiting behave of batch adsorption process was analyzed using pseudo first order and pseudo second order kinetic models.

 

Pseudo First order:

The possibility of adsorption data following Lagergren pseudo-first-order kinetic is given by the linearized eq.

log (q_e - q_t) = log q_e – (k₁/2.303)_t

 

Where q_e (mgg^-1) and q_t (mgg^-1)refer to the amount of dye adsorbed per unit weight of adsorbent at equilibrium and at time t, k is the rate constant of adsorption.

 

The sorption coefficient and equilibrium capacity q_e can be determined from the linear plot of log (q_e – q_t) versus time from the figure 5. It was evident that the linear plot shows the applicability of the Lagergren equation, q_e values were present at table 6. The results indicated that the dye concentration has no significant effect. The correlation coefficient of r² is 0.9943.

Pseudo Second order:

This adsorption kinetic model equation was proposed by Ho (1995) and Ho and MacKay (2000), tried to explain the sorption capacity, the pseudo second order model can be expressed as,

 

t/q_t =1/k₂ q_e² + 1/q_et

 

Where t is the constant time (min), q_e(mgg^-1) and q_t(mg g^-1) are the amounts of dye adsorbed at equilibrium and at any time, t. If second order kinetics is applicable; the plot of t/q_t verses t should give a linear relationship (Fig - 8). The q_e and r²values can be determined from the plots.

The data values were summarized in Table -6. It was seen that the pseudo-second-order model fit very well, giving a very high correlation coefficient of 0.9994 with a q_e123.33.

 

 

Table: 6 Pseudo-first-order and second order kinetic parameters

Pseudo-first-order			Pseudo-second-order
qe(mg/g)			qe(mg/g)
Theoretical	Experimental	r2	Theoretical	Experimental	r2
91.10	123.33	0.9943	111.11	123.33	0.9994

 

 

Figure:7 Pseudo first order kinetic model.

Figure:8 Pseudo second order kinetic model.

 

 

3.7 SEM Analysis:

Scanning Electron microscope (SEM) studies provide useful information regarding morphological characteristics of the biosorbent. SEM image (Figure- 9a) of the unloaded biosorbentshowsthe rough and uneven surface of LPSP. This surface property should be considered as a factor for binding of dye molecules. In Figure- 9b is the surface structure of BBR loaded LPSP. After dye adsorption, a significant change is observed in the structure of the adsorbent. The adsorbent appears to have a rough surface and pores containing new shiny particles after adsorption ²⁵.

 

Figure:9a SEM image of LPSP before adsorption

Figure:9b SEM image of LPSP after adsorption

 

 

4. SUMMARY AND CONCLUSION:

The result of the present investigation shows that biosorbent prepared from cost free material, Laplap purpureus plant stem powder (LPSP) has suitable adsorption capacity with regard to the removal of Bismark Brown R dye from its aqueous solution. The following conclusion drawn from the present studies that LPSP is a suitable material for dye adsorption. pH, Adsorbent dose, Equilibrium time and Initial dye concentration are highly favorable for  the dye removal efficiency of the adsorbent. It was found that the sorption process is pH dependent and the maximum adsorption capacity of BBR dye is at pH 8. The optimum dose was 300 mg. The optimum time was observed to be 50 min and with 77.47% BBR dye removal efficiency. Present result shows that both Langmuir and Freundlich models better fit for the adsorption equilibrium data. In the examined concentration range 50 to 250 mg/L, the results also reveal that, it follows pseudo first order and pseudo second order kinetic models. SEM, XRD and FT-IR analysis clearly reveals that the adsorption of BBR dye onto biosorbent LPSP. Therefore, LPSP can be used for removal of BBR dye from the aqueous solution. Engineering technologies can be developed by using the results of isotherm model for the removal of effluent in the most efficient way.

 

5. ACKNOWLEDGEMENT:

The authors are thankful to the Secretary and Correspondent, A.V.V.M. Sir Pushpam College (Autonomous), Poondi-613503, Thanjavur-(Dt), Tamil Nadu, India, for encouragement to do this study. 

 

6.REFERENCES:

1.     Yesilada O, Asma D, and Cing S. Decolourization of textile dyes by fungal pellets. Process Biochem. 38; 2003: 933-938.

2.     Yasemin B, Haluk A, A Kinetics and thermodynamics study of methylene blue adsorption on Wheat Shell. Desalination. 194; 2006; 259-267.

3.     S. Wang, Z.H. Zhu, Effects of acidic treatment of activated carbons on dye adsorption, Dyes and Pigments. 75 (2007) 306-314.

4.     Santhi, T., Manonmani, S., Removal of methylene blue from aqueous solution by activated carbon prepared from the peel of Cucumis sativa fruit by adsorption. Bioresources.com 5(1), (2010) 419-437.

5.     Farooq, U., Kozinski, J.A., Khan, M.A., Athar,M., Biosorption of heavymetal ions Wheat based biosorbent – A review of recent literature. Biores. Technol. 101 (2010), 5043 – 5053.

6.     Atul Kumar Kushwaha, Neha Gupta and Chattopadhyaya MC. Removal of cationic methylene blue and malachite green dyes from aqueous solution by waste materials of Daucus carata. Journal of Soudi Chemical Society. 2014; 18: 200-207.

7.     Neha Gupta, Atul K, Kushwaha., Chattopadhyaya MC. Application of Potato (Solanum tuberosum) plant wastes for the removal of methylene blue and malachite green dyes from aqueous solution. Arabian Journal of Chemistry. 2016;  9:  S707–S716.

8.     Smitha T, Santhi T, Ashly Leena Prasad and Manonmani S. Cucumis Sativus used as adsorbent for the removal of dyes from aqueous solution.Arabian Journal of Chemistry .2017; 10:  S244–S251.

9.     Etim UJ, Umoren SA and Eduok UM.Coconut coir dust as a low cost adsorbent for the removal of cationic dye from aqueous solution. Journal of Saudi Chemical Society. 2016; 20: S67 – S6.

10.  Ashish S, Sartape, Aniruddha M, Mandhare, Vikas, V, Jadhav, Prakash D, Raut, Mansing A, Anuse, Sanjay S and Kolekar. Removal of malachite green dye from aqueous solution with adsorption technique using Limonia acidissima (wood apple) shell as low cost adsorbent. Arabian Journal of Chemistry. 2017; 10: S3229 – S3238.

11.  Muhammad Khairud Dahri, Muhammad Raziq Rahimi Kooh, and Linda B.L.Lim, Removal of methyl violet 2B from aqueous solution Using Casuarina equisetifolia Needle. Hindawi Publishing Corporation. ISNR Environmental Chemistry. Volume 2013.

12.  Somasekhara Reddy MC and Nirmala V. Bengal gram seed husk as an adsorbent for the removal of dyes from aqueous solutions – Equilibrium studies. Arabian Journal of Chemistry (2017) 10, S2406 – S2416.

13.  Binglu Zhao, Wei Xiao, Yu Shang, Huimin Zhu and Runping Han. Adsorption of light green anionic dye using cationic surfactant – modified peanut husk in batch mode.(2017) 10, S3595-S3602.

14.  Ahmed M, Kamil, Firas H, Abdulrazak, Ahmed F, Halbus and Falah H. Hussein. Adsorption of Bismark Brown R Dye onto Multiwall carbon Nanotubes. Journal of Envronment Analytical Chemistry. 2014; 1:1.

15.  Verma VK and Mishra AK. Kinetic and isotherm modeling of adsorption of dyes onto rice husk carbon. Global NEST Journal. 2010; 12 (2): PP190 – 196.

16.  Maurya NS, Mittal AK and Cornel P. Biosorption of dyes using dead macro fungi: Effect of dye structure, ionic strength and pH. Biores. Technol. 2006; 97: 512 – 521.

17.  Iqbal MJ AM N. Adsorption of dyes from aqueous solution on activated charcoal. Journal of Hazard. Mater. 2007; B139: 57- 66.

18.  Ponnusami V, Gunasekar V and Srivastava SN. Kinetics of methylene blue removal from aqueous solution using gulmohar (Delonix regia) plant leaf powder; multivariate regression analysis. J. Hazard. Mater. 2009; 169: 119 -127.

19.  Hameed, B.H., Equilibrium and kinetic studies of methyl violet sorption by agricultural waste. J. Hazard. Mater.154 (2008), 204 – 212.

20.  SenthilKumar, P., Ramalingam, S., Senthamarai, C., Niranjanaa, M., Vijayalakshmi, P., Sivanesan, S., 2010. Adsorption of dye from aqueous solution by cashew nut shell: studies on equilibrium isotherm, kinetics and thermodynamics of interactions. Desalination 261, 52-60.

21.  Sushmita Banerjee, M.C. Chattopadhyaya., Adsorption characteristics for the removal of a toxic dye, tartrazine from aqueous solutions by a low cost agricultural by-product. Arabian Journal of Chemistry (2017) 10, S1629-S1638.

22.  Ahmad, A., Rafatulla, M., Ibrahim, M.H., Hashim, R., 2009.Scavenging behavior of meranti sawdust in removal of Methylene Blue from aqueous solution. J. Hazard. Mater. 170, 357.

23.  Salleh, M.A.M., Mohmoud, D.K., Karim, W.A., Idris, A., Cationic anionic dye adsorption by agricultural solid waste: a comprehensive review. Desalination. 280 (2011), 1 – 13.

24.  Kannan, N., Sundaram, M.M., Kinetics and mechanism of removal of methylene blue by adsorption on various carbons – a comparative study. Dyes and Pigments. 51 (2001), 25 – 40.

25.  Lata, Hem.,Garg, V.K., Gupta, R.K, 2008. Adsorptive removal of basic dye by chemically activated partheninum biomass: equilibrium and kinetic modeling. Desalination 219, 250-261.

 

 

 

 

Received on 08.02.2018         Modified on 13.03.2018

Accepted on 14.04.2018         © AJRC All right reserved