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Effective natural dye extraction from different plant materials using ultrasound
Industrial Crops and Products 33 (2011) 116–122
Contents lists available at ScienceDirect
Industrial Crops and Products journal homepage: www.elsevier.com/locate/indcrop
Effective natural dye extraction from different plant materials using ultrasound Venkatasubramanian Sivakumar ∗ , J. Vijaeeswarri, J. Lakshmi Anna Chemical Engineering Division, Central Leather Research Institute (CLRI), Council of Scientific and Industrial Research (CSIR), Adyar, Chennai 600 020, India
a r t i c l e
i n f o
Article history: Received 14 June 2010 Received in revised form 9 September 2010 Accepted 14 September 2010
Keywords: Natural dye Solid–liquid extraction Mass transfer Plant materials Ultrasound Sonochemistry
a b s t r a c t Dyes derived from natural sources have emerged as an important alternative to synthetic dyes. Therefore, there is a need for developing better solid–liquid extraction techniques for leaching natural colorants from plant materials for applications in plant research, food as well as dyeing industries. The influence of ultrasound on natural colorant extraction from different potential dye yielding plant materials has been studied in comparison with magnetic stirring process as control. The color yielding plant materials used in the present study include Green wattle bark, Marigold flowers, Pomegranate rinds, 4’o clock plant flowers and Cocks Comb flowers. Analytical studies such as UV–VIS spectrophotometry and gravimetric analysis were performed on the extract. The results indicate there is a significant 13–100% improvement in the extraction efficiency of the colorant obtained from different plant materials due to the use of ultrasound. Therefore, this methodology could be employed for extracting coloring materials from plant materials in a faster and effective manner. © 2010 Elsevier B.V. All rights reserved.
1. Introduction 1.1. Dyes and coloring materials Highly colored substances, widely known as colorants, can be used to impart color to an infinite variety of materials described technically as substrates. Colorants can be subdivided into dyes and dyeing is a common application used for coloring fibrous substances and termed as staining in the case of biological materials. The dye is generally applied in an aqueous solution, and may require a mordant to improve the fastness of the dye on the fibre. Synthetic dyes quickly replaced the traditional natural dyes and being used widely in textile, food and leather dyeing. Azo dyes are synthetic organic colorants, characterized by chromophoric azo groups (–N N–) prepared by generally known unit process of Diazotization and coupling reaction. However, whereas azo dyes are relatively resistant to degradation under aerobic conditions, they can be readily reduced to form aromatic amines under anaerobic conditions. Various health problems associated with azo dyes are well reported (Ahlström et al., 2005; Osman et al., 2004; Chatterjee et al., 2007; Alves et al., 2007). In the case of reactive dyes, as much as 50% of the initial dye load is present in the dye bath effluent (Rai et al., 2005). In order to overcome these problems, bio remediation for azo dyes as end-of-pipe treatment method has been reported (Oztürk and Abdullah, 2006; Fu and Viraraghavan, 2001; Husain,
∗ Corresponding author. Tel.: +91 044 24916706; fax: +91 044 24911589. E-mail address: [email protected] (V. Sivakumar). 0926-6690/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.indcrop.2010.09.007
2006). The effluent treatment can also be done using suitable adsorbents (Crini, 2006), but create disposal problem. Therefore, there is no currently available effective method for removal of these toxic dye effluent wastes. These factors tend to restrict the use of these methods in routine monitoring of industrial effluent discharges to the amines, which have been proven as health hazards, namely the carcinogens (Pinheiroa et al., 2004). With environmental concerns rising on the utilization of synthetic chemical dyes natural dyes offers scope for eco-friendly way for food coloration and dyeing of fibrous materials such as textiles or leather and hence can be also used in specialty applications where non-toxicity is a must.
1.2. Natural dye Although synthetic dyeing methods have taken over in the last century, dyeing materials are still abounding in the natural world today. The global demand for natural dyes world over is about 10,000 tonnes, which is equivalent to 1% of the world synthetic dyes consumption. This is expected to rapidly grow in near future. Natural dyes can be derived from almost anything—plants, minerals, and even some insects. Most natural dye colors are found in the roots, bark, leaves, flowers, skins, and shells of plants. The advantage of natural dyes is eco-friendly, i.e., they do not create any environmental problems at the stage of production or use and maintains ecological balance. The recent ban on the use of azo dyes by European Union has also increased the scope for the use of natural dyes. Studies regarding availability of natural dye yielding plants in north east region of India and various indigenous extraction proce-
V. Sivakumar et al. / Industrial Crops and Products 33 (2011) 116–122
117
dures followed by the local communities were reported (Mehanta and Tiwari, 2005; Bhuyan and Saikia, 2004). These natural dyes can be used for coloring food, cosmetics, and clothing for children. Unlike the synthetic dyes, which are carcinogenic, these dyes are very eco-friendly and hence can be used in specialty applications where non-toxicity is a must. 1.3. Natural dye extraction Extraction of coloring matter is a solid–liquid leaching process involving mass transfer problem. Since the coloring matter is tightly bound with plant cell membranes, extraction could be better by way of some improved methods such as ultrasound. There is a need for novel techniques to improve the major mechanism of natural dye extraction such as rupture the cell wall, release of natural dye and improve the transport of dye in to the external medium. There is also a need for maximizing the efficiency of natural colorant extraction and its application in order to conserve the natural resources available. The gamma ray irradiation technique studied to improve the extraction efficiency led to possible degradation and instability of coloring matter (Nayak et al., 2006). The use of electric pulse studied for the same (Fincan et al., 2004) may involve operational difficulties. Therefore, the use of power ultrasound to improve the natural dye extraction from various plant materials has been reported in this paper. Details regarding different natural dye yielding plants under present investigation are given in Table 1. 1.3.1. Use of power ultrasound Ultrasound is classified according to frequency range as power ultrasound (20–100 kHz) and diagnostic ultrasound (1–10 MHz). When a liquid is irradiated by ultrasound, microbubbles appear, grow and oscillate extremely quickly and even collapse violently if the acoustic pressure is high enough. The occurrence of these collapses near a solid surface will generate microjets and shock waves. Moreover, in the liquid phase surrounding the particles, high micromixing will increase the heat and mass transfer and even the diffusion of species inside the pores of the solid (Contamine et al., 1994). The use of power ultrasound in leather processing in order to improve the efficiency of the process as an eco-friendly approach has been studied and reviewed in detail (Sivakumar and Rao, 2001; Sivakumar et al., 2009c). Recently, the use of ultrasound in the extraction of vegetable tannins (Sivakumar et al., 2007, 2009a) as well as beet dye extraction and natural dyeing of leather (Sivakumar et al., 2009b) has been reported by us. Ultrasound has been used as a process intensifier for various unit operations in leather processing such as leather dyeing, essentially to enhance the diffusion of chemicals through skin/leather matrix. In the case of natural dye extraction, ultrasound is used as a tool for enhancing mass transfer of coloring matter from natural plant material and transport to the solvent medium. The similarity is that ultrasound facilitates the transport processes in both the cases. Hence, ultrasound technique could be beneficial for extraction of natural dyes and subsequently for leather dyeing also. In this regard, the present paper aims at screening the locally available natural dye yielding plants for dyeing purpose. The effect
Fig. 1. Schematic diagram of variable power output ultrasonic probe.
of power ultrasound in the extraction of natural dyes has been studied. 2. Experimental methods 2.1. Experimental setup Ultrasonic extraction experiments were performed using ultrasonic probe (VCX 400, Sonics and Materials, USA, 20 kHz and 0–400 W) in a glass vessel with provisions to set required output power and time as shown in Fig. 1. Control experiments were performed with the help of a magnetic stirrer, which had provisions to control temperature. 2.2. Materials and methods 2.2.1. Natural dye materials Natural dye bearing plant materials such as Green wattle bark, Marigold flowers, Pomegranate rinds, 4’o clock plant flowers and Cocks comb flowers were used. These plant materials were collected fresh from our CLRI Institute garden. The photographs of these materials are shown in Fig. 2a–e, respectively. 2.2.2. Extraction using magnetic stirring (control experiment) The color bearing plant samples were collected fresh from our CLRI Institute garden and separated into individual petals with average size of 1 cm and used for the experiments. Typically 1 g of sample was taken and 50 ml distilled water was added in a glass beaker in order to keep the plant materials along with ultrasound tip fully immerse in solvent. The beaker was covered using aluminum foil to prevent loss of solvent by evaporation. This beaker was stirred magnetically for 3 h. In order to have the fair comparison with ultrasound system, where ultrasonic bath temperature is around 45 ◦ C without external heating, the temperature of the extraction bath for control process was also maintained at 45 ◦ C. This would also provide idea about improvements with ultrasound extraction other than temperature induced effects of ultrasound. Extract samples were taken at every 30 min and the optical density was determined with the help of UV–VIS spectrometer. At the end of 3 h, the yield and extraction efficiency of each sample was determined by gravimetric method. The extract was tightly closed and stored at low temperature for future reference.
Table 1 Natural dye yielding plants used in the present study. S. no.
Botanical name
Common name
Parts used
1 2 3 4 5
Acacia decurrens Tagetes erecta Punica granatum Mirabilis jalpa Celosia cristata
Green wattle Marigold Pomegranate 4’o clock plant Cocks Comb
Bark Flowers Rind Flowers Flowers
Color Dark brown Yellow Yellow Pink Red
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Fig. 2. Natural dye yielding plants used in the present study.
2.2.3. Extraction using ultrasound 1 g of the plant samples was taken and added to 50 ml water taken in the beaker. The beaker was covered using aluminum foil to prevent loss of solvent by evaporation. The ultrasonic probe was positioned in the beaker and the ultrasound power set at 80 W. Since the ultrasonic bath temperature raise from room temperature 30 ◦ C to 50 ◦ C in 3 h time, the temperature was maintained at around 45 ◦ C by using a water bath without any external heating. Samples were taken at every 30 min and the optical density was determined with the help of UV–VIS spectrophotometer. At the end of 3 h, the yield and extraction efficiency of each sample was determined by gravimetric method. The filtrate was tightly closed and stored at low temperature for future reference.
2.3. Analytical methods 2.3.1. Spectrophotometric analysis The extract samples from different plant sources were analyzed using a Shimadzu UV–visible spectrophotometer UV-2101 PC after suitably diluting the extracted dye. The UV–VIS spectrum of the coloring matter from each plant materials were obtained in the visible region of 400–800 nm. Then the dye present in the extracted solution was analyzed by measuring the absorbance value at a wavelength of maximum or peak absorbance (max ) or at a specific wavelength. The wavelength for absorbance measurement for non-peak yielding plant is chosen as the average value from the wavelength range of complementary color of the natural dye.
V. Sivakumar et al. / Industrial Crops and Products 33 (2011) 116–122
a
a
2.00
119
3.00
1.60
Absorbance
ABSORBANCE
2.00
1.20
1.00
0.80
0.40 400.00
0.00 440.00
480.00
520.00
560.00
400.00
600.00
500.00
b
600.00
700.00
800.00
Wavelength (nm)
WAVELENGTH (nm) 5.00
1.60
b
4.50 4.00 1.20
Absorbance
Absorbance
3.50 3.00 2.50
0.80
2.00 Legend 1.50
Legend
with ultrasound
0.40
with magnetic stirring
with magnetic stirring
with ultrasound
1.00 0.50 0.00 0.00
0.00 0
30
60
90
120
150
40.00
180
120.00
160.00
200.00
Time (Min)
Time (min) Fig. 3. (a) UV–VIS spectrum for Green wattle bark (original extract) from 1 g in 50 ml with ultrasound for 3 h. (b) The effect of ultrasound, 80 W on the extraction of Green wattle bark (1 g in 50 ml water) at max −480 nm.
80.00
Fig. 4. (a) UV–VIS spectrum for Marigold flower extract. (b) The effect of ultrasound on the extraction of Marigold flower at max −765 nm.
% improvement due to ultrasound 2.3.2. Gravimetric analysis At the end of the extraction process, the samples taken from both ultrasound and control extracts were filtered and taken in clean, dried and weighed glass dishes. The extracts were dried in a hot-air oven until all the water evaporated and only the extract was left. The dishes were then cooled in a desiccator and weighed. The drying, cooling and weighing procedure was repeated to get the constant weight and the weight of the extract was determined. The weight of the colorant extract obtained per gram of the plant material used was calculated. The yield was calculated using the equation: % yield of natural colorant =
natural dye extract obtained (g) % amount of plant material used (g)
=
% yield of (ultrasound process − control) % yield of control
3. Results and discussions 3.1. Extraction of Green wattle (Acacia decurrens) UV–VIS spectrum of natural dye obtained from Green wattle bark was obtained. Here, the dye was extracted from A. decurrens and analyzed at the wave length of 480 nm. The absorbance values for natural dye extract obtained by ultrasound and magnetic stirring control are shown in Fig. 3. The results indicate that there is about 12.5% improvement in the % yield of extract due to the
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Table 2 The effect of ultrasound on the yields obtained for various samples of dye yielding materials. Material
Magnetic stirring control – yield (%)(A)
Ultrasound – yield (%)(B)
%Improvement due to ultrasound((B − A)/A) × 100
Green wattle Marigold Pomegranate 4’o clock plant Cocks Comb
4 13 16 18 14
4.5 26 20 26 16
12.50 100.00 25.00 44.44 14.28
use of ultrasound as compared to the control process as shown in Table 2. 3.2. Extraction of Marigold (Tagetes erecta) UV–VIS spectrum of natural dye obtained from Marigold flower was obtained. Here, the dye was extracted from Marigold and analyzed at the wave length of 765 nm. The absorbance values
for natural dye extract obtained by ultrasound and magnetic stirring control are shown in Fig. 4. The results indicate that there is about 100% improvement in the % yield of extract due to the use of ultrasound as compared to the control process as shown in Table 2. 3.3. Extraction of Pomegranate (Punica granatum) UV–VIS spectrum of natural dye obtained from pomegranate rinds was obtained. Here, the dye was extracted from pomegranate
a
5.00
a
1.00
4.00
Absorbance
Absorbance
0.80 3.00
2.00
0.60
0.40
1.00
0.20
0.00 400.00
440.00
480.00
520.00
560.00
600.00
Wavelength (nm)
b
0.00
1.00
400.00
500.00
600.00
700.00
800.00
Wavelength (nm)
b
6.00
0.60 4.00
Absorbance
Absorbance
0.80
0.40 Legend
2.00
with magnetic stirring
0.20
with ultrasound
Legend with ultrasound with magnetic stirring
0.00 0.00
40.00
80.00
120.00
160.00
200.00
Time (Min)
0.00 0.00
40.00
80.00
120.00
160.00
200.00
Time (Min) Fig. 5. (a) UV–VIS spectrum for pomegranate rinds extract. (b) The effect of ultrasound on the extraction of pomegranate rinds at max −668 nm during the course of extraction.
Fig. 6. (a) UV–VIS spectrum for 4’o clock plant extract. (b) The effect of ultrasound on the extraction of 4’o clock plant extract at max −475 nm.
V. Sivakumar et al. / Industrial Crops and Products 33 (2011) 116–122
a
121
2.40
Absorbance
2.00
1.60
1.20
0.80 Fig. 8. The photograph of the natural dye extract from different plant materials using ultrasound. AD – Acacia decurrens; MG – Marigold; PG – Pomegranate; MJ – Mirabilis jalpa; CC – Cocks Comb.
0.40 400.00
500.00
600.00
700.00
800.00
Wavelength (nm)
b
3.5. Extraction of Cocks Comb (Celosia cristata)
3.00
UV–VIS spectrum of natural dye obtained from Cocks Comb flower was obtained which indicated prominent peak at 536 nm. The absorbance values for natural dye extract obtained by ultrasound and magnetic stirring control are shown in Fig. 7. Here, the dye was extracted from Cocks Comb and analyzed at the wave length of 536 nm. The results indicate that there is about 14.3% improvement in the % yield of extract due to the use of ultrasound as compared to the control process as shown in Table 2.
2.50
Absorbance
2.00
1.50
3.6. Comparison of extraction yield 1.00
Legend with ultrasound with magnetic stirring
0.50
0.00 0
30
60
90
120
150
180
Time (min) Fig. 7. (a) UV–VIS spectrum for Cocks Comb flower extract. (b) The effect of ultrasound, 80 W on the extraction of Cocks comb flower (1 g in 50 ml) at max −536 nm.
and analyzed at the wave length of 668 nm. The absorbance values for natural dye extract obtained by ultrasound and magnetic stirring control are shown in Fig. 5. The results indicate that there is about 25% improvement in the % yield of extract due to the use of ultrasound as compared to the control process as shown in Table 2.
3.4. Extraction of 4’o clock plant (Mirabilis jalpa) UV–VIS spectrum of natural dye obtained from 4’o clock plant was obtained which indicated prominent peak at 475 nm. The absorbance values for natural dye extract obtained by ultrasound and magnetic stirring control are shown in Fig. 6. Here, the dye was extracted from M. jalpa and analyzed at the wave length of 475 nm. The results indicate that there is about 44.4% improvement in the % yield of extract due to the use of ultrasound as compared to the control process as shown in Table 2.
Extraction of natural dye from six dye yielding plants namely Green wattle bark, pomegranate rinds, 4’o clock plant flowers, Cocks Comb flowers and Marigold flowers were done using water as solvent. Photograph of the extract obtained using different plant materials is show in Fig. 8. The % yield for extraction using mechanical agitation and ultrasound and compared and show in Table 2. The results indicate that there is a significant improvement in the % yield of coloring matter extract obtained due to the use of ultrasound. The difference in the enhancement in extraction yield with ultrasound for different plant material could be due to different degree of binding of coloring matter attached to plant cell membranes. Moreover, another important factor is chemical constituents present in plant material responsible for the color (chromophore group) and their solubility nature. Considering the example of Marigold flower, the basic chromophore group is Carotenoid having hydroxyl group, which is expected to be extracted better with aqueous solvents such as water (Jothi, 2008). Whereas, in the case of Green wattle, the basic chromophore is poly phenolic (Kaempferol) which is expected to be extracted better with organic solvents. Hence, better yields are observed for Marigold flower as compared to Green wattle using water as solvent. These aspects are planned for our future study. 4. Conclusions Natural dyes provide an environmentally safe option for coloring of food and other materials. It was found that the application of ultrasound can increase the extraction of dyes from different parts of various plant resources. Hence five dye yielding plants were considered namely Green, Marigold, Pomegranate, and Cocks Comb. Extraction was done using ultrasound as well as magnetic stir-
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ring methods and the kinetics and the extraction efficiency were compared. The reason for the improvement could be due to better leaching of natural dye material from plant cell membranes and mass transfer to solvent assisted by acoustic cavitation provided by ultrasound. The results indicate that there is about 12–100% improvement in % yield of extract obtained due to the use of ultrasound as compared to magnetic stirring at 45 ◦ C. Various process parameters such as solvent system, temperature, ultrasound power, amount of dye material etc. are interesting for our study as future work. One would expect better extraction efficiency with solvents like n-hexane for those dye materials better soluble in organic solvents. But, our objective is to develop sustainable effective process with aqueous system without using organic solvents. Extraction efficiency may decrease if temperature is lowered than 45 ◦ C; however, higher temperatures could affect plant material itself as they are sensitive to the same. This novel technique can be employed effectively for the extraction of coloring matter from various plant resources even dispensing with conventional heating requirements. This process provides effective utilization of natural resources as eco-friendly method in current situation of global environmental concern. Acknowledgements Authors thank Dr. P.G. Rao, Director, NEIST, Jorhat, Assam and Dr. T. Ramasami, Secretary, DST, Govt. of India for their valuable guidance. Dr. Prof. A.B. Mandal, Director, CLRI and K.V. Raghavan, Research council chairman, CLRI for their encouragement. Prof. R. Kumar and Prof. K.S. Gandhi, IISc, Bangalore for their valuable suggestions. Mr. G. Swaminathan and Dr. R.A. Ramanujam, Head, Chemical Engineering, CLRI for motivation. Author (V.S.) is grateful to CSIR, New Delhi India for the support. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.indcrop.2010.09.007. References Ahlström, L., Eskilsson, C.S., Björklund, E., 2005. Determination of banned azo dyes in consumer goods. Trends Anal. Chem. 24 (1), 49–56. Alves, D.L.R.O., Limaa, A., Paula, B.A., Maria, F.S.D., Maria, R.C., Danielle, D.P.O., Gisela, D.R.U., 2007. Mutagenic and carcinogenic potential of a textile azo dye pro-
cessing plant effluent that impacts a drinking water source. Mutat. Res. 626, 53–60. Bhuyan, R., Saikia, C.N., 2004. Isolation of colour components from native dyebearing plants in Northeastern India. Bioresour. Technol. 95, 363–372. Chatterjee, S., Chatterjee, S., Chatterjee, Guha, A.K., 2007. Adsorptive removal of congo red, a carcinogenic textile dye by chitosan hydrobeads: Binding mechanism, equilibrium and kinetics. Colloids Surf. A: Physicochem. Eng. Aspects 299, 146–152. Contamine, F., Faid, F., Wilhelm, A.M., Berlan, J., Delmas, H., 1994. Chemical reactions under ultrasound. Chem. Eng. Sci. 49 (24B), 5865–5873. Crini, G., 2006. Non conventional low cost adsorbents for dye removal—a review. Bioresour. Technol. 97 (6), 1061–1085. Fincan, M., DeVito, F., Dejmek, P., 2004. Pulsed electric field treatment for solid–liquid extraction of beetroot pigment. J. Food Eng. 64, 381–388. Fu, Y., Viraraghavan, T., 2001. Fungal decolourization of dye wastewaters—a review. Bioresour. Technol. 79 (3), 251–262. Husain, Q., 2006. Potential applications of the oxidoreductive enzymes in the decolorization and detoxification of textile and other synthetic dyes from polluted water: a review. Crit. Rev. Biotechnol. 26 (4), 201–221. Jothi, D., 2008. Extraction of natural dye from African marigold flower (Targetes ereectal) for textile coloration. AUTEX Res. J. 8 (2), 49–53. Mehanta, D., Tiwari, S.C., 2005. Natural dye-yielding plants and indigenous knowledge on dye preparation in Arunachal Pradesh Northeast India. Curr. Sci. 88, 1474–1480. Nayak, C.A., Chethana, S., Rastogi, N.K., Raghavarao, K.S.M.S., 2006. Enhanced mass transfer during solid–liquid extraction of gamma-irradiated red beetroot. Radiat. Phys. Chem. 75, 173–178. Osman, M.Y., Sharaf, I.A., Osman, H.M., El-Khouly, Z.A., Ahmed, E.I., 2004. Synthetic organic food colouring agents and their degraded products: effects on human and rat cholinesterases. Br. J. Biomed. Sci. 61 (3), 128–132. Oztürk, A., Abdullah, M.I., 2006. Toxicological effect of indole and its azo dye derivatives on some microorganisms under aerobic conditions. Sci. Total Environ. 358, 137–142. Pinheiroa, H.M., Touraudb, E., Thomasb, O., 2004. Aromatic amines from azo dye reduction: status review with emphasis on direct UV spectrophotometric detection in textile industry wastewaters. Dyes Pigments 61, 121–139. Rai, H.S., Bhattacharyya, M.S., Singh, J., Bansal, T.K., Vats, P., Banerjee, U.C., 2005. Removal of dyes from the effluent of textile and dyestuff manufacturing industry: a review of emerging techniques with reference to biological treatment. Crit. Rev. Environ. Sci. Technol. 35, 219–238. Sivakumar, V., Rao, P.G., 2001. Application of power ultrasound in leather processing: an eco-friendly approach. J. Cleaner Prod. 9 (1), 25–33. Sivakumar, V., Ravi Verma, V., Rao, P.G., Swaminathan, G., 2007. Studies on the use of power ultrasound in solid–liquid myrobalan extraction process. J. Cleaner Prod. 15 (18), 1815–1820. Sivakumar, V., Jayapriya, J., Shriram, V., Srinandini, P., Swaminathan, G., 2009a. Ultrasound assisted enhancement in wattle bark (Acacia mollissima) vegetable tannin extraction for leather processing. J. Am. Leather Chem. Assoc. 104 (11), 375–383. Sivakumar, V., Lakshmi Anna, J., Vijayeeswaree, J., Swaminathan, G., 2009b. Ultrasound assisted enhancement in natural dye extraction from beetroot for industrial applications and natural dyeing of leather. Ultrason. Sonochem. 16 (6), 782–789. Sivakumar, V., Swaminathan, G., Rao, P.G., Ramasami, T., 2009c. Sono-leather technology with ultrasound: a boon for unit operations in leather processing—review of our research work at Central Leather Research Institute (CLRI), India. Ultrason. Sonochem. 16 (1), 116–119.
Contents lists available at ScienceDirect
Industrial Crops and Products journal homepage: www.elsevier.com/locate/indcrop
Effective natural dye extraction from different plant materials using ultrasound Venkatasubramanian Sivakumar ∗ , J. Vijaeeswarri, J. Lakshmi Anna Chemical Engineering Division, Central Leather Research Institute (CLRI), Council of Scientific and Industrial Research (CSIR), Adyar, Chennai 600 020, India
a r t i c l e
i n f o
Article history: Received 14 June 2010 Received in revised form 9 September 2010 Accepted 14 September 2010
Keywords: Natural dye Solid–liquid extraction Mass transfer Plant materials Ultrasound Sonochemistry
a b s t r a c t Dyes derived from natural sources have emerged as an important alternative to synthetic dyes. Therefore, there is a need for developing better solid–liquid extraction techniques for leaching natural colorants from plant materials for applications in plant research, food as well as dyeing industries. The influence of ultrasound on natural colorant extraction from different potential dye yielding plant materials has been studied in comparison with magnetic stirring process as control. The color yielding plant materials used in the present study include Green wattle bark, Marigold flowers, Pomegranate rinds, 4’o clock plant flowers and Cocks Comb flowers. Analytical studies such as UV–VIS spectrophotometry and gravimetric analysis were performed on the extract. The results indicate there is a significant 13–100% improvement in the extraction efficiency of the colorant obtained from different plant materials due to the use of ultrasound. Therefore, this methodology could be employed for extracting coloring materials from plant materials in a faster and effective manner. © 2010 Elsevier B.V. All rights reserved.
1. Introduction 1.1. Dyes and coloring materials Highly colored substances, widely known as colorants, can be used to impart color to an infinite variety of materials described technically as substrates. Colorants can be subdivided into dyes and dyeing is a common application used for coloring fibrous substances and termed as staining in the case of biological materials. The dye is generally applied in an aqueous solution, and may require a mordant to improve the fastness of the dye on the fibre. Synthetic dyes quickly replaced the traditional natural dyes and being used widely in textile, food and leather dyeing. Azo dyes are synthetic organic colorants, characterized by chromophoric azo groups (–N N–) prepared by generally known unit process of Diazotization and coupling reaction. However, whereas azo dyes are relatively resistant to degradation under aerobic conditions, they can be readily reduced to form aromatic amines under anaerobic conditions. Various health problems associated with azo dyes are well reported (Ahlström et al., 2005; Osman et al., 2004; Chatterjee et al., 2007; Alves et al., 2007). In the case of reactive dyes, as much as 50% of the initial dye load is present in the dye bath effluent (Rai et al., 2005). In order to overcome these problems, bio remediation for azo dyes as end-of-pipe treatment method has been reported (Oztürk and Abdullah, 2006; Fu and Viraraghavan, 2001; Husain,
∗ Corresponding author. Tel.: +91 044 24916706; fax: +91 044 24911589. E-mail address: [email protected] (V. Sivakumar). 0926-6690/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.indcrop.2010.09.007
2006). The effluent treatment can also be done using suitable adsorbents (Crini, 2006), but create disposal problem. Therefore, there is no currently available effective method for removal of these toxic dye effluent wastes. These factors tend to restrict the use of these methods in routine monitoring of industrial effluent discharges to the amines, which have been proven as health hazards, namely the carcinogens (Pinheiroa et al., 2004). With environmental concerns rising on the utilization of synthetic chemical dyes natural dyes offers scope for eco-friendly way for food coloration and dyeing of fibrous materials such as textiles or leather and hence can be also used in specialty applications where non-toxicity is a must.
1.2. Natural dye Although synthetic dyeing methods have taken over in the last century, dyeing materials are still abounding in the natural world today. The global demand for natural dyes world over is about 10,000 tonnes, which is equivalent to 1% of the world synthetic dyes consumption. This is expected to rapidly grow in near future. Natural dyes can be derived from almost anything—plants, minerals, and even some insects. Most natural dye colors are found in the roots, bark, leaves, flowers, skins, and shells of plants. The advantage of natural dyes is eco-friendly, i.e., they do not create any environmental problems at the stage of production or use and maintains ecological balance. The recent ban on the use of azo dyes by European Union has also increased the scope for the use of natural dyes. Studies regarding availability of natural dye yielding plants in north east region of India and various indigenous extraction proce-
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dures followed by the local communities were reported (Mehanta and Tiwari, 2005; Bhuyan and Saikia, 2004). These natural dyes can be used for coloring food, cosmetics, and clothing for children. Unlike the synthetic dyes, which are carcinogenic, these dyes are very eco-friendly and hence can be used in specialty applications where non-toxicity is a must. 1.3. Natural dye extraction Extraction of coloring matter is a solid–liquid leaching process involving mass transfer problem. Since the coloring matter is tightly bound with plant cell membranes, extraction could be better by way of some improved methods such as ultrasound. There is a need for novel techniques to improve the major mechanism of natural dye extraction such as rupture the cell wall, release of natural dye and improve the transport of dye in to the external medium. There is also a need for maximizing the efficiency of natural colorant extraction and its application in order to conserve the natural resources available. The gamma ray irradiation technique studied to improve the extraction efficiency led to possible degradation and instability of coloring matter (Nayak et al., 2006). The use of electric pulse studied for the same (Fincan et al., 2004) may involve operational difficulties. Therefore, the use of power ultrasound to improve the natural dye extraction from various plant materials has been reported in this paper. Details regarding different natural dye yielding plants under present investigation are given in Table 1. 1.3.1. Use of power ultrasound Ultrasound is classified according to frequency range as power ultrasound (20–100 kHz) and diagnostic ultrasound (1–10 MHz). When a liquid is irradiated by ultrasound, microbubbles appear, grow and oscillate extremely quickly and even collapse violently if the acoustic pressure is high enough. The occurrence of these collapses near a solid surface will generate microjets and shock waves. Moreover, in the liquid phase surrounding the particles, high micromixing will increase the heat and mass transfer and even the diffusion of species inside the pores of the solid (Contamine et al., 1994). The use of power ultrasound in leather processing in order to improve the efficiency of the process as an eco-friendly approach has been studied and reviewed in detail (Sivakumar and Rao, 2001; Sivakumar et al., 2009c). Recently, the use of ultrasound in the extraction of vegetable tannins (Sivakumar et al., 2007, 2009a) as well as beet dye extraction and natural dyeing of leather (Sivakumar et al., 2009b) has been reported by us. Ultrasound has been used as a process intensifier for various unit operations in leather processing such as leather dyeing, essentially to enhance the diffusion of chemicals through skin/leather matrix. In the case of natural dye extraction, ultrasound is used as a tool for enhancing mass transfer of coloring matter from natural plant material and transport to the solvent medium. The similarity is that ultrasound facilitates the transport processes in both the cases. Hence, ultrasound technique could be beneficial for extraction of natural dyes and subsequently for leather dyeing also. In this regard, the present paper aims at screening the locally available natural dye yielding plants for dyeing purpose. The effect
Fig. 1. Schematic diagram of variable power output ultrasonic probe.
of power ultrasound in the extraction of natural dyes has been studied. 2. Experimental methods 2.1. Experimental setup Ultrasonic extraction experiments were performed using ultrasonic probe (VCX 400, Sonics and Materials, USA, 20 kHz and 0–400 W) in a glass vessel with provisions to set required output power and time as shown in Fig. 1. Control experiments were performed with the help of a magnetic stirrer, which had provisions to control temperature. 2.2. Materials and methods 2.2.1. Natural dye materials Natural dye bearing plant materials such as Green wattle bark, Marigold flowers, Pomegranate rinds, 4’o clock plant flowers and Cocks comb flowers were used. These plant materials were collected fresh from our CLRI Institute garden. The photographs of these materials are shown in Fig. 2a–e, respectively. 2.2.2. Extraction using magnetic stirring (control experiment) The color bearing plant samples were collected fresh from our CLRI Institute garden and separated into individual petals with average size of 1 cm and used for the experiments. Typically 1 g of sample was taken and 50 ml distilled water was added in a glass beaker in order to keep the plant materials along with ultrasound tip fully immerse in solvent. The beaker was covered using aluminum foil to prevent loss of solvent by evaporation. This beaker was stirred magnetically for 3 h. In order to have the fair comparison with ultrasound system, where ultrasonic bath temperature is around 45 ◦ C without external heating, the temperature of the extraction bath for control process was also maintained at 45 ◦ C. This would also provide idea about improvements with ultrasound extraction other than temperature induced effects of ultrasound. Extract samples were taken at every 30 min and the optical density was determined with the help of UV–VIS spectrometer. At the end of 3 h, the yield and extraction efficiency of each sample was determined by gravimetric method. The extract was tightly closed and stored at low temperature for future reference.
Table 1 Natural dye yielding plants used in the present study. S. no.
Botanical name
Common name
Parts used
1 2 3 4 5
Acacia decurrens Tagetes erecta Punica granatum Mirabilis jalpa Celosia cristata
Green wattle Marigold Pomegranate 4’o clock plant Cocks Comb
Bark Flowers Rind Flowers Flowers
Color Dark brown Yellow Yellow Pink Red
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Fig. 2. Natural dye yielding plants used in the present study.
2.2.3. Extraction using ultrasound 1 g of the plant samples was taken and added to 50 ml water taken in the beaker. The beaker was covered using aluminum foil to prevent loss of solvent by evaporation. The ultrasonic probe was positioned in the beaker and the ultrasound power set at 80 W. Since the ultrasonic bath temperature raise from room temperature 30 ◦ C to 50 ◦ C in 3 h time, the temperature was maintained at around 45 ◦ C by using a water bath without any external heating. Samples were taken at every 30 min and the optical density was determined with the help of UV–VIS spectrophotometer. At the end of 3 h, the yield and extraction efficiency of each sample was determined by gravimetric method. The filtrate was tightly closed and stored at low temperature for future reference.
2.3. Analytical methods 2.3.1. Spectrophotometric analysis The extract samples from different plant sources were analyzed using a Shimadzu UV–visible spectrophotometer UV-2101 PC after suitably diluting the extracted dye. The UV–VIS spectrum of the coloring matter from each plant materials were obtained in the visible region of 400–800 nm. Then the dye present in the extracted solution was analyzed by measuring the absorbance value at a wavelength of maximum or peak absorbance (max ) or at a specific wavelength. The wavelength for absorbance measurement for non-peak yielding plant is chosen as the average value from the wavelength range of complementary color of the natural dye.
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a
a
2.00
119
3.00
1.60
Absorbance
ABSORBANCE
2.00
1.20
1.00
0.80
0.40 400.00
0.00 440.00
480.00
520.00
560.00
400.00
600.00
500.00
b
600.00
700.00
800.00
Wavelength (nm)
WAVELENGTH (nm) 5.00
1.60
b
4.50 4.00 1.20
Absorbance
Absorbance
3.50 3.00 2.50
0.80
2.00 Legend 1.50
Legend
with ultrasound
0.40
with magnetic stirring
with magnetic stirring
with ultrasound
1.00 0.50 0.00 0.00
0.00 0
30
60
90
120
150
40.00
180
120.00
160.00
200.00
Time (Min)
Time (min) Fig. 3. (a) UV–VIS spectrum for Green wattle bark (original extract) from 1 g in 50 ml with ultrasound for 3 h. (b) The effect of ultrasound, 80 W on the extraction of Green wattle bark (1 g in 50 ml water) at max −480 nm.
80.00
Fig. 4. (a) UV–VIS spectrum for Marigold flower extract. (b) The effect of ultrasound on the extraction of Marigold flower at max −765 nm.
% improvement due to ultrasound 2.3.2. Gravimetric analysis At the end of the extraction process, the samples taken from both ultrasound and control extracts were filtered and taken in clean, dried and weighed glass dishes. The extracts were dried in a hot-air oven until all the water evaporated and only the extract was left. The dishes were then cooled in a desiccator and weighed. The drying, cooling and weighing procedure was repeated to get the constant weight and the weight of the extract was determined. The weight of the colorant extract obtained per gram of the plant material used was calculated. The yield was calculated using the equation: % yield of natural colorant =
natural dye extract obtained (g) % amount of plant material used (g)
=
% yield of (ultrasound process − control) % yield of control
3. Results and discussions 3.1. Extraction of Green wattle (Acacia decurrens) UV–VIS spectrum of natural dye obtained from Green wattle bark was obtained. Here, the dye was extracted from A. decurrens and analyzed at the wave length of 480 nm. The absorbance values for natural dye extract obtained by ultrasound and magnetic stirring control are shown in Fig. 3. The results indicate that there is about 12.5% improvement in the % yield of extract due to the
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Table 2 The effect of ultrasound on the yields obtained for various samples of dye yielding materials. Material
Magnetic stirring control – yield (%)(A)
Ultrasound – yield (%)(B)
%Improvement due to ultrasound((B − A)/A) × 100
Green wattle Marigold Pomegranate 4’o clock plant Cocks Comb
4 13 16 18 14
4.5 26 20 26 16
12.50 100.00 25.00 44.44 14.28
use of ultrasound as compared to the control process as shown in Table 2. 3.2. Extraction of Marigold (Tagetes erecta) UV–VIS spectrum of natural dye obtained from Marigold flower was obtained. Here, the dye was extracted from Marigold and analyzed at the wave length of 765 nm. The absorbance values
for natural dye extract obtained by ultrasound and magnetic stirring control are shown in Fig. 4. The results indicate that there is about 100% improvement in the % yield of extract due to the use of ultrasound as compared to the control process as shown in Table 2. 3.3. Extraction of Pomegranate (Punica granatum) UV–VIS spectrum of natural dye obtained from pomegranate rinds was obtained. Here, the dye was extracted from pomegranate
a
5.00
a
1.00
4.00
Absorbance
Absorbance
0.80 3.00
2.00
0.60
0.40
1.00
0.20
0.00 400.00
440.00
480.00
520.00
560.00
600.00
Wavelength (nm)
b
0.00
1.00
400.00
500.00
600.00
700.00
800.00
Wavelength (nm)
b
6.00
0.60 4.00
Absorbance
Absorbance
0.80
0.40 Legend
2.00
with magnetic stirring
0.20
with ultrasound
Legend with ultrasound with magnetic stirring
0.00 0.00
40.00
80.00
120.00
160.00
200.00
Time (Min)
0.00 0.00
40.00
80.00
120.00
160.00
200.00
Time (Min) Fig. 5. (a) UV–VIS spectrum for pomegranate rinds extract. (b) The effect of ultrasound on the extraction of pomegranate rinds at max −668 nm during the course of extraction.
Fig. 6. (a) UV–VIS spectrum for 4’o clock plant extract. (b) The effect of ultrasound on the extraction of 4’o clock plant extract at max −475 nm.
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a
121
2.40
Absorbance
2.00
1.60
1.20
0.80 Fig. 8. The photograph of the natural dye extract from different plant materials using ultrasound. AD – Acacia decurrens; MG – Marigold; PG – Pomegranate; MJ – Mirabilis jalpa; CC – Cocks Comb.
0.40 400.00
500.00
600.00
700.00
800.00
Wavelength (nm)
b
3.5. Extraction of Cocks Comb (Celosia cristata)
3.00
UV–VIS spectrum of natural dye obtained from Cocks Comb flower was obtained which indicated prominent peak at 536 nm. The absorbance values for natural dye extract obtained by ultrasound and magnetic stirring control are shown in Fig. 7. Here, the dye was extracted from Cocks Comb and analyzed at the wave length of 536 nm. The results indicate that there is about 14.3% improvement in the % yield of extract due to the use of ultrasound as compared to the control process as shown in Table 2.
2.50
Absorbance
2.00
1.50
3.6. Comparison of extraction yield 1.00
Legend with ultrasound with magnetic stirring
0.50
0.00 0
30
60
90
120
150
180
Time (min) Fig. 7. (a) UV–VIS spectrum for Cocks Comb flower extract. (b) The effect of ultrasound, 80 W on the extraction of Cocks comb flower (1 g in 50 ml) at max −536 nm.
and analyzed at the wave length of 668 nm. The absorbance values for natural dye extract obtained by ultrasound and magnetic stirring control are shown in Fig. 5. The results indicate that there is about 25% improvement in the % yield of extract due to the use of ultrasound as compared to the control process as shown in Table 2.
3.4. Extraction of 4’o clock plant (Mirabilis jalpa) UV–VIS spectrum of natural dye obtained from 4’o clock plant was obtained which indicated prominent peak at 475 nm. The absorbance values for natural dye extract obtained by ultrasound and magnetic stirring control are shown in Fig. 6. Here, the dye was extracted from M. jalpa and analyzed at the wave length of 475 nm. The results indicate that there is about 44.4% improvement in the % yield of extract due to the use of ultrasound as compared to the control process as shown in Table 2.
Extraction of natural dye from six dye yielding plants namely Green wattle bark, pomegranate rinds, 4’o clock plant flowers, Cocks Comb flowers and Marigold flowers were done using water as solvent. Photograph of the extract obtained using different plant materials is show in Fig. 8. The % yield for extraction using mechanical agitation and ultrasound and compared and show in Table 2. The results indicate that there is a significant improvement in the % yield of coloring matter extract obtained due to the use of ultrasound. The difference in the enhancement in extraction yield with ultrasound for different plant material could be due to different degree of binding of coloring matter attached to plant cell membranes. Moreover, another important factor is chemical constituents present in plant material responsible for the color (chromophore group) and their solubility nature. Considering the example of Marigold flower, the basic chromophore group is Carotenoid having hydroxyl group, which is expected to be extracted better with aqueous solvents such as water (Jothi, 2008). Whereas, in the case of Green wattle, the basic chromophore is poly phenolic (Kaempferol) which is expected to be extracted better with organic solvents. Hence, better yields are observed for Marigold flower as compared to Green wattle using water as solvent. These aspects are planned for our future study. 4. Conclusions Natural dyes provide an environmentally safe option for coloring of food and other materials. It was found that the application of ultrasound can increase the extraction of dyes from different parts of various plant resources. Hence five dye yielding plants were considered namely Green, Marigold, Pomegranate, and Cocks Comb. Extraction was done using ultrasound as well as magnetic stir-
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ring methods and the kinetics and the extraction efficiency were compared. The reason for the improvement could be due to better leaching of natural dye material from plant cell membranes and mass transfer to solvent assisted by acoustic cavitation provided by ultrasound. The results indicate that there is about 12–100% improvement in % yield of extract obtained due to the use of ultrasound as compared to magnetic stirring at 45 ◦ C. Various process parameters such as solvent system, temperature, ultrasound power, amount of dye material etc. are interesting for our study as future work. One would expect better extraction efficiency with solvents like n-hexane for those dye materials better soluble in organic solvents. But, our objective is to develop sustainable effective process with aqueous system without using organic solvents. Extraction efficiency may decrease if temperature is lowered than 45 ◦ C; however, higher temperatures could affect plant material itself as they are sensitive to the same. This novel technique can be employed effectively for the extraction of coloring matter from various plant resources even dispensing with conventional heating requirements. This process provides effective utilization of natural resources as eco-friendly method in current situation of global environmental concern. Acknowledgements Authors thank Dr. P.G. Rao, Director, NEIST, Jorhat, Assam and Dr. T. Ramasami, Secretary, DST, Govt. of India for their valuable guidance. Dr. Prof. A.B. Mandal, Director, CLRI and K.V. Raghavan, Research council chairman, CLRI for their encouragement. Prof. R. Kumar and Prof. K.S. Gandhi, IISc, Bangalore for their valuable suggestions. Mr. G. Swaminathan and Dr. R.A. Ramanujam, Head, Chemical Engineering, CLRI for motivation. Author (V.S.) is grateful to CSIR, New Delhi India for the support. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.indcrop.2010.09.007. References Ahlström, L., Eskilsson, C.S., Björklund, E., 2005. Determination of banned azo dyes in consumer goods. Trends Anal. Chem. 24 (1), 49–56. Alves, D.L.R.O., Limaa, A., Paula, B.A., Maria, F.S.D., Maria, R.C., Danielle, D.P.O., Gisela, D.R.U., 2007. Mutagenic and carcinogenic potential of a textile azo dye pro-
cessing plant effluent that impacts a drinking water source. Mutat. Res. 626, 53–60. Bhuyan, R., Saikia, C.N., 2004. Isolation of colour components from native dyebearing plants in Northeastern India. Bioresour. Technol. 95, 363–372. Chatterjee, S., Chatterjee, S., Chatterjee, Guha, A.K., 2007. Adsorptive removal of congo red, a carcinogenic textile dye by chitosan hydrobeads: Binding mechanism, equilibrium and kinetics. Colloids Surf. A: Physicochem. Eng. Aspects 299, 146–152. Contamine, F., Faid, F., Wilhelm, A.M., Berlan, J., Delmas, H., 1994. Chemical reactions under ultrasound. Chem. Eng. Sci. 49 (24B), 5865–5873. Crini, G., 2006. Non conventional low cost adsorbents for dye removal—a review. Bioresour. Technol. 97 (6), 1061–1085. Fincan, M., DeVito, F., Dejmek, P., 2004. Pulsed electric field treatment for solid–liquid extraction of beetroot pigment. J. Food Eng. 64, 381–388. Fu, Y., Viraraghavan, T., 2001. Fungal decolourization of dye wastewaters—a review. Bioresour. Technol. 79 (3), 251–262. Husain, Q., 2006. Potential applications of the oxidoreductive enzymes in the decolorization and detoxification of textile and other synthetic dyes from polluted water: a review. Crit. Rev. Biotechnol. 26 (4), 201–221. Jothi, D., 2008. Extraction of natural dye from African marigold flower (Targetes ereectal) for textile coloration. AUTEX Res. J. 8 (2), 49–53. Mehanta, D., Tiwari, S.C., 2005. Natural dye-yielding plants and indigenous knowledge on dye preparation in Arunachal Pradesh Northeast India. Curr. Sci. 88, 1474–1480. Nayak, C.A., Chethana, S., Rastogi, N.K., Raghavarao, K.S.M.S., 2006. Enhanced mass transfer during solid–liquid extraction of gamma-irradiated red beetroot. Radiat. Phys. Chem. 75, 173–178. Osman, M.Y., Sharaf, I.A., Osman, H.M., El-Khouly, Z.A., Ahmed, E.I., 2004. Synthetic organic food colouring agents and their degraded products: effects on human and rat cholinesterases. Br. J. Biomed. Sci. 61 (3), 128–132. Oztürk, A., Abdullah, M.I., 2006. Toxicological effect of indole and its azo dye derivatives on some microorganisms under aerobic conditions. Sci. Total Environ. 358, 137–142. Pinheiroa, H.M., Touraudb, E., Thomasb, O., 2004. Aromatic amines from azo dye reduction: status review with emphasis on direct UV spectrophotometric detection in textile industry wastewaters. Dyes Pigments 61, 121–139. Rai, H.S., Bhattacharyya, M.S., Singh, J., Bansal, T.K., Vats, P., Banerjee, U.C., 2005. Removal of dyes from the effluent of textile and dyestuff manufacturing industry: a review of emerging techniques with reference to biological treatment. Crit. Rev. Environ. Sci. Technol. 35, 219–238. Sivakumar, V., Rao, P.G., 2001. Application of power ultrasound in leather processing: an eco-friendly approach. J. Cleaner Prod. 9 (1), 25–33. Sivakumar, V., Ravi Verma, V., Rao, P.G., Swaminathan, G., 2007. Studies on the use of power ultrasound in solid–liquid myrobalan extraction process. J. Cleaner Prod. 15 (18), 1815–1820. Sivakumar, V., Jayapriya, J., Shriram, V., Srinandini, P., Swaminathan, G., 2009a. Ultrasound assisted enhancement in wattle bark (Acacia mollissima) vegetable tannin extraction for leather processing. J. Am. Leather Chem. Assoc. 104 (11), 375–383. Sivakumar, V., Lakshmi Anna, J., Vijayeeswaree, J., Swaminathan, G., 2009b. Ultrasound assisted enhancement in natural dye extraction from beetroot for industrial applications and natural dyeing of leather. Ultrason. Sonochem. 16 (6), 782–789. Sivakumar, V., Swaminathan, G., Rao, P.G., Ramasami, T., 2009c. Sono-leather technology with ultrasound: a boon for unit operations in leather processing—review of our research work at Central Leather Research Institute (CLRI), India. Ultrason. Sonochem. 16 (1), 116–119.