Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 116–119
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa
Synthesis and characterization of palladium nanoparticles using Catharanthus roseus leaf extract and its application in the photo-catalytic degradation Aasaithambi Kalaiselvi a, Selvaraj Mohana Roopan b, Gunabalan Madhumitha b,⇑, C. Ramalingam a,⇑, Ganesh Elango b a b
Industrial Biotechnology, School of Bio Sciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India Chemistry Research Laboratory, Organic Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632014, Tamil Nadu, India
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
Catharanthus roseus leaves
methanolic extract was utilized properly. Pd nanoparticles with 38 nm size confirmed using XRD and TEM. It is in spherical shape. Pd nanoparticles can be used as catalyst in organic synthesis.
a r t i c l e
i n f o
Article history: Received 24 February 2014 Received in revised form 25 June 2014 Accepted 2 July 2014 Available online 9 July 2014 Keywords: Biosynthesis Catharanthus roseus leaves Bio-reduction Palladium nanoparticles
a b s t r a c t The potential effect of Catharanthus roseus leaf extract for the formation of palladium nanoparticles and its application on dye degradation was discussed. The efficiency of C. roseus leaves are used as a bio-material for the first time as reducing agent. Synthesized palladium nanoparticles were supported by UV–vis spectrometry, XRD, FT-IR and TEM analysis. The secondary metabolites which are responsible for the formation of nanoparticles were identified by GC–MS. The results showed that effect of time was directly related to synthesized nanoparticles and functional groups has a critical role in reducing the metal ions and stabilizing the palladium nanoparticles in an eco-friendly process. Ó 2014 Elsevier B.V. All rights reserved.
Introduction In the last decade, formation of nanoparticles using biological material as reducing agents received more attention in the emerging field of nanotechnology [1,2]. Greener synthesis helps to replace the hazardous chemicals that cause toxicity, minimizes harmful pollution to the environment when debris such as surfactants/dispersants released by the large scale industries and lead to an ecofriendly environment [3,4]. The developing technology focuses on transition metal nanoparticles due to their higher potency. They are completely scrutinized in different applications such as SERS ⇑ Corresponding authors. E-mail addresses: [email protected] (G. Madhumitha), cramalin [email protected] (C. Ramalingam). http://dx.doi.org/10.1016/j.saa.2014.07.010 1386-1425/Ó 2014 Elsevier B.V. All rights reserved.
detection [5], catalyst for dehalogenation of waste water, and in soil remediation [6]. Palladium nanoparticles used in various medical diagnostic applications because they get attached with the single strands DNA without destructing the structure [7] also palladium nanoparticles (Pd NP) doped with chitosan–graphene were used as a biosensor for glucose estimation [8]. However, the performance and applicability of synthesized nanoparticles were based on the size, shape, surface morphology, composition and structure [9–11]. The bio-inspired metallic nanoparticles belong to the platinum group which is well known extensively use automotive catalytic converters which are conveniently used to reduce the gaseous emission from vehicle exhaust [12]. Using precious metal for phyto-reduction to synthesis nanoparticles is a promising technology, which has not been extensively
A. Kalaiselvi et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 116–119
researched except Au and Ag. Not much report was generated on palladium nanoparticles using plant material synthesis [13]. The reduction rate of metal ions is comparatively higher when plant material is used than microbial strains as reducing agents. Recent findings proves that, palladium nanoparticles were synthesized in bulk quantities by using coffee and tea extract as reducing agent at room temperature by expelling hazardous chemical surfactants, capping agents [14]. For these reasons we opted a plant material (Catharanthus roseus leaves) as reduction agent of palladium (II) to (0) valent forms. Plant extracts may act both as reducing agent and stabilizing agents in the synthesis of nanoparticles. The source of the plant extract is known to influence the formation of nanoparticles, this is because different plant based extract contains different combinations of organic reducing and capping agent [15,16].
117
Dye degradation The bio-synthesized palladium nanoparticles were further used for application study of the dye degradation. The reaction was carried out using 2 mL of eppendorf vial. About 1 mL (1 104 M) of phenol red was mixed with 0.25 mg of palladium nanoparticles. The pH was varied from 2 to 10. The aliquots were kept in the rotary shaker for 1 h at room temperature. After the incubation period the sample was centrifuged at 1000 rpm. Supernatant was collected for residual dye estimation by UV–vis spectrometry.
Results and discussion UV–visible spectrum of palladium nanoparticles
Materials and methods Plant collection C. roseus (L.) G. Don were collected in and around Arcot (12°560 N, 79°240 E), Vellore District, Tamil Nadu, India. The taxonomic identification and authentication was done from Botanical Survey of India, Coimbatore, Tamil Nadu. The identified plant specimen number was registered (No. BSI/SRC/5/23/2013-14/ Tech.1117) and kept further reference.
The formation of palladium nanoparticles (Pd-NP) were monitored with the help of UV–vis spectrometry at 1 h interval. The absorbance of the reaction was recorded from 200 to 800 nm with effect of time and pH. In which shows the clear surface plasmon resonance (SPR) with the absorbance at the peak range of 350– 400 nm. The color intensity of the mixture turns gradually from brownish color to pale green which slowly turns colorless (Fig. 1) as the time period increases, which indicates the formation of [Pd(OAc)2] nanoparticles. It was observed that, the optimized time for the formation of nanoparticles was 2 h.
Materials palladium acetate [Pd(OAc)2] was obtained from Sigma–Aldrich (India) and used without further purification. Phenol red was procured from Himedia, Methanol from Sisco Research Laboratories (SRL – India). Preparation of the extract The collected fresh C. roseus leaves were cleaned, washed thoroughly with double distilled water, further shade dried and pulverized to fine particles using mechanical grinder. The pulverized plant material was extracted with petroleum ether to remove hydrocarbons followed by extracted with methanol through soxhlet process. The collected fraction was further condensed with rotary vacuum evaporator. About 10 mg of methanolic residue was dissolved with 20 mL of Milli.Q water. The plant material residue was blend uniformly with Milli.Q water.
Fig. 1. UV–vis spectra recorded as a function of time.
Synthesis of palladium nanoparticles About 100 mL of 1 mM Pd(OAc)2 solution was prepared using milli.Q water. 20 mL of methanolic extract was mixed with 80 mL of [Pd(OAc)2] solution and kept for continuous stirring at 60 °C. The process was monitored by UV–vis spectrometry at 1 h interval. Characterization The plant mediated bioreduction of [Pd(OAc)2] suspended solution was monitored by UV–vis spectrometer (Schimadzu UV–spectrophotometer, model UV-1800). Further characterization was done using Fourier transform infrared spectroscopy (FT-IR) with KBr pellets, XRD-analysis (Advance Powder X-ray diffractometer, Bruker, Germany, model D8) and TEM analysis (Transmission electron microscopy-Hitachi H-7100 using an accelerating voltage of 120 kV and methanol is used as solvent). Chemical composition of the methanol leaf extract of C. roseus was analyzed using Gas chromatography – mass spectrometry (GC–MS) [17].
Fig. 2. FTIR spectra of (a) C. roseus leaf extract; (b) Pd(OAc)2; (c) Pd nanoparticles.
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A. Kalaiselvi et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 116–119
Morphology and size distribution of Pd-NP XRD pattern of synthesized nanoparticles XRD studies confirmed the presence of crystalline pattern of palladium which was matched with JCPDS (Joint committee on powder diffraction standards) data it shows that the palladium particles that are formed in our research experimentation was in nano form. It was evidentially proved that the peak value was d = 2.61350 with 2h = 34.284° plane was recorded (Fig. 3). The average particle size was derived using Scherrer equation, in which the particle size on average is 40 nm.
P ¼ kk=b cos h where
Fig. 3. XRD Pattern of synthesized palladium nanoparticles.
P = particle size, k = Scherrer’s constant (0.94), k value can be derived from Bragg’s equation (2dsin h = nk), k = wave length, b – full maxima half width, h – diffraction angle.
FT-IR analysis TEM analysis Fourier Transform Infra Red spectroscopy was carried out for palladium acetate, methanolic extract of C. roseus, and Pd-NP. The samples were prepared using KBr pellets. The results showed a broader band for the extract and palladium acetate at 3453 cm1 region which is due to the presence of –OH groups. Also we could observe a sharp peak at 1634 cm1 due the presence of C@O. It has been observed from FTIR spectrum of synthesized Pd nanoparticles, the intensity peak in the range of 3453 has been cleaved into two different peaks (Fig. 2). The intensity of the peak at 1634 has been reduced when Pd(II) is reduced to Pd (0).
The morphology of the Pd-NP was evaluated with TEM analysis, samples used for this investigated after the termination of the synthesis reaction between C. roseus aqueous extract and [Pd(OAc)2] solution. The palladium nanoparticles with optimized time at 2 h were analyzed. The image indicates that the particle shape was spherical with the particle distribution as 38 ± 2 nm and average particle size was 38 nm. The methanolic plant extract was involved as capping and stabilizing the size of the palladium nanoparticles.
Table 1 Secondary metabolites identification using GCMS. RT
Area (%)
8.34
3.924
9.61
20.870
Structure
O
Name of the compound
O N
N-(1-Methoxycarbonyl-1-methylethyl)-4-methyl-2-aza-1,3-dioxane
O O
O
5-(Hydroxymethyl)- 2-furancarboxaldehyde
O
HO 13.35
13.108
16.33
27.292
1-Fluoro dodecane
F HO
OH
HO
4-Methylmyoinositol
OH OH
OH 18.20
5.901
O
N-hexadecanoic acid
OH O
25.79
9.987
26.95
6.587
Cl
NH
1-(4-Chlorophenylamino)-6-methylfuro[2,3-h]coumarine
O O
1-(4-Chlorophenylamino)-6-methylfuro[2,3-h]coumarine
O HN O
31.52
12.326
N
OH
Cl O 3,5-bis(1,1-Dimethylethyl)-4-hydroxybenzonitrile
A. Kalaiselvi et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 116–119
119
average particle size was calculated as 38 nm. Phenolic compounds present as the secondary metabolites were found to be responsible for reducing the palladium (II) to (0) valent ions. A time dependant study on the yield of biosynthesized Pd-NP revealed higher yield at 2 h of the process. Further, the Pd-NP was used for phenol red degradation. Pd-NP could effectively degrade the dye at an optimum pH of 8.0. Bio-based Pd-NP act through the electron relay effect and which involve in the degradation of phenol red dye. The outcome of the present study can be used to design effective approach in textile effluent remediation. Acknowledgements Author S.M. Roopan thank to DBT-RGYI (No. BT/PR6891/GBD/ 27/491/2012) Government of India, New Delhi for providing research grants to carry out the work. We acknowledge the support extended by VIT-SIF for GCMS analysis. Fig. 4. Photo-catalytic activity of Pd nanoparticles under visible light irradiation.
Mechanism involved in Pd-NP formation GC–MS analysis This study was performed, to predict the plant based reducing agents [14,18,19] that are involved in the reaction between leaves of C. roseus aqueous extract and Pd(OAc)2. It is evaluated that C. roseus aqueous extract contain about 8 major compounds having AOH as functional groups in their structure and the metal ion reduction might be occurred due to the presence of AOH compound (Table 1). Therefore, 4-methylmyoinositol may act as potential reducing and stabilizing agents and also responsible for the formation of palladium nanoparticles. Dye degradation The optimized palladium nanoparticles was taken for the application of dye degradation process by varying the pH from 2 to 10 of different aliquots of palladium nanoparticles dispersions and about 1 mL of phenol red (1 104 M) was mixed with 0.25 mg of palladium nanoparticles and kept for continuous stirring at room temperature. The absorbance of the reaction was observed from 200 to 800 nm (Fig. 4). The clear surface plasmon resonance (SPR) band for dye was observed in 433 nm. At pH 6 SPR band in 433 has been disappeared. From this study we have concluded that optimum pH required for the degradation of dye was pH 6. Conclusion As a conclusion, C. roseus leaves aqueous extract was used to synthesize environmental friendly Pd-NP from [Pd(OAc)2]. The
Appendix A. Supplementary material Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.saa.2014.07.010. References [1] S.M. Roopan, T.V. Surendra, G. Elango, H.S. Kumar, Appl. Microbiol. Biot. 98 (2014) 5289–5300. [2] S.M. Roopan, A. Bharathi, A. Prabhakarn, A.A. Rahuman, K. Velayutham, G. Rajakumar, R.D. Padmaja, M. Lekshmi, G. Madhumitha, Spectrochim. Acta A 98 (2012) 86–90. [3] A. Bharathi, S.M. Roopan, A. Kajbafvala, R.D. Padmaja, M.S. Darsana, K.G. Nandhini, Chin. Chem. Lett. 2 (2014) 324–326. [4] S.M. Roopan, F.N. Khan, Med. Chem. Res. 20 (2011) 732–737. [5] D.S. Shenya, P. Daisy, M. Joseph, Spectrochimica Acta A 91 (2012) 35–38. [6] H. Tom, D.C. Simon, V. Willy, B. Nico, Curr. Opin. Biotechnol. 23 (2012) 555– 561. [7] N. Kaushik, M.S. Thakkar, S. Snehit, M.S. Mhatre, Y.P. Rasesh, Nanomed. Nanotechnol. Bio. Med. 6 (2010) 257–262. [8] Z. Qiong, S.C. Jin, F.L. Xiao, T.B. Hao, H.J. Jian, Biosens. Bioelec. 26 (2011) 3456– 3463. [9] G. Madhumitha, S.M. Roopan, J. Nanomater. 2013 (2013) 1–12. [10] S.M. Roopan, K.R.N. Khan, Chem. Pap. 6 (2010) 812–817. [11] S.M. Roopan, F.N. Khan, B.K. Mandal, Tetrahedron Lett. 51 (2010) 2309–2311. [12] K. Mallikarjunaa, N.S. John, B.V.R. Subba, G. Narasimhad, B.R. Devaprasad, Int. J. Chem. Analy. Sci. 4 (2013) 14–18. [13] S.M. Roopan, A. Bharathi, R. Kumar, V.G. Khanna, A. Prabhakarn, Colloids Surf. B: Biointerf. 91 (2012) 209–212. [14] S.M. Roopan, A. Bharathi, R. Kumar, K.V. Gopiesh, A. Prabhakaran, Colloids Surf. B 92 (2012) 209–212. [15] D.A. Kumar, V. Palanichamy, S.M. Roopan, Spectrochimica. Acta A 127 (2014) 168–171. [16] K.M. Amit, C. Yusuf, C.B. Uttam, Biotechnol. Adv. 31 (2013) 346–356. [17] G. Madhumitha, G. Rajakumar, S.M. Roopan, A.A. Rahuman, K.M. Priya, A.M. Saral, F.R.N. Khan, V.G. Khanna, K. Velayutham, C. Jayaseelan, C. Kamaraj, G. Elango, Parasitol. Res. 26 (2011) 71–72. [18] R. Kumar, S.M. Roopan, A. Prabhakaran, V.G. Khanna, S. Chakroborty, Spectrochimica. Acta A 90 (2012) 173–176. [19] S.M. Roopan, Rohit, G. Madhumitha, A.A. Rahuman, C. Kamaraj, A.T.V. Bharathi, T.V. Surendra, Ind. Crop Prod. 43 (2013) 631–635.
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa
Synthesis and characterization of palladium nanoparticles using Catharanthus roseus leaf extract and its application in the photo-catalytic degradation Aasaithambi Kalaiselvi a, Selvaraj Mohana Roopan b, Gunabalan Madhumitha b,⇑, C. Ramalingam a,⇑, Ganesh Elango b a b
Industrial Biotechnology, School of Bio Sciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India Chemistry Research Laboratory, Organic Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632014, Tamil Nadu, India
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
Catharanthus roseus leaves
methanolic extract was utilized properly. Pd nanoparticles with 38 nm size confirmed using XRD and TEM. It is in spherical shape. Pd nanoparticles can be used as catalyst in organic synthesis.
a r t i c l e
i n f o
Article history: Received 24 February 2014 Received in revised form 25 June 2014 Accepted 2 July 2014 Available online 9 July 2014 Keywords: Biosynthesis Catharanthus roseus leaves Bio-reduction Palladium nanoparticles
a b s t r a c t The potential effect of Catharanthus roseus leaf extract for the formation of palladium nanoparticles and its application on dye degradation was discussed. The efficiency of C. roseus leaves are used as a bio-material for the first time as reducing agent. Synthesized palladium nanoparticles were supported by UV–vis spectrometry, XRD, FT-IR and TEM analysis. The secondary metabolites which are responsible for the formation of nanoparticles were identified by GC–MS. The results showed that effect of time was directly related to synthesized nanoparticles and functional groups has a critical role in reducing the metal ions and stabilizing the palladium nanoparticles in an eco-friendly process. Ó 2014 Elsevier B.V. All rights reserved.
Introduction In the last decade, formation of nanoparticles using biological material as reducing agents received more attention in the emerging field of nanotechnology [1,2]. Greener synthesis helps to replace the hazardous chemicals that cause toxicity, minimizes harmful pollution to the environment when debris such as surfactants/dispersants released by the large scale industries and lead to an ecofriendly environment [3,4]. The developing technology focuses on transition metal nanoparticles due to their higher potency. They are completely scrutinized in different applications such as SERS ⇑ Corresponding authors. E-mail addresses: [email protected] (G. Madhumitha), cramalin [email protected] (C. Ramalingam). http://dx.doi.org/10.1016/j.saa.2014.07.010 1386-1425/Ó 2014 Elsevier B.V. All rights reserved.
detection [5], catalyst for dehalogenation of waste water, and in soil remediation [6]. Palladium nanoparticles used in various medical diagnostic applications because they get attached with the single strands DNA without destructing the structure [7] also palladium nanoparticles (Pd NP) doped with chitosan–graphene were used as a biosensor for glucose estimation [8]. However, the performance and applicability of synthesized nanoparticles were based on the size, shape, surface morphology, composition and structure [9–11]. The bio-inspired metallic nanoparticles belong to the platinum group which is well known extensively use automotive catalytic converters which are conveniently used to reduce the gaseous emission from vehicle exhaust [12]. Using precious metal for phyto-reduction to synthesis nanoparticles is a promising technology, which has not been extensively
A. Kalaiselvi et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 116–119
researched except Au and Ag. Not much report was generated on palladium nanoparticles using plant material synthesis [13]. The reduction rate of metal ions is comparatively higher when plant material is used than microbial strains as reducing agents. Recent findings proves that, palladium nanoparticles were synthesized in bulk quantities by using coffee and tea extract as reducing agent at room temperature by expelling hazardous chemical surfactants, capping agents [14]. For these reasons we opted a plant material (Catharanthus roseus leaves) as reduction agent of palladium (II) to (0) valent forms. Plant extracts may act both as reducing agent and stabilizing agents in the synthesis of nanoparticles. The source of the plant extract is known to influence the formation of nanoparticles, this is because different plant based extract contains different combinations of organic reducing and capping agent [15,16].
117
Dye degradation The bio-synthesized palladium nanoparticles were further used for application study of the dye degradation. The reaction was carried out using 2 mL of eppendorf vial. About 1 mL (1 104 M) of phenol red was mixed with 0.25 mg of palladium nanoparticles. The pH was varied from 2 to 10. The aliquots were kept in the rotary shaker for 1 h at room temperature. After the incubation period the sample was centrifuged at 1000 rpm. Supernatant was collected for residual dye estimation by UV–vis spectrometry.
Results and discussion UV–visible spectrum of palladium nanoparticles
Materials and methods Plant collection C. roseus (L.) G. Don were collected in and around Arcot (12°560 N, 79°240 E), Vellore District, Tamil Nadu, India. The taxonomic identification and authentication was done from Botanical Survey of India, Coimbatore, Tamil Nadu. The identified plant specimen number was registered (No. BSI/SRC/5/23/2013-14/ Tech.1117) and kept further reference.
The formation of palladium nanoparticles (Pd-NP) were monitored with the help of UV–vis spectrometry at 1 h interval. The absorbance of the reaction was recorded from 200 to 800 nm with effect of time and pH. In which shows the clear surface plasmon resonance (SPR) with the absorbance at the peak range of 350– 400 nm. The color intensity of the mixture turns gradually from brownish color to pale green which slowly turns colorless (Fig. 1) as the time period increases, which indicates the formation of [Pd(OAc)2] nanoparticles. It was observed that, the optimized time for the formation of nanoparticles was 2 h.
Materials palladium acetate [Pd(OAc)2] was obtained from Sigma–Aldrich (India) and used without further purification. Phenol red was procured from Himedia, Methanol from Sisco Research Laboratories (SRL – India). Preparation of the extract The collected fresh C. roseus leaves were cleaned, washed thoroughly with double distilled water, further shade dried and pulverized to fine particles using mechanical grinder. The pulverized plant material was extracted with petroleum ether to remove hydrocarbons followed by extracted with methanol through soxhlet process. The collected fraction was further condensed with rotary vacuum evaporator. About 10 mg of methanolic residue was dissolved with 20 mL of Milli.Q water. The plant material residue was blend uniformly with Milli.Q water.
Fig. 1. UV–vis spectra recorded as a function of time.
Synthesis of palladium nanoparticles About 100 mL of 1 mM Pd(OAc)2 solution was prepared using milli.Q water. 20 mL of methanolic extract was mixed with 80 mL of [Pd(OAc)2] solution and kept for continuous stirring at 60 °C. The process was monitored by UV–vis spectrometry at 1 h interval. Characterization The plant mediated bioreduction of [Pd(OAc)2] suspended solution was monitored by UV–vis spectrometer (Schimadzu UV–spectrophotometer, model UV-1800). Further characterization was done using Fourier transform infrared spectroscopy (FT-IR) with KBr pellets, XRD-analysis (Advance Powder X-ray diffractometer, Bruker, Germany, model D8) and TEM analysis (Transmission electron microscopy-Hitachi H-7100 using an accelerating voltage of 120 kV and methanol is used as solvent). Chemical composition of the methanol leaf extract of C. roseus was analyzed using Gas chromatography – mass spectrometry (GC–MS) [17].
Fig. 2. FTIR spectra of (a) C. roseus leaf extract; (b) Pd(OAc)2; (c) Pd nanoparticles.
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Morphology and size distribution of Pd-NP XRD pattern of synthesized nanoparticles XRD studies confirmed the presence of crystalline pattern of palladium which was matched with JCPDS (Joint committee on powder diffraction standards) data it shows that the palladium particles that are formed in our research experimentation was in nano form. It was evidentially proved that the peak value was d = 2.61350 with 2h = 34.284° plane was recorded (Fig. 3). The average particle size was derived using Scherrer equation, in which the particle size on average is 40 nm.
P ¼ kk=b cos h where
Fig. 3. XRD Pattern of synthesized palladium nanoparticles.
P = particle size, k = Scherrer’s constant (0.94), k value can be derived from Bragg’s equation (2dsin h = nk), k = wave length, b – full maxima half width, h – diffraction angle.
FT-IR analysis TEM analysis Fourier Transform Infra Red spectroscopy was carried out for palladium acetate, methanolic extract of C. roseus, and Pd-NP. The samples were prepared using KBr pellets. The results showed a broader band for the extract and palladium acetate at 3453 cm1 region which is due to the presence of –OH groups. Also we could observe a sharp peak at 1634 cm1 due the presence of C@O. It has been observed from FTIR spectrum of synthesized Pd nanoparticles, the intensity peak in the range of 3453 has been cleaved into two different peaks (Fig. 2). The intensity of the peak at 1634 has been reduced when Pd(II) is reduced to Pd (0).
The morphology of the Pd-NP was evaluated with TEM analysis, samples used for this investigated after the termination of the synthesis reaction between C. roseus aqueous extract and [Pd(OAc)2] solution. The palladium nanoparticles with optimized time at 2 h were analyzed. The image indicates that the particle shape was spherical with the particle distribution as 38 ± 2 nm and average particle size was 38 nm. The methanolic plant extract was involved as capping and stabilizing the size of the palladium nanoparticles.
Table 1 Secondary metabolites identification using GCMS. RT
Area (%)
8.34
3.924
9.61
20.870
Structure
O
Name of the compound
O N
N-(1-Methoxycarbonyl-1-methylethyl)-4-methyl-2-aza-1,3-dioxane
O O
O
5-(Hydroxymethyl)- 2-furancarboxaldehyde
O
HO 13.35
13.108
16.33
27.292
1-Fluoro dodecane
F HO
OH
HO
4-Methylmyoinositol
OH OH
OH 18.20
5.901
O
N-hexadecanoic acid
OH O
25.79
9.987
26.95
6.587
Cl
NH
1-(4-Chlorophenylamino)-6-methylfuro[2,3-h]coumarine
O O
1-(4-Chlorophenylamino)-6-methylfuro[2,3-h]coumarine
O HN O
31.52
12.326
N
OH
Cl O 3,5-bis(1,1-Dimethylethyl)-4-hydroxybenzonitrile
A. Kalaiselvi et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 116–119
119
average particle size was calculated as 38 nm. Phenolic compounds present as the secondary metabolites were found to be responsible for reducing the palladium (II) to (0) valent ions. A time dependant study on the yield of biosynthesized Pd-NP revealed higher yield at 2 h of the process. Further, the Pd-NP was used for phenol red degradation. Pd-NP could effectively degrade the dye at an optimum pH of 8.0. Bio-based Pd-NP act through the electron relay effect and which involve in the degradation of phenol red dye. The outcome of the present study can be used to design effective approach in textile effluent remediation. Acknowledgements Author S.M. Roopan thank to DBT-RGYI (No. BT/PR6891/GBD/ 27/491/2012) Government of India, New Delhi for providing research grants to carry out the work. We acknowledge the support extended by VIT-SIF for GCMS analysis. Fig. 4. Photo-catalytic activity of Pd nanoparticles under visible light irradiation.
Mechanism involved in Pd-NP formation GC–MS analysis This study was performed, to predict the plant based reducing agents [14,18,19] that are involved in the reaction between leaves of C. roseus aqueous extract and Pd(OAc)2. It is evaluated that C. roseus aqueous extract contain about 8 major compounds having AOH as functional groups in their structure and the metal ion reduction might be occurred due to the presence of AOH compound (Table 1). Therefore, 4-methylmyoinositol may act as potential reducing and stabilizing agents and also responsible for the formation of palladium nanoparticles. Dye degradation The optimized palladium nanoparticles was taken for the application of dye degradation process by varying the pH from 2 to 10 of different aliquots of palladium nanoparticles dispersions and about 1 mL of phenol red (1 104 M) was mixed with 0.25 mg of palladium nanoparticles and kept for continuous stirring at room temperature. The absorbance of the reaction was observed from 200 to 800 nm (Fig. 4). The clear surface plasmon resonance (SPR) band for dye was observed in 433 nm. At pH 6 SPR band in 433 has been disappeared. From this study we have concluded that optimum pH required for the degradation of dye was pH 6. Conclusion As a conclusion, C. roseus leaves aqueous extract was used to synthesize environmental friendly Pd-NP from [Pd(OAc)2]. The
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