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CHAPTER - VII

7. Green Synthesis, Characterization and Application of NiO Nanoparticles

using Rambutan Peel Extract

7.1. Introduction

Nanoparticles exhibit novel material properties due to their small size that are

significantly different from those of their bulk counterparts. Transition metal oxide

nanoparticles have been investigated by several workers in the last few years. Nanoscale

oxide particles of transition metals are gaining continuous importance for various

applications such as catalysts, passive electronic components and ceramic materials [1].

Nickel oxide (NiO) nanoparticles with a uniform size and well dispersion are desirable for

many applications in designing ceramic, magnetic, electro chromic and heterogeneous

catalytic materials [2]. Several researchers have prepared NiO nanoparticles by various

methods like sol–gel [3], surfactant-mediated synthesis [4] thermal decomposition [5],

polymer-matrix assisted synthesis [6] and spray-pyrolysis [7]. Ultrasonic radiation,

hydrothermal synthesis, carbonyl method, laser chemical method, pyrolysis by microwave,

precipitation-calcination, micro emulsion method and combustion [8-13]. However, to the

best of our knowledge, most of the reported experimental techniques for the synthesis of

nanopowders are still limited in laboratory scale due to some unresolved problems, such as

special conditions, tedious processes, complex apparatus, low yield and high cost [14].

Environmentally benign nanoparticles synthesis procedures do not use any toxic

chemicals in the synthesis protocols. In these aspects synthetic methods based on naturally

occurring biomaterials provide an alternative means for obtaining these nanoparticles. The

spectacular success in this field has opened up the prospect of developing bio-inspired

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methods of synthesis of metal nanoparticles with tailor-made structural properties. Though

numerous chemical methods are available for metal nanoparticles synthesis, many reactants

and starting materials are used in these reactions that are toxic and potentially hazardous.

Increasing environmental concerns over chemical synthesis routes have resulted in attempts

to develop bio-mimetic approaches. One of them is the synthesis using plant extracts

eliminating the elaborate process of maintaining the microbial culture and often found to be

kinetically favourable than other bioprocesses. Bio-molecules as reducing agents are found to

have a significant advantage over their counterparts as protecting agents [15].

The rambutan (Nephelium lappaceum L) belongs to the subtropical fruits, which is a

tropical species common to Southeast Asia. This fruit is an importantly commercial crop in

Asia, where it is consumed fresh, canned, or processed, and appreciated for its refreshing

flavor and exotic appearance. After being processed, the residues consist principally of seeds

and peels. Solis-Fuentes and others [16] reported that the seeds of rambutan were rich edible

fat. Palanisamy and others [17] have studied the phenolic contents of the fruit pulp, seed,

peel, and leaf of rambutan and the antioxidant activities of ethanolic extracts, which indicated

that rambutan peel was a potential source of natural antioxidants. Okonogi and others [18]

reported the high scavenging free radical activities of the ethanolic extract of rambutan peel.

Khonkarn and others [19] studied the effects of different solvents on the yields of total

phenolics of rambutan peel and the antioxidant activities of ethanolic extract.

Textiles made from natural fibres such as cotton also well known to be more

susceptible to microorganisms than the synthetic fibres because they are predominantly

hydrophilic in nature. As a result, they are capable of easily holding water, oxygen and

nutrients and therefore provide a favourable environment for bacterial growth. The major

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benefits of antimicrobial finishing of textile materials are to control the onset and spread of

diseases and to prevent or control the development of odor from perspiration [20]. Our recent

report deals with the antibacterial effect of novel synthesized sulphated-cyclodextrin

crosslinked cotton fabric and its improved antibacterial activities with ZnO, TiO2 and Ag

nanoparticles also reported [21]. Modification of fibre surfaces has been one of the main

areas of research in the development of functional fibres. Surface modification and

antibacterial behavior of magnesium oxide nanoparticles using Rambutan Peel Extract has

been reported [22].

Preparation of NiO nanoparticles by greener method is discussed in this chapter. The

synthesised NiO nanoparticles using Rambutan Peel Extract (RPE) were characterized by

XRD, SEM, TEM and antibacterial analysis. The prepared NiO nanoparticles coated on

cotton fabric and characterized by SEM with EDX and antibacterial analysis. The schematic

representation is given in figure 7.1.

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Figure 7.1: Schematic representation of NiO nanoparticle synthesis

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7.2. Results and discussion

The possible mechanism on the formation of NiO nanoparticles using rambutan peel

extract is similar to the MgO nanoparticle which is already discussed in chapter IV. Among

the various active ingredients present in rambutan peel extract, polyphenolic compounds such

as ellagic acid, corilagin, ellagitannins and geranin are mainly responsible for the formation

of NiO nanoparticles by their chelating effect.

7.2.1. XRD study of NiO nanoparticles

The obtained XRD patterns were verified using the JCPDS software. The size of the

nanoparticles was calculated through the Scherrer’s equation. The distinct Bragg reflections

corresponding to (111), (200) and (220) sets of lattice planes were manifested for the X-ray

diffraction patterns shown in figure 7.2. They may be indexed on the basis of face-centered

cubic structure of nickel oxide. The obtained data was matched with the Joint Committee on

Powder Diffraction Standards (JCPDS) file no. (04-0835). The crystallite size was 2θ

determined as 61.54, 56.76 and 56.10 nm corresponding to the position as 36.90, 42.85 and

62.23.

7.2.2. SEM and TEM study of NiO nanoparticles

Scanning electron microscope analysis was employed to study the morphology of the

nanoparticles that were formed. Representative SEM micrographs of the reaction synthesized

nanoparticles were carried out at different magnifications such as X 2,500, X 5,000, X 10,000

and X 30,000 are shown in figure 7.3 a, b, c and d respectively. From the SEM images it is

noticed that the surface morphologies are existing as granular and clusters in the form of

assemblies. The size of nanoparticle around 50 nm is shown in figure 7.3 (d). NiO

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nanoparticles have agglomerated into clusters because of attractive forces bringing them

together into groups.

TEM analysis was carried out to further confirm the nanosize of nickel oxide

nanoparticles. Figure 7.4 (a & b) shows representative TEM images of NiO nanoparticles. It

can be seen that the uniform NiO nanoparticles have flower like shapes with weak

agglomeration but reasonable distribution. The average particle size from TEM images is 50

nm which agrees well with the size examined from SEM analysis.

7.2.3. SEM & EDX studies of NiO nanoparticles treated and untreated fabrics

The morphological changes of cotton samples after the treatment with nickel oxide

substances can be clearly observed from the SEM images. Figure 7.5 (a1, a2 & b1, b2, b3)

shows the morphology of normal and nickel oxide nanoparticles treated cotton samples. SEM

images clearly show the significant difference between the untreated and treated cotton

fibers, the former has a smooth and uniform surface, whereas the latter is rough due to the

change in position of nickel oxide nanoparticles onto the surface of the fibers. The

micrographs figure 7.5 (b1 & b2) shows that the nickel oxide nanoparticles in the nanoscale

range are well distributed onto the fabric. Figure 7.5 (b3) at 30 micrometer the nickel oxide

nanoparticles are well distributed and absorbed into the fabric.

Energy dispersive X-ray spectroscopy (EDX) was employed to establish the chemical

identity of the observed particles. Figure 7.6 & 7.7 shows the unmodified and modified EDX

images of the cotton samples. It can be clearly seen that in unmodified fabrics (Fig.7.6), there

is no evidence for the existence of nickel ions whereas the nickel ions existed on the surfaces

of the cotton fibers after modified with NiO nanoparticles are clearly exhibited from the EDX

image (Fig.7.7).

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7.2.4. Antibacterial studies of NiO nanoparticles

Figure 7.8 reveals the antibacterial activities of NiO nanoparticles. Antibacterial

activities of NiO nanoparticles have been tested on both gram positive (S.aureus) and gram

negative (E.coli) bacteria. Antibacterial activity towards bacteria E.coli ATCC 10536 and

S.aureus ATCC 11632 of nickel oxide nanoparticles were performed using Kirby-Bauer

diffusion method. The antibacterial activity was evaluated by measuring the zone of

inhibition against the test organisms. Zone of inhibition is the area in which the bacterial

growth is stopped due to bacteriostatic effect of the compound and it measures the inhibitory

effect of compound towards a particular microorganism. The NiO nanoparticles showed zone

of inhibition found in both bacterias and S.aureus found more inhibition compared to the

E.coli.

Figure 7.9 (a & b) shows the antibacterial activity of nickel oxide nanoparticles

treated and untreated fabrics. S.aureus and E. coli were used as test microorganisms to detect

the antibacterial activity. Tabl 7.2 shows the antibacterial results of nickel oxide

nanoparticles. The antibacterial performance of NiO nanoparticles treated fabrics was done

by using disc diffusion method. The disc diffusion method for antibiotic susceptibility testing

is the Kirby-Bauer method. The agar used is Muller-Hinton agar that is rigorously tested for

composition and pH. Further the depth of the agar in the plate is a factor to be considered in

the disc diffusion method. This method is well documented and standard zones of inhibition

have been determined for susceptible and resistant values. There is also a zone of

intermediate resistance indicating that some inhibition occurs using this antimicrobial but it

may not be sufficient inhibition to eradicate the organism from the body. The zone of

inhibition increases with the increase in nickel oxide nanoparticles concentration and

decrease in particle size.

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7.2.5. Wash durability

Wash durability test carried out with the test fabrics showed that the significant

antimicrobial activity was actively retained in the NiO nanoparticles treated fabrics up to 4

washes (Table 7.1) even after repeated wash. Compared to the previous chapters (IV,V & VI)

it show good washing durability. The untreated control fabrics were not subjected to any

wash durability test as it has no antibacterial activity.

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7.3. Conclusion

Rambutan peel extract have been effectively used for the synthesis of NiO

nanoparticles. We have utilized the natural, renewable and low cost biomaterial for the

synthesis of NiO nanoparticles. The XRD and SEM analysis supports the crystallinity and

surface morphology of the biosynthesized nanoparticles. The average crystallite size for the

intense peak measured were 56 nm from XRD analysis. The SEM image shows granular

nanoparticles around 50 nm. TEM analysis confirmed the NiO nanoparticles. SEM and EDX

images confirmed the adsorption of NiO nanoparticles on the cotton fabric. The fabric

strongly increases adsorption of NiO nanoparticles on the surface of the fibres due to the

crosslinker (citric acid) and change of surface charge on the cellulose fibres. The NiO

nanoparticles treated cotton fabric exhibited stronger antibacterial activity due to the

increasing NiO nanoparticles absorption on the surface of cellulosic fibres.

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7.4. References

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(1997)

[2] M. L. Peterson, A. F. White, G.E. Brown, G.A. Jr Parks, Environmental Sci. Technol.

31:1573 (1997)

[3] C.N. R. Rao, Chemical applications of infrared spectroscopy (New York & London:

Academic Press) (1963)

[4] C.N. R. Rao. Chemical approaches to the Synthesis of inorganic materials (New

Delhi: Wiley Eastern Ltd.) (1994)

[5] K. J. Rao and P D Ramesh,. Bull. Mater. Sci. 18:447 (1995)

[6] G. V. Reddy Gopal, Sheela Kalyana and S V Manorama, Int .J. Inorg. Mater. 2:301

(2000)

[7] J. Smith, H. P. T. Wijn, N. N. Phillips and G. Eindnoven, Ferrites (Holland) 144 (1959)

[8] D. A. Sverjensky, Nature 364:776 (2003)

[9] N. N. Mallikarjuna and A. Venkataraman, Talanta 60:147 (2003)

[10] N. N. Mallikarjuna, B. Govindraj, L. Arunkumar and A. Venkataraman, J.

Therm. Anal. Cal. 71:915 (2003)

[11] J. C. Mallinson, The foundations of magnetic recording (San Diego: Academic

Press) (1987)

[12] A. Venkataraman, V. A. Hiremath, S. K. Date and S. M. Kulkarni, Bull. Mater. Sci.

24(6):101 (2001)

[13] V.Sharabasa, V.Ganachari, R.Bhat. R.Deshpande and A.Venkataraman, Recent research

in science and Technology,4,50,2012

[14] H. Vijayanand, L. Arunkumar, N. N. Mallikarjuna and A. Venkataraman,

Asian J. Chem.15:79 (2003)

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[15] J. Huang, Q. Li, D. Sun, Y. Lu, Y. Su, X. Yang, H. Wang, Y. Wang, W. Shao, N. He, J.

Hong, and C. Chen, Nanotechnology 18, 105104 (2007)

[16] J. A Solis-Fuentes, M. R Camey-Ortız G, F. Hernandez-Medel, Perez-Mendoza,

C. D. Dura-de-Bazua, Bioresour Technol 101, 799, (2010)

[17] U. Palanisamy, C.H Ming, T. Masilamani, T. Subramaniam, L. L Teng, A. K

Radhakrishnan, Food Chem 109, 54, (2008)

[18] S. Okonogi, C. Duangrat, S. Anuchpreeda, S. Tachakittirungrod, S. Chowwanapoonpohn

Food Chem 103, 839, (2007)

[19] R. Khonkarn, S. Okonogi, C. Ampasavate, S. Anuchapreeda, Food Chem Toxicol

48, 2122, (2010)

[20] P. Rattanawaleedirojn, K. Saengkiettiyut, S. Sangsuk, J. Nat. Sci. Special issue on

Nanotechnology, 7, 75 (2008)

[21] S. Selvam, R. Rajiv Gandhi, J. Suresh, S. Gowri, S. Ravikumar, M. Sundrarajan,

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[22] J. Suresh, R. Rajiv Gandhi, S. Gowri, S. Selvam, M. Sundrarajan, J.Biobased Materials

and Bioenergy, 6, 1 (2012)

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7.5. Legends

7.5.1. Tables

Table. 7.1. Wash durability of NiO nanoparticles treated cotton fabric

Table.7.2. Antibacterial assessment by agar diffusion method

7.5.2. Figures

Figure 7.1. Schematic representation of Nickel Oxide nanoparticle synthesis

Figure 7.2. XRD spectrum of Nickel Oxide Nanoparticles

Figure 7.3. SEM image of Nickel Oxide Nanoparticles at different magnifications

Figure 7.4. TEM images of Nickel Oxide nanoparticles in 2D and 3D forms Figure 7.5. SEM images of Nickel Oxide nanoparticles (a) untreated (b) treated fabrics

at X100 and X500 magnification

Figure 7.6. EDX image of untreated cotton fabric

Figure 7.7. EDX image of treated cotton fabric with Nickel Oxide nanoparticles

Figure 7.8. Antibacterial activity of Nickel Oxide nanoparticles against (a) S.aureus

(b) E.coli

Figure 7.9. Antibacterial activity of (a) untreated (b) NiO treated cotton fabrics against E.coli

and S.aureus

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Table 7.1: Wash durability of NiO nanoparticles treated cotton fabric

Table.7.2: Antibacterial assessment by agar diffusion method

Fabric treated Organism Zone of Inhibition (in cm)

Fabrics without NiO nanoparticles (Control) S.aureus 0

E.coli 0

Fabrics treated with NiO nanoparticles S.aureus 35

E.coli 25

No. of Washing cycles

Fabrics treated with NiO nanoparticles

% Bacterial Reduction

S.aureus

E.coli

1 80.11 77.10

2 78.21 73.50

5 75.02 70.15

10 62.50 58.50

15 30.20 24.50

20 12.85 10

25 0 0

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Figure 7.2: XRD spectrum of Nickel Oxide Nanoparticles

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Figure 7.3: SEM image of Nickel Oxide Nanoparticles at different magnifications

a) X 2,500 b) X 5, 000 c) X 10, 000 and d) X 30, 000

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Figure 7.4: TEM images of Nickel Oxide Nanoparticles

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Figure 7.5: SEM images of NiO nanoparticles untreated (a1, a2) treated fabrics (b1, b2,

b3) with different magnification (500µm, 100µm & 30µm)

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Figure 7.6: EDX image of untreated cotton fabric

Figure 7.7: EDX image of treated cotton fabric with Nickel Oxide nanoparticles

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Figure 7.8: Antibacterial activity of Nickel Oxide nanoparticles against (a) S.aureus

(b) E.coli

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Figure 7.9: Antibacterial activity of (a) untreated (b) NiO treated cotton fabrics against

E.coli and S.aureus