international journal of scientific & … · nanoparticles dispersed in a base fluid gives a...

INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 5, ISSUE 09, SEPTEMBER 2016 ISSN 2277-8616

189 IJSTR©2016 www.ijstr.org

Synthesis And Study Of Ultrasonic Properties Of Ag, Cu & Ni Nanofluids

Mannu Kaur, Dr. Pankaj Srivastava, Dr. Vaishali Singh

Abstract: By dispersing nanoparticles in a base fluid, we get a colloidal suspension called Nanofluids. These possess important properties required in thermal engineering application, physical, chemical stability and high thermal conductivity. In this work, we have synthesized Silver, Copper and Nickel nanofluids by greener reduction method, using Tannic acid. So prepared nanofluids were characterized by UV-Visible Spectroscopy and Dynamic Light Scattering Techniques. We have measured Ultrasonic Velocity of synthesized nanofluid by using Nanofluid Interferometer NF-10 as a function of concentration, at different temperature, also we have calculated Thermal Conductivity and Adiabatic Compressibility of the nanofluids. Index terms: Nanofluids, Ultrasonic Properties, Ultrasonic Velocity, Thermal Conductivity, Adiabatic Compressibility, Reduction, Tannic Acid.

————————————————————

1. Introduction

The inclusion of nanoparticles in base fluid shows enhancement in its physical chemical and transport properties [4]. Nanoparticles dispersed in a base fluid gives a new class of fluids called Nanofluids. Work of Choi et al., Lee et al., Masuda et al. and Eastman et al. showed incresed thermal conductivity of base fluids. Nanofluids having high thermal conductivities have potential application in heat transfer management [4]. The base fluid used for nanoparticle suspension can be any liquid such as oil, water, ethylene glycol or conventional fluid mixtures [9]. Depending on the type of nanoparticles (metallic/ non-metallic) and base fluid (organic/ inorganic) one can get different nanofluids [9]. The Stability mechanism of nanofluids is based on DLVO theory, which deals with colloidal stability. According to DLVO theory, the stability of a particle in solution is decided by the sum of electrical double layer repulsive forces andvan der Waals attractive that exist between particles as they approach each other, due to the Brownian motion they are undergoing [2]. If the attractive force dominate the repulsive force, the two particles will collide, and the suspension is not stable [2]. If the particles have high repulsive forces, the suspensions will exist in stable state [2]. For stable nanofluids or colloids, the repulsive forces between particles must be dominant [2]. Reduction method have been used by many researchers to synthesize nanofluids, this paper emphasize on a greener method of reduction by using Tannic Acid [7].

It is a polyphenolic plant extract, that act as both reducing and stabilizing agent, i.e. no other surfactant is required [3]. Since it is taken from plant extract it is harmless and environmental friendly [7]. In the cases where the size of the components of heat transfer devices are small, these nanofluids are best heat transfer fluids. Work of Choi and his coworkers has shown that nanofluids have much higher thermal conductivity than their corresponding base fluids [9]. Despite numerous experimental and theoretical studies, the exact mechanism responsible for thermal conductivity enhancements in nanofluids still remains unclear because of the lack of molecular level understanding of the ultrafine particle which demands the systematic studies on the molecular interactions of nanofluids at various concentrations and temperatures. Nevertheless ultrasonic method has proven to be an effective tool to understand the molecular interactions, there are only few reports available on the ultrasonic studies on nanofluids [1].

2 EXPERIMENTAL PROCEDURE

2.1 Chemicals We used analytical grade chemicals such as Silver nitrate (AgNO3 purity 99.95%) from Merck Mumbai, Copper sulphate pentahydrate (CuSO4•5H2O, purity 99.5%) from Central Drug House Mumbai India, Nickel nitrate pentahydrate (NiNO3•5H2O, purity 98%) from Qualigens Mumbai India, Tannic Acid (C76H52O46, purity 99.84%) from Molychem Mumbai India, Ethylene Glycol (CH2OHCH2OH, purity 99%) from SRL Mumbai India. All chemicals were used as received without further purification.

2.2 Synthesis of Ag nanofluids AgNO3 of concentration varying from 2.95 mM-6.95mM was prepared. To 5 ml of above solution, 20 ml 1.4x10

-4M solution

of Tannic Acid was added under stirring. Color of solution changed from colorless toyellowish pink. The synthesized Ag nanofluids of various concentrations are shown in fig. 1.

_________________________

1. Mannu Kaur currently pursuing M.Tech in Nanoscience and Technology from Guru Gobind Singh Indraprastha University, Dwarka Delhi, PH-+91-9582031899, E-mail [email protected]

2. Dr. Pankaj Srivastava Associate Professor ABV-Indian Institute of Information Technology, Gwalior, Madhya Pradesh, PH-+91-9425121627, E-mail [email protected]

3. Dr. Vaishali Singh Associate Professor Guru Gobind Singh Indraprastha University, Dwarka Delhi, PH-+91-9810118128, E-mail [email protected]



2.3 Synthesis of Cu nanofluids CuSO4 solution of concentration varying from 0.07M-0.11M was prepared. To 5 ml of above solution, 5 ml of Tannic acid of concentration 0.018M was added under stirring. Color of solution changed from blue to brownish red Fig. 2 shows Cu nanofluids of various concentrations.

2.4 Synthesis of Ni nanofluids NiNO3 solution of concentration varying from 0.004M-0.12M was prepared in ethylene glycol. Above solution was heated to 90˚C under refluxing and stirring. After heating was done, 5 ml 0.04 M Tannic acid solution was added. Temperature was increased from 90˚C to 140˚C, heating was done for one hour. Fig. 3 shows Ni nanofluids of different concentrations.

2.5 Instrumentation UV-Visible plot of samples was recorded using Perkin Elmer lambda 35 UV-Visible spectroscopy. DLS data was recorded for the synthesized samples using Zetasizer Nano from Malvern. Ultrasonic velocity of synthesized samples was recorded using Nanofluid Interferometer Model NF-10 purchased from Mittal Enterprises. Ultrasonic velocity measurements have been made at 2 MHz of frequency with

help of a interferometer. Water is circulated around the sample using a specific thermostat. The measured value of ultrasonic velocity is accurate to 0.1% with an error of measurement of 0.5°C in temperature. The standard liquids have been used to check the calibration and accuracy of the measurements. The measured value of the temperature is accurate to 0.5°C as in the ultrasonic velocity measurements [10].

3 RESULTS AND DISCUSSION

3.1 Nanoparticle Synthesis Presence of at least two hydroxyl groups at the ortho or para positions to each other is required,for it to undergo two-electron oxidation to the corresponding quinone form for facile reduction of metal ions [6]. Out of 25 phenolic hydroxyl groups, only 10 pairs of o-dihydroxyphenyl groups participate in redox reactions to form quinones [6]. Structural formula of TA is shown in Fig. 4. Thus the probable reaction mechanism for the formation of metal nanoparticles by TA reduction of metal salts, can be represented as below [6]

3.2 Material Characterization

3.2.1 UV-Visible specta The Absorption spectra of Ag, Cu and Ni nanofluids is shown in fig. 6, 7 & 8. The UV-Visible Spectrum of Ag nanofluids show strong absorption peak between 400 to 480 nm, while the absorption peak for Cu nanofluids is between 540 to 620 nm for different concentration. The absorption peak for Ni nanofluids is between 250-340nm for various concentrations. There is a red shift in λmax at high concentrations, this is mainly because of increase in particle size at in more concentrated solutions .

Fig. 1. Ag Nanofluids of various concentrations

Fig. 2. CuNanofluids of various concentrations

Fig. 3. NiNanofluids of various concentrations

Fig. 4. The representative structure of tannic

acid [6]

Fig. 5. Mechanism of reduction by Tannic Acid



3.2.2 DLS Spectral analysis Typical DLS results shown in Fig. 9.(a), (b), (c), (d) & (e) represents the particle size distribution of Ag nanofluids at different concentrations, the size of the particles formed were between 70 to 100 nm.

Fig. 6. UV-Vis spectra of Ag nanofluids

Fig. 7.UV-Vis spectra of Cu nanofluids

Fig. 8. UV-Vis spectra of Ninanofluids

Fig. 9.DLS spectra of Ag nanofluids (a)2.95mM,(b) 3.95 mM,

(c) 4.95mM, (d)5.95mM & (e)6.95mM

(a)

(b)

(c)

(d)

(e)



Similarly Fig. 10.represents particle size distribution of Cu nanofluids, the particles formed were between 20-80 nm.

The DLS results of Ni nanofluids showed particle size below 100nm. Fig. 11. shows the size distribution intensity of Ni nanofluids.

Fig. 11. DLS spectra of Ni nanofluids (a)0.004M,(b) 0.006M, (c) 0.008M, (d)0.010M & (e)0.012M

(a)

(b)

(a)

(c)

(c)

(b)

(d)

(d)

(e)

(e)



It can be seen that with increasing the concentration the size of the particles increase. The values of Ultrasonic Velocity, Thermal Conductivity and Adiabatic Compressibility of above synthesized nanofluids was calculated by equation 1, equation 2 and equation 3 Thermal conductivity and Adiabatic Compressibility respectively as shown in Table 1, Table 2 and Table 3.

v= λ x f (1)

where f= 1.9925 MHz, λ is wavelength determined from Nanofluid interferometer, v is Ultrasonic Velocity.

k= 3 (𝑁/𝑉)2/3 K v (2)

where k is thermal conductivity, N is Avagadro’s number, v ultrasonic velocity.

βad = (ρ x v2)-1

(3)

where ρ is density of nanofluid, βad adiabatic compressibility From Table 1, Table 2it is found that ultrasonic velocity decreases with increase in concentrations of nanofluids, same can be observed from Figure 12(a) &(b). But at certain concentrations it shows variation in the values. The structural changes taking place in the liquid results in weakening of intermolecular forces, which results in decrease in velocity with increase in mole fraction [7]. The decrease in velocity up to 4.95mM and 0.08M for Ag and Cu respectively, is due to interaction between Ag+ and Cu+2 ions and water molecules. Weaker interaction between particles and water molecules results indecrease in velocity in solution [8]. With the propagation of ultrasonic vibrations through the nanofluids, the Brownian motion stops in the fluid resulting in decrease in velocity and the random movements of nanoparticles are increased with increase in concentration [14]. Therefore, at higher concentrations it is found that there is deviation in ultrasonic velocity. Also agglomeration in particles leads to collisions between the suspended particles [8]. While from Table 3 it is found that Ultrasonic velocity shows a decrease for 0.006 M Ni nanofluids with increase in concentration there is increase in ultrasonic velocity for 0.008M which can also be seen from figure 8(c), which in turn also evident from the data [8]. The decrease in velocity suggests that there may be weak interactions between particles and water molecules [8]. The structural changes affect the compressibility and hence there is a change in ultrasonic velocity [8]. The decreased velocity value shows that there is decrease in nanoparticle-fluid interaction and increase of particle–particle interaction. In general,ultrasonic velocity is quite sensitive to the

Size, ultrasonic velocity is quite sensitive to the size, morphology and dispersion of the particles. Ultrasonic velocity decreases with the concentration of nanofluid in respect with particle fraction [8] It is also found that the adiabatic compressibility decreases with increasing concentration of particles [10]. The decrease in adiabatic compressibility shows the weaker force of interaction between particles and base fluid molecules [10]. Compressibility decreases due to the fact that metal ions form a core compact structure with the solvent molecules through hydrogen bonding. Weak forces operating between molecules results in variation in the values of adiabatic compressibility [8]. Comparing the thermal conductivities of Ag, Cu and Ni nanofluids, Ni nanofluid has better thermal conductivity compared to other two. Nanofluids have high thermal conductivities at very low nanoparticles concentrations, the exact mechanism of which is not known. Brownian motion of suspended nanoparticles is attributed as one of the key factors of the greatly enhanced thermal conductivity performance but it is not considered in conventional thermal transport theory [10].

(b)

(c)

Fig. 12. Variation of Ultrasonic Velocity of (a) Ag (b) Cu and (c) Ni

nanofluids with concentration at different temperatures



TABLE 3 Adiabatic Compressibility, Thermal Conductivity & Ultrasonic

Velocity Of Ni Nanofluids

4 CONCLUSION

We have successfully synthesized nanofluids containing Ag, Cu and Ni nanoparticles. UV-Visible Spectrum and DLS analysis confirms the formation of Ag, Cu and Ni nanoparticles. Ultrasonic velocity studies are carried out at different temperatures and the acoustical parameters like adiabatic compressibility and thermal conductivity are calculated. From calculation Ni nanofluids have best thermal conductivity. The particle–fluid interaction which favors increase in velocity. Such

particle–fluid interaction studies are helpful to understand the reasons behind anomalous enhancements in physical properties of nanofluids and to realize the mechanism of fluid flow in nanoscale.

AKNOWLEDGMENT Authors would like to thank Department of Science and Technology, Government of India for funding support, we would also like to thank Dr. Vaishali Singh of Guru Gobind Singh Indraprastha University, Dwarka, Delhi.

REFRENCES

[1] M. Nabeel Rashin and J. Hemalatha, ―A novel ultrasonic approach to determine thermal conductivity in CuO–ethylene glycol nanofluids,‖J. of Molecular Liquids, vol. 197, pp. 257–262, Apr. 2014.

[2] Wei Yu and Huaqing Xie,―A Review on Nanofluids:

Preparation, Stability Mechanisms and Applications,‖ J. of Nanomaterials, Jul. 2011, doi:10.1155/2012/435873

[3] Zao Yia, Xibo Li, Xibin Xua, Binchi Luo, Jiangshan

Luo, Weidong Wu, Yougen Yi,Yongjian Tang, ―Green, effective chemical route for the synthesis of silver nanoplates in tannic acid aqueous solution,‖Colloids Surf., A, vol. 392, pp.131– 136, Sep. 2011.

[4] Ashok K. Singh & Vijay S. Raykar, ―Microwave

synthesis of silver nanofluids with polyvinylpyrrolidone (PVP) and their transport properties,‖Colloid Polym. Sci., vol. 286, pp. 1667–1673, Oct. 2008.

[5] Chapter 2 Silver Nanofluids - Synthesis, Properties

and Applications.

[6] Anamika Dutta, Swapan K. Dolui, ―Tannic acid assisted one step synthesis route for stable colloidal dispersion of nickel nanostructures,‖Appl. Surf. Sci., vol. 257 pp. 6889–6896, Mar. 2011.

[7] Tufail Ahmad, ―Reviewing the Tannic Acid Mediated

Synthesis of Metal Nanoparticles,‖J. of Nanotechnology, Mar. 2014,doi.org/10.1155/2014/954206.

[8] R. Kiruba, M. Gopalakrishnan, T. Mahalingam, and A.

Kingson, ―Ultrasonic Studies on Zinc Oxide Nanofluids, Solomon Jeevaraj,‖ J. of Nanofluids, Vol. 1, pp. 97–100, Jul. 2012.

[9] Vimal Pandey, Giridhar Mishra, Meher Wan, Devraj

Singh, A.K. Tiwari, R.R. Yadav and Bharat Mishra, ―Characterization of Cu-PVA nanofluids: ultrasonic and thermal properties,‖J. Pure Appl. Ultrasonvol. 37, pp. 33-38, Jan. 2015.

[10] Giridhar Mishra, Meher Wan, Vimal Pandey, Devraj

Singh and R.R. Yadav and B. Mishra, ―Ultrasonic and Thermal Properties of Nanofluids Containing Copper Nanoparticles,‖Int. J. Sci. Res., 2013.

TABLE 1 Adiabatic Compressibility, Thermal Conductivity &

Ultrasonic Velocity Of Ag Nanofluids

TABLE 2

Adiabatic Compressibility, Thermal Conductivity & Ultrasonic Velocity Of Cu Nanofluids



[11] Sankar Kalidas Sivaraman, Iniyan Elango, Sanjeev Kumar and Venugopal Santhanam, ―A green protocol for room temperature synthesis of silver nanoparticles in seconds,‖Curr. Sci., vol. 97, pp.1055-1059, Oct. 2009.

[12] D K Singh, D K Pandey, R R Yadav and Devraj

Singh,―A study of nanosized zinc oxide and its nanofluid,‖ Pramana-J. of Phys., Vol. 78, pp. 759-766, May 2012.

[13] A. K Choudhary,Acoustical characterization of copper

nanofluid, Advances in Applied Science Research, vol. 6, pp. 130-134, 2015.

[14] Pramod Warrier, Amyn Teja, ―Effect of particle size on

the thermal conductivity of nanofluids containing metallic nanoparticles,‖ Nanoscale Research Letters, 2011.

[15] Hana KŘÍŽOVÁ, Jana ROTKOVÁ, ―Green Synthesis

of Copper-based Nanostructures using Tannic acid and testing of their antibacterial properties,‖NANOCON, Nov. 2014.

[16] Manual on Nanofluid Interferometer by Mittal

Enterprises. [17] E. Pradeep Jaya Sudhan and K. Shree Meenakshi,

―Synthesis of silver nanofluid by a novel one pot method for heat transfer applications,‖Indian J. of Sci and Tech., Vol. 4, pp. 471-421, Apr. 2011.

[18] Mohit Gupta, Meher Wan, S.K. Verma, R.R. Yadav,

―Elastic and ultrasonic properties of single crystalline nickel nanowires,‖Ultrason., vol. 54, pp. 2115–2118, Jul. 2014.

[19] Szu-Han Wu and Dong-Hwang Chen, ―Synthesis and

characterization of nickel nanoparticles by hydrazine reduction in ethylene glycol,‖J.of Colloid and Interface Sci., vol. 259, pp. 282–286, Nov. 2003.

[20] Giridhar Mishra, Satyendra Kumar Verma, Devraj

Singh, Pramod Kumar Yadawa, Raja Ram Yadav, ―Synthesis and Ultrasonic Characterization of Cu/PVP Nanoparticles-Polymer Suspensions‖, J. of Acoustics, vol.1, pp. 9-14, Feb. 2011.

[21] Sulekh Chandra, Avdhesh Kumar, Praveen Kumar

Tomar, ―Synthesis of Ni nanoparticles and their characterizations,‖J. of Saudi Chem. Soc., vol. 18, pp. 437–442, Sep. 2014.

international journal of scientific & … · nanoparticles dispersed in a base fluid gives a...

Documents