الفهرس 
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Abstract
The aim of the present study was to construct simplified apparatus for producing silver and copper nanoparticles using DC- ARC discharge method after aerosol formation of silver nitrate and copper sulphate respectively using pneumatic nebulizer. And at the same time, comparison of this method as a physical method with silver and copper nanoparticles chemically prepared.
To achieve our target, a simple designed pneumatic nebulizer was used for generation of aerosol solution of silver nitrate and copper sulphate for formation of silver and copper nanoparticles; respectively. The shape and diameter of the sprayed water droplets at different flow rates (2-14 L/min) with constant pressure (6 bar) was studied. The smaller and narrower particle size diameter was obtained at flow rate of 10 L/min.
After sample aerosol was formed using the glass nebulizer, it introduced to the arc discharge system; which consist of two graphite electrodes, the first electrode was a cylindrical shape and the second electrode was a tube electrode.
Through the tube electrode the atomized droplets were introduced to be impacted on the surface of the cylinder electrode to form a thin layer of the sample .The electrical arc power supply was used to form an electrical discharge that evaporated this layer to produce nanoparticles. The formed nanoparticles were trapped in a glass container. The prepared nanoparticles were characterized as follows:
1. Particle size analysis: The mean particle size and distribution of the particle size will be determined by Particle size analyzer.
2. Transmission electron microscope: for studying shape and morphology of the prepared particles.
3. The absorption maxima at different wave lengths of visible light and UV will be determined using UV-visible spectrophotometer.
4. SEM- energy dispersive X-ray (SEM-EDX) for elemental composition analysis.
The DC- arc discharge method after silver nitrate and copper sulphate aerosol formation at initial voltage of 25 KV, peak current 0.005 A, On-pulse duration for 1-2 S, Off-pulse duration for 2-3 S and fabrication time was 60 min resulted in fabrication of silver and copper nanoparticles with production yield 152 and 139 mg/min; respectively. Examination by the transmission electron microscope revealed that the prepared particles by arc discharge method and chemical method were spherical in shape and showed low level of agglomeration among particles and high level of uniformity. The results of particle size analyzer for both silver and copper particles prepared by arc discharge method showed that the average radius of prepared silver particles was 167.2nm and 452.4 nm;
respectively. The charge distribution of these particles revealed that the zeta potential for silver nanoparticles was –17.3 mv ± 4.27 and that for copper nanoparticles was – 20.4 mv ± 6.77.The Optical properties as demonstrated by UV-Visble absorption spectra of the samples indicated a strong absorption peak at 425 nm for silver nanoparticles and 540 nm for copper nanoparticles prepared by arc discharge method.
Silver nanoparticles prepared by citrate reduction method have mean particle size diameter of 82.87 nm and copper nanoparticles prepared using ascorbic acid as a reducing agent showed mean particle size of 97.14 nm. the zeta potential of the silver nanoparticles was - 37.3 mv ± 4.8 and that for copper nanoparticles was - 35.1 mv ± 7.88. The suspension of silver and copper nanoparticles has a strong absorption maximum at 425 nm, 550 nm; respectively.