amide (DMF) and irradiated with a high-intensity ultrasonic horn under 1.5 atm
of AraH 2 at room temperature for 3 h. The product is washed thoroughly with
methanol in an inert glove box and dried overnight in a vacuum. The XRD diffraction indicates that the as-prepared composite material is crystalline. The XRD
diffraction patterns match those of metallic nickel. The particle sizes measured
from the TEM picture are about 5 nm in diameter and were very well dispersed in
the polystyrene. The magnetization measurements established that the as-prepared
nanocomposite materials are super paramagnetic due to their small size. The saturation magnetization (30.1 emu g
À1 ) and coercivity (5 Oe) of the materials were
significantly smaller than those of the bulk nickel, reflecting the nanoparticle
nature.
Kitamoto and Abe applied power ultrasonic waves (19.5 kHz, 600 W) to 300 ml
of FeCl 2 aqueous solution (pH 7.0) at 70
C, and succeeded in encapsulating polyacrylate spheres of 250 nm diameter with magnetite ferrite coatings [49]. From
TEM observations of the cross sections it was seen that the polymer spheres were
covered with uniform columnar crystallites of 30–40 nm in diameter at the bottom
and 60–70 nm at the top. The ultrasound waves produce OH groups on the polymer surfaces which work as ferrite nucleation sites; this improves the quality of
the ferrite coatings. The ferrite-encapsulated particles will greatly improve the performance of the enzyme immunoassay as a cancer test reagent. The above possible
mechanism for the formation of the blue oxide is consistent with explanations in
the literature for a sonochemical reaction.
Finally, it should be mentioned that Suslick sonicated the transition-metal carbonyl in a low volatility solvent in the presence of poly(vinylpyrrolidone) and obtained metallic colloids for Fe and Co [63, 64].
6.1.1.6 Sonochemical Synthesis of Nanometals Encapsulated in a Carbon Matrix
The metal particles of an interstitial solid solution of palladium carbide, PdC x
(0 < x a 0:15), were synthesized [65] at room temperature in an aqueous solution
during the reduction of tetrachloropalladate (II) with sonochemically produced organic radicals. The sonochemical reduction was carried out using a 200 kHz ultrasonic generator operating at 200 W (6 W cm
À2 , 65 mL). An aqueous solution of
PdCl 2 Á2NaCl (1–10 mM, 60 mL) was placed in a cylindrical glass vessel (55 mL),
which had a silicon rubber septum for gas bubbling or sample extraction, without
exposing the sample to air. The vessel was fixed in a constant position and then
irradiated for 1 h under argon at 20
C. Under experimental conditions, the rate of
formation of OH radicals and H atoms in the sonolysis of pure water was estimated to be 20 mM min
À1 .
Organic compounds such as methanol, ethanol, hexanol, isopropanol, tert-butyl
alcohol, and acetone, were injected into the solution using a microsyringe through
the septum just before the irradiation, and acted as accelerators of the reduction of
Pd (II).
The number of carbon atoms in the Pd particles was controlled by changing the
concentration and the type of organic additives. The mechanism proposed for the
PdC formation comprises the following steps: (i) an active Pd cluster is formed
6.1 Sonochemistry 127
of AraH 2 at room temperature for 3 h. The product is washed thoroughly with
methanol in an inert glove box and dried overnight in a vacuum. The XRD diffraction indicates that the as-prepared composite material is crystalline. The XRD
diffraction patterns match those of metallic nickel. The particle sizes measured
from the TEM picture are about 5 nm in diameter and were very well dispersed in
the polystyrene. The magnetization measurements established that the as-prepared
nanocomposite materials are super paramagnetic due to their small size. The saturation magnetization (30.1 emu g
À1 ) and coercivity (5 Oe) of the materials were
significantly smaller than those of the bulk nickel, reflecting the nanoparticle
nature.
Kitamoto and Abe applied power ultrasonic waves (19.5 kHz, 600 W) to 300 ml
of FeCl 2 aqueous solution (pH 7.0) at 70
C, and succeeded in encapsulating polyacrylate spheres of 250 nm diameter with magnetite ferrite coatings [49]. From
TEM observations of the cross sections it was seen that the polymer spheres were
covered with uniform columnar crystallites of 30–40 nm in diameter at the bottom
and 60–70 nm at the top. The ultrasound waves produce OH groups on the polymer surfaces which work as ferrite nucleation sites; this improves the quality of
the ferrite coatings. The ferrite-encapsulated particles will greatly improve the performance of the enzyme immunoassay as a cancer test reagent. The above possible
mechanism for the formation of the blue oxide is consistent with explanations in
the literature for a sonochemical reaction.
Finally, it should be mentioned that Suslick sonicated the transition-metal carbonyl in a low volatility solvent in the presence of poly(vinylpyrrolidone) and obtained metallic colloids for Fe and Co [63, 64].
6.1.1.6 Sonochemical Synthesis of Nanometals Encapsulated in a Carbon Matrix
The metal particles of an interstitial solid solution of palladium carbide, PdC x
(0 < x a 0:15), were synthesized [65] at room temperature in an aqueous solution
during the reduction of tetrachloropalladate (II) with sonochemically produced organic radicals. The sonochemical reduction was carried out using a 200 kHz ultrasonic generator operating at 200 W (6 W cm
À2 , 65 mL). An aqueous solution of
PdCl 2 Á2NaCl (1–10 mM, 60 mL) was placed in a cylindrical glass vessel (55 mL),
which had a silicon rubber septum for gas bubbling or sample extraction, without
exposing the sample to air. The vessel was fixed in a constant position and then
irradiated for 1 h under argon at 20
C. Under experimental conditions, the rate of
formation of OH radicals and H atoms in the sonolysis of pure water was estimated to be 20 mM min
À1 .
Organic compounds such as methanol, ethanol, hexanol, isopropanol, tert-butyl
alcohol, and acetone, were injected into the solution using a microsyringe through
the septum just before the irradiation, and acted as accelerators of the reduction of
Pd (II).
The number of carbon atoms in the Pd particles was controlled by changing the
concentration and the type of organic additives. The mechanism proposed for the
PdC formation comprises the following steps: (i) an active Pd cluster is formed
6.1 Sonochemistry 127