Synthesis of silver nanoparticles by y-ray irradiation using pva as stabilizer

Colloidal silver nanoparticles were synthesized by
Co-60 ray irradiation of Ag+ in aqueous solution containing polyvinyl alcohol (PVA) as stabilizer and 0.5 M ethyl alcohol as free radical (OH• ) scavenger. The effect of Ag+ concentration which varied from 1 to 50 mM on the saturated conversion dose (D) of Ag+ into Ag determined by UV-vis spectroscopy and the size of Ag nanoparticles characterized by transmission electron microscopy (TEM) were investigated. The dependence of D (kGy) and average size (d, nm) of Ag nanoparticles on Ag+ concentration was found out to be as: D (kGy) = 0.0041 [Ag+]2 + 0.8674 [Ag+] + 3.2262 (R2 = 0.9799) and d(nm) = 0.0016 [Ag+]2 + 0.136 [Ag+] + 7.068 (R2 = 0.9736) for Ag+ concentration from 1 to 50 mM stabilized by 2% PVA. Results indicated the Ag nanoparticles size to be in the range of 6 - 18 nm. The concentration of PVA (0.5 - 4.0%) in the irradiated solution also considerably affected the silver nanoparticles size which decreased with increasing the amount of PVA in the solution. Due to the unique features of the processing procedures, thus
Co-60 ray irradiation has been considered as a suitable method for mass production of colloidal silver nanoparticles.
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Synthesis of silver nanoparticles by y-ray irradiation using pva as stabilizer Journal of Chemistry, Vol. 45 (Special issue), P. 136 - 140, 2007 SYNTHESIS OF SILVER NANOPARTICLES BY -RAY IRRADIATION USING PVA AS STABILIZER Received 15 October 2007 Bui Duy Du1, Dang Van Phu2, Bui Duy Cam3, Nguyen Quoc Hien2 1 Institute of Applied Materials Science, Vietnam National Institute for Science and Technology 2 Research and Development Center for Radiation Technology, Vietnam Atomic Energy Commission 3 Natural Science College, Hanoi National University SUMMARY Colloidal silver nanoparticles were synthesized by Co-60 ray irradiation of Ag+ in aqueous solution containing polyvinyl alcohol (PVA) as stabilizer and 0.5 M ethyl alcohol as free radical (OH•) scavenger. The effect of Ag+ concentration which varied from 1 to 50 mM on the saturated conversion dose (D) of Ag+ into Ag determined by UV-vis spectroscopy and the size of Ag nanoparticles characterized by transmission electron microscopy (TEM) were investigated. The dependence of D (kGy) and average size (d, nm) of Ag nanoparticles on Ag+ concentration was found out to be as: D (kGy) = 0.0041 [Ag+]2 + 0.8674 [Ag+] + 3.2262 (R2 = 0.9799) and d(nm) = 0.0016 [Ag+]2 + 0.136 [Ag+] + 7.068 (R2 = 0.9736) for Ag+ concentration from 1 to 50 mM stabilized by 2% PVA. Results indicated the Ag nanoparticles size to be in the range of 6 - 18 nm. The concentration of PVA (0.5 - 4.0%) in the irradiated solution also considerably affected the silver nanoparticles size which decreased with increasing the amount of PVA in the solution. Due to the unique features of the processing procedures, thus Co-60 ray irradiation has been considered as a suitable method for mass production of colloidal silver nanoparticles. I - INTRODUCTION is carried out under ambient pressure at room temperature 2) reducing agents are uniformly Silver nanoparticles have attractive distributed in the solution in neat portion as for considerable interest owing to their potential metal ions 3) reaction rate can be reliably applications in different areas such as in controlled by varying absorbed dose or medicine as biocides for burn and traumatic irradiation time 4) the product namely colloidal wound [1, 2] and radiotherapy [3], in catalysis silver nanoparticles can be obtained without [4], in electronics [5], as well as in agriculture contamination of excessive reductant. [6]. A number of methods have been developed The mechanism of the radiation method for the synthesis of silver nanoparticles based on the reduction of metal ions, stabilized by polymers such as chemical particularly Ag+ ions by hydrated electron (e-aq) reduction [7 - 10], electron and photochemical and hydrogen atom (H•) produced in solution reduction [11, 12], thermochemical treatment during irradiation [14, 16]. [13] and ionizing radiation [14 - 19]. H2O e-aq, H•, OH•, H2O2, H2, H3O+,.. Compared with other methods of preparation (1) of silver nanoparticles, the radiation method 0 - provides several advantages such as: 1) process The solvated electrons with E (H2O/e aq) = 136  2.87 VNHE and H• atoms with E0(H+/H•) = 2.3 Ag+ + H• Ag0 + H+ (3) VNHE are powerful reducing agents so that they 0 Ag + Ag + + Ag + Ag + (4) 2 n+1 easily reduce Ag+ ions to the zero-valent state • Ag0 with E0(Ag+/Ag0) = 1.8 VNHE as shown by OH radical formed during irradiation is (2), (3) and (4) [14, 16]. The reaction process strongly oxidative agent which must be can be written as follows: converted into reducing agent by reacting with alcohol (ethanol, isopropanol,..) resulting Ag+ + e-aq Ag0 (2) alcoholic radicals as follows [16, 17]: RC ...