TY - JOUR
T1 - Technetium(IV) oxide colloids produced by radiolytic reactions in aqueous pertechnetate solution
AU - Sekine, T.
AU - Narushima, H.
AU - Suzuki, T.
AU - Takayama, T.
AU - Kudo, H.
AU - Lin, M.
AU - Katsumura, Y.
N1 - Funding Information:
The authors acknowledge to Prof. T. Ohtsuki and machine group members of the Laboratory of Nuclear Science, Tohoku University, for their help in bremsstrahlung irradiation. They also wish to thank Prof. T. Mitsugashira and Dr. K. Yubuta of the Institute for Material Research, Tohoku University and to Mr. Y. Hayasaka of the High Voltage Microscope Laboratory, Tohoku University, for their help in the TEM measurements of nanoparticles. The authors are indebted to Prof. R. Amano for supplying Tc-99. This study was supported by the Ministry of Education, Culture, Sports, Science and Technology, Japan.
PY - 2004/11/30
Y1 - 2004/11/30
N2 - We report the reduction of pertechnetate (Tc(VII)O4-) to Tc(IV) species by bremsstrahlung irradiation of an aqueous solution of TcO4- at different pHs of the solution. When the TcO 4- solution at pH 1.8 acidified with sulfuric acid was irradiated, soluble Tc(IV) species, which was proposed as polymeric Tc(IV) species, was formed. Amounts of the polymeric Tc(IV) species increased with an increase of absorbed dose and 80% of TcO4- was converted to the polymeric Tc(IV) species at 6.5 kGy. By the irradiation of the TcO 4- solution at pH 2.7, technetium(IV) oxide (Tc(IV)O 2·nH2O) colloids were formed in addition to the polymeric Tc(IV) species. At pH 4.1, only the Tc(IV)O2·nH 2O colloids were observed in the irradiated solution. The colloid particle was found as an aggregate (30-130 nm) of tiny particles of 2-3 nm in diameter. The polymeric Tc(IV) species was not filtered off with an ultrafilter (NMWL 10,000) and changed to TcO2·nH2O colloids as the pH of the solution increased, suggesting that the polymeric Tc(IV) species was a precursor of TcO2·nH2O colloids. The reduction of TcO4- in acidic media proceeds through a bimolecular reaction with hydrogen radicals (a product of water radiolysis) followed by successive disproportionation reactions of Tc(VI) and Tc(V).
AB - We report the reduction of pertechnetate (Tc(VII)O4-) to Tc(IV) species by bremsstrahlung irradiation of an aqueous solution of TcO4- at different pHs of the solution. When the TcO 4- solution at pH 1.8 acidified with sulfuric acid was irradiated, soluble Tc(IV) species, which was proposed as polymeric Tc(IV) species, was formed. Amounts of the polymeric Tc(IV) species increased with an increase of absorbed dose and 80% of TcO4- was converted to the polymeric Tc(IV) species at 6.5 kGy. By the irradiation of the TcO 4- solution at pH 2.7, technetium(IV) oxide (Tc(IV)O 2·nH2O) colloids were formed in addition to the polymeric Tc(IV) species. At pH 4.1, only the Tc(IV)O2·nH 2O colloids were observed in the irradiated solution. The colloid particle was found as an aggregate (30-130 nm) of tiny particles of 2-3 nm in diameter. The polymeric Tc(IV) species was not filtered off with an ultrafilter (NMWL 10,000) and changed to TcO2·nH2O colloids as the pH of the solution increased, suggesting that the polymeric Tc(IV) species was a precursor of TcO2·nH2O colloids. The reduction of TcO4- in acidic media proceeds through a bimolecular reaction with hydrogen radicals (a product of water radiolysis) followed by successive disproportionation reactions of Tc(VI) and Tc(V).
KW - Polymeric Tc(IV) species
KW - Radiolysis
KW - Technetium(IV) oxide colloids
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U2 - 10.1016/j.colsurfa.2004.08.074
DO - 10.1016/j.colsurfa.2004.08.074
M3 - Article
AN - SCOPUS:8844238426
SN - 0927-7757
VL - 249
SP - 105
EP - 109
JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects
JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects
IS - 1-3
ER -