Y/Bi co-doped silicate glasses were prepared,and the effects of Y 2 O 3 on the absorption and emission properties were investigated by spectrum measurement.It was found that the absorption intensity in visible region ...Y/Bi co-doped silicate glasses were prepared,and the effects of Y 2 O 3 on the absorption and emission properties were investigated by spectrum measurement.It was found that the absorption intensity in visible region decreases with increase of Y 3＋ concentration in（70-x）SiO 2 xY 2 O 3-30CaO-1.5Bi 2 O 3（x=0 mol.%,1 mol.%,3 mol.%,5 mol.%,7 mol.%） glasses.The emissions centered at 410,630,1200 and 1290 nm were observed under 280,470,514 and 808 nm excitation,respectively.The emission intensity had the similar change tendency in the visible and near infrared region.We also discussed the actual role of Y 3＋ ions playing in the visible and near infrared emissions of the silicate glasses.展开更多
The micron grade multi-metal oxide bismuth silicate （Bi 12 SiO 20,BSO） was prepared by the chemical solution decomposition technique.Photocatalytic degradation of pentachlorophenol （PCP） was investigated in the pr...The micron grade multi-metal oxide bismuth silicate （Bi 12 SiO 20,BSO） was prepared by the chemical solution decomposition technique.Photocatalytic degradation of pentachlorophenol （PCP） was investigated in the presence of BSO under xenon lamp irradiation.The reaction kinetics followed pseudo first-order and the degradation ratio achieved 99.1% after 120 min at an initial PCP concentration of 2.0 mg/L.The pH decreased from 6.2 to 4.6 and the dechlorination ratio was 68.4% after 120 min at an initial PCP concentration of 8.0 mg/L.The results of electron spin resonance showed that superoxide radical （O 2 · ） was largely responsible for the photocatalytic degradation of PCP.Interestingly,this result was different from that of previous photocatalytic reactions where valence band holes or hydroxyl radicals played the role of major oxidants.Some aromatic compounds and aliphatic carboxylic acids were determined by GC/MS as the reaction intermediates,which indicated that O 2 · can attack the bond between the carbon and chlorine atoms to form less chlorinated aromatic compounds.The aromatic compounds were further oxidized by O 2 · to generate aliphatic carboxylic acids which can be finally mineralized to CO 2 and H 2 O.展开更多
基金supported by Science and Technology Project of Guangdong (2009A090100044)National High-Technology Research and Development Program of China ("863"Program) (2011AA030201)
文摘Y/Bi co-doped silicate glasses were prepared,and the effects of Y 2 O 3 on the absorption and emission properties were investigated by spectrum measurement.It was found that the absorption intensity in visible region decreases with increase of Y 3＋ concentration in（70-x）SiO 2 xY 2 O 3-30CaO-1.5Bi 2 O 3（x=0 mol.%,1 mol.%,3 mol.%,5 mol.%,7 mol.%） glasses.The emissions centered at 410,630,1200 and 1290 nm were observed under 280,470,514 and 808 nm excitation,respectively.The emission intensity had the similar change tendency in the visible and near infrared region.We also discussed the actual role of Y 3＋ ions playing in the visible and near infrared emissions of the silicate glasses.
基金supported by the National Natural Science Foundation of China(No.21077010)the Na-tional Key Technology R&D Program of China(No.2008BAC32B06-3)+1 种基金the National High Technology Research and Development Program (863) of China(No.2009AA05Z306)the Program for Changjiang Schol-ars and Innovative Research Team in University(No.IRT0809)
文摘The micron grade multi-metal oxide bismuth silicate （Bi 12 SiO 20,BSO） was prepared by the chemical solution decomposition technique.Photocatalytic degradation of pentachlorophenol （PCP） was investigated in the presence of BSO under xenon lamp irradiation.The reaction kinetics followed pseudo first-order and the degradation ratio achieved 99.1% after 120 min at an initial PCP concentration of 2.0 mg/L.The pH decreased from 6.2 to 4.6 and the dechlorination ratio was 68.4% after 120 min at an initial PCP concentration of 8.0 mg/L.The results of electron spin resonance showed that superoxide radical （O 2 · ） was largely responsible for the photocatalytic degradation of PCP.Interestingly,this result was different from that of previous photocatalytic reactions where valence band holes or hydroxyl radicals played the role of major oxidants.Some aromatic compounds and aliphatic carboxylic acids were determined by GC/MS as the reaction intermediates,which indicated that O 2 · can attack the bond between the carbon and chlorine atoms to form less chlorinated aromatic compounds.The aromatic compounds were further oxidized by O 2 · to generate aliphatic carboxylic acids which can be finally mineralized to CO 2 and H 2 O.
