In this work, the anataze phase of TiO2 nanoparticles was prepared by sol gel method. We changed time and temperature of calcinations to change size and property of nanoparticles. The Transmission Electron Microscopy ...In this work, the anataze phase of TiO2 nanoparticles was prepared by sol gel method. We changed time and temperature of calcinations to change size and property of nanoparticles. The Transmission Electron Microscopy and Scanning Electron Microscopy were used for characterization of the TiO2 nanoparticles. The nanoparticle size was increased with time and temperature. We found that the average size of samples was changed from 30 to 46 nm with changing temperature from 450℃ to 650℃ and at fixed temperature (450℃) with changing of calcination times from 1 to 3 hours, the size was changed from 30 to 58 nm. For study the dynamic of nanoparticles, the TiO2 nanoparticles were added to water with 2.4 weights present of particles to the water. The different size of TiO2 nanoparticles was studied with photon correlation spectroscopy. The relaxation time was increased with increasing of nanoparticle size and so diffusion coefficient was decreased.展开更多
In the present study,nano-sized TiO2 /Al2O3 modified PVDF membranes (MM) were fabricated and utilized for anionic polyacrylamide ( APAM) separation. The results showed that,compared with PVDF membrane (OM) ,the contac...In the present study,nano-sized TiO2 /Al2O3 modified PVDF membranes (MM) were fabricated and utilized for anionic polyacrylamide ( APAM) separation. The results showed that,compared with PVDF membrane (OM) ,the contact angle of MM decreases from 83. 64° to 67. 42°,which indicates the increase of the hydrophilicity of MM. The relative flux (RF) decline curve of this ultrafiltration of APAM in water with time shows an obvious two stage properties. The cake filtration models were used to predict the performance of different time over the complete range of filtration times. All the four cake models could simulate this UF process to a certain extent,and the suitability of the two kinds of membranes was: cake filtration > intermediate pore blocking > standard pore blocking > complete pore blocking models. However,they became more and more unsuited to this process with time extending. Surface and cross-sectional morphology of membrane was investigated by SEM to make an advanced certificate of this UF mechanism.展开更多
Single-crystal-like TiO2 mesoporous microspheres have been reported with high photocatalytic activity under ultraviolet light （UV light） because of their high specific surface areas and single-crystal-like channel w...Single-crystal-like TiO2 mesoporous microspheres have been reported with high photocatalytic activity under ultraviolet light （UV light） because of their high specific surface areas and single-crystal-like channel walls. In this work, plasmonic gold nanoparticles （Au NPs） and fl-NaYF4： Yb3＋, Er3＋ upconversion nanoparticles （UCNPs） were composited with single-crystal-like TiO2 mesoporous microspheres through a series of facile approaches, aiming at broadening response region of solar light from UV to visible and near infrared light and enhancing the photocata- lyric activity further. The structure was rationally designed by modifying the pore size of TiO2 mesoporous micro- spheres so as to anchor plasmonic Au NPs, and covering β-NaYF4： Yb3＋, Er3＋ with SiO2 in order to embed UCNPs into TiO2 mesoporous microspheres via hydrophilic interaction. This work studied the attribution of Au NPs and UCNPs to photocatalysis and found out that combining Au NPs and certain amount of UCNPs with single-crystal- like TiO2 mesoporous microspheres in a monolithic architecture would bring enhanced broadband photocatalytic activity under simulated solar light. Consequently, the composite photocatalyts containing 150 mg UCNPs showed a significant enhancement in reaction rate, which was 36.02% higher than commercial P25 and 85.09% higher than pure TiO2 mesoporous microspheres under simulated solar light.展开更多
文摘In this work, the anataze phase of TiO2 nanoparticles was prepared by sol gel method. We changed time and temperature of calcinations to change size and property of nanoparticles. The Transmission Electron Microscopy and Scanning Electron Microscopy were used for characterization of the TiO2 nanoparticles. The nanoparticle size was increased with time and temperature. We found that the average size of samples was changed from 30 to 46 nm with changing temperature from 450℃ to 650℃ and at fixed temperature (450℃) with changing of calcination times from 1 to 3 hours, the size was changed from 30 to 58 nm. For study the dynamic of nanoparticles, the TiO2 nanoparticles were added to water with 2.4 weights present of particles to the water. The different size of TiO2 nanoparticles was studied with photon correlation spectroscopy. The relaxation time was increased with increasing of nanoparticle size and so diffusion coefficient was decreased.
基金Sponsored by the National Natural Science Foundation of China (Grant No.50978068)International Cooperation Program (Grant No.2010DFA92460)+1 种基金National High Technology Research and Development Program of China (863 Program,Grant No.2008AA06Z304)Tianjin Key Laboratory of Aquatic Science and Technology
文摘In the present study,nano-sized TiO2 /Al2O3 modified PVDF membranes (MM) were fabricated and utilized for anionic polyacrylamide ( APAM) separation. The results showed that,compared with PVDF membrane (OM) ,the contact angle of MM decreases from 83. 64° to 67. 42°,which indicates the increase of the hydrophilicity of MM. The relative flux (RF) decline curve of this ultrafiltration of APAM in water with time shows an obvious two stage properties. The cake filtration models were used to predict the performance of different time over the complete range of filtration times. All the four cake models could simulate this UF process to a certain extent,and the suitability of the two kinds of membranes was: cake filtration > intermediate pore blocking > standard pore blocking > complete pore blocking models. However,they became more and more unsuited to this process with time extending. Surface and cross-sectional morphology of membrane was investigated by SEM to make an advanced certificate of this UF mechanism.
基金This work is supported by the National Natural Science Foundation of China （Nos. 21236003, 21322607, 21406072, 21471056, 21676093 and 91534202）, Shanghai Educational Development Foundation （No. 14CG29）, the Basic Research Program of Shanghai （No. 14JCI406402）, China Postdoctoral Science Foundation （Nos. 2014M560307, 2014M561497, 2015T80408）, and the Fundamental Research Funds for the Central Universities.
文摘Single-crystal-like TiO2 mesoporous microspheres have been reported with high photocatalytic activity under ultraviolet light （UV light） because of their high specific surface areas and single-crystal-like channel walls. In this work, plasmonic gold nanoparticles （Au NPs） and fl-NaYF4： Yb3＋, Er3＋ upconversion nanoparticles （UCNPs） were composited with single-crystal-like TiO2 mesoporous microspheres through a series of facile approaches, aiming at broadening response region of solar light from UV to visible and near infrared light and enhancing the photocata- lyric activity further. The structure was rationally designed by modifying the pore size of TiO2 mesoporous micro- spheres so as to anchor plasmonic Au NPs, and covering β-NaYF4： Yb3＋, Er3＋ with SiO2 in order to embed UCNPs into TiO2 mesoporous microspheres via hydrophilic interaction. This work studied the attribution of Au NPs and UCNPs to photocatalysis and found out that combining Au NPs and certain amount of UCNPs with single-crystal- like TiO2 mesoporous microspheres in a monolithic architecture would bring enhanced broadband photocatalytic activity under simulated solar light. Consequently, the composite photocatalyts containing 150 mg UCNPs showed a significant enhancement in reaction rate, which was 36.02% higher than commercial P25 and 85.09% higher than pure TiO2 mesoporous microspheres under simulated solar light.
