Search

In order to realize the ideal water treatment in a green and energy saving manner, TiO 2 based multifunctional membrane proved to be a promising approach owing to its capability in utilizing visible light for photocatalytic pollutant degradation and disinfection of bacteria. However, few studies were found about the investigation of antibacterial abilities arising from the intrinsic properties of membrane and its minor composition. Here, a multifunctional membrane was created via a green approach to integrate the merits of hierarchical Ag/AgBr/TNF composites with micro-/-nano porous structures, the intrinsic antibacterial abilities of Ag, and the visible light absorption capability of AgBr. The synergy effects made it being a promising multifunctional membrane for concurrent water filtration and disinfection in a sustainable way. Through a versatile characterization techniques of FESEM, XRD, TES, XPS, and UV-vis spectrometer, the morphology, structure and surface properties of the well prepared Ag/AgBr/TNF multifunctional membrane was thoroughly studied to reveal the deep mechanism behind the high flux, high photocatalytic degradation and disinfection efficiency under visible light. It indicates that the Ag/AgBr/TNF multifunctional membrane exhibited better photocatalytic activity, higher water permeate flux, and higher disinfection abilities over commercial P25 membrane under visible light. Besides the deep mechanism elaborated, the key factors in terms of predominant oxidative species was also exploited in details. This further solidify the broad future of the developed multifunctional membrane. In view of the roaring demand of advanced water treatment and disinfection technology, it is reasonable to believe our developed visible light responsive Ag/AgBr/TNF multifunctional membrane will show great significances to a green and clean future. [ABSTRACT FROM AUTHOR]

Heterojunctioned architectures were facilely fabricated using hydrothermally treated electrospun TiO 2 nanofibers in an alkaline Sr(NO 3 ) 2 precursor solution in an electronic oven. TiO 2 on the fiber surface was partially dissolved into Ti 4+ to react with Sr 2+ in favor of the nucleation of SrTiO 3 on TiO 2 nanofibers, and thus a heterojunction was formed between SrTiO 3 and TiO 2 , which will benefit the improvement of photocatalytic activity. And then a multifunctional membrane was created by functionalizing the surface of commercial cellulose acetate (CA) membrane with heterojunctioned SrTiO 3 /TiO 2 nanofibers. This newly structured membrane exhibited excellent water purification performances in a concurrent photocatalytic membrane filtration system under the irradiation of UV light, because it is able to integrate the advantages of photocatalysis and membrane filtration while minimizes their disadvantages. The high water purification performances in terms of high photodegradation ability and high permeate flux are attributed to the high photocatalytic activity of heterojunctioned SrTiO 3 /TiO 2 nanofibers architectures and their structured porous functional layer favorable for fast water pass through. [ABSTRACT FROM AUTHOR]

Abstract: Here, hierarchically meso/nanoporous TiO2 was successfully fabricated by a facile and efficient hydrolysis and calcination method using Ti(OC4H9)4 and K2S2O8 as precursors. The hydrosol was firstly prepared by drop-wise adding ethanol dissolved Ti(OC4H9)4 solution into acetone dissolved K2S2O8 solution under a vigorous stirring and heating condition. After being sufficiently hydrolyzed, the hydrosol was calcined to promote the crystallization of TiO2 and successfully dope S and C on TiO2. The calcination temperature significantly affects the doping of S and C on TiO2, crystallization of TiO2, formation of hierarchically meso/nanoporous structure of TiO2 and its light absorption capability. The S- and C-codoped TiO2 exhibits high photocatalytic H2 generation efficiency in a water/methanol sacrificial reagent system under the irradiation of UV light. The high photocatalytic efficiency is dependent on the comprehensively competing effects of the codoping of S and C, crystallization, specific surface area and light absorption capability. The S- and C-codoped TiO2 calcined at 600°C demonstrates the highest photocatalytic H2 generation efficiency, which is ascribed to the balanced synergy of the abovementioned factors. [Copyright &y& Elsevier]

Abstract: The effect of fabrication method on the properties of hierarchical 3D TiO2 nanostructures was investigated by employing and developing both hydrothermal method and calcination method to synthesize hierarchical 3D TiO2 nanorod spheres in this study. A comprehensive comparison in terms of morphologies, crystallization, specific surface areas, light absorption capabilities, and photoluminescence spectrum was conducted between 3D TiO2 nanorod spheres synthesized via hydrothermal method and that synthesized via calcination method. A better photocatalytic activity was demonstrated over the TiO2 nanorod spheres synthesized through calcination method. This was ascribed to the better crystallization and monodispersion of the hierarchical 3D TiO2 nanorod spheres resulted from the calcination method; thus rendering it with more superior characteristics such as larger specific surface area, enhanced light absorption capability and faster transfer of electrons which suppress the recombination of photogenerated electrons and holes. This study is thus significant not only in promoting the development of hierarchical 3D TiO2 nanorod spheres via different methods, but also in revealing the effect of fabrication method on the photocatalytic activity of hierarchical 3D TiO2 nanorod spheres. The calcination method is proposed to be a facile and promising method for scale-up production of the hierarchical 3D TiO2 nanorod spheres with high photocatalytic activity for efficient pollutants degradation. [Copyright &y& Elsevier]

Abstract: Hierarchical porous TiO2 hollow microspheres were synthesized by a facile approach from a one-step template method. This novel approach avoids tedious multiple steps from conventional template method for fabricating hierarchical porous and hollow microspheres. The as-prepared microspheres were characterized by XRD, SEM, TEM, nitrogen adsorption, and UV–vis DRS. Its photocatalytic activity was demonstrated in the photocatalytic degradation of Rhodamine B. Structural characterization indicates that the as-prepared microspheres had a hollow interior and a hierarchical porous structure with both large and small mesopores on its surface. The average diameters and BET surface areas of the hierarchical porous TiO2 hollow microspheres were 1.5μm and 117m2/g, respectively. Optical adsorption investigation shows that the hierarchical porous TiO2 hollow microspheres possessed the optical band gap of 3.42eV. A possible formation mechanism for the hierarchical porous TiO2 hollow microspheres was discussed. The hierarchical porous TiO2 hollow microspheres exhibited much higher photocatalytic activity than the commercial P25 TiO2. In addition, the as-prepared microspheres can be easily recycling for reuse. All these advantages show a bright future for this microspheric photocatalyst in environmental purification. [Copyright &y& Elsevier]

Abstract: Here we present a simple two-phase assembling method to produce high-quality graphene oxide–TiO2 nanorod composites (GO–TiO2 NRCs) on gram scale. TiO2 nanorods dispersed in toluene are synthesized from a facile two-phase hydrothermal method. The effective attachment of TiO2 nanorods on the whole GO sheets at the water–toluene interface is confirmed by Transmission Electron Microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The as-synthesized TiO2 nanorods show a slightly higher efficiency in the photocatalytic degradation of C. I. Acid Orange 7 (AO 7) irradiated under UV light (λ =254nm) and higher antibacterial activity under simulated sunlight than that of TiO2 nanoparticles with the same diameter. After combined with graphene oxide (GO), the GO–TiO2 NRCs show much higher photocatalytic activities than that of TiO2 nanorods alone and the GO–TiO2 nanoparticle composites (GO–TiO2 NPCs). The ratio of TiO2 and GO has no evident effect on the photocatalytic activity of GO–TiO2 NRCs when all the TiO2 nanorods are anchored on the GO sheets. The higher photocatalytic activity of GO–TiO2 NRCs is ascribed to the anti-charge recombination and the more (101) facets. Considering the superior photocatalytic activity of GO–TiO2 NRCs and the fact that they can been easily mass-produced, we expect this material may find important applications in environmental engineering and other fields. [Copyright &y& Elsevier]

Abstract: One-dimensional mesoporous TiO2 nanotube (TNT) with large specific surface area was successfully fabricated, and employed in removal of Acid Orange 7 (AO7) via adsorption and heterogeneous photocatalysis. As compared to its precursor, P25 (Degussa), TNT exhibited superior adsorption ability and photocatalytic activity. It was found that the amount of adsorbed dye over TNT surface was critical to the photodegradation efficiency of AO7, and adsorption was further controlled by solution pH and co-existing ions. With an increase in pH, adsorption of AO7 decreased rapidly, and adsorption behavior transformed from monolayer adsorption to asymmetric physisorption. Under low pH conditions, multivalent anions in high concentrations severely limited AO7 adsorption on TNT; whereas the increase of pH led to a less severe inhibition of the adsorption. On the other hand, multivalent cations seem to facilitate adsorption, regardless of pH conditions. Adsorption mechanism and photodegradation kinetics of AO7 on TNT were also discussed in the paper in view of paving the way for efficient dye wastewater treatment with the application of TNT photocatalyst. [Copyright &y& Elsevier]