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Photocatalytic Reactor (photocatalytic + reactor)

Distribution by Scientific Domains

Chemistry	93%

Selected Abstracts

Oxidation of PCE with a UV LED Photocatalytic Reactor

CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2005
D. H. Chen
Abstract This paper is the first to investigate photocatalysis using a cutting-edge and energy-efficient solid-state light source: Ultraviolet (UV) Light Emitting Diodes (LED's). UV LED's do not involve mercury vapor, can be driven with direct current (DC), and have a long lifetime of 100,000 hours. UV LED's with a peak wavelength of 375,nm were tested for perchloroethylene (PCE) photocatalytic oxidation over Degussa P,25 TiO2. At a UV light output of only 49,,W/cm2, the designed reactor delivers a PCE conversion of up to 43,%. If the UV LED price continues to drop, it is very likely that UV LED's will replace UV lamps as the favored light source in photocatalysis applications. [source]

Photocatalytic degradation of gaseous trichloroethene using immobilized ZnO/SnO2 coupled oxide in a flow-through photocatalytic reactor

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2005
Taicheng An
Abstract The photocatalytic degradation of gaseous trichloroethene (TCE) was investigated on immobilized ZnO/SnO2 coupled oxide in a flow-through photocatalytic reactor. It was found that gaseous photocatalysis is an efficient method for volatile organic compounds' abatement and air purification. Degradation of ,100% was found for TCE at the concentrations examined, up to 400 ppmv, in a flow-through dry synthetic gas stream. In our tested conditions, the flow rate had little influence on the photocatalytic degradation efficiencies of TCE, while the relative humidity had a significant influence on the photocatalytic degradation of TCE. The photocatalytic degradation efficiencies of TCE increased slowly below 20% relative humidity and then decreased as the relative humidity increased further. The deactivation of used immobilized photocatalyst was not observed within the 200 h testing period in the present experiment, although the surface of the photocatalyst changed greatly during the use of the photocatalyst. Copyright © 2004 Society of Chemical Industry [source]

Radiation model of a TiO2 -coated, quartz wool, packed-bed photocatalytic reactor

AICHE JOURNAL, Issue 4 2010
G. E. Imoberdorf
Abstract The radiation field of a packed-bed photocatalytic reactor filled with quartz wool coated with titanium dioxide was modeled using the Monte Carlo technique and the following information: the radiation flux emitted by the lamps, the diameter size distribution of the quartz fiber cloth, the mass of quartz fibers and of TiO2 that was immobilized on the fiber surface as well as the refractive index, and the spectral absorption coefficient of the materials of the system. Modeling predictions were validated with radiometer measurements of the transmitted radiation through the reactor, the root mean square error being <9.7%. Finally, by means of a parametric study, the validated model was used to analyze the effect of the design variables, such as the radii of the quartz fibers, thickness of the TiO2 coatings, and amount of TiO2 -coated quartz wool, on the distribution and nonuniformity of the radiative energy distribution inside the reactor. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source]

Three-dimensional CFD model for a flat plate photocatalytic reactor: Degradation of TCE in a serpentine flow field

AICHE JOURNAL, Issue 2 2009
Asefeh Jarandehei
Abstract Computational fluid dynamics (CFD) simulation was applied to a photocatalytic reactor with surface reaction for trichloroethylene (TCE) oxidation at various pollutant concentrations, and flow rates. First-order and Langmuir-Hinshelwood kinetics for TCE removal rate were considered. The results were compared with those from experiments of Demeestere et al. (Appl Catal B Environ. 2004;54:261,274) in a flat plate photocatalytic reactor with serpentine geometry. The flow regime was laminar. Through the CFD simulation, the velocity field and the concentration gradient of TCE in the reactor were studied in detail. At Reynolds numbers around 900, the laminar flow becomes unstable. Under such a condition, when flow passes the 180° sharp turns, due to formation of secondary flow and consequently vortices, there is a lot of cross-sectional mixing in the reactor. This kind of studies can help us to model the photocatalytic reactor as accurately as possible. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source]

Monte Carlo model of UV-radiation interaction with TiO2 -coated spheres

AICHE JOURNAL, Issue 10 2007
Gustavo E. Imoberdorf
Abstract Photocatalysis is one of the advanced oxidation techniques that are being studied for the treatment of polluted air and water from different sources. From a kinetic point of view, photocatalytic reaction rates are strongly dependent not only on the reactant and product concentrations, but also on the rate of photon absorption. Unfortunately, the local rate of photon absorption is usually difficult to evaluate because of (i) the inherent complexity of the system and (ii) the lack of data concerning the photocatalyst optical properties. The final objective of this project is focused on the development of a complete model of the radiation field; the bed structure, and the flow pattern to describe the operation of a fixed bed photocatalytic reactor. In this article, the interaction between radiative energy and TiO2 -coated fused-silica sphere beds was studied. The proposed model was built applying the Monte Carlo method, taking into account the complex reflection/refraction/absorption interactions between radiation and the packed bed. To obtain experimental measurements, an ad hoc device was designed and built. This device allows us to validate the proposed radiation model, and to obtain the optical parameters of the composite photocatalyst, i.e., the refractive index and the surface rough index of the fused-silica spheres, as well as the refractive index and the optical thickness of the TiO2 films. © 2007 American Institute of Chemical Engineers AIChE J, 2007 [source]

Nonuniform radiation modeling of a corrugated plate photocatalytic reactor

AICHE JOURNAL, Issue 7 2005
Huilan Shang
Abstract Corrugated plate photocatalytic reactors provide a promising photoreactor design due to its potential in enhancing energy efficiency. A detailed model of such reactors is needed for engineering applications and process design. The model for the light absorption in a corrugated plate reactor using a nonuniform radiation source is developed based on first principles. The local area-specific rate of energy absorption (LASREA) distribution on the corrugated plates is examined via simulation. The effect of the design parameters on LASREA is investigated. The results from this research provide feasible basis for design and optimization of corrugated plate photoreactors. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source]

Rigorous modeling of UV absorption by TiO2 films in a photocatalytic reactor

AICHE JOURNAL, Issue 7 2000
Z. Zhang
The radiation absorption profiles on the surfaces of TiO2 films in a corrugated-plate photocatalytic reactor were modeled based on first principles. A new term, the local-area-specific rate of energy absorption (LASREA), was adopted to describe the catalyst surface radiation in heterogeneous photoreactors. The LASREA and the energy absorption efficiency were both quite sensitive to the dimensions of the corrugated plates. Due to the multiple photon reflections between the opposing surfaces, corrugated plates possess a superior capability for recapturing longer wavelength photons that would otherwise be reflected out of some reactor designs. This results in higher energy absorption efficiency and more uniform LASREA on the catalyst films. Compared to a flat plate, corrugations are predicted to enhance the energy absorption efficiency by up to 50% for UV-A fluorescent-lamp-powered systems and more than 100% for solar-powered systems. [source]

Nonuniform radiation modeling of a corrugated plate photocatalytic reactor

Active microfiltered sensor interfaces, photocatalytic reactors, and microbatteries using combined micro/nanoporous interfaces

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2009
James L. Gole
Abstract Select active micro/nanoporous porous silicon (PS) interfaces have been formed and treated to form the scaffolding for sensors, photocatalysis-based microreactors, and PS-based lithium ion batteries. The introduction of active nanostructures is used to form sensitive and selective sensors. The introduction of TiO2-xNx visible light absorbing nanophotocatalysts to the PS structure for the purpose of creating a microreactor, the concomitant metal ion seeding of these nanostructures to promote infrared spectral enhancement, introduce rapid room temperature phase transformation, and provide the potential for a novel active photovoltaic response are outlined. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Photocatalytic membrane reactors: case studies and perspectives

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2009
V. Loddo
Abstract Photocatalysis by polycrystalline semiconductor oxides is being successfully applied to the abatement of organic and inorganic pollutants both in gas and in liquid phase. In order to increase the efficiency of this method, the coupling of this technology with the membrane separation process has been the object of sound investigation. In this combination, the membrane may act in different ways: to confine the photocatalytic powder in the reacting suspension, to selectively separate the photoreaction products, or to be the support of photocatalyst. This article reports recent studies in which different types of membranes (such as distillation, dialysis, nanofiltration, pervaporation and osmosis membranes) are used in hybrid systems. An additional advantage of coupling is that the photocatalyst prevents the microbial fouling offering a strong potential for the use of new types of thin-film-composite membrane. Perspectives and future possible application of the synergy between membranes and photocatalytic reactors are also emphasised. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]