Development of Photocatalytically Active Titania Coatings for Water and Wastewater Treatment PDF Download
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Author: Thi Phuong Vu
Publisher:
ISBN: 9783844062922
Category :
Languages : en
Pages :
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Book Description
Author: Thi Phuong Vu
Publisher:
ISBN: 9783844062922
Category :
Languages : en
Pages :
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Book Description
Author: Mohamed A. Barakat
Publisher: Springer
ISBN: 3319242717
Category : Science
Languages : en
Pages : 39
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Book Description
In this brief, a comprehensive review of the UV/visible-TiO2 photocatalytic oxidation process is presented with an insight into the mechanisms involved, the role of titanium dioxide as a catalyst, irradiation sources, types of reactors, and a comparison between various modes of TiO2 application. An overview of the development and enhancement of the activity of TiO2 nanoparticles in photocatalysis is presented. The topics covered include a detailed look at the unique properties of the TiO2 nanoparticles and their relationship to photocatalytic properties. The utilization of the TiO2 nanoparticles as photocatalysts, in the non-doped and doped forms is also reviewed. Finally, the use of modified TiO2 nanoparticles has made a significant contribution in providing definitive mechanistic information regarding the visible light photocatalytic processes.
Author: Yasmine Kamal Abdel-Maksoud Abdel-Salam
Publisher:
ISBN:
Category : Immobilized cell organelles
Languages : en
Pages : 344
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Book Description
Abstract: There have been rising concerns about emerging contaminants that are not efficiently removed by conventional wastewater treatment plants. TiO2 photocatalysis is one of the promising routes for sustainable wastewater treatment. Research on the use of TiO2 photocatalysis for water/wastewater treatment for the removal of persistent non-biodegradable emerging water pollutant is active worldwide. Since the mid-1970s the viability of photocatalytic degradation of organic compounds in water using TiO2 was demonstrated. More than 1,000 substances have been degraded using TiO2. Despite the extensive research on photocatalytic oxidation using TiO2, pilot and demonstration plants through the last four decades are still countable. Widespread use of photocatalytic treatment of water and wastewater require the development of an innovative photocatalytic reactor that is efficient, reliable, simple to construct, easy to maintain, has low energy consumption, low capital and operating cost and provides easy separation of catalyst after treatment ends. In an attempt to develop this desired photo-reactor, three photo-reactors were designed and constructed: the slurry water-bell photo-reactor, the immobilized water-bell photo-reactor and the immobilized tray photo-reactor. The slurry water-bell photo-reactor is based on generating a thin water film to allow for solar light penetration for photo-catalyst activation and continuous oxygenation. Recirculating the reaction solution at a high flow rate ensures good mixing and avoids dead zones in the photo-reactor. the reactor performance for degradation of phenol, as a model compound, was evaluated using commercial TiO2. Factors affecting the degradation efficiency were studied including catalyst loading, light intensity, initial pollutant concentration, oxidant addition and exposure time. Dissolved oxygen levels, temperature and pH were monitored through all the conducted tests. The performance of the slurry water-bell was compared with other photo-reactors using two benchmarks: the degradation rate constant and the reactor throughput. The reactor throughput is a function of the treated volume, treatment duration and reactor area footprint, thus it is as a versatile indicator for comparison between reactors of different types and geometries as well as selection of reactor configurations suitable for scale-up and commercialization. TiO2 was immobilized on sand grains for use as dispersed photo-catalyst in the water-bell reactor. Immobilization of TiO2 was conducted by two methods; direct immobilization using sol-gel synthesis and binding with epoxy coating. Photo-catalyst abrasion was encountered. The strong mixing conditions and flow through the recirculating pump resulted in high abrasion of the photo-catalyst off the sand surface. The tray photo-reactor was developed to avoid the high friction of the photo-catalyst particles in the recirculating pump while maintain fulfilling all the other photocatalytic process requirements of light penetration, continuous oxygen supply, and turbulent flow. The immobilized tray photocatalytic reactor uses a fixed-bed of TiO2 supported on sand grains. The reactor maintains a thin water film over the supported TiO2 catalytic bed. TiO2 was immobilized on the sand grains using 3 different immobilization approaches: 1) direct immobilization using the sol gel technique, 2) coating with TiO2/cement grout; and (3) binding with TiO2-epoxy coating. Reactor performance for the degradation of phenol as a model compound was evaluated for the three photo-catalysts. Immobilization of TiO2 on sand particles using epoxy was successful in achieving the highest phenol degradation and resistance to abrasion. The water turbidity remained unchanged indicating photo-catalyst resistance to abrasion even after multiple use of the catalytic bed. Successful operation of the tray photo-reactor in the continuous mode was also achieved. The performance of the immobilized tray photo-reactor was compared with other photo-reactors using three benchmarks: the initial degradation rate, the reactor throughput and turbidity. The immobilized tray photo-reactor is suitable for scale-up and commercialization due to five distinctive features which are: modular design; integrated storage; passive oxygenation; absence of need for UV transmitting components that are susceptible to breakage and optical losses, and simple and cheap components.
Author: M. Schiavello
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 218
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Book Description
Photocatalysis is a reaction which is accelerated by light while a heterogeneous reaction consists of two phases ( a solid and a liquid for example). Heterogeneous Photocatalysis is a fast developing science which to date has not been fully detailed in a monograph. This title discusses the basic principles of heterogeneous photocatalysis and describes the bulk and surface properties of semiconductors. Applications of various types of photoreactions are described and the problems related to the modeling and design of photoreactors are covered.
Author: Wibawa Hendra Saputera
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659414916
Category :
Languages : en
Pages : 92
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Book Description
Increased industrial activity has created an undesirable chemical pollution in air, water, and soil. Nowadays, around 1.2M tones and more than 10,000 different synthetic dyes and pigments are produced annually world-wide and used extensively in dye and printing industries. It is estimated that about 10-15% are lost in industrial effluents. Industrial waste water may additionally contain streams heavy loads of metals and organic compounds. The release of those colored waste water in the environment is a considerable source of non-aesthetic pollution, since the presence of small amount of dyes (below 1 ppm) is clearly visible. The challenges in treating wastewater are dependent on the origin of water and hence, the degradation of these dyes becomes crucial. Chemical oxidation of different dyes in wastewater is an effective method to remove it without further environmental problems. Photocatalysis is a rapidly developing field of research for a wide range of industrial applications, especially to degrade many kind of dyes. In this book, it will be explained a novel Titanium dioxide composite for photocatalytic waste water treatment.
Author: Hai Zibin
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Photocatalysis is recently extensively studied because it implies a variety of potential industrial applications ranging from the hydrogen generation of water splitting to the treatment of waste water. Among all the semiconductors, TiO2 has attracted the most attention. But the rate of the electron-hole recombinations is very important and TiO2 is active only under UV light. Various methods are developed to enhance the photoactivity of TiO2. Other semiconductors like copper oxides and copper sulfides also attracted attention due to their lower band-gaps which allow applications in solar photocatalysis. In this work, different kinds of photocatalysts were developed and studied: surface modified TiO2 with metal nanoparticles and copper sulfides and oxides. The nanostructures were characterized by different techniques: HRTEM, SEM, XRD, XPS, HAADF-SEM, and TRMC. Their photocatalytic activity was studied for degradation of model pollutants: phenol, rhodamine B and methyl orange. Different chemical and radiolytic methods have been investigated to modify the surface of TiO2 by mono- and bimetallic (Au, Cu and Au-Cu) nanoparticles in the aim to improve its photocatalytic activity. The best results in term of photocatalytic activity have been obtained with reduction of THPC (tetrakis (hydroxymethyl) phosphonium chloride) and with radiolytic reduction after deposition with urea. Titania surface modification with Au, Cu and bimetallic Au-Cu NPs enables the increase of the photocatalytic activity under UV light. We have found that very small amounts of metal (0.5% wt.) can activate titania for photocatalytic applications, thus the costs of photocatalyst preparation are relatively low. Radiolytic syntheses of non-TiO2 photocatalysts including Cu2O and CuS nanostructures with different morphologies have been developed. The photocatalytic activity of the synthesized photocatalysts has been studied. Truncated octahedral Cu2O exhibit an excellent photocatalytic activity under visible illumination. CuS nanotubes (NTs) exhibit both a high ability to adsorb dyes and a photocatalytic activity under visible light.
Author: Hesham Ali Fahmy Abdalla Hamad
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659544842
Category :
Languages : en
Pages : 332
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Book Description
Photocatalysis plays an important role in dealing with today's challenges demand for drinking water and waste water treatment technology. This work involves two directions to improve photocatalytic efficiency with economical benefits by different modification methods. One is the preparation of nanosphere and mesoporous titania nanoparticles. The other, a magnetic photocatalyst was prepared by coating of spinel cobalt ferrite as magnetic core with an insulating silica layer and photocatalytic properties of the outer titanium dioxide shell. Utilization of solar energy for the environmental cleanup becomes the future goal of the scientists. New visible light magnetic - titania photocatalysts that contain a small band gap semiconductor coupling open up new possibilities for the development of solar-induced, separation and recyclability photocatalytic materials.
Author: Maksym Zahornyi
Publisher: Cambridge Scholars Publishing
ISBN: 1527578992
Category : Science
Languages : en
Pages : 275
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Book Description
This book discusses recent advances in the photocatalytic and electrophotocatalytic applications of titanium dioxide nanocomposites containing polymers and other components. These materials possess photocatalytic, virucidal and antimicrobial efficacy and water and air cleaning abilities against eco-toxicants, and allow water splitting for the generation of chemical fuels. The book considers the ability of nanocomposites’ components to reinforce titania functionality in photocatalysis and photoelectrocatalysis, and presents an overview of their occurrence in nature, their thermodynamic properties, and their toxicity. The volume will be of interest to chemists and material science specialists and practitioners, as well as any reader interested in the recent scientific achievements for green and sustainable development.
Author: Aracely Hernández-Ramírez
Publisher: Springer
ISBN: 3319109995
Category : Science
Languages : en
Pages : 298
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Book Description
This critical volume examines the different methods used for the synthesis of a great number of photocatalysts, including TiO2, ZnO and other modified semiconductors, as well as characterization techniques used for determining the optical, structural and morphological properties of the semiconducting materials. Additionally, the authors discuss photoelectrochemical methods for determining the light activity of the photocatalytic semiconductors by means of measurement of properties such as band gap energy, flat band potential and kinetics of hole and electron transfer. Photocatalytic Semiconductors: Synthesis, Characterization and Environmental Applications provide an overview of the semiconductor materials from first- to third-generation photocatalysts and their applications in wastewater treatment and water disinfection. The book further presents economic and toxicological aspects in the production and application of photocatalytic materials.
Author: Dariya Dontsova
Publisher:
ISBN:
Category :
Languages : en
Pages : 204
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Book Description
The photocatalytic properties of commercially available and synthesized catalysts were studied for on-stream decomposition of a model odorous compound hydrogen sulphide (H2S) under UV-A and visible light irradiation. A simplified qualitative model for visualization of the catalyst deactivation is proposed. Further, catalysts were incorporated into multilayer films using different polyelectrolytes. Such films were characterized by ellipsometry, AFM, UV-visible spectroscopy and SEM on model surfaces. These films are homogeneous and transparent, and their porosity allow for almost free mass transport of the volatile compounds within the film. In order to test the photocatalytic activity of LbL films containing catalysts, such films were assembled on tubular glass reactors (with the diameter of 2.7 cm and the length of 40 cm) and subjected to H2S flow under UV-A irradiation. The activity of films was found to be proportional to the number of film constituent layers of catalyst and dependent on the chemical nature of the film constituent polyelectrolyte. After the film structure was optimized with respect to catalytic component and polyelectrolyte component, the most efficient films were deposited on cotton textiles, and their photocatalytic activity was measured for on-stream decomposition of H2S under visible light irradiation. Further, the potential applications of such LbL-coated textiles for the removal of other common indoor pollutants were exemplified by decomposition of acetaldehyde, methyl ethyl ketone and ammonia gas under visible light irradiation.
