Photocatalytic Oxidation of VOC, NOx and Atrazine Using TiO2 Modified with Perovskite Materials PDF Download
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Author: Kayzad Jimmy Vajifdar
Publisher:
ISBN:
Category : Atrazine
Languages : en
Pages : 186
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Author: Kayzad Jimmy Vajifdar
Publisher:
ISBN:
Category : Atrazine
Languages : en
Pages : 186
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Author: Zahra Shayegan
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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The indoor air quality (IAQ) concern has risen since people spend most of their time (>90%) in indoor environments. Volatile organic compounds (VOCs) are categorized as a major group of gas pollutants. Indoor VOCs, known as hazardous compounds with several proven adverse health effects. Among various purification techniques, a heterogeneous photocatalytic oxidation process (PCO) is a promising technology for removing indoor VOC contaminants. Titanium dioxide (TiO2) is the leading candidate for PCO given its unique properties. However, no TiO2-based photocatalysts completely satisfy all practical requirements, considering the photoexcited charge carriers' short lifetime and a wide band gap requiring ultraviolet (UV) radiation. Moreover, the application of PCO for VOCs degradation is greatly hindered at high humidity levels. Herein, TiO2 modification techniques that include approaches for overcoming the inherent TiO2 limitations and improving the photocatalytic degradation of VOCs are studied. In this research, strategies for improving TiO2 photocatalyst activities by doping with different metal and/or non-metal ions as well as surface modification have been examined. Accordingly, the adsorption capacity and photocatalytic activity of P25 and surface fluorinated P25 coated on nickel foam were evaluated for VOCs removal. In addition, the photoactivity of visible-light-driven photocatalysts including; anatase/rutile carbon-doped P25, anatase/brookite cerium-doped TiO2, and anatase/brookite iron-doped TiO2 coated on nickel foam were evaluated for degradation of VOCs under both UV and visible light irradiation. Surface fluorination was then applied to reduce the surface hydrophilicity of Ce-TiO2 and Fe-TiO2 photocatalysts with the optimum Ce and Fe contents. Notably, their photocatalytic performance was investigated in continuous flow mode-of-operation reactors with small residence time, different relative humidity levels, and low-level inlet contaminant concentration. These techniques can improve PCO performance through the following mechanisms: i) by introducing an electron capturing level in the band gap that would generate some defects in the TiO2 lattice and help capture charge carriers and can also be excited under visible irradiation; ii) by slowing down the charge carrier recombination rate and increasing VOCs degradation; and iii) by reducing the surface hydrophilicity, which increases VOCs' adsorption capacity at high humid conditions.
Author:
Publisher:
ISBN:
Category : Air
Languages : en
Pages : 36
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Eva Miriam Land
Publisher:
ISBN:
Category : Air
Languages : en
Pages :
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Experiments were conducted to determine the photocatalytic degradation of three types of gas-phase compounds, NOX, VOCs, and chloramines, by TiO2 impregnated tiles. The oxides of nitrogen NO and NO2 (NOx) have a variety of negative impacts on human and environmental health ranging from serving as key precursors for the respiratory irritant ozone, to forming nitric acid, which is a primary component of acid rain. A flow tube reactor was designed for the experiments that allowed the UV illumination of the tiles under exposure to both NO and NO2 concentrations in simulated ambient air. The reactor was also used to assess NOx degradation for sampled ambient air. The PV values for NO and NO2 were 0.016 cm s-1 and 0.0015 cm s-1, respectively. For ambient experiments a decrease in ambient NOx of ~ 40% was observed over a period of roughly 5 days. The mean PV for NOx for ambient air was 0.016 cm s-1 and the maximum PV was .038 cm s-1. Overall, the results indicate that laboratory conditions generally simulate the efficiency of removing NOx by TiO2 impregnated tiles. Volatile organic compounds (VOC's) are formed in a variety of indoor environments, and can lead to respiratory problems (US EPA, 2010). The experiments determined the photocatalytic degradation of formaldehyde and methanol, two common VOCs, by TiO2 impregnated tiles. The same flow tube reactor used for the previous NOX experiments was used to test a standardized gas-phase concentration of formaldehyde and methanol. The extended UV illumination of the tiles resulted in a 50 % reduction in formaldehyde, and a 68% reduction in methanol. The deposition velocities (or the photocatalytic velocities, PV) were estimated for both VOC's. The PV for formaldehyde was 0.021 cm s-1, and the PV for methanol was 0.026 cm s-1. These PV values are slightly higher than the mean value determined for NO from the previous experiments which was 0.016 cm s-1. The results suggest that the TiO2 tiles could effectively reduce specific VOC levels in indoor environments. Chlorination is a widespread form of water disinfection. However, chlorine can produce unwanted disinfection byproducts when chlorine reacts with nitrogen containing compounds or other organics. The reaction of chlorine with ammonia produces one of three chloramines, (mono-, di-, and tri-chloramine). The production of chloramines compounds in indoor areas increases the likelihood of asthma in pool professionals, competitive swimmers, and children that frequently bath in indoor chlorinated swimming pools (Jacobs, 2007; Nemery, 2002; Zwiener, 2007). A modified flow tube reactor in conjunction with a standardized solution of monochloramine, NH2Cl, determined the photocatalytic reactions over the TiO2 tiles and seven concrete samples. The concrete samples included five different concrete types, and contained either 5 % or 15 % TiO2 by weight. The PV for the tiles was 0.045 cm s-1 for the tiles manufactured by TOTO Inc. The highest PV from the concrete samples was 0.054 cm s-1. Overall the commercial tiles were most efficient at reducing NH2Cl, compared to NOX and VOC compounds. However, the concrete samples had an even higher PV for NH2Cl than the tiles. The reason for this is unknown; however, distinct surface characteristics and a higher concentration of TiO2 in the concrete may have contributed to these findings.
Author: Juan M. Coronado
Publisher: Springer Science & Business Media
ISBN: 1447150619
Category : Technology & Engineering
Languages : en
Pages : 352
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Book Description
Research for the development of more efficient photocatalysts has experienced an almost exponential growth since its popularization in early 1970’s. Despite the advantages of the widely used TiO2, the yield of the conversion of sun power into chemical energy that can be achieved with this material is limited prompting the research and development of a number of structural, morphological and chemical modifications of TiO2 , as well as a number of novel photocatalysts with very different composition. Design of Advanced Photocatalytic Materials for Energy and Environmental Applications provides a systematic account of the current understanding of the relationships between the physicochemical properties of the catalysts and photoactivity. The already long list of photocatalysts phases and their modifications is increasing day by day. By approaching this field from a material sciences angle, an integrated view allows readers to consider the diversity of photocatalysts globally and in connection with other technologies. Design of Advanced Photocatalytic Materials for Energy and Environmental Applications provides a valuable road-map, outlining the common principles lying behind the diversity of materials, but also delimiting the imprecise border between the contrasted results and the most speculative studies. This broad approach makes it ideal for specialist but also for engineers, researchers and students in related fields.
Author: Juan Carlos Colmenares
Publisher: Springer
ISBN: 3662487195
Category : Science
Languages : en
Pages : 419
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Book Description
The book explains the principles and fundamentals of photocatalysis and highlights the current developments and future potential of the green-chemistry-oriented applications of various inorganic, organic, and hybrid photocatalysts. The book consists of eleven chapters, including the principles and fundamentals of heterogeneous photocatalysis; the mechanisms and dynamics of surface photocatalysis; research on TiO2-based composites with unique nanostructures; the latest developments and advances in exploiting photocatalyst alternatives to TiO2; and photocatalytic materials for applications other than the traditional degradation of pollutants, such as carbon dioxide reduction, water oxidation, a complete spectrum of selective organic transformations and water splitting by photocatalytic reduction. In addition, heterogeneized polyoxometalate materials for photocatalytic purposes and the proper design of photocatalytic reactors and modeling of light are also discussed. This book appeals to a wide readership of the academic and industrial researchers and it can also be used in the classroom for undergraduate and graduate students focusing on heterogeneous photocatalysis, sustainable chemistry, energy conversion and storage, nanotechnology, chemical engineering, environmental protection, optoelectronics, sensors, and surface and interface science. Juan Carlos Colmenares is a Professor at the Institute of Physical Chemistry, Polish Academy of Sciences, Poland. Yi-Jun Xu is a Professor at the State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, China.
Author: M. Aldissi
Publisher: Springer Science & Business Media
ISBN: 9401719527
Category : Technology & Engineering
Languages : en
Pages : 233
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Book Description
This book contains the majority of the papers presented at the NATO Ad vanced Research Workshop (ARW) held in Burlington, Vermont, USA on October 12-15, 1992. This ARW was the first of its kind to address the subject of intrinsically conducting polymers with an emphasis on processing and technological applications. The NATO ARW format was followed in that the subjects addressed here were limited in number but discussed in detail with the attendance being limited to a small number of selected scientists. The ARW brought together lecturers who are leaders in their respective fields from a wide range of NATO and non-NATO countries (a total of 11 countries) with the support of the NATO Scientific Affairs Division and some support from Champlain Cable Corporation. The total number of par ticipants was 33 and the number of presentations was 24. The speakers were chosen based on the topics selected for this workshop and repre sented industry, universities and government laboratories. The field of conducting polymers has grown rapidly during the past few years with important developments in materials processing and fabrica tion that brought about active research programs focusing on the use of these polymers as "smart" materials in technological applications and devices in academic and industrial research laboratories.
Author: Angelo Basile
Publisher: John Wiley & Sons
ISBN: 0470977574
Category : Science
Languages : en
Pages : 661
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Book Description
A membrane reactor is a device for simultaneously performing a reaction and a membrane-based separation in the same physical device. Therefore, the membrane not only plays the role of a separator, but also takes place in the reaction itself. This text covers, in detail, the preparation and characterisation of all types of membranes used in membranes reactors. Each membrane synthesis process used by membranologists is explained by well known scientists in their specific research field. The book opens with an exhaustive review and introduction to membrane reactors, introducing the recent advances in this field. The following chapters concern the preparation of both organic and inorganic, and in both cases, a deep analysis of all the techniques used to prepare membrane are presented and discussed. A brief historical introduction for each technique is also included, followed by a complete description of the technique as well as the main results presented in the international specialized literature. In order to give to the reader a summary look to the overall work, a conclusive chapter is included for collecting all the information presented in the previous chapters. Key features: Fills a gap in the market for a scientific book describing the preparation and characterization of all the kind of membranes used in membrane reactors Discusses an important topic - there is increasing emphasis on membranes in general, due to their use as energy efficient separation tools and the ‘green’ chemistry opportunities they offer Includes a review about membrane reactors, several chapters concerning the preparation organic, inorganic, dense, porous, and composite membranes and a conclusion with a comparison among the different membrane preparation techniques
Author: Seema Garg
Publisher: Springer Nature
ISBN: 303077371X
Category : Science
Languages : en
Pages : 855
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Book Description
This book comprises a detailed overview on the role of photocatalysts for environmental remediation, hydrogen production and carbon dioxide reduction. Effective ways to enhance the photocatalytic activity of the material via doping, hybrid material, laser light and nanocomposites have been discussed in this book. The book also further elaborates the role of metal nanoparticles, rare earth doping, sensitizers, surface oxygen vacancy, interface engineering and band gap engineering for enhancing the photocatalytic activity. An approach to recover the photocatalytic material via immobilization is also presented. This book brings to light much of the recent research in the development of such semiconductor photocatalytic systems. The book will thus be of relevance to researchers in the field of: material science, environmental science & technology, photocatalytic applications, newer methods of energy generation & conversion and industrial applications.
