Photocatalytic Degradation of Phenol Solution in the Presence of Au/TiO2 Catalyst Under the Irradiation of UV and Visible Light PDF Download
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Author: 沈運祥
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: 沈運祥
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Seema Garg
Publisher: Springer Nature
ISBN: 3031277074
Category : Science
Languages : en
Pages : 483
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This book explores the modification of various synthesis processes to enhance the photocatalytic activity in varied applications in the fields of environmental remediation and energy production. It outlines the enhancement of photocatalytic activity via alloys synthesis, thin film coatings, electro-spun nanofibers and 3D printed photocatalysts. The book further states the diverse applications of materials for degrading organic pollutants and airborne pathogens, improving indoor air quality and as a potential antimicrobial agent. The application of photocatalysts in green organic synthesis, biomedical field and in hydrogen evolution are also presented in the book. It covers theoretical studies of photocatalytic material and conversion of CO2 to value added chemical feed stocks. The book is of relevance to researchers in academia and industry alike in the fields of material science, environmental science & technology, photocatalytic applications and in energy generation and conversion.
Author: Lindelwa Jay
Publisher:
ISBN:
Category : Water
Languages : en
Pages : 0
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The United States Environmental Protection Agency (USEPA) has enlisted phenolic compounds as pollutants of priority concern, as they tend to persist in the environment over a long period, accumulate and exert toxic effects on humans and animals. The entrance of phenolic compounds into the aquatic environment results from natural, industrial, domestic and agricultural activities. Their presence may be due to the degradation or decomposition of natural organic matter present in the water, through the disposal of industrial and domestic wastes into water bodies and through runoffs from agricultural land. Several specific new technologies, called Advanced Oxidation Processes (AOP), have been developed to eliminate dangerous organic chemicals such as phenol from polluted waters. The photocatalytic process, based on UV irradiated semiconductor (TiO2), represents one of AOP that provide an interesting route to the destruction of many organic substances to CO2, H2O and corresponding mineral acids. TiO2 is usually used as a photocatalyst in two crystal structures: Rutile and Anatase. The photoreactivity of P-25 Degussa, consisting of anatase and rutile (4/1 w/w), exceeds that of pure anatase and rutile in several reaction systems. This study characterised the three TiO2 powder forms by BET, XRD, XRF and SEM analyses to contribute to a better understanding of their physical properties. Anatase was revealed to have 98.4% purity x-ray fluorescence analysis, Degussa at 96.7% and rutile at 75.7% was reported to have the most impurities (~25%). This study investigated the UV/TiO2 photocatalytic degradation of phenol, with emphasis on the effects of; solution pH, catalyst load, initial phenol concentration, dissolved oxygen and UV radiation intensity. Degradation studies were conducted in a batch reactor with photons for catalyst (TiO2) activation supplied by a medium pressure 400 W UV lamp immersed in the pollutant solution housed in a double jacket quartz sleeve, which served as the cooling system for the lamp. Temperature control in the reactor was achieved by circulating cold water through the outer cavity of the quartz sleeve. The reactor contents in all batches were aerated at a flow rate of 10 mL/min. Thorough mixing of the contents of the reactor was achieved by continuous agitation with a magnetic stirrer. The experimental reaction time was set at 60-100minutes. Samples were monitored by GC-MS analysis. Results showed that UV/TiO2 photocatalysis is an effective method for the removal of phenol from wastewaters. The efficiency of the process depends strongly on the experimental conditions. Degradation of organic compounds in water is often accompanied by the formation of several intermediate compounds, some of which may be more toxic than the original pollutant. The carbon-13 isotopic labelling technique was employed to track the degradation mechanism of phenol to better understand the degradation pathway. Carbon-13 tracking results revealed that hydroquinone, catechol, benzoquinone, resorcinol and maleic acid were the main intermediates containing the C-13 isotope. A reaction pathway was postulated based on these findings. Kinetic isotope effect (KIE) experiments were conducted and a primary isotope effect was observed. This confirmed that the C-13 isotope position on the labelled phenol was the site of bond breaking in the rate-limiting step.
Author: Zhen Ma
Publisher: Royal Society of Chemistry
ISBN: 1782621644
Category : Science
Languages : en
Pages : 635
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Once considered an inert element, gold has recently gained attention as a catalyst. With hundreds of papers being published each year, this book presents a comprehensive review of this rapidly-evolving field, with contributions by leading experts across the globe. Going through the chapters citing the primary literature, the reader will gain a thorough background to the use of gold in catalysis, as well as the latest methods for the preparation of gold catalysts. Other chapters demonstrate the characterisation and modelling of gold-catalysed reactions, with consideration given to both the fundamentals and commercial applications of this emerging group of catalysts. Written to be accessible by postgraduates and newcomers to the field, this book will also benefit experienced researchers and therefore be an essential reference in the laboratory.
Author: Adolfo Iulianelli
Publisher: MDPI
ISBN: 303921022X
Category : Science
Languages : en
Pages : 154
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Book Description
This Special Issue is aimed at highlighting the potentialities of membrane and membrane reactor operations in various sectors of chemical engineering, based on application of the process intensification strategy. In all of the contributions, the principles of process intensification were pursued during the adoption of membrane technology, demonstrating how it may lead to the development of redesigned processes that are more compact and efficient while also being more environmental friendly, energy saving, and amenable to integration with other green processes. This Special Issue comprises a number of experimental and theoretical studies dealing with the application of membrane and membrane reactor technology in various scientific fields of chemical engineering, such as membrane distillation for wastewater treatment, hydrogen production from reforming reactions via inorganic membrane and membrane photoassisted reactors, membrane desalination, gas/liquid phase membrane separation of CO2, and membrane filtration for the recovery of antioxidants from agricultural byproducts, contributing to valorization of the potentialities of membrane operations.
Author: Marcos Soto-Hernández
Publisher: BoD – Books on Demand
ISBN: 9535129570
Category : Science
Languages : en
Pages : 458
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Book Description
Phenolic compounds as a large class of metabolites found in plants have attracted attention since long time ago due to their properties and the hope that they will show beneficial health effects when taken as dietary supplements. This book presents the state of the art of some of the natural sources of phenolic compounds, for example, medicinal plants, grapes or blue maize, as well as the modern methods of extraction, quantification, and identification, and there is a special section discussing the treatment, removal, and degradation of phenols, an important issue in those phenols derived from the pharmaceutical or petrochemical industries.
Author: Barbara Bonelli
Publisher: MDPI
ISBN: 3039282867
Category : Science
Languages : en
Pages : 98
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Book Description
The quality of water is not only a technological and scientific issue, but a social and economic problem, in both developed and developing countries. Besides local regulations, which differ between regions and need constant upgrades, significant scientific developments are required in both the detection and removal of water contaminants. This Issue focuses on some recent advancements in the photocatalytic removal of organic pollutants, which is one of the aspects of the problem that involves the need of advanced catalysts and implies significant advancements in the field of materials science and chemical engineering.
Author: Jesus Moreira del Rio
Publisher:
ISBN:
Category :
Languages : en
Pages : 434
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Abstract Scaling up a photoreactor requires both knowledge of optical properties of the slurry medium and an established kinetic model. Measuring the scattering and absorption coefficients of particles suspended in water involves the use of specialized optical equipment, as well as the partial solution of the radiative transfer equation (RTE). In addition, modeling of the radiation field in photoreactors with complicated geometries offers special challenges. On the other hand, most of the kinetic models (KM) for phenol photodegradation reported in the literature were obtained for a single organic chemical species only. In fact, neglecting all the intermediate species generated during the photoreaction, is a common oversimplification that limits the KM application. As a result, once the radiation and kinetic models fully established, energy efficiencies can be obtained. In this PhD dissertation, the photocatalytic degradation of phenol over four different TiO2 catalysts is studied. It is proven that phenol yields hydroquinone, catechol, benzoquinone, and acetic and formic acids as main intermediate species. The radiation field inside photocatalytic reactors is predicted by solving the RTE. From the solution of the RTE, the local volumetric rate of energy absorption (LVREA) is also calculated. The radiation field inside an annular photoreactor is simulated using the Monte Carlo (MC) method for different TiO2 suspensions in water. All simulations are performed by using both the spectral distribution, and the wavelength-averaged scattering and absorption coefficients. The Henyey-Greenstein phase function is adopted to represent forward, isotropic and backward scattering modes. It is assumed that the UV lamp reflects the back-scattered photons by the slurried medium. It is proven, photo-absorption rates, using MC simulations and spectral distribution of the optical coefficients, agree closely with experimental observations from a macroscopic balance (MB). It is also found that the scattering mode of the probability density function, is not a critical factor for a consistent representation of the radiation field. iv When solving the RTE, two optical parameters are needed: (1) the absorption and scattering coefficients, and (2) the phase function. In this research work, the MC method, along with an optimization technique, is shown to be effective in predicting the wavelength-averaged absorption and scattering coefficients for different TiO2 powders. To accomplish this, the LVREA and the transmitted radiation (Pt) in the photoreactor are determined by using a MB. The optimized coefficients are calculated ensuring that they comply with a number of physical constrains, falling in between bounds established via independent criteria. The optimization technique is demonstrated by finding the absorption and scattering coefficients for different semiconductors that best fit the experimental values from the MB. The objective function in this optimization is given by the least-squared error for the LVREA. A photocatalyst is synthesized and its optical properties determined by the proposed method. This approach is a general and promising one; not being restricted to reactors of concentric geometry, specific semiconductors and/or particular photocatalytic reactor unit scale. Based on the proposed intermediate reactions, a phenomenological based unified kinetic model is proposed for describing the obtained experimental observations in phenol photodegradation. This Langmuir-Hinshelwood (L-H) kinetic model is based on a Series- Parallel reaction network. This reaction model is found to be applicable to the various TiO2 photocatalyst in the present study. This unified kinetic network is based on the identified and quantified chemical species in the photoconversion of phenol and its intermediates. In order to minimize the number of optimized parameters, the adsorption constants of the different intermediate species on the different catalysts configuration, are obtained experimentally. It is shown that the unified kinetic model requires a number of significant assumptions to be effective; avoiding overparametization. As a result, the unified kinetic model is adapted for each specific TiO2 photocatalyst under study. These different models adequately describe the experimental results. It is shown that this approach results in good and objective parameter estimates in the L-H kinetic model, which is typically applied to photocatalytic reactors. Finally, two efficiency factors, the quantum yield and the photochemical and thermodynamic efficiency factor, are obtained, in this PhD dissertation. These factors are based on the kinetic model proposed and the radiation being absorbed by the photocatalyst particles. The v efficiency calculations consider stoichiometric relationships involving observable chemical species and OH- groups. The obtained efficiency factors point toward a high degree of photon utilization and, as a result, the value of photocatalysis and Photo-CREC-Water reactors for the conversion of organic pollutants in water is confirmed.
Author: Sunita Varjani
Publisher: Elsevier
ISBN: 0128195940
Category : Technology & Engineering
Languages : en
Pages : 588
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Current Developments in Biotechnology and Bioengineering: Emerging Organic Micropollutants summarizes the current knowledge of emerging organic micropollutants in wastewater and the possibilities of their removal/elimination. This book attempts a thorough and exhaustive discussion on ongoing research and future perspectives on advanced treatment methods and future directions to maintain and protect the environment through microbiological, nanotechnological, application of membrane technology, molecular biological and by policymaking means. In addition, the book includes the latest developments in biotechnology and bioengineering pertaining to various aspects in the field of emerging organic micropollutants, including their sources, health effects and environmental impacts. Includes testing methods for the analysis and characterization of emerging organic micropollutants in wastewater Discusses the environmental impact and health hazards of emerging organic micropollutants in wastewater Provides a useful guide to identify priority areas of research demand in the remediation/removal of emerging organic micropollutants
Author: Zerong Wang
Publisher: John Wiley & Sons
ISBN: 1118470451
Category : Science
Languages : en
Pages : 4542
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Book Description
Winner of 2018 PROSE Award for MULTIVOLUME REFERENCE/SCIENCE This encyclopedia offers a comprehensive and easy reference to physical organic chemistry (POC) methodology and techniques. It puts POC, a classical and fundamental discipline of chemistry, into the context of modern and dynamic fields like biochemical processes, materials science, and molecular electronics. Covers basic terms and theories into organic reactions and mechanisms, molecular designs and syntheses, tools and experimental techniques, and applications and future directions Includes coverage of green chemistry and polymerization reactions Reviews different strategies for molecular design and synthesis of functional molecules Discusses computational methods, software packages, and more than 34 kinds of spectroscopies and techniques for studying structures and mechanisms Explores applications in areas from biology to materials science The Encyclopedia of Physical Organic Chemistry has won the 2018 PROSE Award for MULTIVOLUME REFERENCE/SCIENCE. The PROSE Awards recognize the best books, journals and digital content produced by professional and scholarly publishers. Submissions are reviewed by a panel of 18 judges that includes editors, academics, publishers and research librarians who evaluate each work for its contribution to professional and scholarly publishing. You can find out more at: proseawards.com Also available as an online edition for your library, for more details visit Wiley Online Library
