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Author: On Ting Woo
Publisher:
ISBN:
Category : Photocatalysis
Languages : en
Pages : 256
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Book Description
Author: On Ting Woo
Publisher:
ISBN:
Category : Photocatalysis
Languages : en
Pages : 256
Get Book Here
Book Description
Author: Ho-yin Yip
Publisher:
ISBN:
Category : Oxidation
Languages : en
Pages : 406
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Book Description
Author: Bo Liu
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The growing amount and environmental impact of offshore oily wastewater especially offshore produced water (OPW) have drawn significant attention in recent years. The petroleum hydrocarbons in wastewater can have severe negative effects in a long term on coastal and marine ecosystems if without sufficient treatment before discharge. Polycyclic aromatic hydrocarbons (PAHs) as a representative of dissolved chemical compounds or environmental pollutants in oily wastewater have been a major issue of marine environments due to their carcinogenic or mutagenic, toxic, persistent and bio-accumulative properties. To reduce the negative impact of produced water to the marine ecosystem, it is required to remove all toxicants especially PAHs before discharge. Various challenges have been identified in implementing conventional technologies (e.g., physical separation, chemical oxidation and biological remediation) for treating the dissolved organic pollutants (e.g., PAHs). Therefore, the research and development of more effective technologies to address these concerns are much desired. Photocatalysis generates powerful oxidative radicals which can rapidly mineralize organics especially aromatic compounds, offering a great potential use in removing PAHs from oily wastewater. However, the photocatalytic degradation of organics can be dramatically inhibited by the complex matrix of OPW. Limited in-depth studies were reported on the behaviors and interactions of different components in produced water during photocatalysis. The mechanisms of the interferences are of utmost importance to the development of highly efficiency treatment technologies. The generation of intermediates caused by the complex matrix and inhibited treatment process could further lead to the increase in the toxicity of treated effluent to the marine ecosystem, and consequently reduce its potential in natural attenuation. In addressing these challenges and fulfill the knowledge gaps, this research is focused on the evaluation of the key factors and the mechanisms of OPW matrix in photocatalysis, and the development of enhanced photocatalytic oxidation processes to aid the OPW treatment, thus can achieve both high efficiency in removal of PAHs, and low toxicity and high biodegradability of the effluent. The matrix effect was first investigated in a suspensive photocatalytic oxidation system, in which the synthesized TiO2 nanoparticles were used. It is indicated that the degradation of PAHs was inhibited by the impurities in OPW matrix in many ways: the alkaline-earth cations caused the flocculation of the particle; the insoluble particulate matters competed with PAHs in the adsorption on TiO2; the competition and the fouling effect of other dissolved organic matters were deteriorating the process. To enhance the treatment process, immobilized TiO2 was used instead and it was compared with the TiO2 nano-particles. Improvements were found in both naphthalene adsorption and degradation in the immobilized photocatalytic oxidation system, indicating immobilized TiO2 was more efficient and durable than TiO2 nanoparticles in oily wastewater treatment. The competition of hydrocarbons especially phenols played a key role in the degradation of PAHs. The fouling on the catalyst surface was verified by the scaling of alkaline-earth metals and the deposition of organic matters. Further improvement was aimed at developing a novel UV-light-emitted diode (UV-LED)/TiO2 nanotube array (TNA)/ozonation process for treating OPW. The involvement of ozone was to reduce the competition of other organics and enhance the degradation efficiency. The TNA with hollow 1-D tubular nano-structures was applied because of the combined advantage of nano-particle and immobilization, as well as high quantum yield. UV-LED has the advantage of high energy efficiency and long-life time. In the integrated system, the removal of PAHs can be achieved within 30-min treatment with the half-lives reduced to less than 10 mins. Factorial analysis demonstrates that the best dose of TNA is 0.2 g/L. Light intensity affects the generation of iodine radicals, which is a strong scavenger of ozone thus reduces the efficiency of PAHs removal. Ozone dose is a dominated factor that promotes the degradation. Further results indicate that the degradation of phenols and PAHs with higher solubility favors to undergo to ozone-inducted oxidation, while PAHs with lower solubility are more likely oxidized on the catalyst surface. The toxicity and biodegradability of OPW treated by photocatalytic oxidation were investigated during and after the treatment. Studies on the intermediates formed during the photocatalytic ozonation treatment in the presence of halogen ions reveal the mechanism and various reaction pathways of aromatic compounds. Iodization and bromination were the dominant interfering reactions in sequential stages. Two multivariable regression models were developed to quantify the contributions of key toxicants (e.g., total PAHs, total phenols, dibromo-pentane and bromoform) to the acute toxicity of OPW during the treatment processes. It was observed that by removing the total PAHs and total phenols, the acute toxicity was increased from 3% to 57%, and the biodegradability (BOD28/COD ratio) was doubled more than 80% by the integrated UV-LED/TNA/ozonation process. Further, the biodegradation rate of bromoform was much faster than those of phenols, indicating that the proposed technology features high efficiency and has low impact on marine environment. In this research, I have investigated the matrix effect of OPW on photocatalysis and the impacts to the suspended and immobilized TiO2. A novel integrated UV-LED/TNA/ozonation process was developed to treat OPW. The efficiency of the process, the effects of operational parameters, the intermediates and degradation pathways, and their contribution to the acute toxicity and biodegradability of treated effluent were investigated. The scientific contributions of the research are: 1) revealing and summarizing the key mechanisms of OPW matrix and their key effects on photocatalysis, 2) understanding the interactions of OPW composition with catalyst surface, 3) fulfilling the knowledge gaps on the removal of PAHs from OPW by the UV-A (365 nm) photocatalytic ozonation process, including the interactive mechanisms of the adsorption and photocatalytic oxidation, the behaviors of halogenic ions, and the effects of the operational factors, 4) proposing the altered photodegradation pathways of aromatic organic matter in the presence of halogen ions, and 5) proposing toxicity contribution models targeted on the most toxic compounds in OPW with/without photocatalytic ozonation. The findings of this thesis work also help 1) develop a better strategy to countermeasure the difficulties in the application of photocatalytic oxidation for treating OPW, 2) develop an advanced alternative option for the OPW management, and 3) monitor the composition and toxicity changes during the process and hence the production of by-products in the OPW treatment practice.
Author: Suresh C. Pillai
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110668483
Category : Science
Languages : en
Pages : 396
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Book Description
This book is a concise and up-to-date introduction to the topic of photocatalysis. It covers the fundamentals of photocatalysis, design of photoreactors and modelling and simulations for photoreaction. Also, industrial applications such as hydrogen production, water disinfection, degradation of air pollutants, pesticides and pharmaceuticals are described.
Author: Dionysios D Dionysiou
Publisher: Royal Society of Chemistry
ISBN: 1782627103
Category : Science
Languages : en
Pages : 395
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Book Description
From environmental remediation to alternative fuels, this book explores the numerous important applications of photocatalysis. The book covers topics such as the photocatalytic processes in the treatment of water and air; the fundamentals of solar photocatalysis; the challenges involved in developing self-cleaning photocatalytic materials; photocatalytic hydrogen generation; photocatalysts in the synthesis of chemicals; and photocatalysis in food packaging and biomedical and medical applications. The book also critically discusses concepts for the future of photocatalysis, providing a fascinating insight for researchers. Together with Photocatalysis: Fundamentals and Perspectives, these volumes provide a complete overview to photocatalysis.
Author: Ulick Stafford
Publisher:
ISBN:
Category :
Languages : en
Pages : 438
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Book Description
Author: Emma B. Davis
Publisher: Nova Publishers
ISBN: 9781600210167
Category : Science
Languages : en
Pages : 174
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Book Description
The environment is considered the surroundings in which an organism operates, including air, water, land, natural resources, flora, fauna, humans and their interrelation. It is this environment which is both so valuable, on the one hand, and so endangered on the other. And it is people which are by and large ruining the environment both for themselves and for all other organisms. This book reviews the latest research in this field which is vital for everyone.
Author: Aziz, Hamidi Abdul
Publisher: IGI Global
ISBN: 1522557679
Category : Technology & Engineering
Languages : en
Pages : 519
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Book Description
Population growth and industrial development have increased the amount of wastewater generated by urban areas, and one of the major problems facing industrialized nations is the contamination of the environment by hazardous chemicals. Therefore, to meet the standards, suitable treatment alternatives should be established. Advanced Oxidation Processes (AOPs) in Water and Wastewater Treatment is a pivotal reference source that provides vital research on the current, green, and advanced technologies for wastewater treatment. While highlighting topics such as groundwater treatment, environmental legislation, and oxidation processes, this publication explores the contamination of environments by hazardous chemicals as well as the methods of decontamination and the reduction of negative effects on the environment. This book is a vital reference source for environmental engineers, waste authorities, solid waste management companies, landfill operators, legislators, environmentalists, and academicians seeking current research on achieving sustainable management for wastewater treatment.
Author: R. Dennis Cook
Publisher: John Wiley & Sons
ISBN: 0470317787
Category : Mathematics
Languages : en
Pages : 632
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Book Description
A step-by-step guide to computing and graphics in regression analysis In this unique book, leading statisticians Dennis Cook and Sanford Weisberg expertly blend regression fundamentals and cutting-edge graphical techniques. They combine and up- date most of the material from their widely used earlier work, An Introduction to Regression Graphics, and Weisberg's Applied Linear Regression; incorporate the latest in statistical graphics, computing, and regression models; and wind up with a modern, fully integrated approach to one of the most important tools of data analysis. In 23 concise, easy-to-digest chapters, the authors present:? A wealth of simple 2D and 3D graphical techniques, helping visualize results through graphs * An improved version of the user-friendly Arc software, which lets readers promptly implement new ideas * Complete coverage of regression models, including logistic regression and generalized linear models * More than 300 figures, easily reproducible on the computer * Numerous examples and problems based on real data * A companion Web site featuring free software and advice, available at www.wiley.com/mathem atics Accessible, self-contained, and fully referenced, Applied Regression Including Computing and Graphics assumes only a first course in basic statistical methods and provides a bona fide user manual for the Arc software. It is an invaluable resource for anyone interested in learning how to analyze regression problems with confidence and depth.
Author: Elvis Fosso-Kankeu
Publisher: John Wiley & Sons
ISBN: 1119631416
Category : Science
Languages : en
Pages : 320
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Book Description
Photocatalysts in Advanced Oxidation Processes for Wastewater Treatment comprehensively covers a range of topics aiming to promote the implementation of photocatalysis at large scale through provision of facile and green methods for catalysts synthesis and elucidation of pollutants degradation mechanisms. This book is divided into two main parts namely “Synthesis of effective photocatalysts” (Part I) and “Mechanisms of the photocatalytic degradation of various pollutants” (Part II). The first part focuses on the exploration of various strategies to synthesize sustainable and effective photocatalysts. The second part of the book provides an insights into the photocatalytic degradation mechanisms and pathways under ultraviolet and visible light irradiation, as well as the challenges faced by this technology and its future prospects.
