Author: Michael Sell
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 64
Book Description
Catalytic Nitrate Reduction in Drinking Water, Results and Findings from Industrial Pilot Tests
Author: Michael Sell
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 64
Book Description
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 64
Book Description
Catalytic Nitrate Reduction in Drinking Water Using a Trickle Bed Reactor
Author: Madison Bertoch
Publisher:
ISBN:
Category :
Languages : en
Pages : 80
Book Description
Palladium-based bimetallic catalysts hold promise as an alternative water treatment technology for nitrate (NO3-), but practical application requires development of a flow-through reactor that efficiently delivers hydrogen (H2) from the gas phase into water, where it serves as the electron donor for NO3- reduction. In this work, a trickle bed reactor (TBR) was fabricated and evaluated to address this challenge. A series of batch experiments with Pd-In/[greek small letter gamma]-Al2O3 catalysts were conducted in excess H2 to identify a highly active catalyst for the TBR. A 0.1wt%Pd-0.01wt%In on 1 mm [greek small letter gamma]-Al2O3 catalyst was selected due to its high activity and support size that promotes a uniform liquid distribution in a packed bed. The TBR was packed with the same catalyst, and various liquid and gas flow rates were tested to evaluate apparent catalyst activity. Influent and effluent NO3- concentrations were used to calculate apparent zero-order rate constants, and they generally increased with H2 flow rate. Above 900 mL/min, a change in flow regime from pulse to bubble flow was observed, and the calculated zero-order rate constants decreased. An optimal catalyst activity in the TBR of 19.5 mg NO3-/min[bullet=black small circle]g Pd was obtained at a liquid flow rate of 900 mL/min and H2 flow rate of 320 sccm, which is ~22% of the activity obtained in the batch reactor by the same catalyst, indicating H2 mass transfer limitations. A reactive transport model was developed and used to quantify H2 mass transfer rate coefficients from the liquid to gas phase. Mass transfer coefficients initially decrease and then stabilize as the H2 flow rate increases. At elevated H2 flow rates, the highest mass transfer coefficients were obtained at the 900 mL/min liquid flow rate, in agreement with activity trends. Evaluation of a larger range of liquid and gas flow rates is warranted to determine if H2 mass transfer in the TBR can be further enhanced.
Publisher:
ISBN:
Category :
Languages : en
Pages : 80
Book Description
Palladium-based bimetallic catalysts hold promise as an alternative water treatment technology for nitrate (NO3-), but practical application requires development of a flow-through reactor that efficiently delivers hydrogen (H2) from the gas phase into water, where it serves as the electron donor for NO3- reduction. In this work, a trickle bed reactor (TBR) was fabricated and evaluated to address this challenge. A series of batch experiments with Pd-In/[greek small letter gamma]-Al2O3 catalysts were conducted in excess H2 to identify a highly active catalyst for the TBR. A 0.1wt%Pd-0.01wt%In on 1 mm [greek small letter gamma]-Al2O3 catalyst was selected due to its high activity and support size that promotes a uniform liquid distribution in a packed bed. The TBR was packed with the same catalyst, and various liquid and gas flow rates were tested to evaluate apparent catalyst activity. Influent and effluent NO3- concentrations were used to calculate apparent zero-order rate constants, and they generally increased with H2 flow rate. Above 900 mL/min, a change in flow regime from pulse to bubble flow was observed, and the calculated zero-order rate constants decreased. An optimal catalyst activity in the TBR of 19.5 mg NO3-/min[bullet=black small circle]g Pd was obtained at a liquid flow rate of 900 mL/min and H2 flow rate of 320 sccm, which is ~22% of the activity obtained in the batch reactor by the same catalyst, indicating H2 mass transfer limitations. A reactive transport model was developed and used to quantify H2 mass transfer rate coefficients from the liquid to gas phase. Mass transfer coefficients initially decrease and then stabilize as the H2 flow rate increases. At elevated H2 flow rates, the highest mass transfer coefficients were obtained at the 900 mL/min liquid flow rate, in agreement with activity trends. Evaluation of a larger range of liquid and gas flow rates is warranted to determine if H2 mass transfer in the TBR can be further enhanced.
Catalytic Nitrate Reduction in Water
Author: Priyanka Gheek
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
We chose to study the catalytic conversion of dissolved nitrate, which are a major cause of water contamination. It is a complex process into several steps following the reaction: NO3- → NO2-→ [NO] → N2 + NH4+ + + OH- The scientific goal of this thesis was to determine a relationship between the physico-chemical structure of catalysts and their activity and selectivity in the reduction of nitrates. The reaction kinetics were also studied in relation to the structure of catalysts. The work focused around the following points: 1. Preparation of catalyst supports: Two main groups of materials were studied: carbon materials and inorganic materials that have been modified by acid or base treatment or by deposit oxides (Al2O3, ZrO2 alone or in mixture). 2. Synthesis of catalyst: oxides of noble and transition metals have been established on the supports. Systems with monometallic Pt and Pd and bimetallic Pd-Cu have been studied and characterized by many techniques. The effectiveness of these materials was determined depending on their catalytic activity. 3. Determination of the catalytic properties: The role and effect of parameters such as support, type of medium, active phase composition, the presence of inorganic salts in the reaction medium, nature of reducing on the rate of nitrate reduction and selectivity of the reactions were widely studied. The debate highlights the combination support / most effective catalyst for denitrification of drinking water
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
We chose to study the catalytic conversion of dissolved nitrate, which are a major cause of water contamination. It is a complex process into several steps following the reaction: NO3- → NO2-→ [NO] → N2 + NH4+ + + OH- The scientific goal of this thesis was to determine a relationship between the physico-chemical structure of catalysts and their activity and selectivity in the reduction of nitrates. The reaction kinetics were also studied in relation to the structure of catalysts. The work focused around the following points: 1. Preparation of catalyst supports: Two main groups of materials were studied: carbon materials and inorganic materials that have been modified by acid or base treatment or by deposit oxides (Al2O3, ZrO2 alone or in mixture). 2. Synthesis of catalyst: oxides of noble and transition metals have been established on the supports. Systems with monometallic Pt and Pd and bimetallic Pd-Cu have been studied and characterized by many techniques. The effectiveness of these materials was determined depending on their catalytic activity. 3. Determination of the catalytic properties: The role and effect of parameters such as support, type of medium, active phase composition, the presence of inorganic salts in the reaction medium, nature of reducing on the rate of nitrate reduction and selectivity of the reactions were widely studied. The debate highlights the combination support / most effective catalyst for denitrification of drinking water
Groundwater Quality
Author: Harriet Nash
Publisher: Springer
ISBN: 0412586207
Category : Science
Languages : en
Pages : 204
Book Description
Groundwater quality monitoring and testing is of paramount importance both in the developed and developing world. This book presents a series of papers illustrating the varied nature of current research into groundwater quality. Urban and rural supplies are covered through a case history approach, and the importance of remedial action to prevent deterioration is emphasized.
Publisher: Springer
ISBN: 0412586207
Category : Science
Languages : en
Pages : 204
Book Description
Groundwater quality monitoring and testing is of paramount importance both in the developed and developing world. This book presents a series of papers illustrating the varied nature of current research into groundwater quality. Urban and rural supplies are covered through a case history approach, and the importance of remedial action to prevent deterioration is emphasized.
Report summaries
Author: United States. Environmental Protection Agency
Publisher:
ISBN:
Category :
Languages : en
Pages : 1584
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 1584
Book Description
Selected Water Resources Abstracts
Scientific, Health and Social Aspects of the Food Industry
Author: Benjamin Valdez
Publisher: BoD – Books on Demand
ISBN: 9533079169
Category : Science
Languages : en
Pages : 504
Book Description
This book presents the wisdom, knowledge and expertise of the food industry that ensures the supply of food to maintain the health, comfort, and wellbeing of humankind. The global food industry has the largest market: the world population of seven billion people. The book pioneers life-saving innovations and assists in the fight against world hunger and food shortages that threaten human essentials such as water and energy supply. Floods, droughts, fires, storms, climate change, global warming and greenhouse gas emissions can be devastating, altering the environment and, ultimately, the production of foods. Experts from industry and academia, as well as food producers, designers of food processing equipment, and corrosion practitioners have written special chapters for this rich compendium based on their encyclopedic knowledge and practical experience. This is a multi-authored book. The writers, who come from diverse areas of food science and technology, enrich this volume by presenting different approaches and orientations.
Publisher: BoD – Books on Demand
ISBN: 9533079169
Category : Science
Languages : en
Pages : 504
Book Description
This book presents the wisdom, knowledge and expertise of the food industry that ensures the supply of food to maintain the health, comfort, and wellbeing of humankind. The global food industry has the largest market: the world population of seven billion people. The book pioneers life-saving innovations and assists in the fight against world hunger and food shortages that threaten human essentials such as water and energy supply. Floods, droughts, fires, storms, climate change, global warming and greenhouse gas emissions can be devastating, altering the environment and, ultimately, the production of foods. Experts from industry and academia, as well as food producers, designers of food processing equipment, and corrosion practitioners have written special chapters for this rich compendium based on their encyclopedic knowledge and practical experience. This is a multi-authored book. The writers, who come from diverse areas of food science and technology, enrich this volume by presenting different approaches and orientations.
Manual Nitrogen Control
Selected Water Resources Abstracts
Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards
Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 346
Book Description
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 346
Book Description