Author: A. NiaeiPublisher:
ISBN:
Category : Science
Languages : en
Pages :
Book Description
Selective Catalytic Reduction of NO with Ammonia over Nanostructure H-ZSM-5 Supported Transition Metal Oxide Catalysts.
Selective Catalytic Reduction of NO with Ammonia Over Nanostructure H-ZSM-5 Supported Transition Metal Oxide Catalysts
Author: A. NiaeiPublisher:
ISBN:
Category : Science
Languages : en
Pages :
Book Description
Selective Catalytic Reduction of NO with Ammonia over Nanostructure H-ZSM-5 Supported Transition Metal Oxide Catalysts.
Selective Catalytic Reduction of NOx
Author: Oliver KröcherPublisher: MDPI
ISBN: 3038973645
Category : Electronic books
Languages : en
Pages : 281
Book Description
This book is a printed edition of the Special Issue "Selective Catalytic Reduction of NOx" that was published in Catalysts
Selective Catalytic Reduction (SCR) of Nitric Oxide with Ammonia Using Cu-ZSM-5 and Va-based Honeycomb Monolith Catalysts
Author: Saurabh GuptaPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
In this work, the steady-state performance of zeolite-based (Cu-ZSM-5) and vanadium-based honeycomb monolith catalysts was investigated in the selective catalytic reduction process (SCR) for NO removal using NH3. The aim was to delineate the effect of various parameters including pretreatment of the catalyst sample with H2, NH3-to-NO ratio, inlet oxygen concentration, and space velocity. The concentrations of the species (e.g. NO, NH3, and others) were determined using a Fourier Transform Infrared (FTIR) spectrometer. The temperature was varied from ambient (25 C) to 500 C. The investigation showed that all of the above parameters (except pre-treatment with H2) significantly affected the peak NO reduction, the temperature at which peak NO reduction occurred, and residual ammonia left at higher temperatures (also known as 'NH3 slip'). Depending upon the particular values of the parameters, a peak NO reduction of around 90% was obtained for both the catalysts. However, an accompanied generation of N2O and NO2 species was observed as well, being much higher for the vanadium-based catalyst than for the Cu-ZSM-5 catalyst. For both catalysts, the peak NO reduction decreased with an increase in space velocity, and did not change significantly with an increase in oxygen concentration. The temperatures at which peak NO reduction and complete NH3 removal occurred increased with an increase in space velocity but decreased with an increase in oxygen concentration. The presence of more ammonia at the inlet (i.e. higher NH3-to-NO ratio) improved the peak NO reduction but simultaneously resulted in an increase in residual ammonia. Pretreatment of the catalyst sample with H2 (performed only for the Cu-ZSM-5 catalyst) did not produce any perceivable difference in any of the results for the conditions of these experiments.
Selective Catalytic Oxidation of Ammonia Using Copper and Iron Supported on ZSM-5 Catalysts
Author: Mohammed Ali H. SaadSelective Catalytic Reduction of Nitric Oxide by Ammonia Over Iron Exchanged Y Zeolites
Author: Michael Dimitrios AmiridisPublisher:
ISBN:
Category :
Languages : en
Pages : 684
Book Description
Selective Catalytic Oxidation of Ammonia Using Copper and Iron Supported on ZSM-5 Catalysts
Author: Mohammed Ali H. SaadPublisher:
ISBN:
Category :
Languages : en
Pages : 187
Book Description
A Superior Fe/ZSM-5 Catalyst for Selective Catalytic Reduction (SCR) of Nitric Oxide with Ammonia
Author: Gongshin QiPublisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages :
Book Description
Development and Characterization of Mixed Oxide Catalysts for the Selective Catlytic Reduction of Nitric Oxide from Stationary Sources Using Amonnia
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Seven first row transition metals were deposited on various commercial TiO2, SiO2, and Al2 O3 supports to create mono- and bimetallic catalysts that were compared in the selective catalytic reduction of nitric oxide using ammonia at low temperatures ranging from 373-523 K. The catalyst with the highest activity both in the absence and presence of water in the feed was 20 wt.% Mn/Hombikat TiO2 synthesized from a nitrate precursor and calcined below 673 K. Under those conditions, it was capable of achieving 100% NO conversion at 393 K. Numerous surface characterization techniques were used to identify the surface properties that result in highly active and selective low temperature SCR catalysts. The deposition of manganese as MnO2, the ease of reducibility of the metal oxide, and the symmetric deformation of ammonia coordinated to Lewis acid sites at 1167 cm−1, were all found to be important for good catalytic performance. No synergistic effects were observed from combinations of the three most active transition metals. However, MnO x -NiO/TiO2 had an extended lifetime relative to MnO x /TiO2 in feeds containing SO2 . The extensive data collected from in-situ FTIR experiments in the presence of NO and NH 3 were used to propose a reaction mechanism for MnO x /TiO2 that begins with the coordination of NH3 over Mn4 species and proceeds through the formation of bridged nitrates. A combination of potentiometric titrations and UV/Vis spectroscopy were used to quantify the reduction of V5 to V4 after the addition of oxalic acid as the solution is aged. After approximately four hours, the aging vanadium oxalate solution reaches steady state, and the final distribution of the vanadium present is 89% V+4 and 11% V+5 . TiO2 supported monolayer catalysts synthesized from the aged (V+4) vanadium oxalate solution consistently outperformed catalysts made from freshly prepared (V+5) vanadium oxalate solutions. Surface characterization revealed that surface acid sites increase in strength and vanadia reduces more easily in catalysts synthesized from aged vanadium oxalate solutions, which enhances reaction mechanism depends upon acid sites and redox operation.
X-Ray Absorption and X-Ray Emission Spectroscopy
Author: Jeroen A. van BokhovenPublisher: John Wiley & Sons
ISBN: 1118844238
Category : Science
Languages : en
Pages : 940
Book Description
During the last two decades, remarkable and often spectacular progress has been made in the methodological and instrumental aspects of x–ray absorption and emission spectroscopy. This progress includes considerable technological improvements in the design and production of detectors especially with the development and expansion of large-scale synchrotron reactors All this has resulted in improved analytical performance and new applications, as well as in the perspective of a dramatic enhancement in the potential of x–ray based analysis techniques for the near future. This comprehensive two-volume treatise features articles that explain the phenomena and describe examples of X–ray absorption and emission applications in several fields, including chemistry, biochemistry, catalysis, amorphous and liquid systems, synchrotron radiation, and surface phenomena. Contributors explain the underlying theory, how to set up X–ray absorption experiments, and how to analyze the details of the resulting spectra. X-Ray Absorption and X-ray Emission Spectroscopy: Theory and Applications: Combines the theory, instrumentation and applications of x-ray absorption and emission spectroscopies which offer unique diagnostics to study almost any object in the Universe. Is the go-to reference book in the subject for all researchers across multi-disciplines since intense beams from modern sources have revolutionized x-ray science in recent years Is relevant to students, postdocurates and researchers working on x-rays and related synchrotron sources and applications in materials, physics, medicine, environment/geology, and biomedical materials
Author: Mukundan Devadas