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Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
The complex structures of the Templated Mesoporous Materials (TMMs) are difficult to capture using experiments. On the other hand, detailed structural information is required in order to study the confinement effects and predict material properties. We therefore present a methodology to prepare realistic molecular models of the TMMs using molecular simulations. Mimetic simulations are used to simulate the synthesis of the TMMs resulting in mesoscale models of the materials. Using this technique, we have developed models for SBA-15 and the Mesostructured Cellular Foams (MCF). The mimetic simulations also allow us to study the phase diagrams of the surfactants involved in the synthesis. We have investigated the ternary phase diagrams (surfactant-oil-water and surfactant-silica-water) of model triblock surfactants and have highlighted the effects of oil on the ordered structures. The simulation results for the effect of oil are in partial agreement with the experiments. Next, we devise a technique to convert the mesoscale TMM models into atomistic ones. The method has been demonstrated by preparing atomistic models for SBA-15. The physical properties of the models (pore size distribution, surface area, TEM and AFM images) are compared to the experimental ones. The porosities and the surface areas of the models are in quantitative agreement with those of the experimental SBA-15, whereas the pore size distribution and TEM results agree qualitatively with the experiments. We also present new methods for characterizing model structures including a fast technique for computing pore size distributions. The results from our new technique show speed increases of several orders of magnitude compared to the existing method. Finally we simulate the adsorption of Argon inside the model SBA-15 using Grand canonical Monte Carlo simulations. The adsorption isotherm from the model is in semi-quantitative agreement with that of an experimental SBA-15. The adsorption behavior of several.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
The complex structures of the Templated Mesoporous Materials (TMMs) are difficult to capture using experiments. On the other hand, detailed structural information is required in order to study the confinement effects and predict material properties. We therefore present a methodology to prepare realistic molecular models of the TMMs using molecular simulations. Mimetic simulations are used to simulate the synthesis of the TMMs resulting in mesoscale models of the materials. Using this technique, we have developed models for SBA-15 and the Mesostructured Cellular Foams (MCF). The mimetic simulations also allow us to study the phase diagrams of the surfactants involved in the synthesis. We have investigated the ternary phase diagrams (surfactant-oil-water and surfactant-silica-water) of model triblock surfactants and have highlighted the effects of oil on the ordered structures. The simulation results for the effect of oil are in partial agreement with the experiments. Next, we devise a technique to convert the mesoscale TMM models into atomistic ones. The method has been demonstrated by preparing atomistic models for SBA-15. The physical properties of the models (pore size distribution, surface area, TEM and AFM images) are compared to the experimental ones. The porosities and the surface areas of the models are in quantitative agreement with those of the experimental SBA-15, whereas the pore size distribution and TEM results agree qualitatively with the experiments. We also present new methods for characterizing model structures including a fast technique for computing pore size distributions. The results from our new technique show speed increases of several orders of magnitude compared to the existing method. Finally we simulate the adsorption of Argon inside the model SBA-15 using Grand canonical Monte Carlo simulations. The adsorption isotherm from the model is in semi-quantitative agreement with that of an experimental SBA-15. The adsorption behavior of several.
Author: Lin Jin Publisher: ISBN: Category : Nanopores Languages : en Pages : 180
Book Description
Porous materials have long been a research interest due to their practical importance in traditional chemical industries such as catalysis and separation processes. The successful synthesis of porous materials requires further understanding of the fundamental physics that govern the formation of these materials. In this thesis, we apply molecular modeling methods and develop novel models to study the formation mechanism of ordered porous materials. The improved understanding provides an opportunity to rational control pore size, pore shape, surface reactivity and may lead to new design of tailor-made materials. To attain detailed structural evolution of silicate materials, an atomistic model with explicitly representation of silicon and oxygen atoms is developed. Our model is based on rigid tetrahedra (representing SiO4) occupying the sites of a body centered cubic (bcc) lattice. The model serves as the base model to study the formation of silica materials. We first carried out Monte Carlo simulations to describe the polymerization process of silica without template molecules starting from a solution of silicic acid in water at pH 2. We predicted Qn evolutions during silica polymerization and good agreement was found compared with experimental data, where Qn is the fraction of Si atoms with n bridging oxygens. The model captures the basic kinetics of silica polymerization and provides structural evolution information. Next we generalize the application of this atomic lattice model to materials with tetrahedral (T) and bridging (B) atoms and apply parallel tempering Monte Carlo methods to search for ground states. We show that the atomic lattice model can be applied to silica and related materials with a rich variety of structures including known chalcogenides, zeolite analogs, and layered materials. We find that whereas canonical Monte Carlo simulations of the model consistently produce the amorphous solids studied in our previous work, parallel tempering Monte Carlo gives rise to ordered nanoporous solids. The utility of parallel tempering highlights the existence of barriers between amorphous and crystalline phases of our model. The role of template molecules during synthesis of ordered mesoporous materials was investigated. Implemented surfactant lattice model of Larson, together with atomic tetrahedral model for silica, we successfully modeled the formation of surfactant-templated mesoporous silica (MCM-41), with explicit representation of silicic acid condensation and surfactant self-assembly. Lamellar and hexagonal mesophases form spontaneously at different synthesis conditions, consistent with published experimental observations. Under conditions where silica polymerization is negligible, reversible transformation between hexagonal and lamellar phases were observed by changing synthesis temperatures. Upon long-time simulation that allows condensation of silanol groups, the inorganic phases of mesoporous structures were found with thicker walls that are amorphous and lack of crystallinity. Compared with bulk amorphous silica, the wall-domain of mesoporous silicas are less ordered withlarger fractions of three- and four-membered rings and wider ring-size distributions. It is the first molecular simulation study of explicit representations of both silicic acid condensation and surfactant self-assembly.
Author: A. Galarneau Publisher: Elsevier ISBN: 008054391X Category : Technology & Engineering Languages : en Pages : 525
Book Description
The Zeolites and Mesporous Materials at the Dawn of the 21st Century Proceedings are the expression of the oral and poster communications which where presented during the 13th International Zeolite Conference (IZC). They are subdivided into 32 thematic sessions starting from the genesis of materials to their applications through their characterisation. The paper volume contains the full texts of the 5 plenary and 6 keynote lectures and informative summaries of 150 oral and 540 poster presentations. These contributions have been selected among the 903 submissions received from a total of 57 countries! In order to gather all the communications in a handy document, the full texts of oral and poster presentations are available in CD-ROM. Besides the fields of zeolite science always represented at IZC (synthesis, characterisation, catalysis, etc¿), some subjects strengthened their position (mesoporous materials, theory and modelling), new areas emerge (advanced materials, environmental and life sciences) and older ones regain interest (natural zeolites). The understanding and development of the unique properties of porous materials relies on a unique blend of multidisciplinary knowledge: material science, with the implication of organic and colloid chemistry, to prepare micro- and mesoporous materials, surface and adsorption science sustained by theory and modelling to understand the peculiar behaviour of molecules in confined systems, special branches of catalysis, physics, chemical engineering and life science to design novel applications. The gathering of these elements is at the basis of a fruitful and evolutionary zeolite science, as it is hopefully reflected by these proceedings.
Author: Ruren Xu Publisher: Elsevier ISBN: 0444635955 Category : Science Languages : en Pages : 810
Book Description
Modern Inorganic Synthetic Chemistry, Second Edition captures, in five distinct sections, the latest advancements in inorganic synthetic chemistry, providing materials chemists, chemical engineers, and materials scientists with a valuable reference source to help them advance their research efforts and achieve breakthroughs. Section one includes six chapters centering on synthetic chemistry under specific conditions, such as high-temperature, low-temperature and cryogenic, hydrothermal and solvothermal, high-pressure, photochemical and fusion conditions. Section two focuses on the synthesis and related chemistry problems of highly distinct categories of inorganic compounds, including superheavy elements, coordination compounds and coordination polymers, cluster compounds, organometallic compounds, inorganic polymers, and nonstoichiometric compounds. Section three elaborates on the synthetic chemistry of five important classes of inorganic functional materials, namely, ordered porous materials, carbon materials, advanced ceramic materials, host-guest materials, and hierarchically structured materials. Section four consists of four chapters where the synthesis of functional inorganic aggregates is discussed, giving special attention to the growth of single crystals, assembly of nanomaterials, and preparation of amorphous materials and membranes. The new edition’s biggest highlight is Section five where the frontier in inorganic synthetic chemistry is reviewed by focusing on biomimetic synthesis and rationally designed synthesis. Focuses on the chemistry of inorganic synthesis, assembly, and organization of wide-ranging inorganic systems Covers all major methodologies of inorganic synthesis Provides state-of-the-art synthetic methods Includes real examples in the organization of complex inorganic functional materials Contains more than 4000 references that are all highly reflective of the latest advancement in inorganic synthetic chemistry Presents a comprehensive coverage of the key issues involved in modern inorganic synthetic chemistry as written by experts in the field
Author: M. Jaroniec Publisher: Elsevier ISBN: 0080537227 Category : Technology & Engineering Languages : en Pages : 711
Book Description
Nanoporous Materials III contains the invited lectures and peer-reviewed oral and poster contributions to be presented at the 3rd Conference on Nanoporous Materials, which will be hosted in Ottawa, Canada, June 2002. The work covers complementary approaches to and recent advances in the field of nanostructured materials with pore sizes larger than 1nm, such as periodic mesoporous molecular sieves M41S and FSM16 and related materials including clays, carbon molecular sieves, colloidal crystal templated organic and inorganic materials, porous polymers and sol gels. The broad range of topics covered in relation to the synthesis and characterization of ordered mesoporous materials are of great importance for advanced adsorption, catalytic and separation processes as well as the development of nanotechnology. The contents of this title are based on topics to be discussed by invited lecturers, which deal with periodic mesoporous organosilicas, stability and catalytic activity of aluminosilicate mesostructures, electron microscopy studies of ordered materials, imprinted polymers and highly porous metal-organic frameworks. The other contributions deal with tailoring the surface and structural properties of nanoporous materials, giving a detailed characterization as well as demonstrating their usefulness for advanced adsorption and catalytic applications.
Author: Philip Llewellyn Publisher: Elsevier ISBN: 0080463711 Category : Technology & Engineering Languages : en Pages : 749
Book Description
The 7th International Symposium on the Characterization of Porous Solids (COPS-VII) was held in the Congress Centre in Aix-en-Provence between the 25th-28th May 2005. The symposium covered recent results of fundamental and applied research on the characterization of porous solids. Papers relating to characterization methods such as gas adsorption and liquid porosimetry, X-ray techniques and microscopic measurements as well as the corresponding molecular modelling methods were given. These characterization methods were shown to be applied to all types of porous solids such as clays, carbons, ordered mesoporous materials, porous glasses, oxides, zeolites and metal organic frameworks. * 36 oral presentations and 166 posters and around 230 guests from 27 countries. * A large part of this symposium was devoted to the use computational methods to characterise porous solids
Author: Jiri Cejka Publisher: Elsevier ISBN: 0080457339 Category : Science Languages : en Pages : 395
Book Description
Zeolites are the most frequently used industrial catalysts. Their applications range from oil refining, petrochemistry and the synthesis of special chemicals to environmental catalysis. Rapid progress in basic research and the development of new processes has resulted in the first Federation of European Zeolite Associations (FEZA) School on Zeolites. Zeolites and Ordered Mesoporous Materials: Progress and Prospects reflects the programme of the first School on Zeolites, held in Prague on August 20-21, 2005. Readers gain insight into the synthesis of the ever-expanding spectrum of zeolites, zeotypes and ordered mesoporous materials including the use of zeolites and mesoporous materials as catalysts in organic conversions. These range from the fascinating ship-in-bottle systems via cascade reactions to bulk applications in oil-refining and petrochemistry. Contributions from world experts enhance the book, with select chapters on trends in the molecular sieves field, zeolite structures, ion-exchange properties of zeolites, advanced applications (with unique technologies and opportunities) and a chapter on natural zeolites. * Contains contributions from world experts in the field * Includes an account of the frontier topic of high-throughput techniques* Reviews the application of quantum-chemical methods to zeolite science to show the necessity of combining experimental and theoretical approaches
Author: Publisher: ISBN: Category : Languages : en Pages : 20
Book Description
Mesoporous is defined as 20(less-than or equal to)d(less-than or equal to)500Å. Mesoporous materials with narrow pore size distributions may be useful as hosts, supports, catalysts, or separation media for small molecules. An ensemble of organic molecules to create a larger template has been used to synthesize ordered mesoporous materials. The silicon alkoxide precursors TEOS and TMOS were examined. Cosolvents were used to control pore size and the structure of the mesophase. Effects of anions (salts) on mesophase formation were examined. Properties of mesophases made from homogeneous solutions are discussed.
Author: Beena Rai Publisher: CRC Press ISBN: 1439840784 Category : Science Languages : en Pages : 400
Book Description
Molecular modeling (MM) tools offer significant benefits in the design of industrial chemical plants and material processing operations. While the role of MM in biological fields is well established, in most cases MM works as an accessory in novel products/materials development rather than a tool for direct innovation. As a result, MM engineers and practitioners are often seized with the question: "How do I leverage these tools to develop novel materials or chemicals in my industry?" Molecular Modeling for the Design of Novel Performance Chemicals and Materials answers this important question via a simple and practical approach to the MM paradigm. Using case studies, it highlights the importance and usability of MM tools and techniques in various industrial applications. The book presents detailed case studies demonstrating diverse applications such as mineral processing, pharmaceuticals, ceramics, energy storage, electronic materials, paints, coatings, agrochemicals, and personal care. The book is divided into themed chapters covering a diverse range of industrial case studies, from pharmaceuticals to cement. While not going too in-depth into fundamental aspects, the book covers almost all paradigms of MM, and references are provided for further learning. The text includes more than 100 color illustrations of molecular models.
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Author: 
Author: Supriyo Bhattacharya
Author: Lin Jin
Author: A. Galarneau
Author: Ruren Xu
Author: M. Jaroniec
Author: Philip Llewellyn
Author: Jiri Cejka
Author: 
Author: Beena Rai