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Book Graphene Membranes Synthesis and Mass Transport Across Atomic Thickness Porous Membranes

Download or read book Graphene Membranes Synthesis and Mass Transport Across Atomic Thickness Porous Membranes written by Jakob Kilian Buchheim and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Graphene based Membranes for Mass Transport Applications

Download or read book Graphene based Membranes for Mass Transport Applications written by Pengzhan Sun and published by Royal Society of Chemistry. This book was released on 2018-09-21 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of graphene-based membrane materials and its applications.

Book Two Dimensional Materials Based Membranes

Download or read book Two Dimensional Materials Based Membranes written by Gongping Liu and published by John Wiley & Sons. This book was released on 2022-08-08 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-Dimensional-Materials-Based Membranes An authoritative and up to date discussion of two-dimensional materials and membranes In Two-Dimensional-Materials-Based Membranes: Preparation, Characterization, and Applications, a team of distinguished chemical engineers delivers a comprehensive exploration of the latest advances in design principles, synthesis approaches, and applications of two-dimensional (2D) materials—like graphene, metal-organic frameworks (MOFs), 2D layered double hydroxides, and MXene—and highlights the significance and development of these membranes. In the book, the authors discuss the use of membranes to achieve high-efficiency separation and to address the challenges posed in the field. The book also discusses potential challenges and benefits in the future development of advanced 2D nanostructures, as well as their impending implementation in applications in the fields of energy, sustainability, catalysis, electronics, and biotechnology. Readers will also find: A thorough introduction to fabrication methods for 2D-materials-based membranes, including the synthesis of nanosheets, membrane structures, and fabrication methods Descriptions of three types of 2D-materials-based membranes: single-layer membranes, laminar membranes and mixed-matrix membranes Comprehensive discussions of 2D-materials-based membranes for water and ions separation, solvent-water separation and gas separation Explorations of transport mechanism of 2D-materials-based membranes for molecular separations Perfect for membrane scientists, inorganic chemists, and materials scientists, Two-Dimensional-Materials-Based Membranes will also earn a place in the libraries of chemical and process engineers in industrial environments.

Book Graphene based Membranes for Mass Transport Applications

Download or read book Graphene based Membranes for Mass Transport Applications written by Hongwei Zhu and published by Royal Society of Chemistry. This book was released on 2018-09-21 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is great interest in the novel mass-transport properties of graphene-based membrane materials, especially for environmental applications such as wastewater treatment and reuse, gas separation and water desalination. Graphene-based Membranes for Mass Transport Applications is a comprehensive overview of the research in this area. Starting with current state-of-the-art membrane-based filtration and separation technologies, the book then explores the structure, composition and general properties of graphene-based membranes including nanoporous graphene and graphene oxide followed by the selective mass transport properties of the membranes. The final chapters look at their specific use in barrier applications, purification and separation applications and water desalination. Edited by leading researchers, the book provides an introduction and reference to physicists, chemists, material scientists, chemical engineers and students who are entering or already working in the field of graphene-based membrane materials.

Book Macroscopic Graphene Membranes with Tunable Nanopores for Highly Selective Mass Separation

Download or read book Macroscopic Graphene Membranes with Tunable Nanopores for Highly Selective Mass Separation written by Doojoon Jang and published by . This book was released on 2018 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Membrane-based filtration enables energy-efficient separations of solutes, solvents, or gases, benefiting a wide range of applications including water desalination, nanofiltration, hemodialysis, solvent-based separation, or natural gas purification. Semipermeable polymeric desalination membranes rely on solution-diffusion mechanism to separate water from salts, where selective transport of species arises from their solubility and diffusivity in polymer phase. Despite the remarkable progress in materials, structure, and separation process over the past few decades, today's membranes are subjected to intrinsic challenges ranging from resolving the trade-off between permeability and selectivity to maintaining robust operation with high stability and low fouling. Two dimensional materials have the potential to address some of the above challenges by offering a fundamentally new mechanism to control nanofluidic transport with sustainable nanoscale pores, thereby presenting a platform for next-generation reverse osmosis (RO) or nanofiltration (NF) membranes. Although theoretical investigations of great breadth and depth have been pursued to understand mass transport across the atomically thin materials, experimental efforts are required to engineer and tune nanopore structure in macroscopically large graphene membranes and understand the resulting transport characteristics. Moreover, the effects of interplay between graphene nanopore structure and porous support layer on membrane transport properties need to be considered to identify the structure-function relationship of the nanoporous graphene membranes. This thesis aims at controlling selective graphene nanopore structure for high permeability and selectivity and understanding the tunable membrane transport properties. A two-step process of ion bombardment and oxygen plasma is carried out to introduce a high density of nanopores in large-area graphene membranes. Pore creation parameters are thoroughly explored to investigate the influence on pore size and density. The resulting transport properties of graphene membranes can be tuned to achieve high permeance to water, comparable to that of NF membranes, and highly selective transport of monovalent ions over organic molecules. Nanopore structure introduced in graphene membranes is inspected to quantitatively relate the pore creation parameters with the resulting pore size distributions. A multiscale transport model is constructed to investigate the interplay between nanoporous graphene and support pores that governs osmotic water flux and diffusive solute transport. Internal concentration polarization of draw solutes estimated by the model suggests that achieving narrowly distributed graphene pores with minimal leakage is essential to optimal operation of high-flux asymmetric graphene membranes under forward osmosis. Sterically governed molecular assembly is explored to mitigate residual solute leakage across large, non-selective pores for enhanced membrane selectivity. High molecular weight polymers can electrostatically or covalently assemble across nanoscale defects of graphene to narrow down the effective pore size distribution, sterically and electrostatically hindering transport. Multi-step size-selective polyelectrolyte assembly enables >/=99% retention of divalent ions and organic molecules, promising the potential of graphene in desalination, nanofiltration or organic solvent nanofiltration (OSN). With experimental/theoretical means to characterize membrane structure and transport properties, this thesis forms the basis for regulating nanofluidic mass transport with tunable nanopores and developing atomically thin separation membranes with high selectivity and permeability.

Book Two Dimensional  2D  Nanomaterials in Separation Science

Download or read book Two Dimensional 2D Nanomaterials in Separation Science written by Rasel Das and published by Springer Nature. This book was released on 2021-04-26 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers newly emerging two-dimensional nanomaterials which have been recently used for the purpose of water purification. It focuses on the synthesis methods of 2D materials and answers how scientists/engineers/nanotechnologist/environmentalists could use these materials for fabricating new separation membranes and most probably making commercially feasible technology. The chapters are written by a collection of international experts ensuring a broad view of each topic. The book will be of interest to experienced researchers as well as young scientists looking for an introduction into 2D materials-based cross-disciplinary research.

Book Nanoporous Graphene Membranes for Health and Environmental Applications

Download or read book Nanoporous Graphene Membranes for Health and Environmental Applications written by Chun Man Chow and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Separation processes are found in many diverse applications, including health (drug purification, sterilization) and environment (CO2 capture, water treatment, resource recovery). Compared to thermal-based separation systems, membranes are modular and have the potential for more efficient separations without the need for extreme temperatures and large equipment. However, conventional polymeric membranes can suffer from fouling, poor stability at high temperatures and in harsh chemical environments, are subject to a permeability/selectivity trade-off, and it remains hard to precisely control and engineer their structures on the molecular level. These limitations call for the development of new membrane materials to yield significant performance improvements. The emergence of 2D nanomaterials allows for the creation of atomically thin membranes such as nanoporous graphene (NPG), and offers the opportunity to enhance chemical stability as well as increase both permeability and selectivity via significantly reducing membrane thickness and controlling the pore structure. Despite significant progress in theoretical and experimental work in the development of NPG membranes, challenges remain to be addressed for NPGs to be deployed, particularly in the control of leakages through defects, the limited experimentally-supported transport understanding, and the exploration and design of NPG systems for various health and environment applications. This thesis extends the theoretical understanding of transport across graphene composite membranes and demonstrates how differences in the scaling of transport rates with pore size for viscous flow, gas effusion, dilute solute diffusion, and ion transport, together with the interplay between graphene and support structure and selective pore size distribution, influence leakage and selectivity. This thesis also explores how non-linear current-voltage relationships can arise in ultra-thin membranes due to induced charge effects. These models enable us to estimate permeation rates without the need for computationally-intensive simulations. Furthermore, this thesis presents the application of NPG to hemodialysis, desalination, and ion separations. For dialysis, using system level modeling of the device and its interaction with the body, we show that current dialyzers are membrane mass-transfer limited for protein-bound uremic toxins (PBUTs), and establish performance targets for NPG membranes to enhance PBUT removal. These targets are translated to the novel design and fabrication of 2 an hierarchically-supported NPG composite membrane. We also investigate the desalination performance achievable by practical NPGs with pore size distributions and ways to surpass the polymeric permeability/selectivity trade-off limit, and develop a novel experimental/analysis procedure to study simultaneous ion transport across NPG and strategies to enhance selectivity for the recovery of rare earth elements.

Book Transport of Molecules Through and on Carbon Nanostructures

Download or read book Transport of Molecules Through and on Carbon Nanostructures written by Lee William Drahushuk and published by . This book was released on 2018 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Single-layer graphene membranes and other 2D membranes can realize very high gas permeation fluxes due to their atomic or unit cell thickness. Established modeling approaches for membrane transport consider transport through a finite and continuum thickness, and therefore they do not apply to the emerging field of 2D membranes, motivating the development of new theoretical treatments. In this thesis, I first developed an analytical theory for the transport of gases through single- layer graphene membranes, from the perspective of using pores in the graphene layer as a means for separation. I considered two pathways for the transport. The first being direct gas phase impingement on the pore, for which the large-pore separation factors are dictated by Knudsen selectivity, inversely proportional to the molecular weight; selectivity exceeding Knudsen is possible with smaller pores that reach a size commensurate with the size of the molecule, enabling separation by molecular sieving. The second pathway involves adsorption and transport on the graphene surface, similar to mechanisms in heterogeneous catalysis, which becomes more relevant for larger, strongly-adsorbing molecules. These models and pathways are applied for an estimate of a N2/H2 separation and as an explanation for results observed in the molecular dynamics literature. I applied our understanding of nanopore mechanisms and developed analysis of gas transport through graphene with approximately one selective nanopore etched into it, using experimental data from Bunch et al at Boston University for transport of He, H2 Ne, Ar, and CO2 through a small area graphene membrane with a single or few pores. The transport was measured by collaborators via monitoring the deflection of a graphene flake sealing a pressurized, 5[gamma]m diameter microcavity on the surface of a Si/SiO2 wafer. For this experimental system, I report on a mathematical formalism that allows one to detect and analyze stochastic changes in the gas phase fluxes from graphene membranes, extracting activation energies of pore rearrangements, 1.0 eV, and even identifying contributions from multiple, isolated pores.One opportunity that I identified is the use of a molecularly sized nanopore to 'direct write' the flux using a translatable platform. I performed an exploratory investigation of this concept of using a "nanonozzle," a nanometer scale pore that can deliver a flow of material locally, to grow nanoscale features. The model application was the growth of a graphene nanoribbon on a surface. I explored a variety of analytical mathematical models to understand the parameters and limitations of such a system. I developed a simple simulation of the nanoribbon growth and compared the results to the models for a range of parameters, considering the reasons for differences between the simulated and calculated results. This analysis provides considerations for the experimental design of such a system. Overall, the theories in this thesis and the analysis in they enable should aid the development of 2D membranes for separations applications and a novel direct write method for nanoscale patterning.

Book Current Trends and Future Developments on  Bio   Membranes

Download or read book Current Trends and Future Developments on Bio Membranes written by Angelo Basile and published by Elsevier. This book was released on 2019-07-16 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current Trends and Future Developments on (Bio-) Membranes: Microporous Membrane and Membrane Reactors focuses on the structure, preparation, characterization and applications of microporous membranes and membrane reactors, including transport mechanisms through a range of microporous membranes. It is a key reference text for R&D managers who are interested in the development of gas separation and water/waste treatment technologies, but is also well-suited for academic researchers and postgraduate students working in the broader area of strategic material production, separation and purification. Users will find comprehensive coverage of current methods, their characterization and properties, and various applications in gas separation and water treatment. Reviews gas separation and water treatment processes and relates them to various applications Outlines the use of microporous membranes in gas separations and water treatment Introduces the various types of microporous membranes (graphene, polymeric, etc.) and their mechanism of action Provides simulation models of the various processes

Book Comprehensive Membrane Science and Engineering

Download or read book Comprehensive Membrane Science and Engineering written by Enrico Drioli and published by Elsevier. This book was released on 2017-07-20 with total page 1709 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive Membrane Science and Engineering, Second Edition, Four Volume Set is an interdisciplinary and innovative reference work on membrane science and technology. Written by leading researchers and industry professionals from a range of backgrounds, chapters elaborate on recent and future developments in the field of membrane science and explore how the field has advanced since the previous edition published in 2010. Chapters are written by academics and practitioners across a variety of fields, including chemistry, chemical engineering, material science, physics, biology and food science. Each volume covers a wide spectrum of applications and advanced technologies, such as new membrane materials (e.g. thermally rearranged polymers, polymers of intrinsic microporosity and new hydrophobic fluoropolymer) and processes (e.g. reverse electrodialysis, membrane contractors, membrane crystallization, membrane condenser, membrane dryers and membrane emulsifiers) that have only recently proved their full potential for industrial application. This work covers the latest advances in membrane science, linking fundamental research with real-life practical applications using specially selected case studies of medium and large-scale membrane operations to demonstrate successes and failures with a look to future developments in the field. Contains comprehensive, cutting-edge coverage, helping readers understand the latest theory Offers readers a variety of perspectives on how membrane science and engineering research can be best applied in practice across a range of industries Provides the theory behind the limits, advantages, future developments and failure expectations of local membrane operations in emerging countries

Book Study of Ion and Solvent Transport Through Graphene Oxide Membranes

Download or read book Study of Ion and Solvent Transport Through Graphene Oxide Membranes written by Kai Wang and published by . This book was released on 2016 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filtration membranes are required to be thin, robust, energy efficient, and accurate on selectivity. Graphene oxide (GO) is believed to be a potential next generation material for industrial membrane applications because of its unique properties such as strong mechanical strength, excellent aqueous solution processability, and great flexibility for membrane fabrication. Research on the transport models, the separation performance, and the functionalization of GO membranes has been developed. However, many mechanisms of mass transport through GO membranes still remain debatable. In this work, GO was synthesized, and then functionalized with linear amine-terminated poly(ethylene glycol) (PEG) and aluminum ions (Al). The fabrication and characterizations of GO, PEG-GO, and Al-GO membranes were demonstrated in this work. Water and water/ethanol binary mixture transport through GO, PEG-GO, and Al-GO membranes were studied to investigate the permeation and the rejection rates of solvents through GO-based membranes. The total volumetric flux of water/ethanol mixture through GO membranes was inversely proportional to the viscosity of the solvent mixtures. The steric hindrance effect and the interactions between the solvent molecules and the membrane surfaces dominated the rejection rate of ethanol through GO membranes. The functionalization of GO modified the pore size and the porosity of the membranes, resulting in faster permeation of solvents and reduced rejection rates of ethanol through PEG-GO and Al-GO membranes. Deformation of nanochannels within the functionalized GO membranes was observed when the membranes were operated under highly pressurized conditions. Diffusive transport of two charge equivalent and structurally similar ruthenium complex ions Ru(bpy)32+ and iv Ru(phen)32+ through GO, PEG-GO, and Al-GO membranes were also studied. Our data showed high similarity with the results reported previously in the literature, indicating that the GO and functionalized GO membranes used in this work were highly consistent. Due to the enlarged pore sizes and the reduced interactions between ions and the membrane surfaces, the flux of ions through PEG-GO membranes was 300% higher than that through GO membranes. In contrast, permeation of ions through Al-GO membranes was slower than that through GO membranes. The blocked nanopores and the electrostatic repulsion between the intercalated aluminum ions and complex ions were the main reasons for this observation. In addition, the main reason for the significant permeance difference between Ru(bpy)32+ and Ru(phen)32+ ions was confirmed as the steric hindrance effect. This work contributes to the basic research on GO membranes in potential applications. It can be beneficial to the academic laboratories for understanding the mechanism of mass transport through GO-based membranes. These new membrane materials could replace traditional membrane materials in many industrial applications in the future.

Book Materials for Carbon Capture

Download or read book Materials for Carbon Capture written by De-en Jiang and published by John Wiley & Sons. This book was released on 2020-02-25 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covers a wide range of advanced materials and technologies for CO2 capture As a frontier research area, carbon capture has been a major driving force behind many materials technologies. This book highlights the current state-of-the-art in materials for carbon capture, providing a comprehensive understanding of separations ranging from solid sorbents to liquid sorbents and membranes. Filled with diverse and unconventional topics throughout, it seeks to inspire students, as well as experts, to go beyond the novel materials highlighted and develop new materials with enhanced separations properties. Edited by leading authorities in the field, Materials for Carbon Capture offers in-depth chapters covering: CO2 Capture and Separation of Metal-Organic Frameworks; Porous Carbon Materials: Designed Synthesis and CO2 Capture; Porous Aromatic Frameworks for Carbon Dioxide Capture; and Virtual Screening of Materials for Carbon Capture. Other chapters look at Ultrathin Membranes for Gas Separation; Polymeric Membranes; Carbon Membranes for CO2 Separation; and Composite Materials for Carbon Captures. The book finishes with sections on Poly(amidoamine) Dendrimers for Carbon Capture and Ionic Liquids for Chemisorption of CO2 and Ionic Liquid-Based Membranes. A comprehensive overview and survey of the present status of materials and technologies for carbon capture Covers materials synthesis, gas separations, membrane fabrication, and CO2 removal to highlight recent progress in the materials and chemistry aspects of carbon capture Allows the reader to better understand the challenges and opportunities in carbon capture Edited by leading experts working on materials and membranes for carbon separation and capture Materials for Carbon Capture is an excellent book for advanced students of chemistry, materials science, chemical and energy engineering, and early career scientists who are interested in carbon capture. It will also be of great benefit to researchers in academia, national labs, research institutes, and industry working in the field of gas separations and carbon capture.

Book Inorganic and Organic Thin Films

Download or read book Inorganic and Organic Thin Films written by Yujun Song and published by John Wiley & Sons. This book was released on 2021-03-30 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt: Learn more about foundational and advanced topics in polymer thin films and coatings besides species with this powerful two-volume resource The two-volume Inorganic and Organic Thin Films: Fundamentals, Fabrication, and Applications delivers a foundational resource for current researchers and commercial users involved in the design and fabrication of thin films. The book offers newcomers to the field a thorough description of new design theory, fabrication methods, and applications of advanced thin films. Readers will discover the physics and chemistry underlying the manufacture of new thin films and coatings in this leading new resource that promises to become a handbook for future applications of the technology. This one-stop reference brings together all important aspects of inorganic and polymeric thin films and coatings, including construction, assembly, deposition, functionality, patterning, and characterization. Explorations of their applications in industries as diverse as information technology, new energy, biomedical engineering, aerospace, and oceanographic engineering round out this fulsome exploration of one of the most exciting and rapidly developing areas of scientific and industrial research today. Readers will also learn from: A comprehensive introduction to the progress of thin films and coatings as well as fundamentals in functional thin films and coatings An exploration of multi-layered magnetic thin films for electron transport control and signal sensing, including giant magnetoresistance, colossal magnetoresistance, tunneling magnetoresistance, and the quantum anomalous Holzer effect An in time summary of high-quality magneto-optics, nanophotonics, spin waves and spintronics using bismuth-substituted iron garnet thin films as examples A thorough discussion of template-assisted fabrication of nanostructure thin films for ultrasensitive detection of chemicals and biomolecules A treatment of biomass derived functional films and coatings Perfect for materials scientists and inorganic chemists, Inorganic and Organic Thin Films will also earn a place in the libraries of solid state physicists and physical chemists working in private industry, as well as polymer and surface chemists who seek to improve their understanding of thin films and coatings.

Book Molecular Simulation Study of Transport and Separation of Gas Through Nanoporous Graphene Membranes

Download or read book Molecular Simulation Study of Transport and Separation of Gas Through Nanoporous Graphene Membranes written by Juncheng Guo and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoporous graphene membranes are gaining attention in the field of separation processes. Regarding gas separation, perm-selective membranes technology consumes less energy than other conventional technologies. Due to nanoporous graphene's atomic thickness, controllable pore size in the range of molecular diameters, mechanical and chemical stability, it is considered as one of the most favorable membrane material for industrial gas separation applications. For instance, in the context of natural gas production and air separation, the separation of CH4/CO2, N2/O2 mixtures would greatly benefit from this kind of new materials. With the rapid development in graphene fabrication technology, breakthroughs in nanoporous graphene membranes are expected in the next few years and quite sufficient data can be found in publications. However,there is no accurate theory that can predict gas permeation and separation factor quantitively.In this work, we show that gas permeation through single-layer nanoporous graphene membranes can be divided into three regimes: molecular sieving, crossover regime and effusion. We propose a theoretical framework to explain the mechanisms and predict the diffusive transport coefficient. In our framework, the transport coefficient is related to the parameters which can be computed from the potential of mean force (PMF) between permeating gas molecules and the membrane atoms. By means of Equilibrium (EMD) and Non Equilibrium (NEMD) molecular dynamics simulations, we explore the permeation of pure compounds through nanoporous graphene membranes exhibiting differentpore sizes and geometry. We also investigate the effect of thermodynamic conditions (pressure and temperature) on the transport coefficient. Simulated transport coefficients are in good agreement with the predictions of our theory over the whole range of permeation regimes. Furthermore, based on the knowledge acquired on the permeation of pure compounds, we define the concept of selectivity. By comparing the results of molecular simulations performed with gas mixtures, we show in which cases the results weobtained for pure compounds, and consequently our theoretical framework, allow us to predict the selectivity of mixtures.

Book Advanced Functional Polymers

Download or read book Advanced Functional Polymers written by Khubab Shaker and published by Springer Nature. This book was released on 2023-06-09 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights different domains of functional polymers from membranes and coatings to composite materials. It includes their synthesis routes and techniques, characterization, properties, and applications. The book also provides the basics and advances about different functional polymers and composites with an up-to-date progress in the field of research and their application on a domestic and industrial scale. The main topics to be covered include polymeric membranes, paints and coatings, smart polymers, self-healing elastomers, biodegradable polymers, food packaging, and functional composite materials.

Book Gas Separation Using Nanoporous Single layer Graphene Membranes

Download or read book Gas Separation Using Nanoporous Single layer Graphene Membranes written by Zhe Yuan (Chemical engineer) and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoporous single-layer graphene is regarded as a highly promising membrane material for gas separation due to its atomic thickness. When single-layer graphene contains a high density of gas sieving nanoscale pores, it can exhibit both a high gas permeance and a high selectivity, which is beneficial for reducing the cost of gas separation processes. However, significant challenges remain for matching theoretical predictions with experimental measurements and for the real application of graphene membranes for gas separations. To tackle these challenges, in this thesis, I carry out both theoretical and experimental investigations to understand and to improve the gas separation properties of nanoporous single-layer graphene membranes. On the theoretical side, first, using molecular dynamics simulations, I investigate the mechanism of activated gas permeation through sub-nanometer graphene pores when energy barriers exist for pore crossing. I develop an analytical framework based on transition state theory to predict the gas permeance through a given graphene nanopore. Second, I extend the analytical framework mentioned above from sub-nanometer pores to larger pores. I formulate the transport kinetics associated with the direct impingement from the bulk and with the surface diffusion from the adsorption layer on graphene, and then combine them to predict the overall gas permeation rate using a reaction network model. Last, I apply the theory developed above to predict the total gas permeance through a pore ensemble with a realistic pore size distribution, which is generated by Kinetic Monte Carlo simulations. I show that the total gas permeance through a pore ensemble is dominated by a small fraction of large nanopores having low energy barriers of pore crossing. On the experimental side, I demonstrate temperature-dependent gas mixture separation using single-layer graphene membranes. The membranes contain intrinsic nanopores formed during the chemical vapor deposition synthesis of graphene. I investigate the formation mechanism of the intrinsic graphene nanopores, and systematically control the density of the intrinsic graphene nanopores while maintaining appropriate pore sizes for gas sieving. I identify that nanoscale molecular fouling of the graphene surface where graphene pores are partially blocked by hydrocarbon contaminants under experimental conditions, affects both gas permeance and selectivity.

Book Advanced Water Technologies

Download or read book Advanced Water Technologies written by P.K. Tewari and published by CRC Press. This book was released on 2020-12-07 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book explores basic concepts and advanced topics in the field of water technologies. It deals extensively with advances in materials, material selection, preparation, characterization and application. The relevance of water technologies in industries is considered, and a section is dedicated to describing and analyzing the technologies required for water reuse and advanced purification, including desalination. Nuclear desalination, low-carbon desalination and water purification technologies to address the adverse impacts of climate change are examined from both the adaptation and mitigation points of view. Aimed at senior undergraduate/graduate students in chemical, civil and environmental engineering, along with wastewater and desalination researchers, this book: Details advanced water treatments for varied processes. Describes membrane and desalination techniques for water reuse and advanced purification. Elaborates water technologies at both the front and back ends of the process. Discusses modern technologies for effluent treatment and water recycling. Explores the role of information technology in the water sector.