Download or read book Mechanism of Gas Permeation Through Polymer Membranes Progress Report September 1 1978 May 31 1979 written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new, more exact derivation of the free-volume model of permeation is presented in this report. The free-volume parameters A/sub d/, B/sub d/, and .gamma. have been determined for CO/sub 2/ in polyethylene from diffusivity measurements at 20 and 35/sup 0/C and at pressures of up to 23 atm. The polyethylene was in the form of semicrystalline rods, and the measurements were made with a new type of high-pressure diffusivity apparatus operating under both isobaric and isothermal conditions. The above parameters were used in conjunction with the free-volume model to predict permeability coefficients for the transport of CO/sub 2/ through polyethylene membranes as a function of pressure. The values of the predicted permeability coefficients were found to agree to within 35% or better (on the average) with those obtained directly from permeability measurements with thin polyethylene membranes. The agreement is within the expected limits, considering the assumptions of the free-volume model and the uncertainty in the diffusivity and permeability measurements. A method of determining free-volume parameters directly from permeability measurements was developed for dilute penetrant-polymer systems. This method was used to obtain values of A/sub d/, B/sub d/, and .gamma. for CO/sub 2/, CH/sub 4/, C/sub 2/H/sub 4/, C/sub 2/H/sub 6/, and C/sub 3/H/sub 8/ in polyethylene membranes. The values of B/sub d/ and .gamma. are in about the same range, respectively, as reported for other penetrant-polymer systems. No data appear to have been published previously for A/sub d/. According to the theory, B/sub d/ is thought to be related to the minimum hole size required for the displacement of a penetrant molecule in the polymer, and should depend on both the size and shape of the molecule. This was confirmed by a linear correlation of B/sub d/ with the effective molecular diameters of the above gases; these diameters make allowance for possible orientation of anisometric molecules during diffusion.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1982 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanisms of Gas Permeation Through Polymer Membranes Summary Technical Report September 1991 August 1992 written by and published by . This book was released on 1992 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress is reported in two areas: (1) Concentration-temperature superposition principle (CTSP). CTSP is a theoretical model for describing the gas solubility in glassy polymers swollen by the penetrant gas. It has been extended to describe the dependence of gas diffusivity and permeability on penetrant pressure. Further extension to diffusion of gas mixtures is being studied. (2)Solubility of gases in poly(alkyl methacrylates). Solubility of methane in poly(ethyl methacrylate) and poly(n-butyl methacrylate) was measured; the Langmuir capacity constant was found to not reflect a lower excess free volume; an equation is given for relating the constant to the glass transition temperature. Solubility of ethane in the latter polymer is affected by plasticization.
Download or read book Corrosion Abstracts written by and published by . This book was released on 1980 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanisms of Gas Permeation Through Polymer Membranes Summary Technical Report September 1989 August 1991 written by and published by . This book was released on 1991 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the present study is to investigate the mechanisms of gas transport in and through polymer membranes and the dependence of these mechanisms on pressure and temperature. This information is required for the development of new, energy-efficient membrane processes for the separation of industrial gas mixtures. Such processes are based on the selective permeation of the components of gas mixtures through nonporous polymer membranes. Recent work has been focused on the permeation of gases through membranes made from glassy polymers, i.e., at temperatures below the glass transition of the polymers (Tg). Glassy polymers are very useful membrane materials for gas separations because of their high selectivity toward different gases. Gases permeate through nonporous polymer membranes by a ''solution-diffusion'' process. Consequently, in order to understand the characteristics of this process it is necessary to investigate also the mechanisms of gas solution and diffusion in glassy polymers. 23 refs., 10 figs., 4 tabs.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1980 with total page 1530 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanisms of Gas Permeation Through Polymer Membranes written by and published by . This book was released on 1992 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress is reported in two areas: (1) Concentration-temperature superposition principle (CTSP). CTSP is a theoretical model for describing the gas solubility in glassy polymers swollen by the penetrant gas. It has been extended to describe the dependence of gas diffusivity and permeability on penetrant pressure. Further extension to diffusion of gas mixtures is being studied. (2)Solubility of gases in poly(alkyl methacrylates). Solubility of methane in poly(ethyl methacrylate) and poly(n-butyl methacrylate) was measured; the Langmuir capacity constant was found to not reflect a lower excess free volume; an equation is given for relating the constant to the glass transition temperature. Solubility of ethane in the latter polymer is affected by plasticization.
Download or read book Government reports annual index written by and published by . This book was released on 199? with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1982 with total page 844 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polymer Permeability written by J. Comyn and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymers are permeable, whilst ceramics, glasses and metals are gener ally impermeable. This may seem a disadvantage in that polymeric containers may allow loss or contamination of their contents and aggressive substances such as water will diffuse into polymeric struc tures such as adhesive joints or fibre-reinforced composites and cause weakening. However, in some cases permeability is an advantage, and one particular area where this is so is in the use of polymers in drug delivery systems. Also, without permeable polymers, we would not enjoy the wide range of dyed fabrics used in clothing and furnishing. The fundamental reason for the permeability of polymers is their relatively high level of molecular motion, a factor which also leads to their high levels of creep in comparison with ceramics, glasses and metals. The aim of this volume is to examine some timely applied aspects of polymer permeability. In the first chapter basic issues in the mathema tics of diffusion are introduced, and this is followed by two chapters where the fundamental aspects of diffusion in polymers are presented. The following chapters, then, each examine some area of applied science where permeability is a key issue. Each chapter is reasonably self-contained and intended to be informative without frequent outside reference. This inevitably leads to some repetition, but it is hoped that this is not excessive.
Download or read book Membrane Handbook written by Winston Ho and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 957 pages. Available in PDF, EPUB and Kindle. Book excerpt: Membrane processes have wide industrial ap This handbook reviews the published litera plications covering many existing and emerging ture, presents an in-depth description of com uses in the chemical, petrochemical, petroleum, mercialized membrane processes, and gives a state-of-the-art review of new membrane pro environmental, water treatment, pharmaceutic al, medical, food, dairy, beverage, paper, tex cess concepts under development. It is intended tile, and electronic industries. The existing ap to be a single source of underlying principles, membranes, membrane modules, process de plications include: (1) dialysis for the purifica tion of human blood (the artificial kidney), (2) sign, applications, and cost estimates. It is also electrodialysis for the desalination of brackish a first attempt to bridge the gap between the water to produce potable water, (3) reverse theory and practice. osmosis for the desalination of seawater, (4) There are several groups which may benefit ultrafiltration for the concentration of large pro from this handbook. It can be used as educa tein molecules from cheese, casein whey, and tional material for industrial personnel engaged milk, and (5) microfiltration for the sterilization in membrane separations. For scientists and of pharmaceutical and medical products, beer, engineers active in research and development in wine, and soft drinks. Since membrane pro synthetic membranes, it will serve as a single cesses generally have low capital investment, as source of reference for the entire field.
Download or read book Membrane Technology and Applications written by Richard W. Baker and published by John Wiley & Sons. This book was released on 2004-05-31 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Table of Contents Preface Acknowledgments for the first edition Acknowledgments for the second edition 1 Overview of Membrane Science and Technology 1 2 Membrane Transport Theory 15 3 Membranes and Modules 89 4 Concentration Polarization 161 5 Reverse Osmosis 191 6 Ultrafiltration 237 7 Microfiltration 275 8 Gas Separation 301 9 Pervaporation 355 10 Ion Exchange Membrane Processes - Electrodialysis 393 11 Carrier Facilitated Transport 425 12 Medical Applications of Membranes 465 13 Other Membrane Processes 491 Appendix 523 Index 535.
Download or read book Carbon Membrane Technology written by Xuezhong He and published by CRC Press. This book was released on 2020-11-25 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon membranes have great advantages of strong mechanical strength and high chemical stabilities, as well as high separation performance to reach the industrial attractive region. Further improvement on membrane performance can potentially offset the relatively high production cost compared to polymeric membranes. However, there are still some challenges related to fabrication of asymmetric carbon membranes, the controlling of structure and pore-size and module up-scaling for commercial application. The aim of this book is to provide the fundamentals on carbon membrane materials for the young researchers and engineers to develop frontier membrane materials for energy efficient separation process. This book describes the status and perspectives of both self-supported and supported carbon membranes from fundamentals to applications. The key steps on the development of high performance carbon membranes including precursor selection, tuning carbon membrane structure and regeneration are discussed. In the end, different potential applications both in gas and liquids separation are well described, and the future directions for carbon membrane development were pointed out. To this end, membrane science and engineering are set to play crucial roles as enabling technologies to provide energy efficient and cost-effective future solutions for energy and environment related processes. Based on this approach the research projects which are trying to find attractive carbon materials in our days are many. The published papers, per year, in the topic of carbon membranes, especially for biogas upgrading, natural gas sweetening and hydrogen purification, are numerous with very high impact. However, only few are the books which include relevant to the topic of carbon membrane technology. This book offers the condensed and interdisciplinary knowledge on carbon membranes, and provides the opportunity to the scientists who are working in the field of carbon membrane technology for gas and liquid separations to present, share, and discuss their contributions within the membrane community.
Download or read book Polymeric Gas Separation Membranes written by D.R. Paul and published by CRC Press. This book was released on 2018-05-04 with total page 635 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymeric Gas Separation Membranes is an outstanding reference devoted to discussing the separation of gases by membranes. An international team of contributors examines the latest findings of membrane science and practical applications and explores the complete spectrum of relevant topics from fundamentals of gas sorption and diffusion in polymers to vapor separation from air. They also compare membrane processes with other separation technologies. This essential book will be valuable to all practitioners and students in membrane science and technology.
Download or read book Membranes For Gas Separations written by Moises A Carreon and published by World Scientific. This book was released on 2017-08-11 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims at illustrating several examples of different membrane compositions ranging from inorganic, polymeric, metallic, metal organic framework, and composite which have been successfully deployed to separate industrially relevant gas mixtures including hydrogen, nitrogen, methane, carbon dioxide, olefins/parafins among others. Each book chapter highlights some of the current and key fundamental and technological challenges for these membranes that must be overcome in order to envision its application at industrial level.
Download or read book Mixed Matrix Membranes written by Clara Casado-Coterillo and published by MDPI. This book was released on 2019-12-16 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mixed matrix membranes (MMMs) have attracted a large amount of interest in research laboratories worldwide in recent decades, motivated by the gap between a growing interest in developing novel mixed matrix membranes by various research groups and the lack of large-scale implementation. This Special Issue contains six publications dealing with the current opportunities and challenges of mixed matrix membranes development and applications to solve environmental and health challenges of the society of 21st century.
Download or read book Diffusion in Polymers written by P. Neogi and published by CRC Press. This book was released on 1996-02-06 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Examines various aspects of diffusion in polymers that are being quantitatively described and engineered--detailing the phenomenology of diffusion and outlining areas for future research. Emphasizing the importance of fundamental studies throughout.
