Search results for "gas separation"

Glovebox atmosphere detritiation process using gas separation membranes.

2003

Abstract The use of gas separation membranes in atmospheric detritiation systems has been studied. The main advantage of this new process is to reduce the number and/or the size of the equipment in comparison to conventional tritium removal systems. Owing to the constraints linked to tritium handling, the separation performances of several commercial hollow fiber organic membranes have been analyzed, under various operating conditions, with hydrogen/nitrogen or deuterium/nitrogen mixtures. The experiments are performed with small quantities of hydrogen or deuterium (5000 ppm). The experimental results allow to evaluate the separation efficiency of these membranes and to determine the approp…

Metal–organic covalent network chemical vapor deposition for gas separation

2016

The chemical vapor deposition (CVD) polymerization of metalloporphyrin building units is demonstrated to provide an easily up-scalable one-step method toward the deposition of a new class of dense and defect-free metal–organic covalent network (MOCN) layers. The resulting hyper-thin and flexible MOCN layers exhibit outstanding gas-separation performances for multiple gas pairs.

Glassy PEEK‐WC vs Rubbery Pebax®1657 Polymers: Effect on the Gas Transport in CuNi‐MOF Based Mixed Matrix Membranes

2020

Mixed matrix membranes (MMMs) are seen as promising candidates to overcome the fundamental limit of polymeric membranes, known as the so-called Robeson upper bound, which defines the best compromise between permeability and selectivity of neat polymeric membranes. To overcome this limit, the permeability of the filler particles in the MMM must be carefully matched with that of the polymer matrix. The present work shows that it is not sufficient to match only the permeability of the polymer and the dispersed phase, but that one should consider also the individual contributions of the diffusivity and the solubility of the gas in both components. Here we compare the gas transport performance o…

Xenon Recovery by DD3R Zeolite Membranes: Application in Anaesthetics.

2019

Xe is only produced by cryogenic distillation of air, and its availability is limited by the extremely low abundance. Therefore, Xe recovery after usage is the only way to guarantee sufficient supply and broad application. Herein we demonstrate DD3R zeolite as a benchmark membrane material for CO2 /Xe separation. The CO2 permeance after an optimized membrane synthesis is one order magnitude higher than for conventional membranes and is less susceptible to water vapour. The overall membrane performance is dominated by diffusivity selectivity of CO2 over Xe in DD3R zeolite membranes, whereby rigidity of the zeolite structure plays a key role. For relevant anaesthetic composition ( 320 h). Thi…

Tuning Selectivities in Gas Separation Membranes Based on Polymer-Grafted Nanoparticles

2020

Polymer membranes are critical to many sustainability applications that require the size-based separation of gas mixtures. Despite their ubiquity, there is a continuing need to selectively affect the transport of different mixture components while enhancing mechanical strength and hindering aging. Polymer-grafted nanoparticles (GNPs) have recently been explored in the context of gas separations. Membranes made from pure GNPs have higher gas permeability and lower selectivity relative to the neat polymer because they have increased mean free volume. Going beyond this ability to manipulate the mean free volume by grafting chains to a nanoparticle, the conceptual advance of the present work is…

Supported Liquid Membranes and Their Modifications

2010

Publisher Summary This chapter discusses the principle, kinetic and transport mechanisms, stability of supported liquid membrane (SLM) design followed by thier configuration. In the examples of SLM applications presented in this chapter, the possibility to separate high quantities of compounds using small volumes of organic phases shows that this method is still a very attractive choice when an efficient and selective method is necessary. Also, as a result of the development and commercialization of hydrophobic hollow-fiber membrane contactors, SLM might be applied successfully for industrial purposes. This is due to the high-membrane surface per unit of volume with satisfactory liquid memb…

Gas Separation: Metal-Organic Covalent Network Chemical Vapor Deposition for Gas Separation (Adv. Mater. 34/2016)

2016

Metal-Organic Frameworks as Versatile Heterogeneous Solid Catalysts for Henry Reactions

2021

Metal–organic frameworks (MOFs) have become one of the versatile solid materials used for a wide range of applications, such as gas storage, gas separation, proton conductivity, sensors and catalysis. Among these fields, one of the more well-studied areas is the use of MOFs as heterogeneous catalysts for a broad range of organic reactions. In the present review, the employment of MOFs as solid catalysts for the Henry reaction is discussed, and the available literature data from the last decade are grouped. The review is organized with a brief introduction of the importance of Henry reactions and structural properties of MOFs that are suitable for catalysis. The second part of the review dis…

Investigations of polymerizable multilayers as gas separation membranes

1985

Abstract Polymerizable Langmuir—Blodgett (LB) multilayers of several diacetylenic amphiphiles were investigated on gas-permeable, polymeric supports. Macroscopically homogeneous multilayer films of hexacosa-10,12-diynoic acid and pentacosa-10,12-diyne phosphonate could be built up on polypropylene and polytetrafluoroethylene materials. As shown by scanning electron microscopy, the microscopic homogeneity of the built-up multilayers was mainly controlled by the surface structure of the support material, whereas the chemical nature of the support and photopolymerization of the layers did not affect the high order of the films. Such LB multilayers deposited on porous support materials are able…

First-principles modelling of complex perovskite (Ba1-xSrx)(Co1-yFey)O3-δ for solid oxide fuel cell and gas separation membrane applications

2010

The results of the first principles spin-polarized DFT calculations of the atomic and electronic structure of a complex perovskite (Ba1-xSrx)(Co1-yFey)O3-δ (BSCF) used as a cathode material for solid oxide fuel cells (SOFC) and gas separation membranes are presented and discussed. The formation energies of oxygen vacancies are found to be considerably smaller than in other magnetic perovskites, e.g. (La,Sr)MnO3, which explains the experimentally observed strong deviation of this material from stoichiometry. The presence of oxygen vacancies induces a local charge redistribution, associated with the local lattice perturbation, and expansion of the equilibrium volume, in line with the experime…