Metal–Organic Frameworks for Separations

Kenji Sumida, David L. Rogow, Jarad A. Mason, Thomas M. McDonald, Eric D. Bloch, Zoey R. Herm, Tae-Hyun Bae, Jeffrey R. Long

Carbon Dioxide Capture in Metal–Organic Frameworks

Overview of membrane science and technology membrane transport theory membrane and modules concentration polarization reverse osmosis ultrafiltration microfiltration gas separation pervaporation ion exchange membrane processes - electrodialysis carrier facilitated transport medical applications of membranes other membranes processed.

Membrane Technology and Applications

A ceramic fuel cell in an all solid-state energy conversion device that produces electricity by electrochemically combining fuel and oxidant gases across an ionic conducting oxide. Current ceramic fuel cells use an oxygen-ion conductor or a proton conductor as the electrolyte and operate at high temperatures (>600°C). Ceramic fuel cells, commonly referred to as solid-oxide fuel cells (SOFCs), are presently under development for a variety of power generation applications. This paper reviews the science and technology of ceramic fuel cells and discusses the critical issues posed by the development of this type of fuel cell. The emphasis is given to the discussion of component materials (especially, ZrO2 electrolyte, nickel/ZrO2 cermet anode, LaMnO3 cathode, and LaCrO3 interconnect), gas reactions at the electrodes, stack designs, and processing techniques used in the fabrication of required ceramic structures.

Ceramic Fuel Cells

The escalating level of atmospheric carbon dioxide is one of the most pressing environmental concerns of our age. Carbon capture and storage (CCS) from large point sources such as power plants is one option for reducing anthropogenic CO(2) emissions; however, currently the capture alone will increase the energy requirements of a plant by 25-40%. This Review highlights the challenges for capture technologies which have the greatest likelihood of reducing CO(2) emissions to the atmosphere, namely postcombustion (predominantly CO(2)/N(2) separation), precombustion (CO(2)/H(2)) capture, and natural gas sweetening (CO(2)/CH(4)). The key factor which underlies significant advancements lies in improved materials that perform the separations. In this regard, the most recent developments and emerging concepts in CO(2) separations by solvent absorption, chemical and physical adsorption, and membranes, amongst others, will be discussed, with particular attention on progress in the burgeoning field of metal-organic frameworks.

Carbon Dioxide Capture: Prospects for New Materials

Semiconducting 2D metal oxides have attracted great research interests for gas-sensing applications because of their considerable specific surface area and highly homogeneous surface. Developing a method for fabricating thin films of 2D metal oxides is crucial for minimizing the negative effects on sensing performance caused by slow diffusion. In this work, a simple, versatile, and highly reproducible self-assembly method is developed for fabricating monolayer film sensors made from metal oxide nanosheets with much superior sensing performance compared with their thick film counterparts. To prepare the monolayer film sensors, a monolayer film of metal oxide nanosheets, self-assembled at the air-water interface, is transferred onto a sensor substrate. The CuO monolayer sensors prepared with this self-assembly method show much improved gas sensitivity (sensor signal: 350% vs 100% at 5 ppm of H2S) and faster response and recovery rate (τres: 20 s vs 110 s; τrec: 120 s vs 320 s) than the thick film sensors prepared from the same sensing material. The enhanced sensing performance demonstrated by the monolayer film of CuO nanosheets is explained quantitively with a modified coupled reaction-diffusion model. Similar enhancement on gas-sensing performance is also observed for the ZnO-nanosheet-based monolayer sensors prepared by the same self-assembly method.

Self-Assembled Monolayer of Metal Oxide Nanosheet and Structure and Gas-Sensing Property Relationship.

Tetraethylenepentamine (TEPA) modified silica aerogel CO2 adsorbents were prepared by two methods: evaporative precipitation and wet-impregnation. The distribution of amine on the support and CO2 adsorption performance of these sorbents were studied by nitrogen porosimetry, thermogravimetric analysis, transmission electron microscopy, and CO2 gravimetric adsorption analysis to understand the synthesis-structure-CO2 adsorption property relationships of the silica aerogel supported amine sorbents. The sorbents prepared by evaporative precipitation showed slightly better distributions of TEPA and adsorption performance relative to the wet impregnated analogues. The enhancements observed, however, were unexpectedly small suggesting that the two methods of amine immobilization result in similar TEPA distributions. It appears that the thermodynamic limitation toward lowering the free energy of the system is causing the TEPA to consolidate inside the aerogel network, suggesting that methods of impregnation are o...

Amine distribution and carbon dioxide sorption performance of amine coated silica aerogel sorbents: Effect of synthesis methods.

Effects of water vapor on gas permeation and separation properties of MFI zeolite membranes at high temperatures

Thermal stability improvement of MFI-type zeolite membranes with doped zirconia intermediate layer

Electrical conductivities of samarium (Sm), terbium (Tb), praseodymium (Pr) and zirconium (Zr) doped ceria membranes were measured in T = 600–900°C and pO2 = 10−22–0.21 atm. Doping Sm and Pr in CeO2 respectively enhances the ionic conductivity and electron-hole conductivity of ceria. Sm-Pr doped ceria exhibits both n-type (at lower pO2) and p-type (at high pO2) electronic and ionic conductivity in the temperature range studied. Adding Tb in the Sm doped ceria causes a reduction in ionic conductivity. Zr-Pr doped ceria is an n-type electronic conductor at low \(P_{{\text{O}}_{\text{2}} }\) and p-type electronic conductor at high pO2. The ionic conductivity of Zr-Pr doped ceria is lower than Sm doped ceria but higher than pure ceria. Oxygen permeation flux through the Zr-Pr doped ceria membrane, dominated by the slow oxygen ionic conduction, is similar to the ytttria doped bismuth oxide membrane, and smaller, but close to that of perovskite-type lanthanum cobaltite membrane.

Y.S. Lin

Papers

Self-Assembled Monolayer of Metal Oxide Nanosheet and Structure and Gas-Sensing Property Relationship.

Amine distribution and carbon dioxide sorption performance of amine coated silica aerogel sorbents: Effect of synthesis methods.

Effects of water vapor on gas permeation and separation properties of MFI zeolite membranes at high temperatures

Thermal stability improvement of MFI-type zeolite membranes with doped zirconia intermediate layer

Electric conductivity and oxygen permeability of modified cerium oxides