Adsorbents

RALPH T. YANG, PhD, is Dwight F. Benton Professor of Chemical Engineering at the University of Michigan.

• Preface xi1 Introductory Remarks 11.1. Equilibrium Separation and Kinetic Separation 21.2. Commercial Sorbents and Applications 31.3. New Sorbents and Future Applications 6References 72 Fundamental Factors for Designing Adsorbent 82.1. Potential Energies for Adsorption 82.2. Heat of Adsorption 102.3. Effects of Adsorbate Properties on Adsorption: Polarizability (α), Dipole Moment (μ), and  Quadrupole Moment (Q) 112.4. Basic Considerations for Sorbent Design 122.4.1. Polarizability (α), Electronic Charge (q), and van der Waals Radius (r) 122.4.2. Pore Size and Geometry 13References 163 Sorbent Selection: Equilibrium Isotherms, Diffusion, Cyclic Processes, and Sorbent Selection Criteria 173.1. Equilibrium Isotherms and Diffusion 183.1.1. Langmuir Isotherms for Single and Mixed Gases 183.1.2. Potential Theory Isotherms for Single and Mixed Gases 203.1.3. Ideal Adsorbed Solution Theory for Mixture and Similarities with Langmuir and Potential Theories 223.1.4. Diffusion in Micropores: Concentration Dependence and Predicting Mixed Diffusivities 233.2. Temperature Swing Adsorption and Pressure Swing Adsorption 273.2.1. Temperature Swing Adsorption 283.2.2. Pressure Swing Adsorption 303.3. Simple Criteria for Sorbent Selection 40References 494 Pore Size Distribution 544.1. The Kelvin Equation 544.2. Horv´ath–Kawazoe Approach 554.2.1. The Original HK Slit-Shaped Pore Model 574.2.2. Modified HK Model for Slit-Shaped Pores 604.2.3. Modified Model for Cylindrical Pores 684.3. The Integral Equation Approach 74References 765 Activated Carbon 795.1. Formation and Manufacture of Activated Carbon 795.2. Pore Structure and Standard Tests for Activated Carbon 825.3. General Adsorption Properties 845.4. Surface Chemistry and Its Effects on Adsorption 865.4.1. Effects of Surface Functionalities on Gas Adsorption 895.5. Adsorption from Solution and Effects of Surface Functionalities 925.5.1. Adsorption from Dilute Solution (Particularly Phenols) 935.5.2. Effects of Surface Functionalities on Adsorption 995.6. Activated Carbon Fibers 1045.6.1. Adsorption Isotherms 1095.7. Carbon Molecular Sieves 1095.7.1. Carbon Deposition Step 1145.7.2. Kinetic Separation: Isotherms and Diffusivities 1155.7.3. Carbon Molecular Sieve Membranes 117References 1236 Silica Gel, MCM, and Activated Alumina 1316.1. Silica Gels: Preparation and General Properties 1316.2. Surface Chemistry of Silicas: The Silanol Groups 1346.3. The Silanol Number (OHnm−1) 1356.4. MCM-41 1396.5. Chemical Modification of Silicas and Molecular Imprinting 1416.6. Activated Alumina 1466.7. Activated Alumina as Special Sorbents 150References 1547 Zeolites and Molecular Sieves 1577.1. Zeolite Types A, X, and Y 1587.1.1. Structure and Cation Sites of Type A Zeolite 1587.1.2. Structure and Cation Sites of Types X and Y Zeolites 1607.1.3. Examples of Molecular Sieving 1617.2. Zeolites and Molecular Sieves: Synthesis and Molecular Sieving Properties 1647.2.1. Synthesis of Zeolites A, X, and Y 1647.2.2. Organic Additives (Templates) in Synthesis of Zeolites and Molecular Sieves 1657.3. Unique Adsorption Properties: Anionic Oxygens and Isolated Cations 1737.4. Interactions of Adsorbate with Cations: Effects of Cation Site, Charge, and Ionic Radius 1757.4.1. Cation Sites 1757.4.2. Effects of Cation Sites on Adsorption 1807.4.3. Effects of Cation Charge and Ionic Radius 183References 1878 π-Complexation Sorbents and Applications 1918.1. Preparation of Three Types of Sorbents 1928.1.1. Supported Monolayer Salts 1938.1.2. Ion-Exchanged Zeolites 1978.1.3. Ion-Exchanged Resins 2018.2. Molecular Orbital Theory Calculations 2028.2.1. Molecular Orbital Theory—Electronic Structure Methods 2028.2.2. Semi-Empirical Methods 2038.2.3. Density Functional Theory Methods 2038.2.4. Ab Initio Methods 2048.2.5. Basis Set 2058.2.6. Effective Core Potentials 2058.2.7. Model Chemistry and Molecular Systems 2068.2.8. Natural Bond Orbital 2078.2.9. Adsorption Bond Energy Calculation 2088.3. Nature of π-Complexation Bonding 2088.3.1. Understanding π-Complexation Bond through Molecular Orbital Theory 2098.3.2. π-Complexation Bonds with Different Cations 2128.3.3. Effects of Different Anions and Substrates 2138.4. Bulk Separations by π-Complexation 2168.4.1. Deactivation of π-Complexation Sorbents 2168.4.2. CO Separation by π-Complexation 2168.4.3. OlefinParaffin Separations 2198.4.4. AromaticsAliphatics Separation 2208.4.5. Possible Sorbents for Simulated Moving-Bed Applications 2228.5. Purification by π-Complexation 2238.5.1. Removal of Dienes from Olefins 2248.5.2. Removal of Aromatics from Aliphatics 226References 2279 Carbon Nanotubes, Pillared Clays, and Polymeric Resins 2319.1. Carbon Nanotubes 2319.1.1. Catalytic Decomposition 2339.1.2. Arc Discharge and Laser Vaporization 2419.1.3. Adsorption Properties of Carbon Nanotubes 2439.2. Pillared Clays 2539.2.1. Syntheses of PILCs 2539.2.2. Micropore Size Distribution 2569.2.3. Cation Exchange Capacity 2589.2.4. Adsorption Properties 2609.2.5. PILC and Acid-Treated Clay as Supports 2629.3. Polymeric Resins 2649.3.1. Pore Structure, Surface Properties, and Applications 2669.3.2. Comparisons of Resins and Activated Carbon 2699.3.3. Mechanism of Sorption and Gas-Phase Applications 271References 27310 Sorbents for Applications 28010.1. Air Separation 28010.1.1. 5A and 13X Zeolites 28210.1.2. Li-LSX Zeolite 28310.1.3. Type X Zeolite with Alkaline Earth Ions 28810.1.4. LSX Zeolite Containing Ag (AgLiLSX) 28910.1.5. Oxygen-Selective Sorbents 29610.2. Hydrogen Purification 30310.3. Hydrogen Storage 30510.3.1. Metal Hydrides 30610.3.2. Carbon Nanotubes 30810.4. Methane Storage 32110.5. OlefinParaffin Separations 32610.5.1. Sorbents 32610.5.2. PSA Separations 32810.5.3. Other Sorbents 33410.6. NitrogenMethane Separation 33410.6.1. Clinoptilolites 33610.6.2. ETS-4 34110.6.3. PSA Simulation: Comparison of Sorbents 34410.7. Desulfurization of Transportation Fuels 34410.7.1. Fuel and Sulfur Compositions 34710.7.2. Sorbents Studied or Used 34910.7.3. π-Complexation Sorbent 35010.8. Removal of Aromatics from Fuels 36110.9. NOx Removal 363References 371Author Index 383Subject Index 403

"…a very good book on a very important topic. Well-written, resplendent with figures and tables, and well-referenced are some of my observations." (Journal of Hazardous Materials, 109, 2004) "...fulfils existing demand for a simple and comprehensive text devoted to commercial and novel adsorbents...a valuable guide..." (Journal of the American Chemical Society, Vol. 125, No. 39, 2003)