Development, characterization, and application of new adsorbents for separation by adsorption

A major portion of this dissertation deals with the development, synthesis, characterization, and applications of new adsorbents for gas separation by adsorption. The remaining portion introduces a new Spherical Pore Model for calculating the cavity radius and the potential energy of interactions of various gases in zeolite cavities.; The four new adsorbents developed in this study are Zr or Al-pillared clays, Br or ICl composite sorbents obtained by chemical vapor deposition on activated carbon, molybdenum dioxide/Super 'A' composite sorbents, and ion exchange zeolite (Li-X).; The new adsorbents are characterized using probe molecules adsorption isotherms and diffusivities, while the sorbents elemental compositions are determined using Inductively Coupled Argon Plasma Atomic Emission Spectroscopy. A Nicolet Stoe powder diffractometer with position sensitive detector is used for XRD measurements.; The application of these new adsorbents in adsorption separation processes are illustrated for various gas/solid systems. Using Zr-pillard interlayered clay as the adsorbent, the separation of {dollar}Nsb2{dollar}/{dollar}Osb2{dollar}, {dollar}Nsb2{dollar}/{dollar}CHsb4{dollar}, {dollar}Csb6Hsb6{dollar}/{dollar}Csb6Hsb{lcub}14{rcub}{dollar}, {dollar}CHsb4{dollar}/{dollar}COsb2{dollar}, and the {dollar}Csb8{dollar} aromatic isomers can be accomplished via equilibrium/kinetic modes of operation and elution gas chromatography. In addition, the {dollar}MoOsb2{dollar}/Super 'A' carbon can produce high purity {dollar}CHsb4{dollar} ({dollar}>{dollar}99%) at {dollar}>{dollar}70% recovery, and throughput {dollar}>{dollar}200 {dollar}l STP{dollar}/{dollar}h{dollar}/{dollar}kg{dollar} from a 50-50 feed mixture of methane and nitrogen via pressure swing adsorption. The new zeolite adsorbent (Li-X) has a much higher {dollar}Nsb2{dollar}/{dollar}Osb2{dollar} equilibrium selectivity ratio than the A-type and Na-X zeolites used commercially for air separation by pressure swing adsorption.; Finally, a new Spherical Pore Model for calculating the cavity radius and the potential energy of interactions of gas molecules with the zeolite surface atoms is introduced. The model utilizes the gas adsorption isotherm, and equates the free energy upon adsorption to the potential energy of interaction of the gas molecules with the zeolite cavity. Also, the average potential energies of interactions of various gases with the surface atoms of the zeolite cavities, calculated from the spherical pore model and the adsorption isotherms, compare reasonably well with the internal energies determined from the experimental heats of adsorption.