Seiichi Asano

Adsorption of 1-butanol and p-xylene vapor and their mixtures with high silica zeolites

Abstract Experiments on fixed-bed adsorption of 1-butanol vapor, p -xylene vapor and their mixtures with high silica zeolites (HSZ) were conducted. For the cases of single-component adsorption, the adsorption equilibria obey the Langmuir equation, and the presence of water vapor was found to reduce the amount of adsorption. On the other hand, water vapor showed no effect on adsorption kinetics. For binary adsorption of 1-butanol and p -xylene with HSZ of Y- and Mordenite-type, depending upon the relative concentration of the two species, either species may be preferentially adsorbed. No simple expression was found to represent the equilibrium data. In contrast, the Langmuir equation was found to represent the binary equilibrium data of HSZ of the ZSM-5 type. Further, the dynamics of the fixed-bed adsorption may be predicted with use of the extended mass-transfer-zone method.

Removal and Recovery of a Substitute for Chlorofluorocarbon by High Silica Zeolite

A fixed-bed adsorption experiment was carried out to remove and to recover 2,2,3,3,3-pentafluoropropanol, developed as a substitute for CFC-113, by use of high silica zeolite (HSZ) pellets. For four kinds of HSZs, adsorption equilibria can be correlated to Langmuir equation. The mass transfer was studied in detail for a Y-type zeolite which showed the largest amount adsorbed. Intraparticle diffusion was found to be controlled by macropore diffusion. Further, the regeneration of HSZ was studied under reduced pressure with heating for industrial use. The regeneration of HSZ was completed within a shorter time at higher temperatures. The degradation of HSZ was not observed.

Adsorption of Organics onto High Silica Zeolite

Abstract Liquid phase adsorption equilibria of aromatic species onto high silica zeolite pellets were determined by the so-called batch bottle technique at 298.2K. While benzene compounds showed unfavorable S-shape isotherm, isotherms of pyridine compounds were favorable-types. Because phenyl compounds among adsorbates used here have negative charge within the ring and pyridine compounds have positive charge within the ring, thus-electrostatic affinity seems to be the main factors of adsorbate dependency of isotherms. For the same systems, concentration decay curves were obtained by agitated batch technique at 298.2K. By comparison of the curves with theoretical one, apparent intraparticle diffusivity was determined. Phenols and aminopyridine showed constant diffusivities based on bulk phase concentration difference. For methylpyridine systems, concentration dependency appeared and mass transfer resistance other than molecular diffusion seemed to affect the dependency.

Application of High Silica Zeolite to Remove Organic Vapors from Industrial Effluent Air

A series of small-scall laboratory tests were performed under almost the same conditions used in industry, to remove lacker-solvent vapor from air. A flow method was used to measure breakthrough curves as well as equilibrium data. Starting from single component vapor adsorption, three binary and one ternary vapor systems among 1-Butanol, p-Xylene and 2-Butoxyethanol, respectively, were studied. Equilibria for each single component vapor in air were obtained from the analysis of breakthrough curves, and were expressed by the Langmuir equation. Binary equilibria were obtained in the same way as above, and were correlated by Markham-Benton equation. Regarding intraparticle diffusion, it was found from the analyses of breakthrough curves that macro-pore diffusion was the rate-determining step. Break times could be estimated by Extended-MTZ-Method with fairly good accuracy. Furthermore, for regeneration of spent High Silica Zeolite particles, it was known that degradation of adsorption capacity did not occur when those of higher SiO2/Al2O3 ratio were used.