Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Preparation and characterization of xerogel catalyst microspheres
Ist Teil von
Journal of non-crystalline solids, 2004-12, Vol.350 (Complete), p.290-298
Ort / Verlag
Amsterdam: Elsevier B.V
Erscheinungsjahr
2004
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
For easier handling and use in fixed bed reactors, Pd–Ag/SiO2 aerogel–like xerogel catalysts were shaped into microspheres using the microencapsulation process developed by Brace GmbH. Before the bead production process, the xerogel catalyst was ground in water and mixed with ethylene glycol and sodium alginate, the latter of which is the gelation agent. The beads were formed at a vibrating nozzle and solidified during their fall in a water tank containing calcium ions, which induce cross-linking of the alginate and consequent bead hardening. Preliminary work was done using a syringe instead of the material-consuming Brace unit. The beads were made from a suspension of dried only, dried and calcined, or dried, calcined, and reduced catalyst. The textural properties of the beads were analyzed by nitrogen adsorption–desorption isotherms and mercury porosimetry; and bead catalytic activity was tested for selective hydrodechlorination of 1,2-dichloroethane. The beads made from a suspension of dried catalyst appear to have properties the closest to that of the xerogel reference catalyst. Porosity and surface area are maintained at their level before bead formation. However conversion of 1,2-dichloroethane decreases after the production process, possibly due to poisoning by calcium ions.