ABSTRACT
Zeolite Y is a crystalline aluminum silicate used as an adsorbent matrix in the
purification of proteins. Particle size enlargement is sometimes required and is
achieved by compaction of the zeolite powder followed by heat treatment. To
maintain a large surface area available for adsorption, additives are used in the
pelletizing procedure. Ultrastable zeolite Y (USY) was compacted into pellets
which were heat-treated at 800 or 1000°C without affecting crystallinity. The
samples were characterized by powder X-ray diffraction (XRD), electron
microscopy, and N2-adsorption/desorption. Ammonium acetate, used as an
additive and sublimed off prior to the high temperature treatment, decreased
the bulk density of the material, but did not affect the pore size distribution in
the mesoporous range, i.e., 2–50 nm. Metakaolinite, which was used as a
binder, affected the pore size distribution by splitting a broad local pore
volume maximum at a pore diameter of 38 nm, observed in binderless
ultrastable zeolite Y, into maxima at pore diameters of 20 and 80 nm. The
volume of pores, within the diameter range of 2–5 nm, was decreased by 50%,
probably due to a blocking effect of metakaolinite.