In situ synthesis of binderless ZSM-5 zeolite coatings on ceramic foam supp
orts was studied. The effects were investigated of the rotation of the auto
claves during synthesis, the reaction mixtures SiO2/Al2O3 and dilution rati
os, the reaction mixture-to-support surface area ratio, the synthesis tempe
rature and time as well as the composition of the support material (alpha-A
l2O3, SiC/Al2O3 and ZrO2/Y2O3 foam).
X-ray diffraction patterns showed highly crystalline ZSM-5 structures super
posed on the ceramic foam carrier pattern. The deposition of ZSM-5 was quan
tified by measuring mass increase and BET surface of the samples. Uniform a
nd continuous ZSM-5 coatings with overall specific surface areas of up to 2
00 m(2)/g were obtained. SEM micrographs showed coffin-like, partly intergr
own crystals of 5-10 mu m that appeared to be attached firmly to the suppor
t. (C) 2000 Elsevier Science B.V. All rights reserved.