In situ synthesis of binderless ZSM-5 zeolitic coatings on ceramic foam supports

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.