Fig xA Representative SEM micrographs of the
Since the template pretreatment method has shown significant improvement in the SAPO-34 coverage as discussed previously, further investigations on the increase of catalyst loading versus number of coatings is performed. The specific surface area Erlotinib Hydrochloride as a function of the coating cycles is presented in Fig. 11. The deposition of a dense and a homogeneous layer of SAPO-34 on the SiC surface has significantly increases the overall specific surface area of the final composite from 34 m2/g, for the pristine SiC foam (total pore volume of 0.126 cm3/g and pore size 15 nm), to 390 m2/g for the composite after the third coating cycles. The zeolite loading determined by selective HF dissolution was amounted to about 53 wt.% after third cycles coating. The increase of the composite specific surface area as a function of coating cycles was attributed to the deposition of high intrinsic surface area SAPO-34 crystals on the SiC surface which has similar trend to that reported in the literature for other supported zeolites . The specific surface area of the composite increases with the number of the coating cycles up to third cycles and further decreased. The decrease of the specific surface area after the third coating cycle could be attributed to the excessive intergrowth of the SAPO-34 within the zeolite layer which hinders the accessibility of the nitrogen to the inner zeolite porosity. Moreover, the loss of crystallinity and the increase of crystal size after the 4th coating cycle was observed from the SEM micrographs (not shown) which can contribute in the reduction of the surface area. However, this observation could be mainly attributed to the weak attachment of the zeolite layer formed after the 4th cycle which was detached during the sonication process.