APPLICATION OF THE INDIRECT FOURIER-TRANSFORM METHOD TO A STUDY OF ZEOLITE NUCLEATION

The nucleation events of synthesis reactions of ZSM5 and Na-A zeolites were studied, with particular emphasis on the role of organic templat e, TPA+ (tetrapropylammonium), in the ZSM5 synthesis. Qualitative eval uation of the structural units was obtained by Small-Angle X-ray Scatt ering (SAXS) measurements which were analyzed using an indirect Fourie r transform method. In the presence of organic cation TPA+ in the ZSM5 synthesis we found globular structural units, 5 nm in diameter, which aggregate to elongated bodies 44 nm long. These results suggest that the zeolite ZSM5 building blocks are globular structural units, 5 nm i n diameter, containing silica, alumina, organic cation and water, whic h fuse together to produce elongated aggregates that may compose the f inal unit cell. We found that the Na-A zeolite follows nucleation via 1 nm globular particles, which suggests that the existence of globular structural units in the nucleation of zeolites is a general phenomeno n.