Seeded Hydrothermal Synthesis for Zeolite Preparation

Synonyms

Ex situ zeolite synthesis, Secondary growth method

The hydrothermal synthesis procedures used to prepare zeolite membranes can be classified in two general groups: ex situ and in situ methods, that is with and without a previous seeding step. The secondary (seeded) growth method, decoupling nucleation and membrane growth, is considered as the most successful approach to control membrane formation (Caro et al. 2000; Arruebo et al. 2008).

This method includes a first step, seeding step, in which a closely packed layer of colloidal zeolite crystals, synthesized homogenously, is deposited onto the surface of a support. These seeds, act as nuclei for further crystal growth with a secondary gel under hydrothermal synthesis conditions in the second stage, see Fig. 1.

Seeded Hydrothermal Synthesis for Zeolite Preparation, Fig. 1

Scheme of the hydrothermal synthesis of zeolite membranes by separating the nucleation and the crystal growth steps