Thermodynamics of irreversible adsorption of water vapours by montmorillonite

The adsorption–desorption of water vapours on swelling layer silicate is considered in the framework of the Brunauer-Emmett-Teller (BET) and Frenkel-Halsey-Hill (FHH) formalisms. The theoretical dependencies calculated with reasonable and consistent values of model parameters are shown to agree quite satisfactorily with the experimental data. Based on these equations, the description of the adsorption hysteresis related to Type III adsorption isotherms is proposed, which also yields a good reproduction of the experimentally observed values

A family of zeolites with controlled pore size prepared using a top-down method

The properties of zeolites, and thus their suitability for different applications, are intimately connected with their structures. Synthesizing specific architectures is therefore important, but has remained challenging. Here we report a top-down strategy that involves the disassembly of a parent zeolite, UTL, and its reassembly into two zeolites with targeted topologies, IPC-2 and IPC-4. The three zeolites are closely related as they adopt the same layered structure, and they differ only in how the layers are connected. Choosing different linkers gives rise to different pore sizes, enabling the synthesis of materials with predetermined pore architectures. The structures of the resulting zeolites were characterized by interpreting the X-ray powder-diffraction patterns through models using computational methods; IPC-2 exhibits orthogonal 12- and ten-ring channels, and IPC-4 is a more complex zeolite that comprises orthogonal ten- and eight-ring channels. We describe how this method enables the preparation of functional materials and discuss its potential for targeting other new zeolites.PostprintPeer reviewe