Hydrothermal and microwave synthesis of SAPO (CHA) zeolites on aluminium foams for heat pumping applications

In this paper, a study on direct growth of SAPO (CHA) zeolites on aluminium foamed supports is presented. A preliminary investigation on SAPO-34 and SAPO-44 syntheses was carried out by conventional hydrothermal and microwave route to select appropriate formulations for in situ growth on aluminium foams. Adsorption capacity of coated foams were evaluated by a McBain system and compared to adsorption isobars of pure zeolites measured by a Chan microbalance. Coated samples showed the typical behaviour of the corresponding zeolite, confirming that the interaction with aluminium support was not detrimental to the zeolite adsorption performances. SAPO-34 coatings grew ten times faster by microwaves than by hydrothermal route, while for SAPO-44 the microwave deposition was not feasible for the intense corrosion of aluminium foams.

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► SAPO 34 and SAPO 44 zeolites have been prepared by standard hydrothermal and microwave synthesis.
► Coatings of the two zeolites have been obtained on aluminium foams by in situ synthesis.
► The in situ growth has been achieved by standard hydrothermal and microwave synthesis.
► Water adsorption values of zeolite coatings have been measured and compared to pure zeolites.