Many industrial applications need supporting or shaping powdery zeolites. Since geopolymers can be considered the amorphous counterpart or precursors of crystalline zeolites, it is possible to promote zeolite crystallization inside the geopolymeric matrix by tuning pH, temperature and time of the geopolymerization reaction. In this paper, combining zeolite crystallization with a foaming process initiated by silicon, a multifunctional self-supporting zeolitic material has been obtained with pores ranging from the micro to the macro range. Geopolymerization and crystallization have been realized simultaneously curing the samples at specific temperature and humidity conditions. Every specimen obtained at curing time higher than two days, regardless relative humidity and silicon content, contained zeolite A [LTA] and X [FAU] as the only crystalline phases. Finally, the porosity generated by the foaming process promotes the zeolite nucleation mainly on the surfaces of the pores, whereas the struts remain amorphous.
Self-supporting zeolites by Geopolymer Gel Conversion (GGC)
Roviello, G.;Ferone, C.
2019-01-01
Abstract
Many industrial applications need supporting or shaping powdery zeolites. Since geopolymers can be considered the amorphous counterpart or precursors of crystalline zeolites, it is possible to promote zeolite crystallization inside the geopolymeric matrix by tuning pH, temperature and time of the geopolymerization reaction. In this paper, combining zeolite crystallization with a foaming process initiated by silicon, a multifunctional self-supporting zeolitic material has been obtained with pores ranging from the micro to the macro range. Geopolymerization and crystallization have been realized simultaneously curing the samples at specific temperature and humidity conditions. Every specimen obtained at curing time higher than two days, regardless relative humidity and silicon content, contained zeolite A [LTA] and X [FAU] as the only crystalline phases. Finally, the porosity generated by the foaming process promotes the zeolite nucleation mainly on the surfaces of the pores, whereas the struts remain amorphous.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.