Zeolite-geopolymer composite materials: Production and characterization

This study reports the production and characterization of a new class of geopolymer-zeolite materials obtained adding a commercial synthetic zeolite to a geopolymer matrix, to combine the functional micro-porosity of the zeolite with the meso-porosity of the geopolymer matrix, with the further possibility to consolidate the zeolite powder. Geopolymer-zeolite composites were produced mixing different metakaolin-based geopolymer matrices with zeolite Na13X, largely used for CO2 adsorption. Porous monoliths, with 3-dimensional interconnected open pores, were obtained and characterized. The composites were also tested in term of CO2 uptake, to highlight one of the possible functional properties of the new material. Composite monoliths based on Na-geopolymer matrix with Si/Al molar ratio equal to 1.2 were most promising thanks to a compressive strength of about 3 MPa, the presence of a wide range of porosity (from 5 Å to 2 ?m), a high specific surface area (211 m2 g-1), the formation of a zeolite NaA phase, and an improved CO2 adsorption capacity over the 50% of the expected value (3.1% vs 2.1%).