Tuning of the porosity in geopolymers and geopolymer composites

Geopolymers are synthetic alkali-aluminosilicates, constituting a family of materials with properties varying among those of ceramics, cements, zeolites, or refractories, depending on their formulation. They can be easily formed in complex shapes (spheres, monoliths, panels, honeycombs, etc.) and geopolymer matrices can act as binders for functionalizing fillers in composites. Finally, geopolymers can also be recycled. Since geopolymers are nanostructured and intrinsically mesoporous materials, a complex pore system can be prepared by combining mesopores with micro and macro-porosity. Geopolymers may be used to fabricate porous materials with a total pore volume from 30% up to 90% using different techniques, such as slurry route, foaming and cold sintering process. Furthermore, the addition of fillers such as zeolites, apatites, hydrotalcites and others modifies the porosity and related properties, such as the absorption of pollutants, etc. Research activities were carried in the framework of the MUR PRIN 2022 Project GEA - GEopolymer based Adsorbents for effective adsorption and selective separation of CO2 and eutrophication pollutants, - Prot. 20229THRM2, funded by the European Union – Next Generation EU.