Geopolymer based materials for pollutants removal (from water and gas)

The versatility of geopolymer materials is well known and starting from this assumption, the research on geopolymers at ISTEC is addressed to several application sectors. Geopolymers are synthetic aluminosilicates inorganic polymers obtained through chemical reactions, with the possibility to vary the stoichiometry and the composition, even with the addition of functional fillers. The material is mesoporous and a multidimensional and functional porosity can be generated through the addition of fillers or the use of specific techniques. In the last years, geopolymers have been addressed as alternative, cost-effective, environmentally friendly adsorbents for the removal of pollutants from gaseous or liquid streams. In fact, they are suitable as solid adsorbents because of some peculiar properties: geopolymers are highly porous with the possibility to customize porosity from the micro to the ultramacro scale and the 3-dimensional structure, with aluminium in tetrahedral coordination, confers ionic exchange and electrostatic interaction properties. Different production processes have been developed at ISTEC to easily mold geopolymers into different shapes as monoliths, granules or beads [1] for easiness of operation and to facilitate the handling and storage. To broaden the spectrum of applications, benchmarked geopolymer matrices were functionalized with fillers in order to create more performing composite materials. The materials were then characterized as adsorbents for the removal of CO2 at different temperatures [2-4] or for the treatment of wastewater [5-6].