Geopolymer-composite adsorbents for the treatment of polluted flows

Geopolymers are recently been addressed as alternative, cost-effective, environmentally friendly adsorbents for the removal of pollutants from gaseous or liquid streams. Indeed, these materials have several properties which make them suitable as adsorbents. They are intrinsically mesoporous and their porosity can be further tailored, from the micro to the macro scale, employing several techniques. Different production processes allow geopolymers to be easily molded into different shapes as monoliths, granules or beads for easiness of operation and to facilitate the handling and storage. They have ionic exchange and electrostatic interaction properties deriving from their peculiar 3-dimensional structure, because of the presence of aluminium in tetrahedral coordination. To broaden the spectrum of applications, geopolymer matrices can be functionalized with fillers in order to create more performing composite materials. For all the mentioned reasons, geopolymer-composites, containing zeolites or hydrotalcites, were produced in the shape of monoliths or beads. The materials were then characterized as adsorbents for the removal of CO2 at different temperatures or for the treatment of wastewater.