Adsorption of gaseous pollutants by alkali-activated materials

This chapter introduces the problem related to gaseous pollutants and the possible use of alkali-activated materials, in particular geopolymers, for the production of porous solid adsorbents. It starts by describing the main pollutants and what the possible ways to counter them are. The alkali-activated materials and their peculiar characteristics, capable of making them valid adsorbents, are then introduced. Subsequently, examples reported in the relevant literature, regarding the use of pure or composite geopolymers, especially for the removal of CO2, are provided. Among the cited composites there are those based on zeolites and hydrotalcites for the production of adsorbents active at low or intermediate temperatures. By the end of the chapter, fly-ashes activated or modified in several ways are reported as an alternative low-cost base material for the production of adsorbents suitable to treat air pollution.