Abstract
This research aims to develop water purification geopolymers with high mechanical properties produced at low temperatures from natural raw materials. As a case study, the adsorption of heavy metal ions (Cd2+) onto these geoploymers prepared by solid-state conversion was investigated. The adsorption isotherms were obtained and the Langmuir parameters were calculated in order to make a comparison between the adsorption capacities of geopolymers and their constituents. The results showed that geopolymerization in the presence of natural zeolitic tuff leads to an increase of adsorption towards Cd(II) ions relative to the precursors. This is due to the increase of surface area upon destruction of the precursor's structure, as shown by XRD patterns, and generation of new cation exchange sites upon geopolymerization. Thus, they could be used in water transportation and storage (pools and dams) and other construction applications.