Synthesis of geopolymer emulsions

The understanding of geopolymer emulsion synthesis is a major issue for several industrial applications such as the formation of hierarchically porous material for filtration, lightweight materials for civil engineering or even the conditioning of radioactive mineral oil. The aim of this paper is to study model emulsions (hexadecane dispersed in Na or K-metakaolin based geopolymer) with the highest volume fraction of C16 incorporated. The influence of the viscosity of the geopolymer paste controlled by the water content was studied and results show that emulsions are unstable for a viscosity ratio η_d/η_c lower than 0.01. Up to 70% in volume of C16 was incorporated within the K-geopolymer and hierarchical porous network was thus obtained. After oil removal by solvent extraction, a monolith with a compressive strength of around 0.5-0.6 MPa was characterized in terms of pore size distribution and specific surface area. (author)