Incorporation of organic liquids into geopolymer materials - A review of processing, properties and applications

Geopolymers, composed of an amorphous three-dimensional inorganic network and synthesized by the activation of a solid alumino-silicate precursor with an alkaline activating solution, have attracted increasing attention because of their environmental benefits and favorable characteristics. This review deals with the development of organic/inorganic composite materials made by adding organic liquids into inorganic geopolymer matrices. Firstly, the incorporation processing approaches are presented and are divided into three categories: (i) Direct incorporation, (ii) Pre-emulsification (iii) Solid impregnation. Their main advantages and drawbacks are discussed in relation to the aimed properties. Secondly, this review highlights that geopolymers are low-cost candidates allowing technologically significant applications, through the incorporation of various organic liquids. Aside from the well-studied immobilization of industrial waste streams commonly known as stabilization/solidification (S/S), the development of highly porous geopolymer foams and the design of reinforced organic/inorganic composite matrices are being notably investigated. This review aims at summarizing the main published results, and fostering further investigations into innovative uses of organic liquids incorporated into geopolymers for a wide range of applications. (authors)