Geopolymers are novel inorganic polymeric materials synthesized from three common aluminosilicate sources - coal fly ash and incineration ash; slags such as granulated blast (steel) or furnace (iron) slag; and clays such as metakaolinite or calcined clay, via alkaline activation at relatively low temperatures. Geopolymers often consist of high pore volumes and large surface areas; and can be fabricated into adsorbent materials of different shapes and of larger sizes - spherical and monolithic. Geopolymerisation is not a new concept in environmental remediation; and has been used as barriers in immobilizing toxic and radioactive metals via the combination of physical encapsulation and chemical stabilization, and/or physicochemical, electrostatic, and sorption mechanisms. However, emerging trends in the applications of geopolymers are in the adsorption and/or sequestration of contaminants in aqueous and gaseous phases, mostly toxic trace heavy metals, recalcitrant organic pollutants such as dyes and air pollutants. This paper will provide a state-of-the-art overview of the recent scientific advances on the syntheses of different the types geopolymeric materials derived from these aluminosilicate sources; and their sustainable environmental applications. It will focus concisely on the adsorptive effectiveness of these new materials and comparison against other adsorption technologies utilizing conventional materials such as activated carbon and zeolites; and prospects and challenges for economic large-scale productions and development of new environmentally-sustainable technologies.

An overview of the recent advances in the environmental remediation applications of geopolymers

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.