A state-of-the-art review of recent advances in porous geopolymer: Applications in adsorption of inorganic and organic contaminants in water

This review article discusses the potential of porous geopolymers as a promising approach for the removal of various contaminants, including heavy metals, dyes, drug residues, pharmaceuticals, and pesticides from aqueous solutions. Additionally, this review provides an overview of the recent preparation methods of geopolymers and their characteristics. The high porosity of the geopolymers allows for the adsorption of large quantities of pollutants, as demonstrated by scanning electron microscopy and mechanical evaluations. Thermal analysis also shows that the materials are thermally stable and can withstand high temperatures. The published procedures for porous geopolymers synthesis appear to be efficient and advantageous, however, further optimization of the fabrication procedure is required for each potential application. The authors recommend focusing on novel applications, such as CO2/NOx/SO2 capture in gaseous mediums and the adsorption of new and toxic contaminants. They also suggest exploring the use of waste resources to replace metakaolin clays and studying the economic revenue of the application of geopolymers in wastewater treatment plants (WWTP). Overall, this review can serve as a guide for proposing, studying, and applying different adsorptive processes for the removal of various toxic contaminants present in various water sources.