Research progress in SiO₂ aerogel preparation, modification and adsorption performance of heavy metalions

The pollution of heavy metal ions in wastewater has caused serious harm to human health, and the adsorption method has attracted much attention because of its high efficiency, economy, simplicity, and good selectivity. SiO2 aerogel is a potential adsorbent for removal of heavy metal ions in wastewater due to its high specific surface area (>500 m(2)/g), high porosity (>80%), controllable surface group and good physical/chemical stability. Herein, the preparation methods of SiO2 aerogel and its effect on microstructure were briefly introduced, focusing on the functionalization methods of SiO2 aerogel and the adsorption performance and factors of functionalized SiO2 aerogel for the adsorption of heavy metal ions in wastewater, and the adsorption mechanism and adsorption kinetics process of functionalized SiO2 aerogel as heavy metal ions adsorbent were analyzed. It was pointed out that the controllable preparation with low cost and short process, effective functionalization and efficient adsorption of various heavy metal ions are the future development directions of SiO2 aerogels as absorbent.