Design of palygorskite-based aerogels for organic dye waste-water treatment

It is a challenge to develop high-efficiency, easy-recyclable adsorbents for the removal of dyes from environmental waters. Herein, we report the construction of two types of palygorskite (Pal)-polymer aerogels with distinctive hierarchically meso - microporous structure, which different polymer species-sodium alginate (SA) and chitosan (CS) through the sol-gel method, cross-linking, and freeze-drying, for the removal of dye pollutants from water. A hierarchical porous structure of aerogel accelerates the diffusion of dye water. Notably, this developed strategy enables selective dye adsorption by tuning the polymer and component contents in the Palpolymer aerogel. Indeed, the maximum adsorption capacity of the Pal-SA composite aerogel for malachite green (cationic) dye reached 2008 mg/g and that of the Pal-CS(Fe3+) composite aerogel for sunset yellow (anionic) reached 976 mg/g. In addition, the composite aerogels can be regenerated many times without significant loss of effectiveness. This work provides a new concept and strategy for dye waste-water treatment.