Silver Phosphate/Graphene Oxide Aerogel Microspheres with Radially Oriented Microchannels for Highly Efficient and Continuous Removal of Pollutants from Wastewaters

Abstract

Silver phosphate/graphene oxide aerogel microspheres (SGAMs) with radially oriented microchannels are constructed by electrostatically spraying the as-prepared silver phosphate/graphene oxide/chitosan (Ag3PO4/GO/CS) suspension into numerous microdroplets followed by freezing, lyophilization and cross-linking for highly efficient and continuous removal of pollutants from wastewaters. The resultant aerogel microspheres exhibit both high adsorption rate and large adsorption capacity because of their short internal diffusion pathway and high specific surface area. The synergy between adsorption and visible light photocatalysis endows the porous microspheres an outstanding efficiency of removing pollutants under both static and continuous water treatment conditions. Furthermore, the presence of graphene oxide (GO) efficiently improves the recyclability of Ag3PO4 due to the fast electronic transfer at the interface. More than 95% Rhodamine B (50 mg L–1) is adsorbed by SGAMs in 5 min, and bisphenol A (10 mg L–1) is almost completely photodegraded in 20 min under visible light irradiation. The removal efficiency of bisphenol A in a continuous flow system (0.1 mL min–1) is maintained at 95% over 50 h. In addition, the SGAMs could photodegrade pharmaceuticals and pesticides effectively. This work provides a promising visible light photocatalysis approach for enhancing efficiency and durability of photocatalysts in a continuous water treatment system.