Highly efficient removal of bisphenol A by a three-dimensional graphene hydrogel-AgBr@rGO exhibiting adsorption/photocatalysis synergy

The increasing extent of environmental pollution by industrial chemicals necessitates the development of facile methods of their removal. Among the various techniques employed for this purpose, photocatalytic degradation is particularly attractive, since it does not require the use of other chemicals, achieving pollutant mineralization by the action of light and atmospheric oxygen only. However, most photocatalysts suffer from poor stability and recyclability, which limits their practical applications. This study describes the encapsulation of AgBr by reduced graphene oxide to form a composite ([email protected]) that can be incorporated into graphene to form hydrogels ([email protected]) with three-dimensional (3D) network structures. The core-shell structure of [email protected] inhibited the growth of AgBr particles, achieving excellent control over their size (500-600 nm), while hybridization with graphene promoted the rapid migration and separation of photogenerated charges. Bisphenol A (BPA) were rapidly adsorbed by the 3D graphene nanosheets of [email protected] and promptly degraded by [email protected] nanoparticles under visible-light irradiation, showing that the synergy between adsorption and photocatalytic degradation could significantly improve pollutant removal efficiency. Moreover, the micron-sized 3D mesh structure could be regenerated using a simple filter without the need for a complex catalyst filtration system. The obtained results revealed a superior synergy between photocatalytic and adsorption-based pollutant degradation by [email protected], which achieved a 1.5-fold higher BPA removal degree than pure AgBr, exhibiting values above 90% after five consecutive cycles. Finally, the degree of BPA degradation was maintained at 100% during the first 6 h under continuous flow conditions.