Hierarchically Porous Composite Scaffold Composed of SBA-15 Microrods and Reduced Graphene Oxide Functionalized with Cyclodextrin for Water Purification

Large-scale decontamination of bisphenol A (BPA) from wastewater under field conditions is an urgent need because of the harmful toxic effects of BPA on living organisms. In this study, we report the fabrication of a three-dimensional (3D) hierarchically porous composite scaffold composed of mesoporous SBA-15 silica microrods and reduced graphene oxide (rGO-CD) functionalized with β-cyclodextrin (CD) and its application for BPA separation from contaminated water. The macroporous structure was achieved by sacrificial salt leaching, and the mesoporous structure was derived from the interparticle pores between compressed SBA-15 particles and intrinsic mesopores in SBA-15. The 3D hierarchical macroporous and mesoporous architecture of the scaffold enhances mass transport without any external forces, and the rGO-CD component provides good capture sites for BPA in solution via inclusion complexation between CD and BPA. The inorganic SBA-15 component of the scaffold also allows long-term operation of filters by increasing the mechanical strength of the scaffold. The hierarchically porous SBA-15/rGO-CD composite scaffold could separate BPA from contaminated water significantly better than the scaffold without rGO-CD in both batch and filter systems. Our study indicates that the functional hierarchically porous composite scaffold can be a potential material in wastewater treatment technology.