Hierarchical porous BiOI architectures: Facile microwave nonaqueous synthesis, characterization and application in the removal of Congo red from aqueous solution

Abstract

Three-dimensional (3D) hierarchical porous architectures have become promising candidates for adsorption-based environmental remediation in recent years. However, such type of adsorbents often suffers from the complicated production and undesirable regeneration, limiting their practical environmental application greatly. In this contribution, a novel adsorbent based on hierarchical porous bismuth oxyiodide (BiOI) architectures combining the highly effective adsorption and green photocatalytic regeneration were designed and fabricated by a facile and rapid microwave nonaqueous route. The resultant samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption–desorption measurements, and UV–vis diffuse reflectance spectroscopy (DRS). The BiOI architectures displayed remarkable performance towards removal of Congo red (CR) from aqueous solution, showing a maximum adsorption capacity reached up to 216.8mgg−1. The kinetics and equilibrium of adsorption process were found to follow the pseudo-second-order kinetic and Freundlich isotherm models, respectively. More importantly, the BiOI architectures were not only easy to separate from the reaction system because of the hierarchical structure and large sizes, but also attractive to photocatalytic regeneration due to their intrinsically prominent photoresponse in visible light region. By means of providing the facile preparation, high adsorption efficiency, easy solid–liquid separation, and economical photocatalytic regeneration, the synthesized BiOI architectures established an outstanding example for the design of multifunctionalized adsorbent with high performance for environmental remediation.