Mannitol-assisted solvothermal synthesis of BiOCl hierarchical nanostructures and their mixed organic dye adsorption capacities

Three-dimensional (3D) hierarchical BiOCl nanostructures constructed by interconnected two-dimensional (2D) nanoplates have been successfully synthesized via a facile solvothermal process with the assistance of mannitol. The products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption. In the synthesis, mannitol acted both as a capping agent and a cohesive agent to mediate the formation of a hierarchical structure. A possible growth process involving crystal anisotropic growth habit and assembly process was proposed. The adsorption performance of BiOCl products for mixed organic dye removal was evaluated by using cationic rhodamine B (RhB) and anionic methyl orange (MO) as target substances. The as-prepared hierarchical BiOCl product exhibited excellent adsorption capacity and favorable recycling ability for mixed organic dye removal. This work demonstrated a novel strategy for the design and application of a well-defined complex hierarchical nanostructure.