Quasi-reverse-emulsion-templated approach for a facile and sustainable environmental remediation for cadmium

Abstract

Nanostructured hierarchical hollow α-Fe₂O₃ chestnut buds and nests were fabricated by a solvothermal process at a relatively low reaction temperature using water/glycerol and water/2-propanol as the reaction solvents, respectively. This facile and green quasi-reverse-emulsion soft-templating approach can effectively tailor the monodispersity and nanostructure of the products. The BET surface areas of the chestnut buds and nests were 424.3 and 169.9 m² g⁻¹, respectively. The maximum monolayer adsorption capacities for Cd(II) of the chestnut buds and nests were found to be 175.8 and 126.3 mg g⁻¹, respectively. Both chestnut buds and nests could be recycled with high desorption efficiency and without any remarkable loss of adsorption capacity. Owing to the surface hydroxyl groups, which were determined by FT-IR and TG-MS measurements, and the well-defined hollow mesoporous structure (pore sizes of 5.04 and 6.85 nm, respectively), both hierarchical α-Fe₂O₃ nanostructures exhibited superior prospects for the removal of Cd(II) from wastewater in industrial practice.