Controlled fabrication of hierarchical WO3 hydrates with excellent adsorption performance†
Abstract
Hierarchical WO3 hydrates have been synthesized via an ion exchange method using Na2WO4·2H2O as a precursor. The morphologies and phase structures of WO3 hydrates can be controlled by tuning the concentration of Na2WO4·2H2O solution. The as-synthesized urchin-like WO3·0.33H2O and flower-like WO3·H2O possess high specific surface area and numerous adsorption functional groups, such as WO and O–H bonds, on the surface. These characteristics result in excellent adsorption performance for both organic dyes and heavy metal ions from wastewater. The maximum uptake capacities of the urchin-like WO3·0.33H2O for methylene blue and Pb2+ are 247.3 and 248.9 mg g−1, respectively and those of the flower-like WO3·H2O are 117.8 and 315.0 mg g−1, respectively. The formation mechanism of such hierarchical mesoporous urchin-like WO3·0.33H2O and adsorption mechanism are studied in this paper.