Dye-adsorption properties of WO3 nanorods grown by citric acid assisted hydrothermal methods

Dye-adsorbing tungsten trioxide (WO3) powders were prepared by a simple wet chemical hydrothermal method at 120 degrees C. In order to study the effect of specific surface area on the dye-adsorption properties, various morphologies of WO3 powders were synthesized using different concentrations of a structure-directing agent (citric acid). The morphology, structure, specific surface area, and adsorption characteristics of the synthesized WO3 powders were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller (BET) method, and UV vis adsorption spectroscopy, respectively. The BET measurements showed different surface area values for the samples prepared at different concentrations of citric acid, and the adsorption capacity increased as the surface area increased. WO3 nanorods synthesized using 0.2 mol of citric acid showed the largest surface area of 81.5 m(3)/g and the highest adsorption capacity of 57.6 mg/g at a pH of 7.0.