Ambient pressure drying synthesis of Cs0.33WO3/SiO2 composite aerogels for efficient removal of Rhodamine B from water

Abstract

A novel Cs0.33WO3/SiO2 composite aerogel was synthesized by ambient pressure drying process using hexamethyldisiloxane/HCl for the surface modification of the wet gel. The influences of Cs0.33WO3 content on the microstructure, pore characteristics and adsorption/photocatalytic activity of the composite aerogels were investigated. The as-prepared composite aerogels exhibited higher specific surface area with 265–465m2/g and pore volume with 1.11–1.86cm3/g. After being heat-treated at 550°C, the composite aerogels transformed from hydrophobicity to hydrophilicity without changing the main phase of Cs0.33WO3, which indicated that the outer SiO2 aerogel could improve the oxidation resistance of Cs0.33WO3 greatly. Furthermore, the specific surface area and pore volume of the composite aerogels with appropriate composition even have an increasing trend after heat-treatment. The adsorption mechanism of Rhodamine B on the Cs0.33WO3/SiO2 composite aerogels with different Cs0.33WO3 content was studied using kinetic adsorption models, and the photocatalytic degradation of Rhodamine B was evaluated. The results indicated that the adsorption kinetics of the composite aerogels followed the pseudo-second-order model with the adsorption process being mainly based on chemical adsorption and physical adsorption playing a role as assistance. The composite aerogels exhibited excellent adsorptivity/photocatalytic degradation performance and higher recycling efficiency for the pollutant Rhodamine B.