Construction of hollow mesoporous zirconia nanospheres with controllable particle size: Synthesis, characterization and adsorption performance

Abstract

Organic dyes are difficult to remove effectively in water because of their stable physical and chemical properties. In this study, hollow mesoporous zirconia nanospheres with controllable particle sizes were successfully prepared by in-situ deposition of Zr(OH)4 on the surface of SiO2. The adsorption performance for malachite green (MG) and methylene blue (MB) were tasted. The adsorption removal rates for MG and MB could reach as high as 99 % and 98 %, respectively. The adsorption process could be explained by pseudo-second-order kinetic model and Langmuir isotherm model, and the maximum adsorption capacities for MG and MB were calculated by Langmuir model as 1354.24 and 24.63 mg/g, respectively. Thermodynamic study indicated that the adsorption process of MG and MB were spontaneous endothermic and spontaneous exothermic, respectively. The adsorption mechanism of hollow zirconia nanospheres for MG and MB mainly includes electrostatic interaction, hydrogen bonding and π-π interaction. The results of co-existence ions study demonstrated that the presence of Mg2+ and Ca2+ obviously reduced the removal rates of MB. Desorption-regeneration study showed that the adsorbents can be used for multiple cycles.