Adsorptions of Cd(ii) and methylene blue from aqueous solution by silica hybrid hollow spheres†
Abstract
Silica hybrid hollow spheres were successfully synthesized by co-hydrolysis and condensation reactions of TEOS and vinyltrimethoxysilane (VTMS) under the catalysis of ammonia. The as-obtained silica hybrid hollow spheres were used as adsorbents for the removal of Cd(II) and methylene blue (MB) from aqueous solutions. The isotherm adsorption data of the silica hybrid hollow spheres for Cd(II) and MB followed the Langmuir isotherm model. The silica hybrid hollow spheres exhibited the adsorption capacities as high as 54.702 and 25.242 mg gā1 for Cd(II) and MB, respectively. The adsorption kinetics of Cd(II) and MB onto the silica hybrid hollow spheres can be well fitted to the pseudo-second-order model. The adsorption processes of Cd(II) and MB onto the silica hybrid hollow spheres at 298, 318 and 338 K could be carried out spontaneously.