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Indexed by:期刊论文

Date of Publication:2015-01-21

Journal:INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH

Included Journals:SCIE、EI、Scopus

Volume:54

Issue:2

Page Number:641-648

ISSN No.:0888-5885

Abstract:In this study, double-shelled C/SiO2 hollow spheres with an outer hydrophilic silica shell and an inner hydrophobic carbon shell were initially prepared by activating a solid silica layer of C/SiO2 aerosol particles. This low-cost preparation technique, which can easily be scaled up, includes a rapid aerosol process and a subsequent dissolution-regrowth process. The large surface area (226.3 m(2)/g), high pore volume (0.51 cm(3)/g), and high mechanical stability of the spheres benefit their high adsorption capacities for methylene blue (MB) and metal ions. The novel spheres show a high adsorption capacity of 171.2 mg/g for MB, which is higher than the adsorption capacity of single-shelled silica hollow spheres (150.0 mg/g). The adsorption efficiency of the hollow spheres remains higher than 95% after five cycles of regeneration. The saturation adsorption values of Pb2+ and Ag+ ions on the hollow spheres were found to be 216.5 and 283.1 mg/g, respectively, which are higher than the corresponding values of 189.8 and 213.4 mg/g on the single-shelled SiO2 spheres. Moreover, the adsorption capacities of the five-times-recycled spheres for Pb2+ and Ag+ ions reached as high as similar to 180 and similar to 245 mg/g, respectively. These results reveal that the outer porous silica layer with a zeta-potential of -37.4 mV makes the main contribution to the excellent adsorption performance of the spheres. In addition to the contribution to the adsorption capacity of the double-shelled hollow spheres, the inner carbon layer plays a crucial role in supporting the outer silica shell and in improving the adsorption efficiency, mechanical stability, and recycling properties of the hollow spheres.