An eco-friendly route for template-free synthesis of high specific surface area mesoporous CeO2 powders and their adsorption for acid orange 7

摘要

An eco-friendly route was developed for the synthesis of mesoporous CeO _(2) powders without any additional template. The original cerium precursors were separated from Ce ~(3+) aqueous solution by (NH _(4) ) _(2) CO _(3) or Na _(2) CO _(3) via a chemical precipitation method, then H _(2) O _(2) was introduced to induce the phase transformation from original cerium precursors to CeO _(2) precursors with initial porous structures, finally the crystallinities of CeO _(2) precursors were improved by a hydrothermal treatment, meanwhile the mesoporous structures of final CeO _(2) powders were formed. The BET surface areas of mesoporous CeO _(2) powders synthesized using (NH _(4) ) _(2) CO _(3) and Na _(2) CO _(3) as precipitants were 106.1 and 76.9 m ~(2) g ~(?1) , respectively. Moreover, a mesoporous CeO _(2) sample with BET surface area of 100.0 m ~(2) g ~(?1) was also synthesized using commercial Ce _(2) (CO _(3) ) _(3) · x H _(2) O as an existing cerium precursor under the same conditions as control, which could shorten experimental processes and reduce costs. The oxidation-induced phase transformation from original cerium precursors to CeO _(2) precursors with initial porous structures was the precondition for further forming of mesoporous structures of final CeO _(2) powders during the hydrothermal process. These mesoporous CeO _(2) powders showed the rapid and effective adsorption for acid orange 7 dye from simulated wastewater without pH pre-adjustment at room temperature. Furthermore, the adsorption capacities of these mesoporous CeO _(2) powders for removal of acid orange 7 dye were determined according to the Langmuir linear fits.