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

An eco-friendly route was developed for the synthesis of mesoporous CeO powders without any additional template. The original cerium precursors were separated from Ce aqueous solution by (NH)CO or NaCO a chemical precipitation method, then HO was introduced to induce the phase transformation from original cerium precursors to CeO precursors with initial porous structures, finally the crystallinities of CeO precursors were improved by a hydrothermal treatment, meanwhile the mesoporous structures of final CeO powders were formed. The BET surface areas of mesoporous CeO powders synthesized using (NH)CO and NaCO as precipitants were 106.1 and 76.9 m g, respectively. Moreover, a mesoporous CeO sample with BET surface area of 100.0 m g was also synthesized using commercial Ce(CO)·HO 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 precursors with initial porous structures was the precondition for further forming of mesoporous structures of final CeO powders during the hydrothermal process. These mesoporous CeO 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 powders for removal of acid orange 7 dye were determined according to the Langmuir linear fits.