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

Author:
Xu, Yaohui, Li, Ruixing, Zhou, Yang
Source:
RSC advances 2019 v.9 no.39 pp. 22366-22375
ISSN:
2046-2069
Subject:
acid orange 7, adsorption, ambient temperature, ammonium carbonate, aqueous solutions, ceric oxide, cerium, chemical precipitation, cost effectiveness, hot water treatment, hydrogen peroxide, pH, phase transition, porous media, powders, sodium carbonate, surface area, wastewater
Abstract:
An eco-friendly route was developed for the synthesis of mesoporous CeO₂ powders without any additional template. The original cerium precursors were separated from Ce³⁺ aqueous solution by (NH₄)₂CO₃ or Na₂CO₃via a chemical precipitation method, then H₂O₂ was introduced to induce the phase transformation from original cerium precursors to CeO₂ precursors with initial porous structures, finally the crystallinities of CeO₂ precursors were improved by a hydrothermal treatment, meanwhile the mesoporous structures of final CeO₂ powders were formed. The BET surface areas of mesoporous CeO₂ powders synthesized using (NH₄)₂CO₃ and Na₂CO₃ as precipitants were 106.1 and 76.9 m² g⁻¹, respectively. Moreover, a mesoporous CeO₂ sample with BET surface area of 100.0 m² g⁻¹ was also synthesized using commercial Ce₂(CO₃)₃·xH₂O 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 CeO₂ precursors with initial porous structures was the precondition for further forming of mesoporous structures of final CeO₂ powders during the hydrothermal process. These mesoporous CeO₂ 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 CeO₂ powders for removal of acid orange 7 dye were determined according to the Langmuir linear fits.
Agid:
6542885