title: Supported cobalt catalysts by one-pot aqueous combustion synthesis for catalytic phenol degradation.
abstract: Cobalt oxides (Co) and Al(2)O(3)-, SiO(2)-, and TiO(2)-supported cobalt oxide catalysts were prepared by an aqueous combustion method using urea and glycine as fuels. Their catalytic performance in activation of OXONE® for phenol degradation in aqueous solution was investigated. It was found that unsupported Co oxide and supported Co oxide presented different mechanisms in activation of OXONE® for phenol degradation. The supported Co catalysts presented higher activity in activation of OXONE® for phenol degradation due to higher dispersion of Co(3)O(4) on the supports and Co(II) coordination sites. The major oxidizing radicals were identified to be SO(4)(-) by competitive radical reactions. The Co oxides synthesized from urea or glycine showed a similar activity; however, the supported Co catalysts prepared by glycine fuel exhibited better activity than those prepared by urea. For Al(2)O(3)-, SiO(2)-, and TiO(2)-supported Co catalysts, Co/TiO(2) presented a higher activity in phenol degradation compared with Co/SiO(2) and Co/Al(2)O(3). But, Co/SiO(2) showed the best stability among the catalysts. Total organic carbon could be reduced by 80%, 72%, and 45% on Co/TiO(2), Co/SiO(2), and Co/Al(2)O(3), respectively, at 30 ppm phenol. Phenol degradation was found to follow the zero-order kinetics. The causes of deactivation were investigated, and the regeneration methods were proposed.
authors.affiliation: Department of Chemical Engineering, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
authors.forename: Hongqi
authors.initials: H
authors.lastname: Sun
authors.forename: Hanwen
authors.initials: H
authors.lastname: Liang
authors.forename: Guanliang
authors.initials: G
authors.lastname: Zhou
authors.forename: Shaobin
authors.initials: S
authors.lastname: Wang