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Catalytic Activity and Mechanism of Ordered Mesoporous Iron Oxides on Hydrogen Peroxide for Degradation of Norfloxacin in Water at Neutral pH
The catalytic activity of ordered mesoporous Fe2O3 (om-Fe2O3) on H2O2 oxidation of norfloxacin (NOR) under neutral pH condition in water was investigated. Using non-ordered-mesoporous Fe2O3 as a reference (nom-Fe2O3), om-Fe2O3 with high specific surface area of 176.4 m2/g and a uniform pore structure exhibited high catalytic activity on the decomposition of H2O2 as well as the degradation of NOR at neutral pH. To compare with nom-Fe2O3, om-Fe2O3 promoted the decomposition of H2O2 differently. The adsorption ability of om-Fe2O3 on NOR was much higher than that of nom-Fe2O3. The adsorption efficiency of NOR on om-Fe2O3 accounted for 60.2% - 64.9% of the degradation efficiency in om-Fe2O3/H2O2. tert-butanol (TBA) which was resistant to be adsorbed by om-Fe2O3 had no effect on the degradation of NOR by om-Fe2O3/H2O2. However, the presence of tromethamine (TMA), which was favorable to be adsorbed by om-Fe2O3, inhibited the degradation of NOR significantly. Based on the different effects of TBA and TMA on the degradation of NOR, it was proposed that the catalytic degradation of NOR may occur on the surface of om-Fe2O3. And hydroxyl radicals (·OH) generated may be bound on the surface of om-Fe2O3 without diffusing into aqueous solution. It was proposed that the adsorption of target organic pollutants must be considered when assessing the suitability of the om-Fe2O3/H2O2 process. The mechanism of om-Fe2O3 to promote H2O2 to decompose into ·OH was also investigated.
EN17119 Accepted 10 August 2017
© CSIRO 2017