Enhanced photocatalytic degradation of sulfadiazine by Fe^(3+) in aqueous TiO_2 suspension

Fe^(3+)强化TiO_2光催化降解磺胺嘧啶(英文)

In order to explore the reaction mechanism of Fe^3＋ and the mineralization effect of the micropollutant, Fe^3＋ assisted photocatalytic oxidation of sulfadiazine （SD） in the TiO2 suspended solution is investigated. The effect of Fe^3＋ participation, the degradation kinetics of SD, the effect of SD mineralization and the possible mechanism of Fe^3＋ participation in TiO2 suspension are analyzed by adding FeCl3, taking samples at a given time and determining the SD concentration. Results indicate that the degradation of SD catalyzed by TiO2/ Fe^3＋ is faster than that catalyzed by TiO2 or Fe^3＋ separately. The photocatalytic degradation of SD follows the pseudo-first- order kinetics model in a range of 20 to 80 mg/L of initial concentration. The mineralization rate of SD can be enhanced by the addition of Fe^3＋ in the TiO2 suspended solution. The mechanism of the rapid degradation of SD is proposed, which indicates that Fe^3＋ adsorbed on the surface of TiO2 particles acts as an electron acceptor. The amount of recombining electronhole pairs decreases, and the amount of hydroxyl radicals increases. The increased hydroxyl radical strengthens the degradation of SD in the TiO2/Fe^3＋ suspended solution.

为了分析Fe3+参与TiO2的反应机理及微污染物的矿化效果,研究了Fe3+辅助TiO2光催化氧化降解磺胺嘧啶(SD).通过TiO2悬浮液中预添加FeCl3和既定的时间取样并测定SD浓度的方式,分析了Fe3+参与TiO2催化降解反应后的效能、SD的降解反应动力学和SD的矿化效果,探讨了溶液中Fe3+与TiO2之间可能存在的作用机理.结果表明,光催化TiO2/Fe3+降解SD的效果远好于单独使用TiO2或Fe3+催化降解时的效果.SD的初始浓度在20～80mg/L时,其降解过程遵守准一级降解动力学模型.TiO2悬浮液中预添加Fe3+能够提高SD的矿化率.Fe3+参与TiO2光催化降解反应的机理可能是部分Fe3+承担着TiO2的电子受体,降低了TiO2的电子-空穴复合的程度,因而增加了溶液中羟自由基的产率,而羟自由基产率增加强化了溶液中SD的降解.