针铁矿非均相Fenton法对抗生素的降解特征及其动力学研究

Heterogeneous Fenton degradation characteristics and Its Reaction Kinetics of Tetracycline in aqueous solution Catalysed by Goethite

  • 摘要: 采用合成的针铁矿为催化剂与H2O2构成非均相Fenton试剂,开展对盐酸四环素(TC)的氧化分解特征及其动力学研究.考察pH、H2O2 浓度、催化剂投加量、TC初始浓度、温度对TC氧化分解过程的影响.研究结果表明,在优化条件下,针铁矿催化对TC的Fenton氧化分解效果明显,240 min后氧化分解率达到97.2%.而且,针铁矿氧化分解TC的反应仍主要是通过?OH作用, 因为加入叔丁醇自由基捕获剂后,TC的氧化分解率明显降低.此外,动力学模型拟合结果表明,针铁矿表面催化氧化分解TC是符合准一级动力学反应(R2>0.97),其表观活化能为Ea=31.86 kJ/mol.可见,该氧化分解反应表观活化能相对比较低,说明该反应比较容易进行,温度升高也有助于提高反应速率.

     

    Abstract: The oxidative decomposition character and its degradation kinetic model of Tetracycline (TC) were investigated using goethite/H2O2 as the heterogeneous Fenton reagent, with emphasis on the evaluation of the several Fenton-like oxidation system parameters, including initial solution pH, concentrations of hydrogen peroxide (H2O2) and α-FeOOH, initial concentration of TC, and reaction temperature. The results showed that a 97.2% decomposition efficiency for TC was obtained within 180 min under optimum conditions. Moreover, the addition of tertiary butyl alcohol (used as the ?OH quencher) to the reaction system can cause obviously the decrease of TC decomposition rate, it suggested that the TC decomposition was dominated by ?OH. In addition, goethite surfaces catalysed a heterogeneous Fenton-like reaction responsible for the TC decomposition following pseudo-first order kinetics (R2 >0.97), and their apparent activation energy (Ea) measured was a relatively low (31.86 kJ?mol-1), which implied that the ease of the Fenton decomposition reaction occurred generally and thus it is convenient for the actual application.

     

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