光助Fenton反应催化氧化降解罗丹明B表观动力学研究

Fenton反应作为处理难降解有机污染物有效的高级氧化技术之一，其氧化能力来自于在酸性条件下催化分解H₂O₂产生强氧化性(2.8 eV)的羟基自由基。而太阳光照下可促进羟基自由基的产生，从而提高Fenton反应氧化降解能力。文章在初始pH 3.5，太阳光直射的情况下研究了罗丹明B，Fe2+和H₂O₂等因素的初始浓度对光助Fenton反应降解罗丹明B速率的影响，采用求解拟合幂函数动力学方程获得了该反应体系的表观动力学方程。主要研究内容包括：罗丹明B溶液的紫外-可见光谱图；罗丹B溶液的浓度-吸光度工作曲线；不同初始罗丹明B浓度体系反应的分析；不同初始Fe2+浓度体系反应的分析；不同初始H₂O₂浓度体系反应的分析；表观动力学方程参数的计算。实验结果表明，该反应体系的动力学方程为：V=5×10-9P1.28F0.366E0.920,反应总级数为2.57。

Study on Apparent Kinetics of Photocatalytic Oxidation Degradation Rhodamine B by Photo-Fenton Reaction

The Fenton process, mixed by hydrogen peroxide and iron salts with highly oxidative effect, is recognized as one of powerful advanced oxidation technologies available and can be used to destroy a variety of persistent organic pollutants. The oxidation power of Fenton reagent is due to the generation of hydroxyl radical (·OH) during the iron catalysed decomposition of hydrogen peroxide in acid medium. The hydroxyl radical with a high oxidation potential (2.8 eV) attacks and completely destroys the pollutants in Fenton process. The degradation of pollutants can be considerably improved by using sunlight radiation, which is due to the generation of additional hydroxyl radicals. This photo-Fenton process had been effectively used to degrade the pollutants. In this paper, the definite quantity of Fenton reagent was added in the definite concentration of Rhodamine B solution. The degradation reaction was carried out at pH 3.5 under natural sunlight. The factors influencing on photocatalytic oxidation degradation rate of Rhodamine B were studied following: the initial concentration of Rhodamine B, initial concentrateions of Fe2+ and H₂O₂. The orders of degradation reaction were obtained by solving exponential kinetics equations of curve fitting, thereby gaining the kinetic parameters and reaction dynamics equation of the reaction system. The research contents included mainly: the UV-Vis spectra of Rhodamine B solution, the concentration-absorbency work curve of Rhodamine B solution, the analysis of the reaction system at various initial Rhodamine B concentrations, the analysis of the reaction system at various initial Fe2+concentrateions, the analysis of the reaction system at various initial H₂O₂ concentrations, and the calculation of the apparent kinetics parameters in reaction dynamics equation. The reaction dynamics equation from experiments was constructed: V=5×10-9P1.28F0.366E0.920, and overall reaction order was 2.57.