酸性红37光催化降解动力学的响应曲面法优化及其转化机制

为探索单偶氮染料酸性红37 在水溶液中降解的可行性及在活性氧物种作用下可能的迁移转化机制，利用光催化技术并根据中心复合实验设计原理建立了不同因素对酸性红37 光催化降解效率影响的二次回归方程，得出酸性红37光催化降解的最优条件：催化剂（P25TiO2）质量浓度为2.3 g/L，底物浓度为90μmol/L，温度为12.5 ℃，溶液初始pH值为8.7。研究结果表明：水溶液中不同阴阳离子对酸性红37 降解动力学的影响较大，其中Na+、Fe2+、Fe3+和Zn2+ 等对酸性红37 的降解具有明显的抑制作用，而Cu2+则体现了一定程度的促进作用；然而CrO42-、SO42-、ClO3-、MnO4- 和Cl- 则对其降解均体现了不同程度的抑制作用。最后利用气相色谱质谱联用仪对酸性红37的光催化降解产物进行了初步的分离并进行分析，认为光催化过程中酸性红37分子中N=N和C-N键断裂后的进一步羟基化反应是其主要的降解途径。

Photocatalytic degradetion kinetics optimization of acid red 37 by response surface method and transformation mechanism thereof

In ordrt to explore the degradation possibility of monoazo dye acid red(AR37) and its transformation mechanism under attack of reactive oxygen species, a semi-empirical experssion was obtained by means of photocatalytic technology and central composite design based on the responsesurface method. The influences of different factors on the photocatalysis efficiency of acid red(AR37) were investigated. The optimal conditions are：substrate concentrationof 90 μmol/L, TiO2 amountof 2.3 g/L, reaction temperatureof 12.5 ℃ and initial solution pH valueof 8.7. The influences ofselected anions and cations on the degradation of AR37 were also studied. It was observed that Na+, Fe2+, Fe3+ and Zn2+ have significant inhibitory effect on the degradation ofAR37 while Cu2+accelerate the degradation of AR37. On the other hand, anions such as CrO42-, SO42-, ClO3-, MnO4- and Cl- has certain inhibitory effect on thedegradation of AR37. Finally, the degradation intermediates of AR37 were identified by gas chromatography-mass spectrometer. The results show that in the photocatalytic process, after N=N and C-N bonds in AR37 molecules are broken, the further hydroxylation reaction is the main degradation path.