利用Ce-Fe/Al2O3为催化剂的非均相光Fenton体系降解阳离子红GTL,考察H2O2浓度、催化剂用量、初始pH值及不同工艺过程对降解效果的影响:依据紫外-可见吸收光谱、离子色谱、气相色谱-质谱联用对降解中间产物和最终产物的分析结果,探讨阳离子红GTL的降解路径和机理。研究结果表明:在功率为11W的低压汞灯照射下,非均相光Fenton体系能够有效地降解结构稳定的阳离子红GTL,在pH=6.0,反应温度为20℃,时间为90min,Ce-Fe/Al2O3催化剂用量为2g/L,H2O2质量浓度为0.34g/L,含50mg/L阳离子红GTL模拟废水总有机碳TOC去除率为92.40%:降解路径为:助色基团脱落,偶氮键断裂,苯环化合物和小分子醇、醛等中间产物形成,中间产物继续降解为小分子有机酸,最终产物为Cl^-,NO3^-,SO4^2-,CO2和H2O。
Degradation of cationic red GTL by heterogeneous photo-Fenton system using Ce-Fe/Al2O3 as catalyst was studied. The effects of initial concentration of H2O2, catalyst loading, initial pH value and various processes on degradation were investigated. The intermediates and final products during the reaction were detected by UV-vis absorption spectrography, ion chromatography and gas chromatography-mass spectrography. Degradation pathways and mechanism of cationic red GTL were discussed. The results show that cationic red GTL with stable structures can be degraded by heterogeneous photo-Fenton system. 92.40% of total organic carbon (TOC) removal ratio is achieved at pH=6.0, 20 ℃ of reaction temperature, 90 min of reaction time, 2 g/L of catalyst loading, 0.34 g/L of H2O2 concentration and 11 W low mercury light to 50 mg/L GTL-containing simulated wastewater. Degradation pathways include de-auxochrome, cleavage of azo bond, formation of benzene ring and small molecular compounds alcohol, aldehyde, further degradation of intermediate products to low molecular weight organic acid. The final products are Cl^-, NO3^-, SO4^2-, CO2 and water.