UV-TiO_(2)-PS光催化降解煤化工废水中含氮有机物

Photocatalytic degradation of nitrogen-containing organic compounds in coal chemical wastewater by UV-TiO_(2)-PS system

比较了由紫外光(UV)、TiO_(2)、H_(2)O_(2)、过硫酸盐(PS)组合而成的5种工艺对溶液中喹啉的光催化降解效果,分析了影响UV-TiO_(2)-PS降解喹啉的主要因素和降解机理,考察了该体系对吲哚和吡啶的降解效果。实验结果表明:相同条件下,5种体系对喹啉的去除效果依次为UV-TiO_(2)-PS>UV-TiO_(2)-H_(2)O_(2)>UV-PS>UV-H_(2)O_(2)>UV-TiO_(2),氧化剂H_(2)O_(2)或PS与UV-TiO_(2)联用,能提高喹啉去除率;在喹啉溶液初始质量浓度20 mg/L、TiO_(2)加入量1.2 g/L、PS加入量0.012 mol/L、初始pH 6.5的最佳工艺条件下,光反应150 min,喹啉去除率为97.07%,光反应180 min,TOC去除率为72.32%;在UV-TiO_(2)-PS降解喹啉的最佳工艺条件下,光反应150 min,该体系对吡啶和吲哚的去除率分别为41.12%和80.13%;UV-TiO_(2)-PS氧化降解喹啉过程中,活性物种的贡献依次为SO_(4)^(-)·>O_(2)-·>·OH>h^(+)。

Five systems including UV,TiO_(2),H_(2)O_(2)or persulfate(PS)were combined with each other respectively.The photocatalytic degradation of quinoline in solution by these systems was investigated,and the factors and mechanism of quinoline degradation by UV-TiO_(2)-PS system were discussed.On this basis,the degradation effect of indole and pyridine by UV-TiO_(2)-PS system was further investigated.Results show that:Under the same conditions,the order of quinoline removal effect of the 5 systems is UV-TiO_(2)-PS>UV-TiO_(2)-H_(2)O_(2)>UV-PS>UV-H_(2)O_(2)>UV-TiO_(2),indicating that the quinoline removal rate can be improved by combining oxidant H_(2)O_(2)or PS with UV-TiO_(2);Under the optimum process conditions of initial quinoline mass concentration 20 mg/L,TiO_(2)amount 1.2 g/L,PS amount 0.012 mol/L,and initial pH 6.5,the removal rate of quinoline and TOC is 97.07%and 72.32%after photoreaction for 150 min and 180 min,respectively.Under the optimum conditions for quinoline degradation by UV-TiO_(2)-PS system,the removal rate of pyridine and indole is 41.12%and 80.13%respectively after 150 min of photoreaction;In the oxidative degradation process of quinoline by UV-TiO_(2)-PS system,the order of contribution of different active species is SO_(4)^(-)·>O_(2)-·>·OH>h^(+).