| 摘要: |
| 【目的】探讨罗丹明B（RB）在Fe(Ⅲ)/UV/空气下的催化降解过程及其机理。【方法】在间歇式光反应器中，研究了pH分别为1.0，3.0和4.3，Fe(Ⅲ)质量浓度为1.68～28 mg/L，RB的初始质量浓度为4～150 mg/L时RB的光降解过程，通过抑制剂NaN3和异丙醇研究了降解过程可能发生的机理，同时测定了降解过程中Fe2+质量浓度的变化。【结果】RB直接UV光解和Fe(Ⅲ)/UV/空气下的降解表观动力学均符合表观一级动力学规律。RB在Fe(Ⅲ)/UV/空气下降解时，随Fe(Ⅲ)质量浓度的增加，RB降解速率常数增大，但增加程度受到pH的影响，pH=3.0时增加程度最大，pH=1.0次之，pH=4.3时最小；RB初始质量浓度增加，降解速率减小，当RB初始质量浓度高于20 mg/L时，继续增加RB质量浓度对其光解速率影响不明显；反应过程中，Fe2+质量浓度在反应初期快速增加，此后维持在一定的水平。【结论】Fe(Ⅲ)/UV/空气能够快速催化RB光解，但在不同pH条件下，Fe(Ⅲ)催化UV光解RB的机理并不相同。 |
| 关键词: 罗丹明B 光催化降解 Fe(Ⅲ）催化 降解机理 |
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| 基金项目:陕西省教育厅专项科研基金项目（07JK349）；西北大学研究生创新基金项目（09YSY21） |
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| Photocatalytic degradation of rhodamine B in Fe(Ⅲ)/UV/air system |
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| Abstract: |
| 【Objective】 The degradation of rhodamine B(RB) under UV irradiation in the presence of Fe(Ⅲ) catalyst was investigated in a batch photoreactor.【Method】 Different process parameters that may influence the UV photocatalytic degradation were studied.These parameters included pH,concentration of Fe(Ⅲ) and concentration of RB.NaN3 and isopropyl alcohol were added to the system to explore the possible photocatalytic degradation mechanisms involved. The concentration of ferrous ions formed in the course of the degradation of RB was also determined.【Result】Degradation of RB under UV irradiation in the presence and absence of Fe(Ⅲ) followed the first-order kinetics.The degradation rate coefficients k increased with increasing concentrations of Fe(Ⅲ),the extent of which depended on the pH of the solutions,when pH=3.0,the degradation of RB had the maximum value of reaction rate constant,then pH=1.0,pH=4.3 had the minimum value in the experiment condition.Concentration of RB had negative effects on its degradation.The concentration of ferrous ion formed during degradation process increased sharply at the initial reaction period,and then maintained at a certain level.【Conclusion】Degradation of RB under UV irradiation could be accelerated by using Fe(Ⅲ) as catalyst,the mechanisms of photocatalytsis by UV and Fe(Ⅲ) varied with the pH of the solutions. |
| Key words: rhodamine B photocatalytic degradation photocatalysis by ferric sulfate degradation mechanism |
