微波对Fenton试剂降解苯酚反应活化能的影响

Effect of Microwave on Reaction Activation Energy of Phenol Degradation by Fenton Reagent

研究了在微波场条件下Fenton试剂降解含酚废水的反应.分别在常规和微波场条件下进行反应,测定了反应动力学曲线,发现在常规条件下和微波条件下,反应动力学曲线可分成两个阶段,第一阶段为二级反应,第二阶段为一级反应;讨论了温度、微波功率对总有机碳(TOC)去除率的影响,估算了反应活化能.实验结果表明:微波辐射可提高Fenton试剂降解苯酚的反应速率和TOC去除率,降低反应活化能;当微波功率分别为100、200和600W时,在反应的第一阶段,苯酚降解反应活化能分别为9.833、9.139和8.579 kJ/mol,在第二阶段分别为28.245、27.560和26.710 kJ/mol,低于常规条件下相应阶段的苯酚降解反应的活化能(第一阶段为10.782 kJ/mol,第二阶段为30.294 kJ/mol),且反应活化能随着微波强度的增大而减小.

This work aims at the degradation of phenol in wastewater by Fenton degradation experiments were carried out respectively in microwave field and in reagent in microwave field. The normal condition, and the corresponding reaction kinetic curves were obtained, which were divided into two stages respectively according with the second-order and the first-order rate equations. The effects of reaction temperature and microwave power on the total organic Carbon （TOC） removal were then discussed, and the reaction activation energies were finally estimated. The results show that （ 1 ） microwave radiation not only obviously improves the reaction rate and the TOC removal, but also reduces the reaction activation energy; （2） when the microwave powers are 100,200 and 600 W, the corresponding reaction activation energies at the first stage are respectively 9. 833, 9. 139 and 8. 579kJ/mol, and those at the second stage are respectively 28. 245, 27. 560 and 26. 710kJ/mol, which are all less than the values in normal condition （ 10. 782 kJ/mol in the first stage and 30. 294 kJ/mol in the second stage） ; and （3） the reaction activation energy decreases with the increase in microwave power.