Fenton试剂氧化降解腐殖酸动力学

研究了Fenton试剂氧化降解腐殖酸废水的过程及动力学.结果表明,Fenton法能通过氧化和混凝作用有效去除腐殖酸,其中氧化降解速率主要与Fenton试剂投量、腐殖酸初始浓度和初始pH值有关,且氧化作用主要发生在反应前60 min.在pH为4.0,Fe2+]0为5～40 mmol.L-1,H2O2]0为40～120 mmol.L-1,HS]0为250～1 000 mg.L-1,温度为278～318 K的实验范围内,反应初始阶段腐殖酸的氧化降解符合表观反应动力学模型.模型值与实验值吻合良好,说明该反应动力学模型能较好地描述Fenton氧化降解腐殖酸过程.Fenton氧化降解腐殖酸的初始反应活化能Ea为14.9 kJ.mol-1,说明反应较易进行.动力学模型的反应总级数为2.34,其中H2O2的反应分级数(0.86)高于Fe2+的分级数(0.47),表明H2O2浓度比Fe2+浓度对Fenton氧化降解反应的影响大.

Kinetics of humic substances oxidation degradation by Fenton's reagent

Humic substances (HS) oxidation degradation by Fenton's reagent was kinetically investigated in this study. HS was removed by both oxidation and coagulation during Fenton treatment. Moreover, initial pH, the dosage of Fenton's reagent and initial concentration of HS had a significant impact on HS oxidation rate and the oxidation mainly occurred at the first 60 min of reaction time. The empirical kinetic equation for HS oxidation by Fenton's reagent under the conditions of 308 K of temperature, 4.0 of pH, 5-40 mmol x L(-1) of Fe2+, 40-120 mmol x L(-1) of H2O2, 250-1 000 mg x L(-1) of HS, could be described using a kinetic model, which was fitted very well with the experimental data. The overall reaction order is 2.34. The lower activation energy of 14.9 kJ x mol(-1) shows that Fenton reaction can be initiated easily. The reaction order of H2O2 (0.86) is higher than that of Fe2+ (0.47), which indicates that the effect of initial H2O2 concentration is greater than that of Fe2+ on the oxidation degradation of HS by Fenton process.