零价铁与双氧水异相Fenton降解活性艳橙X-GN

Effective degradation of reactive brilliant orange X-GN by heterogeneous Fenton reaction using zero-valent iron and H_2O_2

采用Fe0与H2O2构成异相Fenton体系降解偶氮染料活性艳橙X-GN,考察了初始pH、H2O2和Fe0投加量、温度等对反应过程的影响。实验结果表明,在初始pH值为3.0、Fe0投加量为0.8 g/L、H2O2投加量为5 mmol/L和反应温度30℃的条件下,反应60 min后活性艳橙降解率达到96.2%。Fe0与H2O2投加量都存在一个最佳范围,当Fe0与H2O2浓度大于0.8 g/L和5 mmol/L时,羟基自由基会通过其他方式消耗,致使活性艳橙降解率下降。酸性条件和提高温度均有利于反应的进行。反应符合准一级动力学,表观反应速率常数k为0.064 min-1(30℃),反应活化能为80.62 kJ/mol。UV-Vis光谱扫描表明,反应过程中活性艳橙的发色基团及苯环结构均被破坏。

Heterogeneous Fenton like system was established with zero-valent iron and hydrogen peroxide to degradate an azo dye reactive brilliant orange （X-GN）. The effects of initial pH, ZVI and H202 dosage, and reaction temperature were investigated. The results showed that 96.2% degradation efficiency of X-GN after 60 min reaction was achieved in the presence of Fe0（0.8 g/L） and H202（5 mmol/L） at initial pH 3.0 and 30℃. Optimum dosage for ZVI and H202 were found to be 0. 8 g/L and 5 mmol/L. · OH would be consumed in other ways causing the decrease of X-GN degradation efficiency as the dosage of ZVI and H202 were higher than 0. 8 g/L and 5 mmol/L. Lower pH and higher reaction temperature were favorable for X-GN degradation. The degra- dation of X-GN followed the pseudo first order kinetics and the pseudo-first order rate constant k was estimated as 0. 064 rain-1 （30℃）. The activity energy of X-GN degradation was found to be 80.62 kJ/mol. The UV-vis spectra indicated that both the naphthalene ring and the N = N group of X-GN were destroyed during the reaction.