Fe^(2+)与Fe^0活化过二硫酸盐降解活性艳蓝KN-R

Degradation of Reactive Bril iant Blue KN-R by Persulfate Activated with Fe^(2+)and Fe^0

为了解Fe2+与Fe0在活化PDS(过二硫酸盐)降解活性艳蓝KN-R时的差异,通过序批试验,考察了Fe2+/PDS和Fe0/PDS体系中c(Fe2+)、ρ(Fe0)、c(PDS)和初始p H对KN-R降解的影响.结果表明:在Fe2+/PDS体系中,最佳反应条件〔初始pH为3.0,c(Fe2+)为1.0 mmol/L,c(PDS)为2.0 mmol/L〕下,180 min后KN-R的去除率达到96.55%;过高的p H和c(Fe2+)对KN-R的降解均有明显的抑制作用.在Fe0/PDS体系中,当p H和ρ(Fe0)过高时,KN-R的去除率仍维持在较高水平,当p H为9.0时,180 min后KN-R的去除率为90.53%;当ρ(Fe0)为448 mg/L时,50 min后KN-R的去除率就能达到94.35%.在2个体系中,c(PDS)的升高均能显著提高KN-R的去除率,当c(PDS)由0.5 mmol/L增至8.0 mmol/L时,KN-R的去除率由47.25%(Fe2+/PDS体系)和57.00%(Fe0/PDS体系)增至100%.动力学分析显示,KN-R的降解均遵循一级反应动力学;最佳反应条件下2个体系中的活性自由基均以硫酸根自由基(SO4-·)为主.因此,在降解KN-R过程中,Fe0/PDS体系的性能明显优于Fe2+/PDS体系.

Batch experiments were conducted to understand the main differences between Fe^2＋/PDS and Fe^0/PDS systems during the degradation process of reactive brilliant blue KN-R. The effects of dosages of Fe^2 ＋ , Fe^0 and PDS, and the initial pH on KN-R degradation were investigated. In the Fe^2＋/PDS system, when the initial pH was set at 3.0, Fe^2＋ concentration was 1.0 mmol/L and PDS concentration was 2.0 mmol/L, the maximum degradation ratio was 96.55% after 180 minutes. The faster the pH or Fe^2＋ concentration increased, the worse the KN-R degradation decreased. However, in the Fe^0/PDS system, pH and Fe^0 dosage did not restrain the KN-R removal. The degradation ratio of KN-R was 90.53% after 180 minutes at pH = 9.0, while it reached 94.35% within 50 min at Fe^0 dosage of 448 mg/L. In the Fe^2＋/PDS and Fe^0/PDS systems, PDS could improve the removal rate of KN-R remarkably. When the concentrations of PDS increased from O. 5 mmol/L to 8.0 mmol/L, the removal ratios increased from 47.25% and 57.00% to 100% in the Fe^2＋/PDS and Fe^0/PDS systems, respectively. Kinetic analysis indicated that the degradation of KN-R followed a first order kinetics equation. Radical identification showed that SO4 - · were the main radicals in the Fe^2＋/PDS and Fe^0/PDS systems. In conclusion, the Fe^0/PDS system was superior to the Fe^2＋/PDS system during the degradation process of KN-R.