类光-芬顿体系PW_(11)O_(39)Fe(Ⅲ)(H_2O)^(4-)/H_2O_2可见光催化降解罗丹明B

Visible photocatalytic degradation of rhodamine B by a photo fenton-like system consisting of PW_(11)O_(39)Fe(Ⅲ)(H_2O)^(4-)/H_2O_2

以Keggin型铁取代杂多阴离子PW11O39Fe(Ⅲ)(H_2O)4-(PW11Fe)为可见光活性组分构建了一个类光-芬顿体系(PW11Fe/H2O2),并用于模型污染物罗丹明B(Rh B)的可见光催化降解,同时考察了H2O2浓度、PW11Fe浓度、Rh B初始浓度及溶液p H值对Rh B可见光催化降解速率的影响,讨论了Rh B光催化降解的动力学性质。实验结果表明,当溶液p H=4.5时,由0.6 mmol·L-1PW11Fe和4 mmol·L-1H2O2构成的体系对Rh B的光催化降解效果最佳,0.01 mmol·L-1的Rh B在250 W金卤灯照射下反应60 min,其降解率达到100%,反应240 min,总有机碳(TOC)去除率约48%。羟基自由基猝灭和电子顺磁共振(EPR)实验表明,PW11Fe/H2O2体系在可见光照射下产生羟基自由基,从而导致Rh B的快速降解,降解反应的表观速率常数k为(6.2±2)×10-2mmol·L-1·min-1。

A photo-Fenton-Like system（ PW11 Fe / H2O2） using Keggin-type Fe（ Ⅲ）-substituted heteropolyanion PW11O39Fe（ Ⅲ）（ H2O）4-（ PW11Fe） as the visible light activity component was studied,which was employed for the photocatalytic degradation of model pollutant rhodamine B（ Rh B） under an artificial VIS irradiation. Influences of the H2O2 concentration,the PW11 Fe concentration,the initial Rh B concentration and the solution p H on the photocatalytic degradation rate of Rh B was also examined,together with a discussion on the kinetics of Rh B degradation. The results showed that the degradation ratio of 100% was obtained at 60 min for 0. 01 mmol·L- 1Rh B with the optimum conditions of p H 4. 5,0. 6 mmol·L- 1PW11 Fe and 4 mmol·L- 1H2O2 under the irradiation of 250 W metal halide lamp. The total organic carbon（ TOC） removal was about 48% at 240 min. The hydroxyl radical quenching and electron paramagnetic resonance（ EPR） experiments revealed that hydroxyl radicals generated by PW11 Fe /H2O2 system under visible light irradiation were the main reactive oxygen species,resulting in the rapid degradation of Rh B. The apparent rate constant of Rh B degradation was estimated to be（ 6. 2 ± 2） 10- 2mmol·L- 1· min- 1.