摘要
制备了以Al2O3/TiO2为载体的负载型铁氧化物催化剂,对催化剂进行SEM、XRD、UV-vis-DRS和XPS分析,考察H2O2投加量、催化剂投加量、4-氯酚初始质量浓度对4-氯酚处理效果的影响,分析了非均相光Fenton体系的氧化机理。结果表明,所制备的负载型铁氧化物催化剂为α-FeOOH与γ-Fe2O3的混合物,其表面存在较多的颗粒和孔穴,吸附性强,具有很高的催化活性。H2O2、铁氧化物催化剂、紫外灯之间存在协同作用,所构成的非均相光Fenton体系对4-氯酚具有良好的去除效果。其反应机理为表面催化,催化剂表面的Fe(III)在光照的作用下被还原为Fe(II)。在催化剂投加量为1 g/L,H2O2浓度为7.84 mmol/L时,对4-氯酚的降解效果达到最佳,反应进行30min后4-氯酚的去除率大于99%,反应1 h矿化度可达91.4%。
This paper aims to introduce our preparation of catalysts loaded on Al2O3/TiO2 and the heterogeneous photo-Fenton reaction system we have established for the study of the degradation efficiency of the 4-chlorophenol. The catalysts we have prepared are character- ized by SEM, XRD, by means of which we have investigated the effect of H2O2 dosage, along with the catalyst dosage and initial con- centration of the 4-chloropbenol on 4-chlorophenol degradation need- ed. In addition, we have also done experiments to explore the oxida- tion mechanism of heterogeneous photo-Fenton system. The results of our research show that the ingredients of iron oxidate catalysts loaded on Al2O3/TiO2 were the mixture of α - FeOOH and γ - Fe2O3; and, as compared with Al2O3/TiO2 carrier, it has been found that there exist more surface particles and cavity on the catalyst surface, whose specific surface area proves to be wider for its adsorption, and, therefore, helps to enhance their catalytic activity. The heterogeneous photo-Fenton system we have established proves to be highly effective for degrading 4-chlorophenol. Furthermore, we have worked out the maximum removal rote on the condition when the catalyst dosage and H2O2 dosage were 1 g/L and 7.84 mmol/L, respectively. And,when the removal rates of 4-chlorophenol reach 99% or even higher after 30 min, and when the mineralization ratio reaches 91.4% after lh, the initial concentration of 4-chlorophenol would make a great effect on the degradation rate. However, higher 4-chlorophenol concentra- tion tends to decrease the reaction efficiency significantly. It is for this reason that we have spared no efforts in having studied five differ- ent systems UV, the catalysts/H2O2, UV/H2O2, and UV/H2O2/catalysts. The results of our investigations indicate that the heteroge- neous photo-Fenton reaction system composed of UV, H2O2, and cat- alysts prove to be most efficient, with their synergistic effects prevail- ing in the H2O2, iron oxide catalysts and UV in the heterogeneous photo-Fenton reaction. In addition, UV- vis -DRS and XPS are per- fect in confirming that Fe（ Ⅲ ）can be used to transform Fe（ lI ）under UV radiation onto the catalyst surface. And, last of all, a new ab- sorption band has been found following the reaction in UV - vis - DRS result, which can account for the Fe（ Ⅲ ）converted into Fe（ Ⅱ ）after UV irradiation, which is affirmed by XPS, with the binding energy of Fe 2P3/2 slightly shifted from 711.345 eV to 710.600 eV after the Uv irradiation.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2013年第1期31-35,共5页
Journal of Safety and Environment
关键词
环境工程学
非均相FENTON
4-氯酚
降解
催化剂
environmental engineering
heterogeneous Fenton
4-ehlorophenol
degradation
catalysts
