介孔Fe/SBA-15非均相芬顿氧化水中难降解染料罗丹明B

摘要

以介孔二氧化硅SBA-15为载体,采用等体积浸渍法制备了Fe/SBA-15.通过X射线衍射(XRD)、N2吸附-脱附、扫描电镜(SEM)、透射电镜(TEM)和X射线光电子能谱(XPS)等技术对其进行了表征,并用于对水溶液中罗丹明B (RhB)的芬顿氧化.表征结果表明了Fe/SBA-15维持了长程有序的介孔结构,孔径和比表面积都有所下降,并呈现棒状体的聚集态,平均直径为0.6μm. Fe以α-Fe2O3的形态同时存在于介孔孔道内外.在Fe/SBA-15和H2O2同时存在条件下RhB的去除是吸附和催化氧化降解的协同作用所致,并且与Fe/SBA-15投加量密切相关,但与初始溶液pH几乎无关.当Fe/SBA-15投加量为0.15 g∙L-1, RhB初始浓度为10.0 mg∙L-1, H2O2/Fe3+摩尔比为2000：1,初始溶液pH为5.4和反应温度为21°C时, RhB去除率达到了93%. Fe/SBA-15的Langmiur单分子层饱和吸附量为99.11 mg∙g-1.此外,采用H2O2浸泡方式对使用过的Fe/SBA-15可进行再生,连续6次循环使用后仍可维持80%的RhB去除率,且每次使用后Fe浸出浓度都在0.1 mg∙L-1(或者0.6%(质量分数))以下.基于淬灭实验、UV-Vis光谱和气相色谱-质谱(GC-MS)联用仪分析的结果,提出了RhB的去除机理.非均相芬顿催化剂Fe/SBA-15可用于去除像RhB这样的生物难降解有机物.%An Fe-loaded mesoporous silica SBA-15, Fe/SBA-15, was prepared by incipient wetness impregnation, characterized by X-ray diffraction (XRD), N2 adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques and used for heterogeneous Fenton oxidation of dye Rhodamine B (RhB) in aqueous solution. The characterization showed that the Fe/SBA-15 retained a mesoporous structure with a long-range ordered arrangement, reduced pore diameter and surface area, and existed as agglomerates of rod-like crystal ites with a mean diameter of 0.6μm. The Fe species occurred both inside and outside the support pores in the form ofα-Fe2O3 crystal ites. The removal of RhB in the presence of Fe/SBA-15 and H2O2 was shown to be caused by the synergistic effects of adsorption and catalytic oxidative degradation, and was closely related to Fe/SBA-15 dosage. Removal was almost independent of initial solution pH, with approximately 93%achieved at an Fe/SBA-15 dosage of 0.15 g∙L-1, initial RhB concentration of 10.0 mg∙L-1, H2O2/Fe3+molar ratio of 2000:1;initial solution pH of 5.4 and 21 °C. The Langmuir monolayer adsorption capacity of the Fe/SBA-15 was 99.11 mg∙g-1. In addition, Fe/SBA-15 can be easily regenerated by soaking in H2O2 then reused for up to six runs, with RhB removal greater than 80%and Fe leaching below 0.1 mg∙L-1 (or 0.6%(mass fraction)) for each run. A removal mechanism for RhB by Fe/ n SBA-15 and H2O2 was proposed based on the quenching tests, UV-Vis spectra, and gas chromatography-mass spectrometry (GC-MS) analysis. The heterogeneous Fenton catalyst Fe/SBA-15 can be applied to remove non-biodegradable organics such as dye RhB.