介孔Fe/SBA-15非均相芬顿氧化水中难降解染料罗丹明B

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0.6 μm. 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 ℃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.

Heterogeneous Fenton Oxidation of Refractory Dye Rhodamine B in Aqueous Solution with Mesoporous Fe/SBA-15

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 crystallites with a mean diameter of 0.6 μm. The Fe species occurred both inside and outside the support pores in the form of α-Fe₂O₃ crystallites. 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 ℃. 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/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 nonbiodegradable organics such as dye RhB.