Mechanism of Catalytic Ozonation in Fe2O3/Al2O3@SBA-15 Aqueous Suspension for Destruction of Ibuprofen
Mechanism of Catalytic Ozonation in Fe2O3/Al2O3@SBA-15 Aqueous Suspension for Destruction of Ibuprofen
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DOI：
10.1021/es503729h
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发表时间：
2015-02-03
影响因子：
11.4
通讯作者：
Qu, Jiuhui
中科院分区：
文献类型：
--
作者：
Bing, Jishuai;Hu, Chun;Qu, Jiuhui
以AlCl 3和AlCl 3为金属前驱体，采用浸渍法和煅烧法将Fe 2 O3和/或Al 2 O3负载到介孔SBA-15上，并通过X射线衍射（XRD）、X射线光电子能谱（XPS）和吡啶吸附的傅里叶变换红外光谱（FTIR）对其进行了表征。Fe_2O_3/Al_2O_3@SBA-15对布洛芬水溶液的臭氧矿化有很好的效果。表征结果表明，Al 3+取代了SBA-15表面Si-OH基团上的氢，形成了Al-O-Si结构，不仅使Al 2 O3和Fe 2 O3在SBA-15表面高度分散，而且使SBA-15表面产生了最多的刘易斯酸中心。通过原位衰减全反射傅里叶变换红外光谱（ATR-FTIR）、原位拉曼光谱和电子自旋共振（ESR）光谱研究发现，化学吸附的臭氧在Al 3+的刘易斯酸位上分解为表面原子氧，在Fe 3+的刘易斯酸位上转化为表面吸附的（OHads）-O-中心点和O-2（-）自由基.在Fe 2 O3/Al2O3@SBA-15上，铁和铝的刘易斯酸中心的结合促进了（OHads）-O-中心点和O-2（-）自由基的形成，导致最高的反应活性。在此基础上，提出了催化臭氧化的机理。
Fe2O3 and/or Al2O3 were supported on mesoporous SBA-15 by wet impregnation and calcinations with AlC(l)3 and FeCl3 as the metal precursor and were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectra (FTIR) of adsorbed pyridine. Fe2O3/Al2O3@SBA-15 was found to be highly effective for the mineralization of ibuprofen aqueous solution with ozone. The characterization studies showed that Al-O-Si was formed by the substitution of Al3+ for the hydrogen of surface Si-OH groups, not only resulting in high dispersion of Al2O3 and Fe2O3 on SBA-15, but also inducing the greatest amount of surface Lewis acid sites. By studies of in situ attenuated total reflection FTIR (ATR-FTIR), in situ Raman, and electron spin resonance (ESR) spectra, the chemisorbed ozone was decomposed into surface atomic oxygen species at the Lewis acid sites of Al3+ while it was converted into surface adsorbed (OHads)-O-center dot and O-2(-) radicals at the Lewis acid sites of Fe3+. The combination of both Lewis acid sites of iron and aluminum onto Fe2O3/Al2O3@SBA-15 enhanced the formation of (OHads)-O-center dot and O-2(-) radicals, leading to highest reactivity. Mechanisms of catalytic ozonation were proposed for the tested catalysts on the basis of all the experimental information.