Evidence for immobilized photo-Fenton degradation of organic compounds on structured silica surfaces involving Fe recycling
Evidence for immobilized photo-Fenton degradation of organic compounds on structured silica surfaces involving Fe recycling
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DOI：
10.1039/b316027k
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发表时间：
2004-03
影响因子：
3.3
通讯作者：
A. Bozzi;T. Yuranova;J. Mielczarski;J. Kiwi
中科院分区：
文献类型：
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作者：
A. Bozzi;T. Yuranova;J. Mielczarski;J. Kiwi
本研究报告使用新型结构的无机二氧化硅织物负载铁离子交换浸渍作为一种多相光催化剂。这些Fe-二氧化硅织物表示为EGF/Fe（0.4%）。实验证据表明，Fe离子从二氧化硅织物中释放出来，并与H2 O2反应，在溶液中形成氧化自由基;在草酸和草酸盐氧化过程中，Fe离子被还原为Fe（II）。将Fe 3+从载体提取到水性介质中，在水性介质中通过再吸附到二氧化硅织物上而再氧化。草酸和草酸盐降解过程中的均相和非均相氧化过程的贡献被量化为溶液pH值的函数，并且所呈现的结果与在不同pH值下草酸盐存在下的氧化铁表面的建模一致。通过衰减全反射红外光谱法（ATRIR），在光催化降解的过程中，跟踪了1740 cm-1处的不对称伸缩振动双峰和对应于表面羧酸盐的卫星峰。结果表明，草酸盐分解通道中存在铁络合物的快速光活化脱羧反应：[RCO 2Fe]2+ → [Rstec] + CO2 + Fe 2+。通过高分辨透射电子显微镜（HRTEM）、X射线光电子能谱（XPS）和气体吸附（BET）研究了草酸盐修饰前后EGF/Fe（0.4%）表面的结构特征。
The present study reports on the use of novel structured inorganic silica fabrics loaded with Fe ions by exchange-impregnation as a heterogeneous photocatalyst. These Fe–silica fabrics are denoted EGF/Fe(0.4%). Experimental evidence shows that Fe ions are released from the silica fabrics and react with H2O2 to form oxidative radicals in solution; the Fe ions are reduced to Fe(II) during oxalic acid and oxalate oxidation. The Fe3+ is extracted from the support to the aqueous medium where it is re-oxidized by being re-adsorbed onto the silica fabric. The contributions of the homogeneous and heterogeneous photocatalysis processes during the degradation of oxalic acid and oxalates were quantified as a function of the solution pH and the results presented agree with the modeling of the iron oxide surface in the presence of oxalates at different pH values. By attenuated total reflection infrared spectroscopy (ATRIR), the asymmetric stretching vibration doublet band at 1740 cm−1 and the satellite peaks corresponding to surface carboxylates were followed during the photocatalytic destruction of the oxalates. The results obtained indicate that the oxalate decomposition channel involves a fast light-activated decarboxylation of the Fe complex: [RCO2Fe]2+ → [R˙] + CO2 + Fe2+. The structural features of the EGF/Fe(0.4%) surfaces were investigated before and after the oxalate photocatalysis by high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and gas adsorption studies (BET).