Feng Jiyun, Hu Xijun, Yue Po Lock
Department of Chemical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Environ Sci Technol. 2004 Jan 1;38(1):269-75. doi: 10.1021/es034515c.
A novel bentonite clay-based Fe-nanocomposite (Fe-B) was successfully developed as a heterogeneous catalyst for photo-Fenton discoloration and mineralization of an azo-dye Orange II. X-ray diffraction (XRD) analysis clearly reveals that the Fe-B nanocomposite catalyst mainly consists of Fe2O3 (hematite) and SiO2 (quartz) crystallites, and the Fe concentration of the Fe-B catalyst determined by X-reflective fluorescence (XRF) is 31.8 wt %. The catalytic activity of the Fe-B was evaluated in the discoloration and mineralization of Orange II in the presence of H2O2 and UVC light (254 nm). It was found that the optimal Fe-B catalyst dosage is around 1.0 g/L, and the efficiency of discoloration and mineralization of Orange II increases as initial Orange II concentration decreases or reaction temperature increases. In addition, at optimal conditions (10 mM H2O2, 1.0 g of Fe-B/L, 1 x 8W UVC, and pH = 3.0), complete discoloration and mineralization of 0.2 mM Orange II can be achieved in less than 60 and 120 min, respectively. The result strongly indicates that the Fe-B nanocomposite catalyst exhibits a high catalytic activity not only in the photo-Fenton discoloration of Orange II but also in the mineralization of Orange II. The reaction kinetics analysis illustrates that the photo-Fenton discoloration of Orange II in the first 15 min obeys the pseudo-first-order kinetics. The reaction activation energy calculated was 9.94 kJ/mol, indicating that the photo-Fenton discoloration of Orange II is not very sensitive to reaction temperature.
一种新型的膨润土基铁纳米复合材料（Fe-B）被成功开发为一种非均相催化剂，用于偶氮染料橙黄II的光芬顿褪色和矿化。X射线衍射（XRD）分析清楚地表明，Fe-B纳米复合催化剂主要由Fe2O3（赤铁矿）和SiO2（石英）微晶组成，通过X射线荧光光谱（XRF）测定的Fe-B催化剂的铁浓度为31.8 wt%。在H2O2和UVC光（254 nm）存在下，评估了Fe-B在橙黄II的褪色和矿化中的催化活性。发现最佳Fe-B催化剂用量约为1.0 g/L，橙黄II的褪色和矿化效率随着初始橙黄II浓度的降低或反应温度的升高而增加。此外，在最佳条件下（10 mM H2O2、1.0 g Fe-B/L、1×8W UVC和pH = 3.0），0.2 mM橙黄II分别在不到60分钟和120分钟内可实现完全褪色和矿化。结果有力地表明，Fe-B纳米复合催化剂不仅在橙黄II的光芬顿褪色中表现出高催化活性，而且在橙黄II的矿化中也表现出高催化活性。反应动力学分析表明，橙黄II在前15分钟的光芬顿褪色遵循准一级动力学。计算得到的反应活化能为9.94 kJ/mol，表明橙黄II的光芬顿褪色对反应温度不太敏感。
