纳米氧化铁/膨润土催化剂的制备、表征及复相光降解罗丹明B的研究

钠基膨润土与羟基铁溶液反应，经过焙烧，制得性能良好的纳米复合型催化剂，结合比表面孔隙分析(BET)、X射线衍射谱(XRD)和高分辨扫描电镜(HRTEM)对催化剂的比表面积、晶相和粒度进行表征。用光度法对该催化剂降解染料罗丹明B进行了研究，详细考察了溶液起始pH值、H₂O₂浓度、催化剂用量和起始浓度对降解的影响以及催化剂的可重复使用性，紫外-可见光谱对降解过程进行跟踪检测，并对复相光助Fenton过程与均相光助Fenton过程进行了比较。结果表明，复合型催化剂具有很高的比表面积，铁以高催化活性的α-Fe₂O₃存在于复合催化剂中;在pH 3.0，催化剂浓度为0.3 g·L-1,H₂O₂浓度为10 mmol·L-1实验条件下，100 mL 2.5×10-5 mol·L-1罗丹明B，紫外光照射4 h后，紫外-可见光谱显示罗丹明B的特征峰消失，其脱色率和COD_Cr去除率分别为97%和71%，对该催化剂进行处理后，可以重复使用，复相光降解率要远大于均相光降解率。

Synthesis, Characterization and Photo Degradation Application for Dye-Rhodamine B of Nano-Iron Oxide/Bentonite

The iron oxide/bentonite was prepared through a reaction of a solution of OH-Fe salt with bentonite clay dispersion. BET, XRD an d HRTEM were used t o study i ts surface area, microstructure, and average particle size. The iron oxide/bentonite nano composite was developed as the heterogeneous catalyst for successful discoloration and mineralization of dye rhodamine B And the effects of solution pH, H2O2 molar concentration, catalyst loading and initial rhodamine B concentration were studied in detail by photometric method. The process of degradation was traced by UV-Visible spectrum. Besides, the comparison between the heterogeneous photo-Fenton process and homogeneous photo-Fenton process was performed. The result shows that, it has large surface area and mainly consists of high catalytic activity alpha-Fe2O3. The discoloration ratio is up to 97% and the COD(Cr), removal ratio is 71% after 4 h in the presence of pH 3.0, 2.5 x 10(-5) mol x L(-1) rhodamine B 100 mL, 0.3 g x L(-1) catalyst, 10 mmol x L(-1) H2O2 and UV. The rhodamine B degradating speed of heterogeneous photo-Fenton process is much faster than that of homogeneous photo-Fenton process. The catalyst can be reused after being treated.