磁性膨润土的制备、表征及类Fenton催化降解橙黄Ⅱ

Synthesis,characterization and Fenton-like degradation for Orange Ⅱ of magnetic bentonite

以铝柱撑膨润土和铁盐为原料,采用共沉淀法制备纳米Fe3O4负载的磁性膨润土复合材料。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和比表面孔隙分析(BET)对样品进行表征,研究了磁性膨润土对橙黄Ⅱ的类Fenton催化降解性能,并考察了催化剂用量、温度和初始pH、H2O2初始浓度等因素对降解效果的影响。结果表明,Fe3O4均匀负载在膨润土表面,未发生明显团聚,并且改善了膨润土的孔隙结构,增加了其比表面积。在磁性膨润土用量为0.6 g/L,温度为40℃,pH为3.0,H2O2初始浓度为21 mmol/L的条件下,0.5 mmol/L橙黄Ⅱ溶液在180 min内色度去除率和UV254去除率分别达到100%和97%,且催化剂重复使用4次效果稳定。

Magnetic bentonite with much improved Fenton-like catalytic activity was successfully prepared through co-precipitation method using iron salt and Al-pillared bentonite as primary raw materials.The characterizations with XRD,SEM and BET indicated that the magnetite nanoparticles exist on the surface of bentonite, with better dispersing,less coaggregation and greater BET surface area(129.41 m2/g) than the ones without bentonite support.The degradation of Orange Ⅱ in UV-Fenton system was carried out to investigate the catalytic activity of synthesized magnetic bentonite.The effects of catalysts dosage,temperature,initial pH and concentration of H2O2 on Orange Ⅱ degradation were studied in detail.As a result,100% decolorization and 97% UV254 removal rate of 0.5 mmol/L of Orange Ⅱcould be obtained at 180 min in the presence of 0.6 g/L of magnetic bentonite,21 mmol/L of H2O2,pH = 3 and T = 40℃.The catalysts also show good stability in recycling test with acceptable activity decay.