Abstract:

Fe₃O₄@TiO₂ magnetic nanocomposites with photocatalytic activity were successfully prepared by sol-gel, hydrothermal methods and calcination method. Combine superparamagnetism Fe₃O₄ and TiO₂, which can not only realize the rapid recovery of materials but also made the materials have visible light response capability. The Fe₃O₄@TiO₂ magnetic nanocomposites were further applied to the removal of Cr(Ⅵ). The results show that when Fe₃O₄@TiO₂ has a TiO₂ content of 1.0 g/g and the addition of formic acid as a hole remover and the solution pH=2, Fe₃O₄@TiO₂ has the best removal ability of Cr(Ⅵ). Under this condition, Cr(Ⅵ) removal rate reached 99.85%, and the catalytic performance remained high even used 4 times. In addition, Fe₃O₄@TiO₂ has good removal ability for Cr(Ⅵ) in the range of 5—500 mg/L. Fe₃O₄@TiO₂ has excellent removal ability for Cr(Ⅵ) magnetic nanocomposites and has a good application prospect.

Key words: Fe₃O₄@TiO₂, photocatalysis, removal of Cr(Ⅵ), magnetic nanoparticles, hole scavenger

摘要：

通过溶胶-凝胶法、水热法和煅烧法，成功制备出具有光催化活性的Fe₃O₄@TiO₂磁性纳米复合材料，将超顺磁性的Fe₃O₄与TiO₂复合，实现材料的快速回收与可见光响应能力的结合。进一步将Fe₃O₄@TiO₂磁性纳米复合材料应用于Cr(Ⅵ)的去除，实验结果表明，在可见光照射下Fe₃O₄@TiO₂对Cr(Ⅵ)的去除能力是P25的1.96倍。并深入探究了Fe₃O₄@TiO₂中TiO₂含量、Cr(Ⅵ)溶液的pH以及空穴去除剂对Fe₃O₄@TiO₂可见光下光催化还原Cr(Ⅵ)能力的影响，实验表明当Fe₃O₄@TiO₂中TiO₂含量为1.0 g/g，添加甲酸作为空穴去除剂并且溶液pH=2时Fe₃O₄@TiO₂对Cr(Ⅵ)的去除能力最佳，此条件下Cr(Ⅵ)的去除率达到99.85%，重复使用4次，催化能力依然保持较高水平。此外，Fe₃O₄@TiO₂对5~500 mg/L浓度范围内的Cr(Ⅵ)都具有良好的去除能力。Fe₃O₄@TiO₂磁性纳米复合材料对Cr(Ⅵ)具备优异的去除能力，具有良好的应用前景。

关键词: Fe₃O₄@TiO₂, 光催化, 六价铬去除, 磁性纳米粒子, 空穴去除剂