连铸铁泥制备纳米α-Fe2O3及光催化去除Cr(Ⅵ)

连铸铁泥富含铁元素,资源化利用是必然选择。以连铸铁泥为原料,采用水热法成功制备纳米α-Fe₂O₃,实现高附加值利用。研究结果显示,所制备的纳米α-Fe₂O₃为均匀的球状介孔结构,比表面积为48.78 m2/g,平均晶粒尺寸约40~50 nm,较大的比表面积与较小的晶粒尺寸可提供大量的光催化活性位点,有利于提升材料的光催化性能。将纳米α-Fe₂O₃应用于Cr(Ⅵ)脱除的光催化剂,显示较好的Cr(Ⅵ)废水脱除效果,180 min内去除率可达100%。经过5次循环后,Cr(Ⅵ)的去除效率仍可达到89.2%,说明纳米α-Fe₂O₃具有良好的可重复使用性。对光催化去除Cr(Ⅵ)的反应机理进行研究,表明光生电子(e-)、羟基自由基(·OH)和超氧阴离子(·O₂-)是参与Cr(Ⅵ)去除的主要活性物质。本研究可将工业副产品连铸铁泥转化为高附加值的纳米材料,并为重金属废水脱除提供了一个新的思路,有较高的实际应用价值。

Photocatalytic removal of Cr(Ⅵ) from α-Fe2O3 nanoparticles prepared by continuous casting iron sludge

Continuous cast iron mud is rich in iron, so resource utilization is an inevitable choice. In this paper, we successfully prepared α-Fe₂O₃ nanoparticles from continuous casting iron sludge by hydrothermal method and realized high value-added utilization. The prepared α-Fe₂O₃ nanoparticles were polymerized into uniform spherical mesoporous structure with a specific surface area of 48.78 m2/g and the average grain size was about 40-50 nm. Large specific surface area and small grain size provided a large number of photocatalytic active sites, which was conducive to improving the photocatalytic performance of the material. Therefore, the α-Fe₂O₃ nanoparticles has a good removal rate of Cr(Ⅵ) polluted wastewater, and the removal rate can reach 100% within 180 min. In addition, after 5 cycles, the removal efficiency of Cr(Ⅵ) can still reach 89.2%, indicating that α-Fe₂O₃ nanoparticles has good reusability. The mechanism of photocatalytic removal of Cr(Ⅵ) was studied. Photogenerated electron (e-), hydroxyl radical (·OH) and superoxide anion (·O₂-) are the main active substances involved in the removal of Cr(Ⅵ). Therefore, this study can transform the industrial by-product of continuous cast iron sludge into high value-added nanomaterials, and provides a new idea for the removal of heavy metal wastewater, which has high practical application value.