Fe^(3+)掺杂纳米管TiO_2光催化臭氧化去除水中腐植酸

Fe^(3+)-Doped TiO_2 Nanotubes Combined with Photocatalytic Ozonation for Removal of Humic Acids in Water

HA(humic acids,腐植酸)是一种难降解天然有机物,常规饮用水处理工艺很难将其去除.采用水热合成法制备纳米管TiO2,并通过TEM(透射电镜)、XRD(X射线衍射)、XPS(X射线光电子能谱)和BET比表面积分析对催化剂进行表征,考察纳米管TiO2光催化臭氧化对HA的去除效果.结果表明:①254 nm紫外光照射下,500℃煅烧纳米管TiO2催化臭氧化HA的工艺去除效果最佳,HA去除率可达42.1%,较单独臭氧化工艺提高92.2%.②采用Fe3+掺杂纳米管TiO2催化臭氧化工艺时,Fe3+掺杂量为1.0%(原子百分含量),煅烧温度为550℃时,催化效果最好,HA去除率可达79.5%.③HA去除率高于TOC,0~10min内该现象更为明显.④考察陶粒和活性炭负载Fe3+掺杂纳米管TiO2的催化效果及催化次数对催化性能的影响发现,陶粒和活性炭负载Fe3+掺杂纳米管TiO2存在下,HA去除率分别为85.1%和97.7%,使用4次后,HA去除率分别为73.9%和82.8%.

As a natural organic matter, humic acids （HA） are very difficult to be removed by conventional drinking water treatment processes, and pose a variety of problems during the treatment operation. Ion-doped TiO2 nanotubes were synthesized via a hydrothermal method and characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and specific surface area analyses. HA were treated by photocatalytic ozonation process, and the effects of the TiO2 nanotubes on HA removal efficiency were observed. The results indicated that, 1 ） compared with ozonation alone, the HA removal efficiencies through ultraviolet radiation and TiO2 catalysis were higher. The HA removal efficiency through photoeatalytic ozonation process was 42. 1% in the presence of Fe~ ~ -doped TiO2 nanotubes calcined at 500 ℃ , 92. 2% higher than with ozonation alone. 2）The optimized catalyst was 1.0% Fe3~ -doped TiO2 nanotubes calcined at 550 ℃. 3）In addition, the removal efficiency of HA was higher than that of TOC, especially in the first 10 min. 4）The HA removal efficiency in the presence of the activated carbon supported Fe3＋ -doped TiO2 nanotubes was 97.7% , when the catalyst was used for the first time, while that in the presence of the ceramsite supported Fe3 ＋ -doped TiO2 nanotubes was 85. 1%. After use for four times, the HA removal efficiencies changed to 82. 8% and 73.9% for the ceramsite and activated carbon supported catalysts, respectively. The results show that the HA removal efficiency in the presence of activated carbon supported Fe3 ＋ -doped TiO2 nanotubes was higher than that in the presence of ceramsite supported Fe3＋ -doped TiO2 nanotubes, and the two catalysts had a high catalytic activity after repeatedly being used four times.