Abstract:

Catalytic wet air oxidation (CWAO) technology can efficiently treat organic wastewater, but the performance of existing catalysts, especially its stability, is far from industrial applications. In this study, ZrO₂ was used to modify TiO₂ support to form the stable Ru/TiO₂-ZrO₂ catalysts. It was found that the Ru/TiO₂-ZrO₂ catalysts showed excellent performance for catalytic wet air oxidation of phenolsulfonic acid wastewater. They gave high total organic carbon (TOC) conversions (>90%) and remained stable in 5 consecutive running in the Ti/Zr ratio range from 9∶1 to 7∶3. On the other hand, TOC conversion decreased from 99.1% to 65.3% in 5 consecutive cycles for the conventional Ru/TiO₂ catalyst. The characterization results of XRD, BET, XPS, H₂-TPR and ICP-OES indicated that ZrO₂ can enter the lattice of TiO₂ to form TiO₂-ZrO₂ solid solution, which prevented the transformation of TiO₂ from anatase to rutile. In addition, the modification of ZrO₂ strengthened the interaction between Ru and the support, which effectively inhibited the leaching of Ru metal. The stable support structure and good anti-loss performance are the main reasons for the excellent reaction performance of Ru/TiO₂-ZrO₂ catalyst.

Key words: catalytic wet air oxidation, composite oxide support, phenolsulfonic acid wastewater, stability, harmless treatment

摘要：

催化湿式氧化（CWAO）技术可高效处理有机废水，但现有催化剂的性能，尤其是其稳定性距工业应用还有很大差距。利用ZrO₂对TiO₂载体进行掺杂调变，研制出了具有良好稳定性的Ru/TiO₂-ZrO₂催化湿式氧化催化剂。结果表明， Ru/TiO₂催化剂在进行连续5次催化湿式氧化降解苯酚磺酸（phenolsulfonic acid，PSA）废水的反应后，总有机碳（total organic carbon，TOC）转化率由99.1%降低至65.3%；而Ru/TiO₂-ZrO₂催化剂在Ti/Zr质量比为9∶1~7∶3范围内，能表现出优良的反应性能，在连续5次反应后， TOC转化率稳定保持在90%以上。X射线仪衍射（XRD）、N₂吸脱附（BET）、X射线扫描微探针电子能谱仪（XPS）、氢气程序升温还原（H₂-TPR）和电感耦合等离子体发射光谱（ICP-OES）表征结果表明：ZrO₂能够进入TiO₂的晶格，TiO₂-ZrO₂固溶体的生成阻止了TiO₂由锐钛矿相向金红石相的转变。另外，ZrO₂的调变加强了Ru与载体的相互作用，有效抑制了活性金属Ru的流失。稳定的载体结构和良好的抗流失性能是Ru/TiO₂-ZrO₂催化剂具有优良反应性能的主要原因。

关键词: 催化湿式氧化, 复合氧化物载体, 苯酚磺酸废水, 稳定性, 无害化处理