光催化氧化技术作为一种绿色环保的新型脱汞技术，应用前景广阔。目前的光催化反应器系统大多采用粉末状催化剂，对光催化过程中的光源利用率欠佳，不易回收，工业化应用前景受限。设计新型插槽板式光催化反应器，具有受光佳、耐磨损、寿命长、体积小等优点。采用板式催化剂进行汞氧化试验，对催化剂进行详细表征。相较于普通固定床反应器，插槽板式TiO2（VTiB）在80 mW/cm2紫外光强条件下汞氧化效率由64.8%提高至86.0%。催化剂的汞氧化效率随反应温度升高而下降，随紫外光强升高而提升。在板式催化体系中，经Ce掺杂后的TiO2（Ce-VTiB）催化剂光催化氧化汞性能大幅上升，其中以Ce-VTiB质量分数提升至1.0%效率最高，达92.4%。原因有2点：一方面掺杂Ce后将有效降低催化剂带隙能，Ce-VTiB催化剂质量分数提升至1.0%，相较VTiB催化剂带隙能下降0.68 eV，使催化剂对紫外光的吸收能力增强；在紫外光照射下，Ce-VTiB催化剂颗粒表面受激发产生·OH活性自由基，将Hg0氧化为Hg2+，另一方面部分Ce原子可以与电子结合，减少e-/h+的复合。

Photocatalytic oxidation technology, as a green and environment-friendly new mercury removal technology, has broad application prospects. At present, most of the photocatalysis reactor systems use powdered catalyst, which has poor utilization of light source in the photocatalysis process, is not easy to recover, and has limited prospects for industrial application. Therefore, a new type of slot plate photocatalytic reactor was designed, which had the advantages of good light reception, wear resistance, long service life, small size. The mercury oxidation experiment was carried out with plate catalyst, and the catalyst was characterized in detail. Compared with the conventional fixed bed reactor system, the mercury oxidation efficiency of the slotted plate TiO2(VTiB) is increased from 64.8% to 86.0% under the UV light intensity of 80 mW/cm2. The mercury oxidation efficiency of the catalyst decreases with the increase of reaction temperature and increases with the increase of UV light intensity. In the plate catalytic system, the photocatalytic mercury oxidation performance of the Ce doped TiO2(Ce-VTiB) catalyst increases significantly, and the efficiency of 1.0% Ce-VTiB is the highest, reaching 92.4%. There are two main reasons. On the one hand, Ce doping can effectively reduce the band gap energy of the catalyst. Compared with VTiB catalyst, the band gap energy of 1.0% Ce-VTiB catalyst decreases by 0.68 eV, so that the absorption ability of the catalyst to ultraviolet light is enhanced. Under ultraviolet irradiation, the surface of Ce-VTiB catalyst particles is excited to generate ·OH active radicals, which oxidize Hg0 to Hg2+. On the other hand, some Ce atoms can combine with electrons to reduce the recombination of e-/h+.

0 引言

1 试验

   1.1 试验样品制备

   1.2 插槽板式光催化试验系统

2 催化剂表征

   2.1 XRF表征

   2.2 XRD表征

   2.3 SEM表征

   2.4 UV-vis及XPS价带谱表征

3 插槽板式催化剂光催化氧化汞试验

   3.1 空白试验

   3.2 板式与固定床光催化反应器比较

   3.3 紫外光强和反应温度的影响

   3.4 Ce改性的影响

4 插槽板式催化剂光催化汞氧化反应机理

5 结论