Abstract:

UV photocatalysis-assisted adsorptive desulfurization of bi-functional Ti-Si-O materials was investigated for clean gasoline. The Ti-Si-O materials were prepared by the sol-gel method and then characterized by N₂ adsorption, X-ray diffraction, etc. Desulfurization performances of the Ti-Si-O materials were examined. Sulfur species in gasoline were measured by HPLC, coulomb instrument, GC-MS and GC-SCD. The results showed that at the Ti/Si mole ratio of 3:7, the desulfurization efficiency of the Ti-Si-O material reached the maximum [96%, 11.52 mg S·(g sorb)^-1], which was more superior than those of the pure TiO₂ and SiO₂ materials. The photocatalysis-assisted adsorptive desulfurization (PADS) rates of Ti_0.3Si_0.7O₂ for the three organosulfur compounds followed the order of T > MT > BT. On the basis of GC-MS analysis for desulfurized products, it could be judged that the organosulfur compounds in gasoline were firstly photocatalytically oxidized to polar sulfone over Ti_0.3Si_0.7O₂, and then selectively adsorbed on Ti_0.3Si_0.7O₂. Ti_0.3Si_0.7O₂ can be efficiently regenerated by acetone washing and then hot air oxidation. The regenerated Ti_0.3Si_0.7O₂ exhibited very good activity of oxidation and adsorption after five cycles of oxidation/adsorption and regeneration, and with this PADS technology, the real gasoline can be desulfurized to < 10 mm·g^-1 by using Ti_0.3Si_0.7O₂.

Key words: gasoline desulfurization, bi-function, photocatalysis, selectivity, preparation, regeneration

摘要：

研究新型双功能Ti-Si-O吸附催化材料在紫外光照射下对汽油的光催化-吸附耦合脱硫性能。采用溶胶-凝胶法制备了Ti-Si-O双功能催化吸附材料,并用N₂吸附法、XRD等对Ti-Si-O进行了结构表征;有机硫化物的含量和种类采用液相色谱、库仑仪、GC-MS和GC-SCD检测。实验结果表明:当钛硅摩尔比为3:7时,所制得的Ti-Si-O材料的光催化-吸附耦合脱硫性能最好,脱硫率达96%,优于单一的TiO₂和SiO₂材料;Ti_0.3Si_0.7O₂对汽油中的3种有机硫化物的光催化-吸附耦合脱硫速率大小顺序为T > MT > BT;GC-MS产物检测表明汽油中的有机硫在Ti_0.3Si_0.7O₂双功能催化吸附材料表面转化成极性较强的砜类物质,而后选择性地吸附在Ti_0.3Si_0.7O₂表面;Ti_0.3Si_0.7O₂可经过丙酮洗涤和热空气氧化法再生,5次循环使用后的脱硫性能基本维持不变;在光催化-吸附耦合工艺下,Ti_0.3Si_0.7O₂材料可将真实汽油的硫含量降低至10 mg·g^-1以下。

关键词: 汽油脱硫, 双功能, 光催化, 选择性, 制备, 再生