Fernandes Simone, Flores Daniela, Silva Daniel, Santos-Vieira Isabel, Mirante Fátima, Granadeiro Carlos M, Balula Salete S
LAQV/REQUIMTE & Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal.
CICECO-Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
Nanomaterials (Basel). 2022 Aug 22;12(16):2887. doi: 10.3390/nano12162887.
An effective and sustainable oxidative desulfurization process for treating a multicomponent model fuel was successfully developed using as a heterogeneous catalyst a composite material containing as an active center the europium Lindqvist [Eu(WO)] (abbreviated as EuW) encapsulated into the nanoporous ZIF-8 (zeolitic imidazolate framework) support. The EuW@ZIF-8 composite was obtained through an impregnation procedure, and its successful preparation was confirmed by various characterization techniques (FT-IR, XRD, SEM/EDS, ICP-OES). The catalytic activity of the composite and the isolated EuW was evaluated in the desulfurization of a multicomponent model fuel containing dibenzothiophene derivatives (DBT, 4-MDBT and 4,6-DMDBT) with a total sulfur concentration of 1500 ppm. Oxidative desulfurization was performed using an ionic liquid as extraction solvent and aqueous hydrogen peroxide as oxidant. The catalytic results showed a remarkable desulfurization performance, with 99.5 and 94.7% sulfur removal in the first 180 min, for the homogeneous active center EuW and the heterogeneous EuW@ZIF-8 catalysts, respectively. Furthermore, the stability of the nanocomposite catalyst was investigated by reusing and recycling processes. A superior retention of catalyst activity in consecutive desulfurization cycles was observed in the recycling studies when compared with the reusing experiments. Nevertheless, the nanostructure of ZIF-8 incorporating the active POM (polyoxometalate) was shown to be highly suitable for guaranteeing the absence of POM leaching, although structural modification was found for ZIF-8 after catalytic use that did not influenced catalytic performance.
一种用于处理多组分模型燃料的有效且可持续的氧化脱硫工艺被成功开发出来。该工艺使用一种含有封装在纳米多孔ZIF-8（沸石咪唑酯骨架）载体中的铕林德奎斯特配合物[Eu(WO)]（简称为EuW）作为活性中心的复合材料作为多相催化剂。通过浸渍法获得了EuW@ZIF-8复合材料，并通过各种表征技术（傅里叶变换红外光谱、X射线衍射、扫描电子显微镜/能谱分析、电感耦合等离子体发射光谱）证实了其成功制备。在总硫浓度为1500 ppm的含有二苯并噻吩衍生物（DBT、4-MDBT和4,6-DMDBT）的多组分模型燃料的脱硫过程中，评估了该复合材料和分离出的EuW的催化活性。使用离子液体作为萃取溶剂，过氧化氢水溶液作为氧化剂进行氧化脱硫。催化结果显示出显著的脱硫性能，对于均相活性中心EuW和多相EuW@ZIF-8催化剂，在最初180分钟内的脱硫率分别为99.5%和94.7%。此外，通过重复使用和循环过程研究了纳米复合催化剂的稳定性。与重复使用实验相比，在循环研究中观察到连续脱硫循环中催化剂活性的优异保留率。尽管在催化使用后发现ZIF-8的结构发生了改变，但这种改变并不影响催化性能，不过，含有活性多金属氧酸盐（POM）的ZIF-8纳米结构被证明非常适合保证不存在POM浸出。
