Adsorption Behavior of Metal–Organic Frameworks for Thiophenic Sulfur from Diesel Oil
2012
Zhang, Hong-Xing | Huang, Hong-Liang | Li, Chun-Xi | Meng, Hong | Lu, Ying-Zhou | Zhong, Chong-Li | Liu, Da-Huan | Yang, Qing-Yuan
Four metal–organic frameworks (MOFs) are synthesized using two different metal centers and two different organic ligands, viz., Cu₃[C₆H₃(CO₂)₃]₂ (Cu-BTC), Cu[O₂C–C₆H₄–CO₂] (Cu-BDC), Cr(OH)[O₂C–C₆H₄–CO₂] (Cr-BDC), and Cr₃F(H₂O)₃O[C₆H₃(CO₂)₃]₂ (Cr-BTC). Their adsorption behaviors for thiophenic sulfurs in model diesel oils are systematically investigated at mild temperatures and follow the order Cu-BTC > Cr-BDC > Cr-BTC ≫ Cu-BDC. Meanwhile, the adsorption capacity of different sulfur compounds follows the order dibenzothiophene (DBT) > benzothiophene (BT) > 3-methylthiophene (3-MT). The MOFs adsorption mechanism is regarded as a combined effect of many factors involving appropriate framework structure, suitable pore size and shape, and exposed Lewis acid site matching the S-compound to be adsorbed. The difference in adsorptive activity among the organosulfurs is mainly ascribed to their π-electron number and the electron density on the S-atom. Finally, the used MOF can be easily regenerated by solvent washing and recycled at least five times.
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