Adsorption Behavior of Metal–Organic Frameworks for Thiophenic Sulfur from Diesel Oil

Abstract

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.

Highly Dispersed HKUST-1 on Milimeter-Sized Mesoporous γ-Al2O3 Beads for Highly Effective Adsorptive Desulfurization

“…44 The increasement of adsorbent concentration signified that the DBT concentration around adsorbent molecule decreased and hence led to decrease in adsorption desulphurization capacity. It was also found that the adsorptive desulfurization capacities for DBT of HKUST-1@γ-Al 2 O 3 were On the basis of the above results, it is known that under the optimum experimental conditions, the adsorptive desulfurization capacities of pristine HKUST-1 and HKUST-1@γ-Al 2 O 3 for DBT were 49.5 and 59.7 mg S/g, respectively, i.e., the adsorptive desulfurization capacity of HKUST-1@γ-Al 2 O 3 increased by 17.8% compared to pristine HKUST-1.…”

Adsorption on Mesoporous Metal–Organic Frameworks in Solution: Aromatic and Heterocyclic Compounds

“…For the adsorption of T, BT, DBT on MIL‐100(Cr)(F), MIL‐100(Fe)(F), and MIL‐100(Al) from n ‐heptane/toluene, the amounts adsorbed were <1 % due to competitive adsorption of toluene 102. The adsorption capacity of MIL‐100(Cr)(F) was118 DBT>BT>3‐MT, and for MIL‐100(Fe)(F) it was 4,6‐DMDBT>DBT>BT:120 the larger the molecule, the higher the adsorbed amount. MIL‐100(Cr)(F) was modified with ethylenediamine (ED), and the capacity of ED‐MIL‐100(Cr)(F) for BT was 23 mg g −1 in comparison with 28 mg g −1 on MIL‐100(Cr)(F), due to repulsion of BT molecule from the electron donor ED group 105…”

“…For N‐heterocyclic compounds, the trend was reversed:102 2‐methylindole (34 %)> N ‐methylcarbazole (27 %), and the adsorption mechanism must be different. The adsorption capacity of MIL‐101(Cr)(F) decreases118 as DBT>BT>3‐methylthiophene (3‐MT): the larger the molecule, the higher the capacity. For adsorption of BT in n ‐octane/ p ‐xylene (75:25 v/v),104 an acidic sorbent PWA/MIL‐101(Cr)(F) did not show an increase of adsorption capacity versus MIL‐101(Cr)(F).…”

Modification of a Copper‐Based Metal–Organic Framework with Graphene Oxide for the Removal of Sulfur Compounds

“…The desulfurization mechanism was considered to originate from the weak interactions between the amino groups in the MOFs and the sulfur atoms of the sulfides. MOF‐199 was studied by Zhang and co‐workers for the adsorption of thiophenic sulfur from diesel oil . They found that the different adsorptive activities of the organosulfur compounds are mainly due to their π‐electron numbers and the electron density at the S atom.…”