What Matters to the Adsorptive Desulfurization Performance of Metal-Organic Frameworks?

Abstract

Metal−organic frameworks (MOFs) show high potential in adsorptive removal of aromatic sulfur compounds; however, the crucial factors affecting the adsorption performances are scarcely clarified. In the present study, three classic aromatic sulfur compounds (i.e., thiophene, benzothiophene, and 4,6-dimethyldibenzothiophene) as well as five typical MOFs (i.e., MOF-5, HKUST-1, MIL-53(Fe), MIL-53(Cr), and MIL-101(Cr)) were selected for study. The adsorptive desulfurization performances of MOFs were investigated by using a fixed-bed adsorption system. In the case of thiophene, the adsorption capacity of MOFs decreases in the order MIL-53(Cr) > HKUST-1 > MOF-5 > MIL-53(Fe) > MIL-101(Cr). For the first time, the adsorbate−adsorbent interaction was examined in detail by using infrared spectra and temperature-programmed desorption. Such an interaction was demonstrated to be the most important factor affecting adsorption performance. When the molecular size of aromatic sulfur compounds is comparable to or smaller than the window diameter of MOFs, the influence of window diameter becomes apparent. It is surprising to find that the adsorbate−adsorbent interaction plays a major role, which is responsible for the poor adsorption performance of MIL-101(Cr) with quite high porosity. Therefore, metal sites and structure that contribute to the adsorbate−adsorbent interaction should be considered to be the most significant factor aiming to develop new MOFs for adsorptive desulfurization.

Efficient adsorption separation of xylene isomers using a facilely fabricated cyclodextrin‐based metal–organic framework

“…The isomer pX is widely used as the key raw material in the production of terephthalic acid. [10][11][12] As an emerging family of porous materials with zeolite topologies, metal-organic frameworks (MOFs) possess well-defined channels or cavities that are constructed by metal cations/clusters and functional organic linkers, making them highly suitable for diverse adsorption applications, [13][14][15][16][17][18][19] such as xylenes separation. 7 The slight differences in the boiling points of the xylene isomers lead to the difficulty and inefficiency of distillation separation processes.…”

“…8,9 Current industrial practice for separating xylenes involves slow and energy-consuming processes such as fractional crystallization, or adsorption separation on zeolites. [10][11][12] As an emerging family of porous materials with zeolite topologies, metal-organic frameworks (MOFs) possess well-defined channels or cavities that are constructed by metal cations/clusters and functional organic linkers, making them highly suitable for diverse adsorption applications, [13][14][15][16][17][18][19] such as xylenes separation. [20][21][22][23][24][25][26][27][28][29] Some MOFs show the separation mechanisms of commensurate stacking separation and molecular sieving.…”

Remarkable adsorptive removal of nitrogen-containing compounds from a model fuel by a graphene oxide/MIL-101 composite through a combined effect of improved porosity and hydrogen bonding

“…The applicability and stability of MOFs in adsorption conditions make MOFs one of the most promising groups of materials for several adsorption-related processes [18][19][20][21][22][23][24][25]. Several reports have been published on ADN [26][27][28][29] and ADS [30][31][32][33][34][35][36][37][38] with pristine or modified MOFs that have shown successful removal of NCCs and SCCs from fuels. Various adsorption mechanisms were also presented in these reports.…”

Hydrotreatment Followed by Oxidative Desulfurization and Denitrogenation to Attain Low Sulphur and Nitrogen Bitumen Derived Gas Oils

“…The alternative processes such as adsorption and oxidative desulfurization and denitrogenation has been of interest to achieve ultra-low sulphur level in oil because of very mild operating conditions and no usage of hydrogen. Various adsorbents including activated carbon, ionic resins, metal organic frameworks, metal oxides and zeolites have been used to adsorb sulphur containing compounds from diesel oil [3][4][5][6][7][8][9][10]. Ganiyu et al [6] utilized activated carbon doped with 1.0 wt.% boron to selectively adsorb 4,6-DMDBT from model fuel.…”

“…Ganiyu et al [6] utilized activated carbon doped with 1.0 wt.% boron to selectively adsorb 4,6-DMDBT from model fuel. Srivastav and Srivastava [7] carried out the adsorption of DBT dissolved in hexanes on commercial grade activated alumina and Li et al [4] presented a study on the challenges associated with removal of aromatic sulphur compounds using metal-organic frameworks.…”