State Key Laboratory of Chemical Resource Engineering, Institute of Science, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
Dalton Trans. 2019 Oct 7;48(39):14792-14800. doi: 10.1039/c9dt02674f.
Desulfurization of oragnosulfur-containing fuels signify a great importance in improving the quality of fuel and is also beneficial to the environment. In this work, we report two new composites, namely, MOF-5@γ-Al2O3 and IRMOF-3@γ-Al2O3, synthesized by loading iso-structural MOF-5 and amino bearing IRMOR-3 onto the γ-Al2O3 beads (the loading amount of MOF-5 and IRMOF-3 are 13.4 wt% and 16.3 wt%, respectively). The composites are fully characterized by IR spectroscopy, XRD, SEM, BET and XRF. These iso-structural MOFs and their composites exhibit substantially high adsorptive desulfurization capacities for benzothiophene (BT), 3-methylthiophene (3-MT), dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The adsorption capacities of amino bearing IR-MOF-3 and IRMOF-3@γ-Al2O3 are significantly greater than those of MOF-5 and MOF-5@γ-Al2O3, e.g., the adsorption capacities for DBT of IRMOF-3@γ-Al2O3, IRMOF-3, MOF-5@γ-Al2O3 and MOF-5 are 54.9, 45.1, 31.4 and 24.1 mg S g-1 MOFs, respectively, under optimal conditions (time 60 min, temperature 30 °C, MOFs@γ-Al2O3/Moil = 1/40). The adsorption results revealed the predominant role of hydrogen bonding between the Lewis basic S atoms of the organo sulfurs and -NH2 groups in IR-MOF-3 and also the π-π interactions that works well in MOF-5. The enhancement in the desulfurization capability of MOFs@γ-Al2O3versus the corresponding pristine MOFs shall be attributed to the advantage of the confinement effect of the γ-Al2O3 pores that results in larger specific surface area, much more exposed active sites, and shorter diffusion channels of the MOFs. The kinetics and thermodynamic parameters indicate that the adsorption process is spontaneous and endothermic, and the increase in entropy is the primary driving force for the desulfurization. In addition, it is found that the composites possess good reusability and can be regenerated by simple washing due to enhanced mechanical strength.
含硫有机燃料的脱硫在提高燃料质量和保护环境方面具有重要意义。在这项工作中，我们报告了两种新的复合材料，即 MOF-5@γ-Al2O3 和 IRMOF-3@γ-Al2O3，它们是通过将同构的 MOF-5 和带有氨基的 IRMOF-3 负载到 γ-Al2O3 珠上合成的（MOF-5 和 IRMOF-3 的负载量分别为 13.4wt%和 16.3wt%）。这些同构的 MOFs 和它们的复合材料对苯并噻吩（BT）、3-甲基噻吩（3-MT）、二苯并噻吩（DBT）和 4,6-二甲基二苯并噻吩（4,6-DMDBT）表现出很高的吸附脱硫能力。带有氨基的 IR-MOF-3 和 IRMOF-3@γ-Al2O3 的吸附能力明显大于 MOF-5 和 MOF-5@γ-Al2O3，例如，IRMOF-3@γ-Al2O3、IRMOF-3、MOF-5@γ-Al2O3 和 MOF-5 对 DBT 的吸附容量在最佳条件下（时间 60 分钟，温度 30°C，MOFs@γ-Al2O3/油=1/40）分别为 54.9、45.1、31.4 和 24.1mg S g-1 MOFs。吸附结果表明，有机硫中的路易斯碱性 S 原子与 IR-MOF-3 中的 -NH2 基团之间的氢键以及在 MOF-5 中起作用的 π-π 相互作用起着主要作用。MOFs@γ-Al2O3 相对于相应的原始 MOFs 的脱硫能力增强应归因于 γ-Al2O3 孔的限制效应的优势，这导致更大的比表面积、更多暴露的活性位点和 MOFs 的较短扩散通道。动力学和热力学参数表明，吸附过程是自发的和吸热的，熵的增加是脱硫的主要驱动力。此外，发现由于机械强度增强，复合材料具有良好的可重复使用性并且可以通过简单的洗涤再生。
