Modulated Synthesis of a Novel Nickel-Based Metal-Organic Framework Composite Material for the Adsorptive Desulfurization of Liquid Fuels

Removing sulfur from liquid fuels has become an important issue in a global society. Modulated synthesis is known to improve the crystallinity of materials, ease of handling, control of crystallite size, and degree of aggregation. A group of adsorbents [activated carbon (AC), a novel synthesized Ni-based metal-organic framework (Ni-BDC), and composites of AC@Ni-BDC treated with different concentrations of nitric acid and modulator (formic acid)] were characterized using X-ray diffractometer (XRD), high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and temperature-programmed desorption (TPD)-pyridine studies. The adsorbents were also evaluated for adsorptive desulfurization. The quantities of both AC and the modulator were observed to influence the nucleation of Ni-BDC, crystallite size, and crystallinity. The adsorption activity of the composite toward thiophene (TH) was the average of the two materials (i.e., AC and Ni-BDC), while the activity doubled toward dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) with respect to the excepted average. The improved activity was attributed to enhanced pore structure, crystallinity, and synergistic effects that produced stronger acidic sites.