Synergistic desulfurization over Ni(II) and Fe sites in adsorbent Ni@MIL-100(Fe)

Abstract

SOx released from the combustion of sulfur-containing compounds in fuels pollute the environment and have a serious impact on human health. Adsorption desulfurization is an effective and environmentally friendly technique for removing sulfur-containing compounds from fuels. Metal-organic frameworks (MOFs) have high specific surface areas and can be easily modified and functionalized, making them excellent candidates for adsorption desulfurization in fuels. In this work, the precursor MIL-100(Fe)-SA was prepared using the hydrothermal method, and the adsorbent Ni@MIL-100(Fe)-SA was obtained by doping Ni2+ into the resulting MIL-100(Fe)-SA using the impregnation method. FT-IR, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption isotherms were used to analyze the samples. The results indicated that Ni2+ was successfully loaded onto MIL-100(Fe)-SA, and the MOF's structure remained stable. The adsorption performance of benzothiophene and thiophene was evaluated through batch adsorption experiments. The adsorption capacities of Ni@MIL-100(Fe)-SA for thiophene and benzothiophene were 23.68 mg S/g and 49.58 mg S/g, respectively. These observations could be ascribed to the π-complexation interactions between Ni2+ of the framework and thiophenic compounds. The regeneration experiments demonstrated that the spent 11Ni@MIL-100(Fe)-SA-1.5 reach 86% of the adsorption capacity of fresh adsorbent after four cycles. Additionally, the regenerated adsorbent maintained good crystallinity after recycling.