Adsorptive desulfurization from the model fuels by functionalized UiO-66(Zr)

Metal organic frameworks (MOFs) have recently emerged as promising candidates for efficient removal of sulfur-containing compounds (SCCs) from liquid fuels. In this study, adsorptive desulfurization (ADS) is performed by adsorbing thiophene (TP) and benzothiophene (BT) from model fuels over pristine and functionalized UiO-66 (Zr). The introduction of amino (-NH2) and carboxylic (-COOH) groups reduces the porosity of UiO-66. However, the adsorption capacities of functionalized UiO-66 improved remarkably. Especially for the adsorbent functionalized with amino moieties (UiO-66-NH2), its maximum adsorption capacities for TP (29.5 mg S/g) and BT (35.7 mg S/g) are 1.7 and 1.8 times to that of bare UiO-66. The superior performance of UiO-66-NH2 is ascribed to the higher availability of hydrogen-bond donor sites in the surface and the favorable interactions between H atoms of -NH2 and sulfur species. UiO-66-COOH is beneficial for the adsorption of SCCs than that of pristine UiO-66 because of the existence of acid-base interactions. Moreover, the reusability of UiO-66-NH2 is confirmed by regenerating it via a simple solvent washing.