Removal of nitrogen-containing compounds from microalgae derived biofuel by adsorption over functionalized metal organic frameworks

Considering the depletion of fossil fuel, alternative energy resources have been continuously investigated. Microalgae-derived biofuel can be a solution to replace traditional fuel; however, biofuel contains much nitrogen-containing compounds (NCCs) such as carbazole (CBZ) and benzonitrile (PhCN). In this work, effective denitrogenation of biofuel was investigated by using MOFs, especially having multi-functional groups and high porosity. MIL-101-NH₂ was modified with oxalyl chloride (OC) to have a MOF called M101-OC. The M101-OC showed remarkable performance in adsorptive denitrogenation from biofuel. Or, M101-OC had 3.8- and 19.6-times adsorption capacity for CBZ and PhCN that of activated carbon, respectively; and showed the highest adsorption capacity, compared with any known adsorbent. The noticeable performances of M101-OC could be explained with hydrogen bonding due to ample hydrogen donor and hydrogen acceptor sites on the M101-OC. Finally, the investigated MOF was also easily recycled via simple ethanol washing. Therefore, M101-OC might be a promising adsorbent for the purification of microalgae-derived biofuel having much NCCs.