Cu₂O-incorporated MAF-6-derived highly porous carbons for the adsorptive denitrogenation of liquid fuel

Metal-organic framework (MOF)-derived carbons (MDCs) with remarkable porosity were synthesized through pyrolysis of a MOF (metal-azolate framework-6 or MAF-6) in the presence of KOH activating agent. Further, Cu₂O particles were synthesized under a mild condition within the MDCs. The Cu₂O/MDCs showed very efficient adsorptions of both quinoline (454 mg/g) and indole (435 mg/g) from liquid fuel. Or, the Cu₂O/MDC resulted in increase of quinoline and indole adsorption, by around 213% and 243%, respectively, compared with simple MDC, prepared without KOH. Additionally, the new adsorbent showed around 5–6 times efficiency in removal of such adsorbates to that of conventional activated carbon. The maximum adsorption capacities (Q_m) of the studied adsorbent for quinoline and indole also stand at the first and second positions, respectively, among the carbon-based adsorbents reported so far. Moreover, compared with other studied adsorbents, the Cu₂O-incorpoarated MDCs had a good selectivity towards both adsorbates, especially during the adsorptions in the presence of toluene as a co-solvent. The remarkable adsorptions with Cu₂O/MDC were explained by the π-complexation and huge porosity. In addition, the adsorbents could be regenerated for several cycles via a simple solvent wash.