Oxidative denitrogenation using sustainable carbon nanotubes: Effect of reaction conditions on hydrogen peroxide efficiency

Nitrogenated compounds in fuels contribute significantly to NOₓ emissions, prompting the need for efficient and sustainable removal technologies. Oxidative denitrogenation (ODN) has emerged as an alternative or complement to hydrodenitrogenation (HDN) to remove undesired nitrogenated compounds. While ODN requires significantly milder conditions compared to HDN, it relies on the use of hydrogen peroxide as oxidant source. Most works report the removal of nitrogenated compounds but neglect the rate of consumption and efficiency of use of hydrogen peroxide. In this work, the operational conditions during ODN (hydrogen peroxide concentration, catalyst concentration, temperature, and pH) were optimized to maximize the removal of nitrogenated compound, using quinoline as model compound, from a simulated fuel. Two sustainability-oriented parameters were introduced: (i) the abatement of total organic carbon and (ii) the efficiency of hydrogen peroxide consumption. Under optimum conditions ([H 2 O 2 ] 0 = 12 g L -1 , 70 °C, [cat] = 2.5 g L -1 , pH 0 = 3.0), the process achieved 89% quinoline removal, 35% TOC abatement, and more than 77% H 2 O 2 consumption efficiency. These results demonstrate the potential of ODN to operate under mild conditions while maintaining high oxidant efficiency for model nitrogen-containing fuel compound, contributing to cleaner and more sustainable fuel purification strategies. • Sustainable CNTs enable efficient biphasic oxidative denitrogenation • CNT surface oxidation enhances quinoline mass transfer and oxidant use efficiency • Sustainability metrics introduced to optimize ODN performance and efficiency • Catalyst deactivation is linked to surface chemistry changes, not bulk structure