Selective biphasic oxidation of nitrogenated contaminants with H2O2 using polyolefin-derived carbon nanotubes

Liquid/liquid biphasic oxidations are extensively employed in the chemical industry to manufacture a variety of chemicals and for environmental issues, such as the oxidative denitrogenated (ODN) and desulfurization of fuels. The ubiquitous presence of nitrogenated and sulfonated compounds in petroleum-derived fuels is associated with environmental and health issues, driving legislation to become stricter regarding the content or related emissions of those impurities. However, catalysts with high performance, low cost and high activity towards selective oxidation of targeted contaminants should be developed. This work deals with the oxidative denitrogenation of quinoline and pyridine, used as model nitrogenated compounds, using carbon nanotubes as catalysts, which were derived from polyolefins (low-density polyethylene, high-density polyethylene and propylene) representative of plastic solid waste (PSWs) mixtures found in municipal solid wastes. The carbon precursor used offers not only a solution to reduce PSWs accumulation in waste management systems but also a cheap feedstock for preparing CNTs. All PSWs-derived CNTs allowed to remove quinoline completely, pyridine, and both of them in a mixture under the same conditions (1 h, 80 °C, c cat = 2.5 g L −1 , [H 2 O 2 ] 0 = 247 g L −1 , O/W volume ratio = 80:20, [N] 0 = 108 mg L −1 ). These results were maintained for up to 5 additional reuse cycles for the catalyst prepared with mixed polyolefins. • CNTs are used as phase-transfer catalysts in a biphasic medium. • Quinoline and pyridine are used as nitrogenated pollutants. • Catalytic activity of CNTs leads to the complete removal of nitrogenated compounds. • CNTs show high stability in successive cycles of use for selective oxidation. • Kinetic modeling allows some insight into the CNT role.