Development of surface functionalized activated carbon fiber for control of NO and particulate matter

This study investigates the development and potential application of activated carbon fibers (ACF) functionalized with ammonia for control of NO and particulate matter (PM) in diesel engine exhaust. A tubular reactor packed with ACF was used to experimentally study the oxidation of NO at room temperature. Tests were conducted at ACF functionalized with three aqueous ammonia concentrations (3, 5, 10 M), three basic reagents (ammonia, pyridine, amine) and three NO concentrations (100, 300, 500 ppm). After offline investigation, the ACF-packed tubular reactor was installed downstream of the engine's exhaust to ascertain the PM capturing efficiency of ACF. The experimental conditions for PM removal included three weights of ACF (2, 3.5, 4.5 g), three engine loads (0, 25, 50 Nm) and three temperatures (150, 300, 450 °C). The maximum 70% conversion for NO was obtained at NO concentration of 300 ppm for ACF functionalized with 5 M ammonia, whereas maximum 90% reduction in PM was observed at engine load of 25 Nm and 450 °C. The study shows significant potential for the ACF based filters in capturing both homogeneous and heterogeneous pollutants emitted from automobiles. Our previously developed transport model incorporating the mechanism for the oxidation of NO was also used to explain the experimental data.