Development and CO2 Capture of Nitrogen-Enriched Microporous Carbon by Coupling Waste Polyamides with Lignocellulosic Biomass

Due to the substantial emissions of global CO2, there has been growing interest in nitrogen-enriched porous carbonaceous materials that possess exceptional CO2 capture capabilities. In this study, a novel N-enriched microporous carbon was synthesized by integrating waste polyamides with lignocellulosic biomass, involving carbonization and physicochemical activation. As-synthesized adsorbents demonstrated significant characteristics including a high specific surface area (1710 m2/g) and a large micropore volume (0.497 cm3/g), as well as abundant N- and O-containing functional groups, achieved through activation at 700 °C. They displayed remarkable CO2 capture capability, achieving uptake levels of up to 6.71 mmol/g at 1 bar and 0 °C, primarily due to the filling effect of narrow micropore along with electrostatic interaction. Furthermore, the adsorbent exhibited a rapid capacity for CO2 capture, achieving 94.9% of its saturation capacity within a mere 5 min at 30 °C. This impressive performance was accurately described by the pseudo second-order dynamic model. Additionally, as-synthesized adsorbents displayed a moderate isosteric heat of CO2 adsorption, as well as superior selectivity over N2. Even after undergoing five consecutive cycles, it maintained ∼100% of its initial capacity. Undoubtedly, such findings hold immense significance in the mitigation of global plastic pollution and greenhouse effect.