Investigating the dual activation synergistic mechanism of KOH activation and sodium self-catalysis to uncover microporous mechanisms in CO2 adsorption

This research delves into the combined impact of employing sodium lignosulfonate as a feedstock, along with its inherent self-activating property and co-activation with KOH, in the preparation of activated carbon. Studies suggest that the natural activator, Na, aids in the internal creation of pores, thereby decreasing the reliance on KOH. The resulting activated carbon boasts a substantial specific surface area of 3362 m²/g, a significant micropore volume of 1.3435 cm³ /g, and considerable doping levels of nitrogen (1.09 %) and sulfur (2.46 %). Analysis of CO 2 adsorption indicates that the adsorption heat escalates with the quantity of CO 2 adsorbed, highlighting the pivotal role of micropores in this process. Monte Carlo simulations further demonstrate that narrowing the pore size range boosts CO 2 adsorption uptake. Nevertheless, as the temperature rises, the ability of micropores to capture carbon dioxide decreases, as shown by the increasing difference in adsorption capacity from 0 °C to 25 °C.