Root nodule-assisted activation for the preparation of micropore-graded porous carbon for VOC adsorption

In order to address the evolving emission characteristics of oxygenated volatile organic compounds (OVOCs), it is essential to develop adsorbent materials specifically designed for the efficient adsorption of OVOCs with large kinetic diameters. In this study, we used co-pyrolysis to prepare a series of graded porous carbon materials with well-developed micropores by adjusting the doping ratios of root nodules and pretreated cellulose. The material with root nodule to cellulose mass ratio of 1:1 (TCC-RN-1) exhibited the highest saturated adsorption capacity for butyl acetate (834 mg/g). This can be attributed to enhanced pore size distribution from nodule doping, which facilitates the development of a micropore-graded structure. Additionally, the nodules acted as auxiliary activating agents that enhanced the KOH micropore regulation effect during the activation stage, resulting in the highest micropore volume (0.863 cm³/g). The doping of root nodules facilitated the formation of additional defects on the surface of the porous carbon material, leading to a more disordered arrangement that improved pollutant adsorption. Furthermore, TCC-RN-1 demonstrated good thermal stability in an air atmosphere, maintaining a butyl acetate adsorption capacity exceeding 95 % after five adsorption-desorption cycles. This indicates its favorable potential for industrial applications.