Three-dimensional lignin-based polyporous carbon@polypyrrole for efficient removal of reactive blue 19: A synergistic effect of the N and O groups

Reactive blue 19 is one of the abundant carcinogens commonly used in industrial applications. This study transformed industrial lignin into a lignin-based polyporous carbon@polypyrrole (LPC@PPy) by a hydrothermal-activation-in situ polymerization strategy for removal of reactive blue 19. The hydrothermal reaction and polypyrrole polymerization provide abundant O and N groups, and the pore-making process promotes the even distribution of O and N groups in the 3D pore of LPC@PPy, which is favorable for the adsorption of reactive blue 19. The adsorption capacity of LPC@PPy for reactive blue 19 is 537.52 mg g−1, which is 2.04 times the performance of LPC (only hydrothermal and activation process, only have O groups) and 3.36 times that of LC (direct lignin activation, lack of O and N groups). After 8 cycles, LPC@PPy still maintained a high adsorption capacity of 92.14 % for reactive blue 19. In addition, this study found that N and O groups in the material played an important role in adsorption, mainly pyridinic–N, C–OH, –COOR, –C–O– and CC. This work provides a new strategy for the removal of reactive blue 19 and determines the groups that mainly interact with reactive blue 19, which provides a new reference for adsorption, catalysis and related fields. •A novel lignin-based polyporous carbon@polypyrrole adsorbent was prepared.•The adsorption performance of LPC@PPy for RB 19 was 537.52 mg g−1.•The pyridinic-N, C-OH, -COOR, -C-O- and CC are the key of adsorption sites.•LPC@PPy has excellent selective adsorption performance for RB 19.•LPC@PPy maintains 92.14 % performance after 8 regeneration cycles.