Super facile one-step synthesis of aromatic amine waste residue derived N-rich porous carbon for hyper efficient p-nitrophenol adsorption

Abstract

Both nitrophenol wastewater and aromatic amine industrial waste residue are serious threats to our environment. In this paper, N-rich porous carbons (NPC) derived from industrial aromatic amine waste residue were prepared via a facile “carbonization-activation” one-step approach. Owing to the extremely high activation efficiency of amine residue-NaOH matching strategy, NPC prepared with 1.5 of NaOH-residue ratio obtained an ultra-high specific surface area of 3120 m2/g with a huge pore volume of 2.381 cm3/g. XPS analysis shows that graphitic-N and pyridinic-N are the main N-doped species. The plentiful pore structure, ultra-high surface area, and modification of nitrogen-doped sites rendered the NPCs remarkable adsorption capacity (1030.51 mg/g) for p-nitrophenol (PNP). Adsorption isotherms and adsorption kinetics indicated the adsorption behavior of PNP molecules on NPCs surface adhered to the mechanism of monolayer adsorption and pseudo-second-order kinetic. DFT calculation studies revealed that N-doped species could effectively enhance the adsorption energy of PNP on carbon surface due to the enhanced dispersion and electrostatic attraction. Particularly, the pyridinic-N made an outstanding contribution to improve the interactions through hydrogen bonding. Furthermore, the NPC-1.5 showed an excellent adsorption stability for PNP in the reusability test of 12 cycles, reflecting its great potential in practical application.