Waste eliminated by waste: Industrial o-phenylenediamine residue derived N,O co-doped hierarchical porous carbon for efficient onitroaniline removal

Abstract

The flourishing fine chemical industry has concurrently precipitated dual environmental challenges in the form of wastewater and solid waste. In the present study, the o-phenylenediamine distillation residue was employed as raw material and a recyclable Mg(CH3COO)2 template pore-forming strategy was established to fabricate a series of in-situ N/O co-doped porous carbons. The as-prepared porous carbons were utilized for the efficient adsorptive removal of o-nitroaniline (ONA) from aqueous solutions. By benchmarking against K2CO3-activated porous carbon, the structure-activity relationship between the pore structure and ONA adsorption capacity was systematically evaluated. The optimized carbon sample (AWC-M-1) possessing high specific surface area of 1209.21 m2·g-1 and hierarchical pore structure, demonstrated a remarkable ONA adsorption capacity of 639.9 mg·g-1 and outstanding continuous fixed-bed adsorption-regeneration performance. Furthermore, the AWC-M-1 exhibits excellent tolerance for ONA adsorption under various ionic backgrounds and real water matrix conditions. The combined physio-chemistry characterization, adsorption equilibrium, kinetic study and DFT calculation reveal the adsorption performance and mechanism of ONA enhanced by the mesopore-dominated hierarchical pore structure and surface functionalization with N,O co-doped species.