Nitrogen-doped bamboo-like carbon nanotubes encapsulated with nickel nanoparticles (Ni@NCNTs) were feasibly fabricated by a one-pot pyrolysis route. The characterization techniques revealed the surface morphology, structure and chemical composition of the as-prepared catalysts synthesized in different conditions. Ni@NCNTs were employed as both adsorbents and catalysts for activating persulfate to remove an emerging pollutant, antibiotic sulfachloropyridazine. The nitrogen modification enhanced both adsorption capacity and catalytic ability of Ni@NCNTs and proved to be a promising alternative to metal oxides and other carbon catalysts. Moreover, Ni@NCNTs showed an excellent stability because of nitrogen heteroatom doping and Ni nanoparticle encapsulation. Electron paramagnetic resonance (EPR) and classical radical quenching tests discovered a simultaneous radical/non-radical mechanism in Ni@NCNTs/persulfate system. The results indicated that the novel nano-architectured catalyst materials can show emerging functionalities for environmental remediation processes.