A novel magnetic Fe3C@Fe3O4 core–shell biochar nanocomposite derived from Zanthoxylum bungeanum pruned branches for efficient adsorption of imidacloprid

Biomass-derived magnetic biochar is a promising imidacloprid adsorbent because of its low cost, easy separation, and eco-friendly features. This study prepared a novel magnetic Fe 3 C@Fe 3 O 4 core–shell biochar nanocomposite (Fe 3 C@Fe 3 O 4 /BC) using a facile one-step method with Zanthoxylum bungeanum pruning branches as raw materials and K 3 [Fe(C 2 O 4 ) 3 ]•3 H 2 O as the pore-forming agent and Fe source. The prepared Fe 3 C@Fe 3 O 4 /BC had a well-developed porous structure, a considerable specific surface area of 1471.3 m 2 g −1 , good magnetic separation performance, and excellent adsorption performance of imidacloprid. The adsorption capacity of Fe 3 C@Fe 3 O 4 /BC toward imidacloprid reached 288.9 mg g −1 within 1 min, and its maximum adsorption capacity was 557.1 mg g −1 . The adsorption performance of Fe 3 C@Fe 3 O 4 /BC was was stable under extreme environmental conditions, and its regeneration was excellent, which was superior to typical commercial adsorbents. The adsorption mechanism of imidacloprid by Fe 3 C@Fe 3 O 4 /BC involved the comprehensive effects of pore capture, van der Waals forces, hydrogen bonding, electrostatic attraction, and complexation of oxygen-containing functional groups. This work can provide an advanced strategy for the fabrication of high-performance adsorbents from biomass resources for the effective treatment of imidacloprid wastewater.