A facile one‐step pyrolysis preparation of iron‐modified corn cob biochar with an efficient adsorption performance towards atrazine

BACKGROUND Efficient removal of atrazine (ATZ) from water is crucial but remains challenging. This study aimed to develop a novel iron‐modified biochar from corn cob for ATZ adsorption. RESULT Iron‐modified corn cob biochar was fabricated via a facile one‐step pyrolysis method under nitrogen atmosphere, and systematically characterized using various techniques. The optimal sample (BCA700) exhibited a specific surface area of 411.6 m 2 g −1 , high crystallinity, rich functional groups and strong magnetism. Adsorption experiments showed that 10 mg of BCA700 could remove >94% of ATZ (100 mL, 5 mg L −1 ) at room temperature within 1 h, with a saturated adsorption capacity of 47.10 mg g −1 . The adsorption process was well fitted to the pseudo‐second‐order kinetic model and Freundlich isotherm model, and thermodynamic parameters (Δ G < 0, Δ H = 73.32 kJ mol −1 ) confirmed it was a spontaneous and endothermic process. The adsorption mechanism was attributed to π – π conjugation and electrostatic attraction. BCA700 showed high adaptability to initial pH (3–11), reaction temperature (15–35 °C) and organic pollutant type, and retained >80% ATZ removal rate after three adsorption–desorption cycles. CONCLUSION This work provides a novel approach for corn cob resource utilization and an efficient adsorbent for pesticide‐contaminated wastewater treatment.