Mesoporous magnetic activated carbon for chlorpyrifos removal: Kinetics, isotherms, regeneration and real water matrix evaluation

Chlorpyrifos contamination in water bodies is a major environmental and public health concern due to its persistence, potential for bioaccumulation, and strong neurotoxic effects. This study reports the preparation of magnetically recoverable activated carbon (MCMAC) using Magnolia champaca leaves . BET analysis revealed a mesoporous nature (3.07 nm) with a specific surface area of 462.65 m 2 /g. The pseudo-second-order kinetic model and the Freundlich isotherm best represented the adsorption kinetics and isotherm. The maximum adsorption capacity (q m ) determined using Langmuir isotherm was 115.04 mg/g. The thermodynamic evaluation indicated that the adsorption process occurs spontaneously and absorbs heat, confirming its endothermic nature (∆H°: 21.34 kJ/mol) and physisorption-driven mechanism. Regeneration showed that MCMAC exhibits significant adsorption performance across multiple cycles, and a real water matrix test revealed the effects of competing ions and the efficiency of MCMAC in different real water matrices. The proposed mechanism includes pore diffusion, hydrogen bonding, π-π stacking, van der Waals forces, and surface complexation. Hence, MCMAC is a cost-efficient, sustainable adsorbent for the remediation of chlorpyrifos-contaminated water.