Eco‐friendly dye removal: Optimized synthesis of a magnetic Schiff base biocomposite from peanut shell chitosan for enhanced Reactive Blue 19 adsorption

This study reports the synthesis and application of a Schiff base–functionalized magnetic biocomposite, CS/CLS/Benz/Fe 3 O 4 , developed from peanut shell–derived chitosan–cellulose, benzoin, and Fe 3 O 4 nanoparticles for the efficient adsorption of Reactive Blue 19 (RB19) dye from aqueous media. The composite was characterized using Brunauer–Emmett–Teller (BET), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), confirming a well‐developed porous structure and active functional groups. The adsorption process was optimized using Box–Behnken design (BBD) and response surface methodology (RSM), identifying optimal parameters of pH 4.15, contact time 18.16 min, adsorbent dosage 0.04 g, and temperature 56.63°C, which yielded a 99.05% removal efficiency. Kinetic and equilibrium studies revealed that the adsorption followed a pseudo‐second‐order kinetic model and was best described by the Freundlich isotherm, indicating multilayer adsorption on a heterogeneous surface. The maximum adsorption capacity reached 496.4 mg/g at 350 mg/L. The composite maintained excellent magnetic separability and reusability, ensuring easy recovery and stable performance over multiple cycles. These results demonstrate that the developed biocomposite offers a sustainable, cost‐effective, and regenerable adsorbent derived from agricultural waste, presenting a promising material for eco‐friendly water treatment and dye remediation applications.