Cornus Mas L. Seed‐Derived Biosorbent for Methylene Blue Removal: Surface Characterization and Biosorption Performance

ABSTRACT This study investigates the potential of Cornus mas L. seeds as an eco‐friendly and low‐cost biosorbent for the removal of Methylene Blue (MB) from aqueous solutions. The valorization of this agricultural by‐product offers a sustainable approach to wastewater treatment. Scanning electron microscopy (SEM) and Fourier‐transform infrared (FTIR) spectroscopy characterize the biosorbent, revealing a porous structure rich in functional groups such as hydroxyl and carbonyl, which facilitate dye binding. Batch adsorption experiments evaluate the effects of pH, biosorbent dosage, and initial dye concentration. Kinetic analyses demonstrate that the process follows the pseudo‐second‐order model (PSO), suggesting that chemisorption is the rate‐limiting step, supported by intraparticle diffusion. Equilibrium data fit the Freundlich isotherm model ( R ² = 0.9892), indicating multilayer adsorption. Kinetic analyses demonstrate PSO behavior ( R ² = 0.9905), confirming chemisorption as the rate‐limiting step, supported by thermodynamic analysis ( E _DR = 16.24 kJ mol ^{− 1} ). Furthermore, Response Surface Methodology (RSM) with a Central Composite Design (CCD) optimizes the operational parameters, identifying initial dye concentration and contact time as the most significant factors influencing adsorption capacity. The optimized conditions yield a maximum predicted biosorption capacity of 71.71 mg g ^{− 1} . These findings establish Cornus mas L. seeds as a highly effective and sustainable material for dye‐contaminated wastewater remediation.