Preparation of Chitosan Schiff Base‐4‐Hydroxybenzaldehyde/CuO Nanocomposite for Eosin Y Dye Removal

ABSTRACT This study presents the synthesis of a multifunctional polymer nanocomposite (hereinafter, chitosan‐4‐hydroxybenzaldehyde/CuO [CHI‐4HBA/CuO]) based on 4‐hydroxybenzaldehyde (4HBA)‐modified chitosan Schiff base and CuO nanoparticles. The CHI‐4HBA/CuO nanocomposite was characterized using field emission scanning electron microscopy with energy‐dispersive x‐ray spectroscopy (FESEM–EDX), Brunauer–Emmett–Teller (BET) surface area analysis, differential scanning calorimetry–thermogravimetric analysis (DSC–TGA), x‐ray diffraction (XRD), and Fourier‐transform infrared spectroscopy (FTIR). The adsorption properties of CHI‐4HBA/CuO were investigated through the removal of organic dye (eosin Y, EOY). Box–Behnken design (BBD) was used to optimize the adsorption of EOY. The CHI‐4HBA/CuO demonstrated a BET surface area of 24.43 m 2 /g and a total pore volume of 0.02135 cm 3 /g. The optimal adsorption conditions (0.075 g dose, pH ∼ 4, 39 min) yielded 91.43% EOY removal efficiency. The CHI‐4HBA/CuO demonstrated an adsorption capacity of 250.43 mg/g.