Synthesis of facile polystyrene/pol(N-methylaniline)/CuO composite for methyl orange uptake

Polystyrene (PS) was modified by grafting with poly(N-methylaniline) (PNMANI) and assembling on CuO nanoparticles to be a good adsorbent to methyl orange (MO). Dye-contaminated wastewater remains a critical environmental concern, requiring efficient and economically viable treatment strategies. Herein, polystyrene/poly(N-methylaniline) (PS/PNMANI) and polystyrene/ poly(N-methylaniline)/ CuO (PS/PNMANI/CuO) composite which not prepared before, were synthesized and characterized for MO uptake from aqueous media. Both structural and surface properties were analyzed using SEM, XRD, FTIR, BET, and TGA analyses. Batch adsorption experiments demonstrated that PS/PNMANI and PS/PNMANI/CuO composite achieved a maximum uptake efficiency of 95, 100% at pH 7 with an equilibrium time of 60 min using 0.10 and 0.25 g of composite respectively. The adsorption kinetics obey the pseudo-second-order model (R² = 0.997), while equilibrium data indicated mixed adsorption behavior with a maximum adsorption capacity (Qmax) of 43.29 mg/g for PS/PNMANI/CuO and 7.17 mg/g for PS/PNMANI. BET analysis revealed that the surface area of PS/PNMANI is 33.91 m²/g and 42.28 m²/g for PS/PNMANI/CuO, confirming that CuO incorporation enhanced surface characteristics and removal efficacy of graft. The improved adsorption performance is attributed to increased surface activity, synergistic polymer-CuO interactions, and porous morphology facilitating dye diffusion.