Sonochemically Engineered CuO/Sulfonated Charcoal Nanocomposite as a High-Performance, Sustainable Adsorbent for Dye...

Developing cost-effective and reusable adsorbents is critical for sustainable wastewater remediation. This study addresses this need by presenting a sonochemically synthesized CuO-sulfonated charcoal nanocomposite (CuO@charcoal-SO₃H) for the efficient removal of Congo red dye (CR). Different analytical tools are used to confirm the structure of as- prepared materials. The composite achieved a high specific surface area (465.2 m²/g) and an enhanced adsorption capacity of 355.8 mg/g, surpassing both pristine charcoal (300.1 mg/g) and sulfonated charcoal (325.6 mg/g). Under optimal conditions (pH 6, 30°C, 0.5 g/L adsorbent dose, 180 min), adsorption followed pseudo-second-order kinetics (R² = 0.998, k₂ = 0.0062 g/mg min), indicating chemisorption as the dominant mechanism. Thermodynamic analysis confirmed a spontaneous and endothermic process, with ΔG = -10.50 kJ/mol, ΔH = 31.75 kJ/mol, and ΔS = 98.55 J/mol K. The nanocomposite maintained 85% efficiency over five regeneration cycles and demonstrated economic viability with a production cost of 0.32-0.65 USD/g. These results establish CuO@Charcoal-SO₃H as a high-performance, reusable, and cost-effective adsorbent for industrial dye removal.