Akademik Veri Yönetim Sistemi
International Refereed Journal of Engineering and Science, cilt.14, sa.6, ss.92-103, 2025 (Hakemli Dergi)
Industrial processes commonly use azo dyes such as Tropaeolin OOO (TOOO) and Eriochrome Black T (EBT), which are environmentally persistent and toxic. This study presents a green-synthesized NiO@WO₃– chitosan nanocomposite using Azadirachta indica for the effective photocatalytic degradation of these dyes under solar irradiation. Characterization revealed semi-crystalline spherical nanoparticles with strong Ni–O– W, Ni–N, and W–N interactions. Under optimum conditions (pH 7, 20 mg catalyst), complete decolorization of 10 mg/L dye solutions was achieved within 3 hours, with degradation efficiencies of 96% for TOOO and 92% for EBT. The reaction followed pseudo-first-order kinetics, supported by the material’s high surface area (75 m²/g) and low band gap energy (2.1 eV). Scavenger analysis confirmed the involvement of •OH, O₂⁻•, and h⁺ species in the degradation mechanism. The catalyst maintained its activity over eight reuse cycles, demonstrating its potential as a sustainable and cost-effective solution for industrial wastewater treatment. Azo dyes such as Tropaeolin OOO (TOOO) and Eriochrome Black T (EBT), widely used in industrial processes, are environmentally persistent and toxic. This study presents a green-synthesized NiO@WO₃-chitosan nanocomposite using Azadirachta indica for effective photocatalytic degradation of these dyes under sunlight. Characterization revealed semi-crystalline spherical particles with strong Ni–O–W, Ni–N, and W–N interactions. Under optimal conditions (pH 7, 20 mg catalyst), complete decolorization of 10 mg/L dye solutions was achieved within 3 hours, with degradation efficiencies of 96% (TOOO) and 92% (EBT). The reaction followed first-order kinetics, supported by the material’s high surface area (75 m²/g), low band gap (2.1 eV), and strong negative zeta potential (−29.5 mV). Scavenger analysis confirmed the involvement of •OH, O₂⁻•, and h⁺ species in the degradation mechanism. The catalyst remained active over 8 reuse cycles, demonstrating its potential as a sustainable and cost-effective solution for industrial wastewater treatment.