“Efficient degradation of mordant Orange 1 dye using Alg/Bi2WO6/g-C3N4 composite and evaluation of Phytotoxicity for water treatment applications”

Abstract

Industrial effluents containing synthetic dyes pose serious environmental risks due to their toxicity and persistence against conventional treatment methods. In this work, alginate-based composites incorporating Bi₂WO₆ and graphitic carbon nitride (g-C₃N₄) (Alg/Bi₂WO₆/g-C3N₄) were fabricated and fully characterized (XRD, FTIR, SEM, EDS). Sodium alginate, a sustainable biopolymer, provides structural stability and facilitates catalyst recovery, while the synergistic combination of Bi₂WO₆ and g-C₃N₄ enhances catalytic performance. The catalytic activity was evaluated for the NaBH₄ assisted degradation of Mordant Orange 1 (MO1). Kinetic analysis revealed a dose-dependent enhancement, with apparent rate constants increasing from 0.1321 min⁻¹ (30 mg catalyst) to 0.2001 min⁻¹ (45 mg) and 0.4168 min⁻¹ (55 mg). The composite exhibited good mechanical robustness and reusability over several catalytic cycles. Phytotoxicity assays confirmed the environmental safety of the treated effluent: Alg/Bi₂WO₆/g-C₃N₄ promoted seed germination and root elongation without adverse effects, whereas pure Bi₂WO₆ displayed concentration dependent inhibition at 500 ppm. These results demonstrate that Alg/ Bi₂WO₆/g-C₃N₄ composites are efficient, reusable, and eco-friendly catalysts with strong potential for sustainable water purification.