Optimization of methyl orange bio-decolorization by UiO-66 and brown rot fungus Daedalea dickinsii composite using response surface methodology

• Biocomposite of Daedalea dickinsii and UiO-66 in PVA-SA matrix was synthesized. • The UiO-66/DD@PVA-SA beads was able to degrade methyl orange (MO). • Kinetic studies of the MO decolorization process followed a pseudo-second-order model. • Optimal conditions for MO decolorization: 50 mg.L -1 MO, 20 °C, and 5.75 days. Azo dyes, particularly methyl orange (MO), pose environmental challenges due to their stability, toxicity, and carcinogenicity. This study explored the potential of a novel composite material for MO removal. The composite comprised UiO-66 (a metal-organic framework), Daedalea dickinsii (DD) fungus biomass, and a polyvinyl alcohol-sodium alginate (PVA-SA) matrix. DD and UiO-66 were homogeneously distributed within the PVA-SA matrix to form beads. These beads achieved a promising MO decolorization efficiency of 68.95 % after 7 days, outperforming PVA-SA (43.30 %) and UiO-66@PVA-SA (54.49 %) alone. Kinetic studies revealed that the decolorization process followed a pseudo-second-order model with a high correlation coefficient (R² = 0.999). Further optimization using response surface methodology (RSM) identified the most effective conditions for MO biodecolorization: 50 mgL -1 MO concentration, 20 °C incubation temperature, and 5.75 days incubation time. Experimental verification under these optimized conditions yielded a decolorization efficiency of 76.71 %, closely matching the RSM prediction (77.40 %). These findings suggest significant potential for this composite material in textile wastewater treatment for MO removal.