Graphene oxide supported Fe₃O₄-MnO₂ nanocomposites for adsorption and photocatalytic degradation of dyestuff: ultrasound effect, surfactants role and real sample analysis

Present work demonstrates the synthesis, characterisation and application of a novel hybrid nanocomposite GO@Fe3O4-MnO2 for adsorption catalytic degradation dyestuff malachite green tartrazine from wastewater. The was characterised by FT-IR, XRD, SEM-EDS pHzpc. Effects various optimising parameters such as contact time, solution pH, surfactants, light, adsorbent dose, ultrasonication coexisting ions were investigated. removal efficiencies observed high 99.9% 98% under direct sunlight, respectively. kinetics follows pseudo-second order model (R2 = 0.99) where k2 0.0097 0.0011 g mg−1 min−1, respectively, that means controlled chemisorption. Equilibrium isotherm these dyes analysed in context Langmuir Freundlich models, maximum capacity found to be 8.0 5.1 mg g−1 tartrazine, percentage initially low, but when ultrasound irradiated, (96% tartrazine) drastically increased because formation highly active •H •OH radicals water through decomposition molecules hot spots. On treatment with H2O2, advance oxidation processes remediation (99.5% dye. synthesised finally used real samples. separated using an external magnet recycled 0.1 N HCl or NaOH desired.