Optimisation of graphene oxide–iron oxide nanocomposite in heterogeneous Fenton-like oxidation of Acid Orange 7

•GO–Fe3O4 nanocomposites were suitable as heterogeneous Fenton-like catalysts.•Fast 80% degradation of Acid Orange 7 dye (AO7) measured in ∼20 min.•The degradation kinetics of AO7 was most influenced by pH and temperature.•A pseudo-first-order reaction prevailed following a Langmuir–Hinshelwood mechanism.•Spent catalysts remained unchanged though minor pore volume losses occurred.

Well-dispersed iron oxide nanoparticles supported onto graphene oxide sheets (i.e. GO–Fe3O4 nanocomposite) were synthesised and used as heterogeneous Fenton-like catalyst for the degradation of Acid Orange 7 dye (AO7). The reaction was systematically investigated under various experimental conditions such as nanocomposite dosage, pH, temperature, oxidant and dye concentrations. Best results showed a fast 80% degradation in ∼20 min, whilst ∼98% of AO7 was successfully removed after 180 min of reaction time. The degradation kinetics of AO7 was most influenced by pH and temperature, and can be described by a pseudo-first-order reaction following the Langmuir–Hinshelwood mechanism. Analysis of the spent nanocomposite suggested that the phase of iron oxide nanoparticles remained unchanged whilst minor pore volume losses occurred via carbon deposition and/or re-stacking of GO sheets.