Green synthesis of bimetallic nanoparticles of Fe/Ni (G-Fe/Ni-NPs) and zeolite-5A supported (G-Z-Fe/Ni-NPs) as heterogeneous Fenton-like oxidation for the decolourisation of reactive red 120-dye (RR120) from the aqueous medium using green tea extract as a reducing agent. Zeolite-5A from local kaolin is prepared and characterised using the hydrothermal method and is used as a supporting material for Fe/Ni-NPs. (SEM), (EDX), (AFM), (XRD), (FT-IR), (BET). Its zeta potential were used to characterise G-Fe/Ni-NPs and G-Z-Fe/Ni-NPs. The decolourisation efficiency (Ed) of the RR120-dye using a heterogeneous Fenton-like for G-Fe/Ni-NPs and G-Z-Fe/Ni-NPs is 99.8% and 99.9%, respectively, under the optimum conditions: [H2O2] = 20 and 1 mmol/L, respectively, by G-Fe/Ni-NPs, NPs dosage = 0.1 g/L, [RR120-dye] = 25 mg/L and pH = 3. The results show that the reactivity of Fe/Ni-NPs was improved when zeolite-5A was used as support, showing fast removal. Three kinetic models (first-order, second-order, and Behnajady–Modirshahla–Ghanbary, BMG) were evaluated. The first-order, (econd-order and BMG models were found to be the best models representing the experimental kinetic data of RR120-dye in the state of G-Fe/Ni-NPs and G-Z-Fe/Ni-NPs, respectively. The study of the thermodynamic parameters (ΔG°, ΔH°, and ΔS°) for the removal of RR120-dye at 30°C, 40°C and 50°C indicates an appropriate, spontaneous, and endothermic reaction. The Ed using Fenton-like and adsorption processes are compared.
