The role of graphene oxide anchored 1-amino-2-naphthol-4-sulphonic acid on the adsorption of uranyl ions from aqueous solution: kinetic and thermodynamic features

Graphene oxide-1-amino-2-naphthol-4-sulphonic acid (GOANS) adsorbent synthesised successfully from a natural source (Cattle bones) for the U(VI) ions removal from liquid waste solutions. The synthesised adsorbent characterised via Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) Surface Area Analysis, Energy-dispersive X-ray spectroscopy(EDX) pattern and scanning electron microscopy (SEM). Various experimental parameters (time, adsorbent weight, initial uranium concentration and temperature) investigated and the results reveal that a higher uptake capacity of 311.5 mg/g achieved at pH 4 within 60 minutes. The obtained findings fitted well with thermodynamic, isothermal (Langmuir and Freundlich model) and pseudo second order kinetics. The negative sign of (ΔG∘) specified the spontaneity of adsorption process in the thermodynamic study, ΔH∘ (endothermic) and positive sign ΔS∘ indicate high randomness after adsorption.