Adsorption behavior of methyl orange onto nanoporous core-shell Cu@Cu2O nanocomposite

In this work, the adsorption behavior of methyl orange onto nanoporous core-shell Cu@Cu2O nanocomposite has been investigated using an UV-vis spectrophotometer, considering the influence of pH value, temperature, additive amount of nanocomposite and initial methyl orange (MO) concentration. The adsorption kinetics of MO on the Cu@Cu2O nanocomposite has been discussed based upon the pseudo-first-order model, intraparticle diffusion model and Langmuir adsorption model. Thermodynamic parameters such as change in Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) have also been evaluated. The negative changes in Gibbs free energy (−18.4 to −15.1 kJ mol−1) and enthalpy (−51.5 kJ mol−1) indicate the spontaneous and exothermic nature of the adsorption process of MO. The activation energy (Ea) of 12.4 kJ mol−1 reveals the physisorption nature of MO adsorption onto the nanoporous Cu@Cu2O nanocomposite.