Effective removal of cadmium ions from wastewater using modified mesoporous zeolite-A /reduced graphene oxide nanocomposite: kinetic and thermodynamic studies

This study discusses the capability of the prepared modified mesoporous zeolite-A /reduced graphene oxide nanocomposite (MZ-A/RGO) in removal of cadmium (Cd 2+ ) ions from wastewater, in which 3-aminopropyl- trimethoxysilane (APTMS) was used as a mesopore generating and cross linkage agent in this preparation. X-ray diffraction, attenuated total reflectance- Fourier transform infrared spectroscopy (ATR-FTIR) and field emission scanning electron microscope were used to confirm the successful preparation of MZ-A/RGO nanocomposite. The results indicated that the modified mesoporous zeolite-A (MZ-A) was attached to the surface of the reduced graphene oxide (RGO) nanosheets without any aggregation. The adsorption treatment experiments were conducted for Cd 2+ ions removal and the adsorption capacities of MZ-A/RGO were determined under different adsorption parameters including, the contact time, initial adsorbate concentrations and temperature. The adsorption results revealed that 15 minutes was quiet enough to ensure the equilibrium state with maximum adsorption capacity 222.23 mg/g and the experimental data was fitted well with the pseudo-second-order kinetic model. The isotherm studies refer to the Langmuir model exhibits best fitting for the obtained experimental data and the thermodynamic results confirm that the endothermic nature of the adsorption of Cd 2+ ions on MZ-A/RGO nanocomposite.