Developing a magnetic nanocomposite adsorbent based on carbon quantum dots prepared from Pomegranate peel for the removal of Pb(II) and Cd(II) ions from aqueous solution

Agriculture waste is a good choice for the production of carbon dots owing to its abundance, wide availability, eco-friendly nature. In this study a novel magnetic bioadsorbent based on carbon quantum dots (Fe3O4-PPCQDs) from Pomegranate peel (PP) was used as adsorbent to remove lead (Pb) and cadmium (Cd) from 50 mL of water and wastewater samples by magnetic solid phase extraction (MSPE). After adsorption ions with Fe3O4-PPCQDs at pH=6, the concentration of Pb(II) and Cd (II) ions were determined by flame atomic absorption spectrometry (F-AAS). The manufactured of Fe3O4-PPCQDs and GO nanostructures were structurally characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The quantum dots were optically characterized by UV–Vis spectroscopy. Batch adsorption experiment was conducted to examine the effects of pH, contact time, temperature and initial concentration of Pb(II) and Cd(II) from the water. The preconcentration factor and LOD for Cd and Pb were obtained 50 and (1.3 μg L-1; 15.5 μg L-1), respectively. The equilibrium data of ions sorption were well described by Langmuir and Freundlich model. The R2 values obtained by Langmuir model were higher. The absorption capacity of Fe3O4-PPCQDs for cadmium and lead were obtained 17.92 and 23.75 mg g-1, respectively.