Abstract:
Heavy metal contamination in water poses significant ecological and health risks, necessitating effective removal methods. This study reports the green synthesis of CdO nanoparticles (NPs) and Ag-CdO nanocomposites (NCs), characterized by XRD, FTIR, SEM, zeta potential, and UV-Vis spectroscopy. The optimal adsorption conditions were 0.1 g/100 mL adsorbent dose, pH 2, initial Cr(VI) concentration of 10 mg/L, 25°C temperature, and 5-minute contact time. Under these conditions, Ag-CdO NCs achieved a removal efficiency of 99.6 ± 0.31%, surpassing CdO NPs (96.72 ± 0.27%). The adsorption capacity of Ag-CdO NCs was 87.95 mg/g, with isotherm data fitting well to Freundlich (R²=0.991) and Langmuir (R²=0.898) models. Kinetic studies aligned with a second-order model (R²=0.9994). The separation factor (RL) values is 0.0493 which is below 1 indicated favorable adsorption. The enhanced performance of Ag-CdO NCs is attributed to lower band energy (1.84 eV), increased surface area, and synergistic semiconducting properties compared to CdO NPs (2.73 eV). Overall, Ag-CdO NCs demonstrate high potential as efficient adsorbents for hexavalent chromium removal from industrial wastewater
