Enhanced heavy metal removal using silver-yttrium oxide nanocomposites as novel adsorbent system

The present study demonstrates development of silver-yttrium oxide nanopcomposites (SYONs) and its use as novel adsorbent for efficient removal of Cu(II), Cr(VI)and multiple metal ions from waste water. The nanocomposite was synthesized using solution combustion synthesis method and characterized using standard technique viz. with X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, thermo gravimetric analysis (TGA), zeta potential and Fourier transform infrared spectroscopy (FTIR) analysis. The particles were elliptical in shape with the size predominantly ranging between 41 and 70 nm. A series of experiments was performed to study the effect of various parameters (contact time, concentration of metal ions, pH, adsorbent dose, temperature) on the metal ion removal potential of SYONs. The maximum adsorption capacity for Cu(II) and Cr(VI) was obtained as 773 ± 4.94 mg g−1 and 720 ± 8.48 mg g−1 respectively. The equilibrium time of contact for adsorption was found as 720 min and adsorption of Cu(II) and Cr(VI) was found maximum at pH = 6. Thermodynamic studies revealed that the adsorption of Cu(II) and Cr(VI) on SYONs surface was an endothermic process. The nanoadsorbent was successfully regenerated using acid treatment for consecutive cycles.