The high efficiency of Al2O3-SiO2-CuO nanocomposites as an adsorbent: synthesis and dye removal efficiency

In this study, Al2O3-SiO2 and Al2O3-SiO2-CuO nanocomposites with different amounts of CuO (40, 50 and 60 %) were synthesized by the sol-gel method and characterized by thermogravimetric and differential thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive spectrometry and zeta potential analysis. The nanocomposites were applied as an adsorbent for removal of methylene blue (MB) from aqueous solution. The relation between removal percentages with variables such as adsorbent dosage (0.001, 0.003, 0.005, 0.01 and 0.02 g), adsorbent type and initial MB concentration (10, 20, 30 and 40 mg/L) was investigated, and optimized conditions were found to be 0.01 g, 50 % CuO and 10 mg/L, respectively. In this condition, the removal efficiency of MB was 98 %. The resulting zeta potential showed that the surfaces of Al2O3-SiO2-CuO nanocomposite and of Al2O3-SiO2 have negative charges, at -45 and -15 mV, respectively, while that of CuO has a positive charge of approximately +13 mV.