Microwave assisted decoration of titanium oxide nanotubes with CuFe2O4 quantum dots for solid phase extraction of uranium

Abstract

Titanium oxide nanotubes (TiO_xNTs) were prepared using a hydrothermal method followed by ion exchange and phase transformation. The obtained TiO_xNTs were decorated with CuFe₂O₄ quantum dots by assisted microwave procedures. The prepared nanomaterials were characterized by XRD, TEM, and IR spectroscopy. The decorated nanotubes (DTiO_xNTs) were used as adsorbents for the removal of U(VI) from aqueous solutions prior to its determination by inductively coupled plasma-optical emission spectrometry. Experimental parameters including pH, contact time and amount of adsorbent were investigated by batch mode. Optimum sorption of U(VI) ions obtained at pH 6–8. The maximum adsorption capacity of DTiO_xNTs towards U(VI) was found to be 366 mg g⁻¹ which is better than that obtained by using TiO_xNTs (277 mg g⁻¹). The equilibrium adsorption isotherm of U(VI) was fitted with the Langmuir adsorption model. Moreover, a mini-column packed with DTiO_xNTs was used for column-mode extraction and preconcentration of U(VI). The effects of layer thickness, sample volume, sample flow rate and eluent conditions were studied. Under the optimized column procedures, the preconcentration factor for U(VI) was 200. The 3σ detection limit and 10σ quantification limit were found to be 0.12 and 0.40 ng mL⁻¹, respectively. The calibration curve was linear up to 1500 ng mL⁻¹. The proposed method showed good performance in analyzing water samples of different sources and soil sample digests collected from agriculture land near an industrial area.