Facile fabrication of a novel silico vanadate ion exchanger: evaluation of its sorption behavior towards europium and terbium ions
E.A. Abdel-Galil, A. B. Ibrahim, W.M. El-Kenany
Abstract
ABSTRACT A novel inorganic silico vanadate (SiV) was synthesized via a sol–gel technique. The granulometry, morphology, and structure of the prepared exchanger were studied using different analytical tools such as X-ray fluorescence, Fourier-transform infrared, scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and thermogravimetric analysis–differential thermal analysis. The structure of SiV exchanger may be composed as (H 2 V 2 O 8 )(HSiO 2 ) 2 ·1.5H 2 O. Batch tests were done to examine the sorption behavior of SiV towards Eu(III) and Tb(III) considering the influence of independent parameters including pH of the solution, contact time, sorbent weight, and initial metal ions concentration. The sorption efficiency values of 95.40% and 88.70% were respectively obtained for Eu(III) and Tb(III) at optimum conditions (pH = 5.5, C 0 = 50 mg/L, weight = 0.03 g, and time = 200 min). The equilibrium data fitted well to the non-linear Freundlich and Langmuir isotherm models and the maximum adsorption capacity (q m ) of SiV for Eu(III) and Tb(III) get from the non-linear Langmuir model was 44.23 and 34.39 mg/g, respectively. Kinetic studies showed that the sorption of Eu(III) and Tb(III) followed both pseudo-second-order and intra-particle diffusion models. The thermodynamic studies showed an endothermic and spontaneous sorption process. The sorbent material can also be reactivated by utilizing the solution of 0.4 mol/L HNO 3 and re-used again effectively.