Chemical Engineering Journal, Vol.267, 245-252, 2015
Strontium(II) adsorption on Sb(III)/Sb2O5
The rapid development of the nuclear power plants (NPPs) in China leads to an increasing attention to the treatment of low-level radioactive wastewater (LLRW). One of the possibilities is the application of antimony pentoxide based ion exchange materials, which can exhibit effective adsorption of Sr-90. In this paper, a novel sorbent Sb(III)/Sb2O5 is prepared by sol-gel method and its structure and surface properties are determined by X-ray photoelectron spectra (XPS), X-ray diffraction (XRD), zeta potential, surface area and porosity analysis. The batch experiments demonstrate a very efficient and selective Sr(II) elimination over a wide pH range from 2.0 to 12.0. At Sb(III)/Sb (total) ratio of 0.41, the optimum adsorption can be achieved with K-d value of 8.8 x 10(8) mL/g. The co-existing calcium ions can affect the adsorption of strontium, since the K-d value drops to 10(3)-10(2) mL/g with calcium concentration increases to 0.1 mol/L. Compared with divalent cations, the monovalent cations like Na+ and K+ have only minor influence. The strontium adsorption isotherm coincides very well with Freundlich model. The K-F values are 10.7 mg/g at 283 K, 23.2 mg/g at 303 K, and 40.6 mg/g at 323 K. The thermodynamic studies reveal an endothermic and spontaneous process. The kinetic performance follows the pseudo-second-order adsorption model, with intra particle diffusion as the rate controlling step. (C) 2014 Elsevier B.V. All rights reserved.