Simultaneous separation and recovery of Cs(I) and Sr(II) using a hybrid macrocyclic compounds loaded adsorbent. Kinetic, equilibrium and dynamic adsorption studies

In this study, simultaneous separation and recovery of Cs(I) and Sr(II) from nitric acid solution was investigated using a silica-based hybrid adsorbent. The adsorbent was prepared by successive impregnation and fixing of two supramolecular recognition agents namely, 1,3-[(2,4-diethylheptylethoxy)oxy]-2,4-crown-6-Calix[4]-arene(Calix[4]arene-R14) and 4',4' (5)-di(tert-butylcyclohexano)-18-crown-6, onto a silica-based polymer support(SiO2-P). Uptake properties, characterization, equilibrium kinetics, and dynamic adsorption properties of Cs(I) and Sr(II) were then assessed. Distribution coefficients (K-d) higher than 10(2) cm(3)/g for Cs(I) and Sr(II) were obtained using 3M HNO3 at 298K, and the K-d values decreased with increasing temperature. Adsorption kinetics and equilibrium studies fitted well with pseudo-second-order model and Redlich-Peterson isotherm model, respectively. The constant total organic carbon values in the aqueous phase were obtained after adding 10(-3) approximate to 4M HNO3. Results of the dynamic adsorption/elution test indicated that Cs(I) and Sr(II) were efficiently and simultaneously captured and eluted even under a flow rate of 1.5 cm(3)/min.