Sorption of cesium and strontium ions by natural zeolite and management of produced secondary waste

The aim of this work is sorptive removal of cesium and strontium ions from aqueous solution using natural zeolite and management of produced secondary waste. Characterization of the natural zeolite was performed by X-ray diffraction (XRD), X-ray fluorescence (XRF), Brunauer-Emmett-Teller (BET), and field emission scanning electron microscopy (FE-SEM). The effective parameters on the sorption process such as initial solution pH, adsorbent dosage, and concentration of cesium and strontium ions were optimized by using experimental design method. Based on the results, removal efficiency for cesium ion was about 67.8% at the optimum condition of adsorbent dosage of 0.40 g, pH = 7.23 and Cs+ concentration of 10 mg L-1, and for the strontium ion was about 93.5% at the optimum condition of adsorbent dosage of 0.3 g, pH = 7.9 and Sr2+ concentration of 10 mg L-1. Kinetic studies showed that the removal process follow pseudo-secondorder kinetic model for both ions. The sorption results showed that the data for cesium and strontium ions were fitted by Freundlich isotherm better than Langmuir isotherm. Finally, to manage secondary waste produced from the sorption process, the cesium and strontium ions stabilized in zeolite structure and related tests such as compressive strength and leaching were evaluated. The results of waste management section showed that the stabilization process was performed as well by heat preparation process. (C) 2019 Elsevier B.V. All rights reserved.