Investigations on the ion exchange process of Cs+ and Sr2+ cations by ETS materials

• Microporous titanosilicates ETS-4 and ETS-10 are used as effective ion exchangers.
• Ionic selectivities for Cs and Sr ions were estimated from ion exchange isotherms.
• ETS titanosilicates show high affinity towards Cs and Sr cations.
• ETS materials have good potential for removal of Cs/Sr from nuclear waste solution.

Ion exchange experiments were carried out for evaluation the removal capability of cesium and strontium ions by the microporous Engelhard Titanium Silicates – 4 and 10 (ETS-4 and ETS-10, respectively) synthesized from alkaline gels. Ionic selectivities were estimated from the ion exchange isotherms, Kielland and Langmuir plots. It is shown that both microporous titanosilicates perform under a similar ion exchange profile against Cs+ cations and the selectivity of ETS-4 for Sr2+ is highly depended on temperature. ETS-10 is unselective for Sr2+ over a wide range of equivalent ionic fraction of strontium in solution. The Langmuir isotherms indicate that in the absence of ionic competition both titanosilicates retain Cs+ and Sr2+ cations, as much as their ion exchange capacities. These positive results promote ETS materials as very good candidates for the removal of both cesium and strontium from nuclear waste solutions.

Figure optionsDownload as PowerPoint slide