Cs⁺and Sr²⁺adsorption selectivity of zeolites in relation to radioactive decontamination

Abstract

Zeolites are used as adsorbents of cationic elements in the radioactive decontamination process of water, soil and others. We determined Cs + and Sr 2+ adsorption selectivity of some zeolites to know effective zeolite species for the decontamination of radioactive Cs and Sr. A 30 mL mixed solution containing up to 15 mg L −1 of non-radioactive Cs + or Sr + and up to 0.50 M of Na + or K + was mixed with 0.5 g of Lindetype A, Na-P1, faujasite X, faujasite Y and mordenite. Among the zeolites, mordenite had the highest Cs + adsorption selectivity, and the selectivity had no correlation to the cation exchange capacity (CEC) of the zeolites. In contrast, Sr 2+ adsorption selectivity of the zeolites positively correlated with the CEC of the zeolites; Linde-type A with the highest CEC showed the highest adsorption selectivity, and its adsorption rate was more than 99.9% even in the presence of 0.5 M K +. A simulated soil decontamination experiment of Cs from a Cs-retaining vermiculite by using mordenite and that of Sr from a Sr-retaining vermiculite by using Linde-type A showed decontamination rates of more than 90%.

Sub-nanomolar detection of cesium with water-gated transistor

“…it no longer increases with increasing Cs + concentration. The known selectivity of mordenite for Cs + over other cations [21] does translate to the WGTFT transducer. We have repeated the experimental series shown in Fig.…”

“…Selectivity of mordenite for Cs + is well established [21,22], but for confirmation we here tested the selectivity of the mordenite membrane for Cs + vs. other alkali ions on the example of Na + . Fig.…”

“…Here, we used the natural zeolite known as 'mordenite', which has main channels with a crosssection of 0.65 nm x 0.70 nm and smaller channels of 0.26 nm x 0.57 nm [18,19,20]. Mordenite exhibits a high selectivity towards the alkaline metal cation, Cs + , which it extracts from aqueous media even when these contain a vast excess of Na + and K + [21,22]. This qualifies mordenite as sensitiser for the selective detection of waterborne Cs + , as well as for its specific removal.…”

“…Detection of Cs + in drinking water (and removal from it) is therefore relevant for the detection of such incidents, which may be concealed, and the protection of humans and animals from drinking contaminated water. Prior work on detecting Cs + ions with mordenite used atomic absorption spectroscopy (AAS) [21] applied to mordenite after contact with Cs + -contaminated water. However, the WGTFT transducer has a much lighter experimental footprint than AAS.…”

Preparation of colloidal hydrated alumina modified NaA zeolite derived from rice husk ash for effective removal of fluoride ions from water medium

“…However, searching a new type of adsorbent with its interesting properties toward the removal of fluoride is of utmost important in terms of low cost and high efficiency. Zeolites have been used for the removal of radioactive cations like Cs + and Sr 2+ [14].…”