Effective and Rapid Adsorption of Sr²⁺ Ions by a Hydrated Pentasodium Cluster Templated Zinc Thiostannate

Abstract

Separation of 90Sr from radioactive wastewater not only is essential for human public health and environmental remediation but also bears importance for alternate medical and industrial applications. Here, we report the facile synthesis of an open framework zinc thiostannate, Na5Zn3.5Sn3.5S13·6H2O (ZnSnS-1), templated by hydrated pentasodium clusters. This compound exhibits an effective and rapid ion exchange property for Sr2+ ions. The exchange kinetics conforms to a pseudo-second-order model, implying that the chemical adsorption of Sr2+ may be the rate-determining step. According to the Langmuir–Freundlich isotherm, the maximum exchange capacity of ZnSnS-1 for Sr2+ is 124.2 mg/g and ranks ahead of those of all the reported metal sulfide Sr2+ adsorbents. High exchange performance is observed over the broad pH range 2.5–13, although it could be inhibited to some extent by coexisting ions, especially Na+ and Ca2+. ZnSnS-1 shows a higher affinity for Sr2+ compared to Cs+, and the performance is almost unaffected by the presence of coexisting Cs+ even in excess amounts. Importantly, the Sr2+ in the exchanged product can be conveniently eluted by a concentrated KCl solution, and the recycled exchanger can be further used for Sr2+ exchange. These advantages combined with the robust framework for recycling concerns make ZnSnS-1 a highly promising exchanger for removal of radioactive Sr from the liquid nuclear waste.

Efficient Cs+–Sr2+ Separation over a Microporous Silver Selenidostannate Synthesized in Deep Eutectic Solvent

“…However, it was seldomly explored for chalcogenide ion exchangers, e.g. K 6 Sn­[Zn 4 Sn 4 S 17 ], [NH 3 CH 3 ] 4 [In 4 SbS 9 SH], [(CH 3 ) 2 NH 2 ] 2 ­Ga 2 Sb 2 S 7 ·H 2 O, Na 5 Zn 3.5 Sn 3.5 S 13 ·6H 2 O ( ZnSnS-1 ), [(Me) 2 NH 2 ] 0.75 ­[Ag 1.25 SnSe 3 ] . The dynamic response presented here provides useful insights into the selective ion exchange mechanism that are crucial for material innovation.…”

“…KMS-1, KMS-2, KTS-3, FJSM-SnS, and FJSM-GAS-1, making it impossible to separate these two elements. (2) Such layered materials usually exhibit a lower mechanical strength, and this would probably lead to the stripping-induced powdering failure, increasing the column pressure drop and thus hinder the practical application. , (3) The metal sulfide materials commonly suffer from poor adsorption performance in strongly acidic solutions (pH < 2) that are often required for scenarios in practical waste partitioning.…”

pH‐Controlled Switch over Coadsorption and Separation for Mixed Cs+ and Sr2+ by an Acid‐Resistant Potassium Thioantimonate

“…Overall, it has been well documented for 2D or 3D metal chalcogenide exchangers, e.g. KMS‐1, [ 29 ] KMS‐2, [ 31 ] KTS‐3, [ 32 ] NaTS, [ 57 ] and InS‐1 [ 45 ] and ZnSnS‐1, [ 43 ] that their interlamellar distance or channel dimension undergo irritable expansion upon the incorporation of large hydrated metal ions. However, to the best of our knowledge, 1D chalcogenide material has never been reported about its ion exchange performance until the present work on SbS‐1 , which exhibits remarkable mechanical strength and structure flexibility that can withstand the transfer of metal ions.…”

“…Very recently, the alkylammonium-directed metal selenide AgSnSe-1 [40] was emplored for extracting Cs + from Sr 2+ , with an excellent separtion factor SF Cs/Sr large than 120. Conversely, selective ion exchange for Sr 2+ against Cs + has also been achieved by inorganic materials such as MOFs (e.g., SZ-4, [21] MOF-808-SO 4 , [41] and MOF-808-C 2 O 4 [41] ) and metal sulfides (e.g., ZnSnS [42][43][44] and InS [45][46][47] series) as a result of collaborative coordination by the host network and/or particular ion-trapping interactions. In short, increasing efforts have been put on developing high-performance single-functional ion exchangers as either coadsorbent or separator for mixed Cs + and Sr 2+ in aqueous solutions.…”

Removal of Sr2+ Ions by a High-Capacity Indium Sulfide Exchanger Containing Permeable Layers with Large Pores

“…Such a high q m ranks InS-2 ahead of the reported metal sulfide Sr 2+ adsorbents, with q m varying from 22.3 to 124.2 mg g –1 (Figure c and Table S1). − ,− …”