Rapid and selective removal of Cs+ from water by layered potassium antimony thiostannate

Cs-137 is radioactive and highly hazardous to human health and the environment and its efficient removal from water is still challenging. In this study, potassium antimony tin sulfide (KATS-2) was synthesized using a hydrothermal method and utilized for the first time for cesium removal from water. KATS-2 showed a high maximum ion exchange capacity (358 mg g(-1)) and distribution coefficient (1.59 x 105 mL g(-1)) toward Cs+. In particular, KATS-2 showed rapid ion exchange kinetics and reached the adsorption equilibrium within 5 min with 99% removal efficiency. The adsorption was good at a wide active pH range (1-12) even in extreme alkaline conditions (K-d = 3.26 x 10(4) mL g(-1) at pH 12). The effect of coexisting ions was also investigated, and a high selectivity toward Cs+ was maintained even in artificial seawater (K-d = 3.28 x 10(3) mL g(-1)). Powder X-ray diffraction and thermogravimetric analysis demonstrated that KATS-2 was chemically and thermally stable. The results showed that owing to its excellent adsorption performance as well as chemical and thermal stability, KATS-2 is a promising adsorbent for Cs+ removal from contaminated water.

Automated summary

This study demonstrated that potassium antimony tin sulfide (KATS-2) had a high ion exchange capacity and selectivity for cesium removal from water, showing rapid ion exchange kinetics and excellent stability, making it a promising adsorbent for contaminated water treatment.