Reversible and Efficient Sequestration of Cesium from Water by the Layered Metal Thiophosphate K0.48Mn0.76PS3⋅H2O

5 years ago

Reversible and Efficient Sequestration of Cesium from Water by the Layered Metal Thiophosphate K0.48Mn0.76PS3⋅H2O

Ekashmi Rathore, Provas Pal, Kanishka Biswas

Water body contamination with radioactive species is an important issue due to significant developments in nuclear energy. Cesium (137Cs) radioisotope is a non-actinide fission product of uranium and plutonium that is long-lived. Hence, selective removal/capture of cesium is essential for managing radioactive waste. Herein, a detailed Cs+ ion-exchange study on a potassium intercalated layered metal thiophosphate, K0.48Mn0.76PS3⋅H2O (K-MPS-1), is reported. The sorption of Cs+ by K-MPS-1 follows the Langmuir model with a high capacity of 337.5 mg g−1 and high distribution coefficients in the order of about 104 mL g−1. K-MPS-1 can sequester Cs+ efficiently, even from very low concentrations (ppb level). K-MPS-1 exhibits high cesium uptake over a broad pH range of 2–12 and the ion-exchange process reaches equilibrium within a short time (≈15 min), following pseudo-second-order kinetics. Moreover, K-MPS-1 demonstrates selectivity towards Cs+ capture in the presence of complex solutions containing excess Na+, Ca2+, and Mg2+ ions; this is due to favorable interactions between Cs (soft Lewis acid) and S (soft Lewis base). K-MPS-1 reversibly captures Cs+ and it can be regenerated by treating Cs-MPS-1 with a solution of KCl. Radioactive clean up: A potassium intercalated layered metal chalcophosphate, K0.48Mn0.76PS3⋅H2O, rapidly and reversibly captures Cs+ with a high capacity of 337.5 mg g−1 and high distribution coefficients in the order of about 104 mL g−1, even when the concentration of Cs+ is very low (5–100 ppb), through utilizing the concept of hard/soft acid–base interactions (see figure).

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201701883