Rathore Ekashmi, Pal Provas, Biswas Kanishka
New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore, 560 064, India.
Chemistry. 2017 Aug 16;23(46):11085-11092. doi: 10.1002/chem.201701883. Epub 2017 Jul 26.
Water body contamination with radioactive species is an important issue due to significant developments in nuclear energy. Cesium ( Cs) 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, K Mn PS ⋅H O (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 and high distribution coefficients in the order of about 10 mL g . 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 , Ca , and Mg 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.
由于核能的重大发展，水体受到放射性物质的污染是一个重要问题。铯（Cs）放射性同位素是铀和钚的一种非锕系裂变产物，具有较长的半衰期。因此，选择性去除/捕获铯对于放射性废物的管理至关重要。在此，报道了对一种插层钾的层状金属硫代磷酸盐K₂MnPS₄·H₂O（K-MPS-1）进行的详细铯离子交换研究。K-MPS-1对铯的吸附遵循朗缪尔模型，吸附容量高达337.5 mg g⁻¹，分配系数约为10³ mL g⁻¹。即使在极低浓度（ppb水平）下，K-MPS-1也能有效地螯合铯。K-MPS-1在2至12的宽pH范围内表现出高铯摄取量，离子交换过程在短时间内（约15分钟）达到平衡，遵循准二级动力学。此外，在含有过量Na⁺、Ca²⁺和Mg²⁺离子的复杂溶液存在下，K-MPS-1对铯的捕获具有选择性；这是由于Cs⁺（软路易斯酸）与S²⁻（软路易斯碱）之间存在有利的相互作用。K-MPS-1可逆地捕获Cs⁺，并且可以通过用KCl溶液处理Cs-MPS-1来使其再生。
