H2Ti6O13 Nanosheet/ Polymethyl Methacrylate (PMMA) for the adsorption of cesium ions

Radioactive Cs+ is one of the most dangerous environmental pollutants. It is necessary for radioactive Cs+ management and removal. Titanium-type cesium ion sieve with a strong Ti–O bond has the advantages of structural stability, radiation resistance and no secondary contamination, which is a promising adsorbent material. In this paper, The CTO (Cs2Ti6O13) is prepared for the first time by sol-gel and de-templating methods, and cesium ion sieves (HTO/PMMA) are further obtained with diluted HCl elution. Compared with the ionic sieves (HTO) prepared by direct sol-gel method, the adsorption capacity is improved from 224.32 mg/g to 299.15 mg/g. The prepared HTO/PMMA has a larger specific surface area (67.282 m2/g). More exchange sites are provided for the adsorption of Cs ions. Moreover, Adsorption involves the cleavage of O–H bonds and the formation of O–Cs bonds, which is a typical ion exchange reaction. A series of batch experiments are carried out. The results showed that the equilibrium adsorption capacity of HTO/PMMA is 307.69 mg/g and remained high in the interfering ion solution as well (280.38 mg/g). The pseudo second order model and Freundlich model can well describe the ion exchange process. Thermodynamic study shows that adsorption is spontaneous and exothermic, and low temperature is conducive to adsorption in H+- Cs+ exchange system. Finally, the reusability of HTO/PMMA is evaluated. The adsorption capacity did not decrease significantly after 5 cycles of use. Therefore, HTO/PMMA is expected to be an excellent material for recovering radioactive Cs+.