Rapid Synthesis of a Cesium Removal Ion Exchanger by Microwave Radiation

The microwave radiation synthesis technology and crystallized mechanism of ion exchanger silicotitanate NaTS were studied in this work. The effects of autoclave pressure and synthetic time on the crystallinity and cesium removal properties were investigated in a sealed microwave reactor. The results show that microwave radiation can significantly reduce the synthetic reaction time from 120 h to 2 h at the pressure of 5atm compared with the conventional sol-gel hydrothermal method. The analysis of XRD and SEM show that there is no obvious difference between the conventional method and microwave method for the cesium removal ability of the products. The product has open 8-membered ring pore framework consisted Ti-O octahedral cluster and Si-O tetrahedron and belongs to P4(3) space group. The cell parameters are a=b=0.7781 nm and c=1.1945 nm. The kinetic model indicates the microwave synthetic mechanism is a spontaneous nucleation system. The whole process consists of the induction period and the growth period. The calculated crystal growth constant of the microwave process is 30, about 10(8) times higher than that of the sol-gel hydrothermal method. The reaction efficiency was improved greatly. The study of the rapid microwave synthesis can provide a technical base for industrialized production and application of NaTS as cesium remover in the future.