全微波法快速合成纳米尺寸高钛硅比分子筛

Rapid Synthesis of a Cesium Removal Ion Exchanger by Microwave Radiation

采用全微波辐射法快速合成了NaTS,并研究了合成的反应动力学。结果表明,全微波辐射法明显缩短了产物的晶化反应时间,合成时间从溶胶凝胶水热法的120h缩短为2h。XRD和SEM分析表明:微波法合成样品为两端开放的八元环孔道结构化合物,属P43空间群,晶胞参数分别为a=b=0.7781nm,c=1.1945nm;除铯性能与传统水热法产品无明显区别。晶化动力学模型研究表明:全微波法合成结晶度随时间变化曲线均为S型,属自发形核。合成过程可分为诱导期和生成期,微波辐照法合成过程的生长速率常数为30,是溶胶凝胶水热法的108倍。微波快速合成大大提高产品的合成速率,为NaTS的工业化生产和应用奠定了基础。

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 P43 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 108 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.