Synthesis and ion exchange properties of the ETS-4 and ETS-10 microporous crystalline titanosilicates

This paper deals with the ETS-4 and ETS-10 titanosilicates synthesised hydrothermally using titanium (IV) chloride as titanium source, without any organic additives and no seeding. The starting materials were gels of molar composition: 1.49SiO(2):xNa(2)O:yTiO(2):0.6KF: 1.28.xHCl:39.5H(2)O, where: 0.5less than or equal toxless than or equal to2.5 and 0.1less than or equal toyless than or equal to0.4. By varying the amount of Na2O and TiO2 respectively, the crystallization domains of the titanosilicates mentioned above were found. The optimal gel composition for crystallization was found kinetically. A high purity and crystallinity ETS-10 was obtained for 1.0 mole Na2O and 0.2 mole TiO2. The ETS-4 and ETS-10 phase mixture is due to a co-crystallization process. The physico-chemical characterisation of these synthesised materials was carried out by XRD, SEM, TG/TDG/DSC, EDS and sorption of Cs-137 and Co-60 radionuclides.