Use of nano crystalline silicotitanate for the removal of Cs, Co and Sr from low-level liquid radioactive waste

The uptakes of Cs, Co and Sr ions onto nano crystalline silicotitanate (IONSIV™ IE-911, UOP) were investigated by using batch sorbers. The nanostructured adsorbent has many advantages such as high active surface area, fast diffusion rates and lower amount needs. Equilibrium sorption characteristics of Cs, Co and Sr ions onto the sorbent were investigated. The Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherm models were fitted to the experimental data. Using the Langmuir model, the predicted sorption capacity of Cs, Co and Sr onto the silicotitanate at pHs 5, 7 and 9 was in the order Cs > Sr > Co. The silicotitanate was highly selective for Cs due to the ion exchange with sodium and hydrogen ions. The Langmuir model fitted better than the Freundlich and D-R models to the experimental data for the metals (0.83 < R2 < 0.97).