Presentation Information
[2B09]Cs+, Sr2+ and Co2+ uptake in metakaolin-based geopolymer
*Yogarajah Elakneswaran1, Xiaobo Niu1, Yuka Morinaga1, John Provis2, Tsutomu Sato1 (1. Hokkaido University, 2. The University of Sheffield)
Keywords:
Adsorption,Ionic exchange,Zeta potential,Geochemical model
In this study, the interaction of Cs+, Sr2+ and Co2+ with Na/K-geopolymer is investigated. The geopolymer samples with the composition of SiO2/K2O: Al2O3/K2O: H2O/K2O = 1:1:11 (where K: Na or K) were synthesised for the experiments, and the surface electrostatic characteristics of the geopolymer is examined by zeta potential measurement. The zeta potential experimental results show that Sr2+ and Co2+ can be adsorbed on the surface of the geopolymer, but not Cs+. The ion-exchange with Na+/K+ is the main mechanism for the Cs+ incorporation into the geopolymer. An ion-exchange model is developed in a geochemical code PHREEQC to predict the adsorption behaviour of Cs+ and the modelling results predict satisfactorily the experimental data.