Physical barrier effect of geopolymeric waste form on diffusivity of cesium and strontium

J G Jang; S M Park; H K Lee

doi:10.1016/j.jhazmat.2016.07.003

Physical barrier effect of geopolymeric waste form on diffusivity of cesium and strontium

J Hazard Mater. 2016 Nov 15:318:339-346. doi: 10.1016/j.jhazmat.2016.07.003. Epub 2016 Jul 4.

Authors

J G Jang¹, S M Park¹, H K Lee²

Affiliations

¹ Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea.
² Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea. Electronic address: haengki@kaist.ac.kr.

PMID: 27434737
DOI: 10.1016/j.jhazmat.2016.07.003

Abstract

The present study investigates the physical barrier effect of geopolymeric waste form on leaching behavior of cesium and strontium. Fly ash-based geopolymers and slag-blended geopolymers were used as solidification agents. The leaching behavior of cesium and strontium from geopolymers was evaluated in accordance with ANSI/ANS-16.1. The diffusivity of cesium and strontium in a fly ash-based geopolymer was lower than that in Portland cement by a factor of 10(3) and 10(4), respectively, showing significantly improved immobilization performance. The leaching resistance of fly ash-based geopolymer was relatively constant regardless of the type of fly ash. The diffusivity of water-soluble cesium and strontium ions were highly correlated with the critical pore diameter of the binder. The critical pore diameter of the fly ash-based geopolymer was remarkably smaller than those of Portland cement and slag-blended geopolymer; consequently, its ability physically to retard the diffusion of nuclides (physical barrier effect) was superior.

Keywords: Cesium; Diffusivity; Geopolymer; Solidification; Strontium.