Cesium and Strontium Retentions Governed by Aluminosilicate Gel in Alkali-Activated Cements

Abstract

The present study investigates the retention mechanisms of cesium and strontium for alkali-activated cements. Retention mechanisms such as adsorption and precipitation were examined in light of chemical interactions. Batch adsorption experiments and multi-technical characterizations by using X-ray diffraction, zeta potential measurements, and the N2 gas adsorption/desorption methods were conducted for this purpose. Strontium was found to crystalize in alkali-activated cements, while no cesium-bearing crystalline phases were detected. The adsorption kinetics of alkali-activated cements having relatively high adsorption capacities were compatible with pseudo-second-order kinetic model, thereby suggesting that it is governed by complex multistep adsorption. The results provide new insight, demonstrating that characteristics of aluminosilicate gel with a highly negatively charged surface and high micropore surface area facilitated more effective immobilization of cesium and strontium in comparison with calcium silicate hydrates.

Incorporating Cs and Sr into blast furnace slag inorganic polymers and their effect on matrix properties

“…A similar result was reported by Guangren et al (2002) [2]. Some authors have added GGBFS as an additive in IPs based on different precursors [14,15,22]. However, the effect of caesium-and strontium-addition on the IP-characteristics is not thoroughly investigated.…”

Inorganic and Hybrid (Organic–Inorganic) Lamellar Materials for Heavy Metals and Radionuclides Capture in Energy Wastes Management—A Review

“…The effluents produced by nuclear industries contain mainly two radionuclides, 137 Cs and 90 Sr, which have a very short half-life (around 30 years) making them particularly radiotoxic [91,92]. Their selective extraction is therefore a prerequisite for the remediation of these contaminated waters, but it is made difficult by the presence of other alkaline and alkaline earth ions naturally present in these waters.…”

Encapsulation of Sr-loaded titanate spent adsorbents in potassium aluminosilicate geopolymer

“…Conventional cementitious material is an attractive option due to a simple manufactural process and minimal secondary waste generation. However, high free water content which may induce problematic hydrogen generation, low resistance to acid and fire conditions, and incompatibility with several types of waste have been noted as disadvantages of conventional cementitious materials [7][8][9][10][11].…”