Evaluation of physicochemical properties of cementitious materials incorporated with SrCO3 formed by bio-mediated Sr adsorptive removal mechanism

Abstract

Research on the development of treatment technology is being actively conducted, due to the danger of radioactive waste discharged from nuclear power plants. In particular, the need for removal of strontium (Sr) has been increased, since Sr has a half-life of 29 years and causes fatal damage to the human body by replacing calcium in the body due to similar chemical structure. Although various methods for Sr treatment such as an ion exchanger, adsorption, microfiltration, and chemical precipitation, have been proposed, recently, as a semi-permanent Sr removal method, and adsorptive removal mechanism through a biological precipitation has been in the spotlight. However, the bio-mineralization metabolism, which is the fundamental mechanism for biological precipitation, depends on the various environmental conditions

hence, it is necessary to evaluate the adsorptive removal performance of Sr and metabolic capacity under various parameter. In addition, development of post-treatment techniques for long-term stable sequestration of Sr converted to the form of carbonate minerals by bio-mineralization should be implemented. In this study, ureolytic bacteria with optimal bio-mineralization performance were selected from the natural environment, and bio-mineralization properties and Sr adsorptive removal efficiency under various parameters were evaluated. In addition, as a post-treatment of SrCO3 produced by the bio-mediated Sr removal mechanism, SrCO3 was incorporated in cementitious materials in which blast furnace slag and fly ash were mixed in various ratios, and the physicochemical properties and hydration kinetics were investigated.