Advances in immobilization of radionuclide wastes by alkali activated cement and related materials

Eco-Geopolymers: Physico-Mechanical Features, Radiation Absorption Properties, and Mathematical Model

“…Moreover, geopolymer production is cost-effective and has a 60-80% lower carbon footprint and resource consumption. Existing studies usually focus on ecological aspects of geopolymers, including synthesis of geopolymers from waste and disposal of radioactive waste in the geopolymer matrix [9][10][11]. Geopolymers are also novel in the context of removing organic pollutants from water and air to protect and improve the environment [12,13].…”

“…Different types of harmful radiation, i.e., neutron, X-ray, and gamma-ray can penetrate the conventional cement walls and roofs and easily escape from accelerators, hospitals, and nuclear power plants. If required, heavy concrete (approximately 1.5 times heavier and denser than OPC, with density 2900-6000 kg m −3 ) is used for wall and roof barriers [22]; however, interest in the production of the geopolymer barriers that absorb radiation more efficiently than concrete has gradually increased [11,[23][24][25][26]. A number of studies investigating geopolymer barriers focus on their behavior in the context of radioactive element leaching (e.g., cesium (Cs), strontium (Sr)).…”

“…A number of studies investigating geopolymer barriers focus on their behavior in the context of radioactive element leaching (e.g., cesium (Cs), strontium (Sr)). In this case, the selection of a precursor material and appropriate activator has a key impact due to immobilization occurring via ion exchange, physical adsorption, and encapsulation by the gel matrix [11]. The FA-based geopolymer showed an excellent immobilization of Cs and Sr, while slag-blended geopolymers and OPC were less suitable [27].…”

“…Radioactive borate waste was solidified using metakaolin activated with KOH [28]. Low-Ca geopolymers had a unique ability to immobilize nuclide ions, due to the cross-linked network [11]. In the case of the geopolymer barrier, the effect of barite in FA-based geopolymer was also investigated [22].…”

The Transformation and Leachability of Fly Ash/Cement Waste Forms Subjected to the Simultaneous Effect of Heat and Chemistry

“…After reaction, such mineral admixtures will transform into geopolymers [1,2]. Besides, the y ash-based geopolymer is regarded as a new potential solidi ed material for LILRW due to the characteristics of environmental protection, strong acid resistance, low permeability, and drying shrinkage [3][4][5][6], especially the excellent selective absorption and retention ability on simulated nuclides [7,8].…”