Silica-based ammonium molybdophosphate (AMP/SiO2) is an absorbent material that can effectively remove Cs from radioactive-contaminated wastewater (RCW) generated by Fukushima nuclide accident. Pressing/sintering method was used for final disposal of secondary waste (spent absorbent) to achieve the volume reduction of AMP–Cs/SiO2 (AMP/SiO2 saturation adsorption of Cs) and stable solidification of Cs by adding natural allophane. The structure of AMP–Cs completely collapsed at approximately 700 °C, and most Mo and P species in AMP sublimed. The optimal sintering temperature was estimated as 900 °C. The stable crystalline phase of Cs4Al4Si20O48 was recrystallized by the reaction of Cs2O, Al2O3, and SiO2, and the immobilization ratio of Cs was approximately 100%. The leachability of Cs from the sintered product in distilled water was approximately 0.41%. The high immobilization and low leachability of Cs were attributed to the excellent solidification properties of the sintered products of AMP–Cs/SiO2–allophane.
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Environmental Chemistry
- Waste Management and Disposal
- Health, Toxicology and Mutagenesis