Removal of Dioxouran (VI) Cations from Aqueous Solution by Natural Sorbents

The paper presents investigations of the mechanism of UO22+ cation sorption by natural zeolites and peat from aqueous solutions using a limited volume method. It is proved that the sorption rate depends on sorbent granulating, dioxouran (VI) temperature and concentration. The results show that sorption of UO22+ cations by natural sorbents is the mixed-diffusional mechanism. The use of 24-hour interruption technique ('kinetic memory') demonstrates that in the mixed-diffusional mechanism for natural peat and zeolites the internal ion diffusion predominates. The coefficients of internal diffusion and activation energy are calculated in this paper. The infrared spectroscopy technique and synchronous thermal test are used to identify the interaction between dioxouran (VI) and energy components of natural sorbents. The synchronous thermal test shows that UO22+ cation sorption decreases the thermal stability of peat as compared to its original state. The peat decomposition is determined after UO22+ cation removal as well as the appearance of end-effect maximum of 777.5 degrees C. An assumption is made on a possible decomposition of different metal oxalates in peat and clay peat bonds which irreversibly absorb UO22+ cations. These research findings can be recommended for water purification at nuclear fuel cycle facility.