Nuclear energy is essential for the production of cleaner energy, but the radioactive pollution that comes with it necessitates strategic solutions. Cesium (Cs+) is a harmful radionuclide produced by nuclear power plants that must be immobilized and absorbed at high rates in order to avoid polluting the environment.
Although phosphate-based adsorbents are excellent cleanup options, their limited adsorption capacity is due to their ineffective ion exchange. Phosphate adsorbents’ experimental adsorption capacities do not match their theoretically high adsorption capacities.
Dittmarite-type phosphates with a layered structure, ideal for easy ion exchange, have been synthesized by Pusan National University researchers led by Professor Kuk Cho from the Department of Environmental Engineering to remove harmful Cs+ from radioactive wastewater.
“Dissolution-precipitation and the presence of exchangeable ions allowed for record-breaking Cs+ adsorption capabilities that were greater than those of common adsorbents.”
Professor Kuk Cho from the Department of Environmental Engineering
Due to exchangeable ions and dissolution precipitation, the team discovered that their magnesium phosphates had adsorption capacities for Cs+ that were higher than those of conventional adsorbents. “The presence of exchangeable ions and dissolution precipitation enabled record-high adsorption capacities for Cs+ that are higher than those of standard adsorbents,” asserts Professor Cho.
The research was presented in the Journal of Hazardous Materials. The team created KMgPO4H2O (KMP) and NH4MgPO4H2O (NMP), dittmarite-type compounds with theoretical adsorption capacities of 754 mg g 1 and 856 mg g 1 for Cs+, respectively, using a one-pot hydrothermal method.
The remarkable adsorption capacities of the synthesized KMP and NMP were 84% and 711 mg g-1, respectively, of their theoretical capacities. Among all Cs+ adsorbents that have been reported, these experimentally measured adsorption capacity values are the highest.
Then, the group described and examined the physical and compound properties of the phosphates. They demonstrated that these phosphates are not ideal for use in water with high divalent ion concentrations based on the Cs+ adsorption performance of KMP and NMP. Notwithstanding, they can in any case be utilized in Cs+ readsorption processes, following desorption processes, to focus Cs+ and lessen squander volume.
“Cs+ is a popular radionuclide produced by nuclear power plants, and the volume of its waste must be minimized for disposal,” says Prof. Cho. The adsorbent with a higher adsorption capacity is advantageous for reducing volume.”
The new phosphates were found to effectively adsorb Cs+, making them a cost-effective option for disposing of radioactive waste. This is especially significant in our current reality, where thermal energy stations are supposed to increase in number and legitimate stockpiling with proper adsorbents will become urgent for maintainability.
In conclusion, the synthesized phosphates’ stability and high adsorption capacities make them potential solutions to the problem of disposing of radioactive waste.
More information: Zeqiu Li et al, Dittmarite-type magnesium phosphates for highly efficient capture of Cs+, Journal of Hazardous Materials (2023). DOI: 10.1016/j.jhazmat.2023.131385
