Various phosphate adsorbents have been synthesized and used to adsorb radioactive cesium from aqueous solutions, but available materials have demonstrated limited adsorption capacity. An improved adsorbent featuring a layered structure ideal to facilitate ion exchange has been engineered at South Korea’s Pusan National University.

A one-pot hydrothermal method was used to develop two dittmarite-type magnesium phosphates — KMP and NMP — with high cesium adsorption capacities of 630 mg/g and 711 mg/g, respectively. These experimentally measured values are the highest among all reported adsorbents for the radionuclide.

While the synthesized phosphates are effective for use in water with high divalent ion concentrations, they can still be applied in cesium readsorption processes following desorption in order to concentrate cesium and reduce waste volume.

The high adsorption capacities and stability of the synthesized dittmarite-type magnesium phosphates described in the Journal of Hazardous Materials make them promising candidates to deal with the radioactive waste disposal challenge.