Iodide removal using LDH technology

The presence of radioactive iodine (radioiodine) in drinking water is a significant health hazard that originates from nuclear medicine and atomic energy industries. The application of LDHs to the removal of iodine offers potential for iodine capture and entrapment. Mg/Al and Zn/Al layered double hydroxides (LDHs) have been prepared and have been evaluated for the sorption of iodide in some small-scale batch experiments. All LDHs were prepared by the co-precipitation method and characterised by a range of techniques including powder X-ray diffraction, transmission electron microscopy and elemental analysis. Adsorption experiments were carried out at high iodide concentrations up to 1000 ppm and no control or pH or atmospheric carbonate commonly used in most studies. The highest iodide uptake of approximately 71% was observed using a 3:1 Zn/Al LDH thermally activated to 500 °C, however, a 3:1 Mg/Al LDH exhibited similar results. LDHs potentially offer a technology for the removal of iodine from aqueous media.