In situ electrochemical synthesis of Zn-Al layered double hydroxides for removal of strontium

Abstract

In situ electrochemical synthesis method of Zn-Al layered double hydroxides (LDHs) was used to treat the simulated strontium containing liquid radioactive waste (LRW) from nuclear power plants. The removal rate of strontium can reach 98.48±0.20 % (the adsorption capacity is 0.45 mg/g) under the optimal experimental conditions of reaction temperature of 60 °C, reaction time of 240 min, Al electrode current density of 45 mA/cm2, Zn/Al current ratio of 3:1 and initial pH of 10. The composite samples were characterized by XRD, FT-IR and SEM. The results of the characterization and the leaching experiments indicated that Zn-Al LDHs was the major phase in the composite samples, and strontium was removed by substituting the zinc in the crystalline lattice of Zn-Al LDHs or by bonding with hydroxyl on the surface or carbonate in the interlayer of Zn-Al LDHs. In situ electrochemical synthesis method of Zn-Al LDHs has been proved feasible for the removal of strontium in LRW.