Efficient Removal of Cationic and Anionic Radioactive Pollutants from Water Using Hydrotalcite-Based Getters.
Hydrotalcite (HT)-based materials are usually applied to capture anionic pollutants in aqueous solutions. Generally considered anion exchangers, their ability to capture radioactive cations is rarely exploited. In the present work, we explored the ability of pristine and calcined HT getters to effectively capture radioactive cations (Sr(2+) and Ba(2+)) which can be securely stabilized at the getter surface. It is found that calcined HT outperforms its pristine counterpart in cation removal ability. Meanwhile, a novel anion removal mechanism targeting radioactive I(-) is demonstrated. This approach involves HT surface modification with silver species, namely, Ag2CO3 nanoparticles, which can attach firmly on HT surface by forming coherent interface. This HT-based anion getter can be further used to capture I(-) in aqueous solution. The observed I(-) uptake mechanism is distinctly different from the widely reported ion exchange mechanism of HT and much more efficient. As a result of the high local concentrations of precipitants on the getters, radioactive ions in water can be readily immobilized onto the getter surface by forming precipitates. The secured ionic pollutants can be subsequently removed from water by filtration or sedimentation for safe disposal. Overall, these stable, inexpensive getters are the materials of choice for removal of trace ionic pollutants from bulk radioactive liquids, especially during episodic environmental crisis.
School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology , Brisbane, Queensland 4001, Australia.
Arixin
A
Bo
School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology , Brisbane, Queensland 4001, Australia.
Sarina
S
Sarina
Australian Centre for Microscopy and Microanalysis, The University of Sydney , Sydney, New South Wales 2006, Australia.
Hongwei
H
Liu
Institute of Coal Chemistry, Chinese Academy of Sciences , Taiyuan, Shanxi 030001, China.
Zhanfeng
Z
Zheng
School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology , Brisbane, Queensland 4001, Australia.
Qi
Q
Xiao
School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology , Brisbane, Queensland 4001, Australia.
Yuantong
Y
Gu
School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology , Brisbane, Queensland 4001, Australia.
Godwin A
GA
Ayoko
School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology , Brisbane, Queensland 4001, Australia.
Huaiyong
H
Zhu
anion removal; cation removal; hydrotalcite; radioactive waste; water cleaning