Effective removal of strontium from wastewater using Co-doped layered sodium vanadosilicate

The effective removal of strontium (Sr) from radioactive wastewater is essential for human health and ecological sustainability. However, due to the existence of a large number of coexisting ions, the selective removal of Sr²⁺ from it remains a significant challenge. Herein, three novel metal-doped sodium vanadosilicates were developed by structural regulation. It was found that Co-doping can not only significantly reduce the dissolution loss of vanadosilicate (NaVOSi) from the adsorbent in extreme environments by adjusting the orbital energy distribution, energy band structure, bond length, and bond energy of sodium vanadosilicate crystals, but also further enhance the adsorption performance by reducing its zeta potentials and agglomeration phenomenon. The maximum adsorption capacity of the developed adsorbent (Co-NaVOSi) was up to 319.10 mg·g^-1 within 5 min. When applied to Sr²⁺ removal from simulated wastewater, the distribution coefficients of Sr²⁺ reached 2943.15 mL·g^-1, and the separation coefficients between Sr²⁺ and coexisting ions were above 64. DFT calculations further revealed the highly selective removal mechanism of Sr²⁺ from wastewater. In addition, NaNO₃ was proved to be an efficient eluent. The excellent properties above make NaVOSi an excellent candidate for effectively removing Sr²⁺ from wastewater.