Metal silicate nanotubes with nanostructured walls as superb adsorbents for uranyl ions and lead ions in water

Abstract

Silica nanotubes with mesoporous walls of 30 nm thickness were used as morphology templates, as well as the silicon source, to produce various metal silicate nanotubes with nanostructured walls, including magnesium silicate, copper silicate, nickel silicate, cobalt silicate and manganese silicate. These silicate materials retained the tubular structure of the templates, which resulted in large surface areas as high as 649 m² g⁻¹, large total volumes as high as 1.433 cm³ g⁻¹ and facile mass transportation on their surfaces. These features enabled them to be superb adsorbents for adsorption in water; in particular, magnesium silicates showed maximum adsorption capabilities of 929 mg g⁻¹ for uranyl ions and 424 mg g⁻¹ for lead ions, respectively. In practical usage, magnesium silicates could effectively adsorb uranium directly from the salt lake water, with a practical adsorption capacity of 0.23 mg g⁻¹, and was able to enrich the uranium concentration by 8 times.