Environmental-friendly preparation of Ni-Co layered double hydroxide (LDH) hierarchical nanoarrays for efficient removing uranium (VI)

With the wide application of nuclear energy and the rapid development of mining, a great quantity of uranium (U(VI)) containing wastewater is inevitably generated. In this work, a facile environmental-friendly coprecipitation method was proposed for the green synthesis of binary layered double hydroxides (Ni-Co LDHW-7), which could be used to efficiently adsorb U(VI) from wastewater. Pseudo-second-order kinetic model and Dubinin-Radushkevich model fitted well with the adsorption of U(VI) on Ni-Co LDHW-7, the maximum adsorption capacity of U(VI) on Ni-Co LDHW-7 was 201.09 mg/g calculated by the Langmuir model. Adsorption equilibrium reached after 30 min, which is a spontaneous and endothermic process. Fourier Transform Infrared Spectrometer (FTIR) and X-ray Photoelectron Spectroscopy (XPS) measurements manifested that the favorable U(VI) extraction on Ni-Co LDHW-7 is mainly ascribed to inner-layer surface electrostatic interaction and complexation, which is dominated by abundant oxygen-containing M-OH and interlayer OH- ions. Briefly, this work provides a facial and environmental-friendly Ni-Co LDHW-7 for removing U(VI) in actual uranium-containing wastewater.

Automated summary

A facile and environmentally-friendly coprecipitation method was proposed to synthesize Ni-Co LDHW-7 for efficient removal of U(VI) from wastewater. The adsorption kinetics and mechanism were investigated, revealing the maximum adsorption capacity, equilibrium time, and inner-layer electrostatic interaction as the dominant factors. The study provides a promising material for the removal of U(VI) in uranium-containing wastewater.