Mechanochemically prepared Zn-Al LDH precursor for rare earth elements recovery

The ionic rare earth elements (REEs) was mainly recovered by in-situ leaching process. The concentration of rare earth ions in the leaching solution after long-term leaching process would be too low for traditional precipitation process for REEs recovery. The adsorption process was ideal for the low concentration REEs recovery. In this study, Zn-Al LDH precursor were successfully synthesized by mechanochemical method for the adsorption of REEs (including La-, Eu3+ and Er3+). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron energy spectrometer (XPS), and Zeta potential test was applied for adsorption mechanism illustration. The maximum adsorption capacity of the Zn-Al LDH precursor for La3+, Eu3+ and Er3+ reached 492 mg/g, 346 mg/g, and 1154 mg/g which was significantly higher than other types of adsorbents. The adsorbed REEs on the Zn-Al LDH was hard to be desorbed. The Zn-Al LDH precursor after REEs adsorption could be directly used as high content REEs resources for further process.Therefore, the Zn-Al LDH precursor could be a promising adsorbent for REEs recovery in practical application.

Automated summary

In this study, Zn-Al LDH precursor was successfully synthesized and demonstrated promising adsorption capacity for rare earth elements (REEs) recovery. The adsorbed REEs on Zn-Al LDH were hard to be desorbed, making it a potentially valuable adsorbent for practical application in REEs recovery.