Highly efficient separation and enrichment of hafnium from zirconium oxychloride solutions by advanced ion-imprinted membrane separation technology

Hafnium (Hf) is an important strategic material for the semiconductor, aerospace and nuclear industries. In this paper, an advanced ion-imprinted membranes (IIMs) separation system was prepared for the first time to achieve efficient separation and enrichment of Hf ions from zirconium oxychloride solutions. IIMs were constructed by a keyhole complex imprinting method with N, N-di-2-ethylhexyl diglycolamic acid (D2EHDGAA) as the carrier molecule, cellulose triacetate (CTA) as the base polymer and Hf ions as the template ion. In addition, amide acid driven IIMs were coupled with aspartic acid in the feed phase, which changes from preferential extraction of Zr to preferential extraction of Hf. To characterize it, we used Fourier transform infrared (FT-IR) spectroscopy and scanning election microscopy (SEM). The results showed that IIMs can increase CHf/CZr from 2.33:100 to 33.33:100 within 1 h compared with polymer inclusion membranes (PIMs) and ionic liquid supported liquid membranes (SLMs), which increased by 3.33 and 3.67 times. The selectivity and enrichment performance for the enrichment of Hf ions from Zr solution were significantly improved due to the high recognition selectivity of ion imprinting. Therefore, IIMs, as an advanced membrane separation system, may have good potential for industrial application in the field of efficient separation and enrichment of Hf ions.