A high-capacity amidoxime-functionalized magnetic composite for selective uranium capture in Salt Lake water

In order to promote the sustainable development and utilization of nuclear energy, it is essential to develop convenient and efficient methods for uranium enrichment. In this work, an amidoxime functionalized magnetic composite (CS-Ppy-Fe3O4-AO) was synthesized by a simple two-step process and applied for selective adsorption of uranium from natural Salt Lake water. The effect of CS-Ppy-Fe3O4-AO on the uranium adsorption capacity under different conditions such as pH, contact time, temperature, ionic strength and interfering ions were firstly investigated by batch experiments. The results indicated that the maximum adsorption capacity was 937.14 mg/g at pH=6 and T = 298 K, which was higher than that of most currently reported magnetic adsorbents. Moreover, the adsorbent could be easily regenerated and still maintained high adsorption capacity after five adsorption-desorption cycles. Meanwhile, the adsorption mechanism of CS-Ppy-Fe3O4-AO on uranium was investigated by FT-IR and XPS, and they showed that nitrogen-oxygen functional groups (e.g. amidoxime and amino groups) played a predominant role on the adsorption of uranium. What' s more, the CS-Ppy-Fe3O4-AO showed excellent selectivity and adsorption capacity (3.75 mg/g) on uranium in Salt Lake water, which implied that the CS-Ppy-Fe3O4-AO could be potentially used as a desired adsorbent on uranium enrichment.