A molecular extraction process for vanadium based on tandem selective complexation and precipitation.

Osin, Oluwatomiwa A; Lin, Shuo; Gelfand, Benjamin S; Lee, Stephanie Ling Jie; Lin, Sijie; Shimizu, George K H · Nat Commun · 2024

basic_science · Level V

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Abstract

Recycling vanadium from alternative sources is essential due to its expanding demand, depletion in natural sources, and environmental issues with terrestrial mining. Here, we present a complexation-precipitation method to selectively recover pentavalent vanadium ions, V(V), from complex metal ion mixtures, using an acid-stable metal binding agent, the cyclic imidedioxime, naphthalimidedioxime (H<sub>2</sub>CID<sup>III</sup>). H<sub>2</sub>CID<sup>III</sup> showed high extraction capacity and fast binding towards V(V) with crystal structures showing a 1:1 M:L dimer, [V<sub>2</sub>(O)<sub>3</sub>(C<sub>12</sub>H<sub>6</sub>N<sub>3</sub>O<sub>2</sub>)<sub>2</sub>]<sup>2-</sup>, 1, and 1:2 M:L non-oxido, [V(C<sub>12</sub>H<sub>6</sub>N<sub>3</sub>O<sub>2</sub>)<sub>2</sub>] <sup>̶</sup> complex, 2. Complexation selectivity studies showed only 1 and 2 were anionic, allowing facile separation of the V(V) complexes by pH-controlled precipitation, removing the need for solid support. The tandem complexation-precipitation technique achieved high recovery selectivity for V(V) with a selectivity coefficient above 3 × 10<sup>5</sup> from synthetic mixed metal solutions and real oil sand tailings. Zebrafish toxicity assay confirmed the non-toxicity of 1 and 2, highlighting H<sub>2</sub>CID<sup>III</sup>'s potential for practical and large-scale V(V) recovery.