Neodymium(III) and lanthanum(III) separation by magnetic nanohydrometallurgy using DTPA functionalized magnetite nanoparticles

•Nanohydrometallurgy can be successfully applied for rare earths separation.•Engineered DTPA nanoparticles discriminate neodymium from lanthanum.•Magnetic separation allows recycling the functional magnetic nanoparticles.•Green and sustainable conditions are achieved with the new method.

A successful nanohydrometallurgical separation of neodymium and lanthanum ions has been demonstrated by using superparamagnetic nanoparticles functionalized with ethylenediaminepropylsilane/diethylenetriaminepentaacetic acid, as complexing agents. Neodymium is preferentially captured in relation to lanthanum, reflecting the trends of the stability constants dictated by the lanthanide contraction. A high separation efficiency (> 99%) has been achieved after three successive complexation and releasing stages. The overall process can be performed under green and sustainable conditions, e.g., at room temperature, in aqueous solution and mild pHs, allowing the nanoparticles recycling, and dispensing the use of more time/energy consuming physical separation processes.

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