Recovery Process for Critical Metals: Selective Adsorption of Nickel(II) from Cobalt(II) at Acidic Condition and Elevated Temperature

Effective and sustainable separation processes for critical metals, especially the physicochemically similar elements nickel cobalt in battery recycling, are of great interest future. Selective adsorption represents a highly potential process this purpose. In publication, silica adsorbent functionalized with an amino-polycarboxylate derivate (HSU331) was investigated regarding selective Ni(II) presence Co(II) acidic solution (pH range at equilibrium 1.8–2.3) elevated temperature. Comparable maximum loadings ( q max ) 0.59 μmol(Ni(II)) · μmol(Ligand)-1 (18.3 mg(Ni(II)) g(Adsorbent)-1), 0.52 μmol(Co(II)) (16.0 mg(Co(II)) respectively, were achieved T = 50°C single-component experiments. Under competitive conditions, loading remained constant 0.60 (18.4 while drastically decreased to 0.09 (2.7 g(Adsorbent)-1) equimolar dual-component system. Calculated stability constants 3 103 0.7 L mol-1, formed metal ion complexes onto HSU331, clarify clear selectivity towards even temperature (T 50°C).