Towards Sustainable Battery Recycling: Selective Separation of Nickel(II) and Cobalt(II) in an Adsorbent Fixed-Bed Reactor

Abstract

Caused by scarce resources of critical heavy metals and the increasing resource requirements e.g. for lithium-ion batteries, effective selective separation processes for the reuse of such materials are of high interest. In this study, the competitive dynamic adsorption of nickel (Ni(II)) and cobalt (Co(II)) by a silica adsorbent functionalized with amino-polycarboxylate derivative ligands (HSU331) under recycling process conditions, but adsorption adverse prerequisites, like acidic pH-value, and high temperatures, respectively (pH = 3.5, T = 20°C, and T = 50°C, respectively) and varying concentrations (Ni(II):Co(II) 1:1 (5.0, and 10 mmol∙L− 1, respectively), Ni(II):Co(II) 3:1 and 1:3 (3.0 mmol∙L− 1 and 1.0 mmol∙L− 1 vice versa) were investigated. A displacement desorption of Co(II) in favour of the binding of more Ni(II) was observed. Maximum loadings of 0.95 µmolNi(II)∙µmolLigand−1 (28,3 mgNi(II)∙gAdsorbent−1), and 0.48 µmolCo(II)∙µmolLigand−1 (14,3 mgCo(II)∙gAdsorbent−1) at T = 20°C and 1.0 µmolNi(II)∙µmolLigand−1 (29,9 mgNi(II)∙gAdsorbent−1) and 0.18 µmolCo(II)∙µmolLigand−1 (5,38 mgCo(II)∙gAdsorbent−1) at T = 50°C, were achieved, respectively. These results demonstrate a distinctly selective separation of Ni(II) in the presence of Co(II) by HSU331.