Sustainably recycling spent lithium-ion batteries to prepare magnetically separable cobalt ferrite for catalytic degradation of bisphenol A via peroxymonosulfate activation

A selective separation-recovery process based on tuning organic acid was proposed to the resource recycling of spent lithium-ion batteries (LIBs) for the first time. The low-cost preparation of CoFe 2 O 4 , reuse of waste acid and recovery of Li can be realized in this process, simultaneously. Li and Co in spent LIBs can be leached efficiently using citric acid as a leaching agent, and separated effectively from leaching solution by tuning oxalic acid content. The results from the characterizations of the prepared CoFe 2 O 4 (CoFe 2 O 4 -LIBs) show that it possesses higher ratio of Co(II)/Co(III) and Fe(II)/Fe(III), larger surface specific area and more number of acid sites in comparison with pure CoFe 2 O 4 . Besides, CoFe 2 O 4 -LIBs was used to activate peroxymonosulfate (PMS) for the degradation of bisphenol A (BPA). Interestingly, its degradation performance is superior to that of pure CoFe 2 O 4 and the related Co-based catalysts. The excellent degradation performance can be maintained in presence of inorganic ions (e.g., C l − , HC O 3 − , H 2 P O 4 − and N O 3 − ) with high concentration or humic acid . Moreover, surface-bound S O 4 ∙ − is considered as the main reactive species for the degradation of BPA. More importantly, CoFe 2 O 4 -LIBs can be readily recycled by using an external magnet and own superior ability of regeneration.