The escalating volume of spent lithium-ion batteries (LIBs) presents a critical challenge for environmental protection and resource sustainability, driving the need for efficient cobalt(II) recovery. To overcome the limitations of conventional adsorbents, such as complex synthesis and poor selectivity, this study developed a novel imidazole-grafted polyacrylonitrile nanofiber composite (Im-g-PAN-NFs) through a facile stepwise functionalization strategy. The material was fabricated via electrospinning followed by sequential grafting with ethylenediamine and 4-methyl-5-imidazolecarboxaldehyde, introducing high-affinity coordination sites. Comprehensive characterization (FT-IR, SEM, XPS, BET) confirmed successful functionalization and revealed a roughened fibrous morphology with enhanced surface area. Batch adsorption experiments demonstrated exceptional performance: a high maximum capacity of 95.2 mg/g (Langmuir model), fast kinetics (pseudo-second-order), and outstanding selectivity for Co(II) over Li(I) (separation coefficient k(Co/Li) = 61.4). XPS analysis identified coordination with imidazole and Schiff base nitrogen as the primary mechanism. Moreover, the adsorbent exhibited excellent reusability, retaining over 83% of its initial capacity after six adsorption-desorption cycles. This work not only presents a high-performance adsorbent but also elucidates a rational design strategy combining electrospun nanofibers with targeted ligand chemistry, offering a promising and sustainable approach for selective metal recovery from complex waste streams.
Sun et al. (Mon,) studied this question.