Development of Nylon 6 nanofibers modified with Cyanex-272 for cobalt recovery

With a worldwide ever increasing demand for metals, particularly for the manufacture of electronics and batteries, there is not only a concurrent need to recover these materials from their subsequent waste streams but also a need to make advancements to do this via development of more efficient and eco-friendly processes for metal recovery; solid-phase extraction can be considered a promising alternative to conventional processes. This work studied the production of novel nanofibers modified with Cyanex 272 and their application in the recovery of cobalt present in aqueous solution The nanofibers produced by forcespinning were characterized by SEM, FT-IR and TGA and the extraction of cobalt was evaluated by variation of the pH, solid:liquid (S:L) ratio, extraction time and Cyanex 272 content in the nanofibers. The best extraction efficiency was 99.96%, achieved under the following conditions: pH 8; (S:L) ratio of 1:200; 25% of Cyanex 272; Extraction time of 60 min. The maximum extraction capacity obtained was 15.46 mg Co/g of nanofiber and 70.15 mg Co/g of extractor. In successive reuse cycles, the results demonstrated that the extraction efficiency was maintained at over 85%. The findings showed that Nylon 6/Cyanex 272 nanofibers are a new robust and promising material for the recovery of heavy metals from aqueous solution, confirming that nanofibers have an efficiency similar to conventional liquid-liquid extraction, without the disadvantage of volatile organic compounds emissions generated by the use of organic diluents.