An efficient cobalt separation using PVDF-co-HFP based ultrafiltration polymer inclusion membrane by room temperature ionic liquids

Cobalt has been used enormously in industrial and technological applications, especially lithium-ion batteries. Continuing production of cell phones and laptops containing lithium-ion batteries has increased demand for cobalt, which has resulted in a global accumulation of industrial waste in the world. As a result, the separation and purification of cobalt from industrial waste become quietly important. In this study, the high-efficiency recovery of cobalt ions was achieved by PVDF-co-HPF (polyvinylidene fluoride hexafluoropropylene) based ultrafiltration polymer inclusion membranes (UPIM), which were produced by mixing room temperature ionic liquids, plasticizers, and the polymer under optimal conditions. The highest mass transfer coefficient (J(o)) of cobalt transport was determined as 3.36x10(-6) mol/s m(-2) for the optimized UPIM containing 11.35 % (w/w) ONPOE (2-nitrophenyl octyl ether) and 12.27 % (w/w) RTIL4 (1,3-decyl-1H-imidazol-3-ium bromide). Morphological and structural analysis of all UPIMs were investigated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). A good relationship was determined between the cobalt peaks in the ATR-FTIR pattern and the color intensity of UPIMs with corresponding room temperature ionic liquids. It indicates that the optimized UPIM has a good potential not only for cobalt recovery but also for qualitative and quantitative direct colorimetric cobalt determination.