Multiwalled Carbon Nanotubes/Polyethersulfone Mixed Matrix Nanofiltration Membrane for the removal of cobalt ion

In the present research work, the mixed matrix membranes (MMMs) containing various amount of polyethersulfone (PES) and functionalized multi-walled carbon nanotubes (fMWCNTs) were fabricated and used to investigate the removal of cobalt ions from wastewater by nanofiltration process. Pristine MWCNTs and fMWCNTs were characterized by Fourier transformed infrared spectroscopy and thermogravimetric analysis. FESEM analysis revealed that the mixed matrix membranes have less surface defects and better membrane performance compared with neat polymeric in the removal of cobalt ions. Permeation test results showed that the MMM containing 22 wt. % PES and 0.6 wt. % fMWCNTs (with outer diameter of 10-20 nm) has the optimum performance from the permeability and cobalt removal point of view. In continuation, the effect of pressure, feed flow rate, cobalt concentration, permeation test time and feed solution pH on the removal of cobalt by selected the MMM was investigated. The obtained results indicated that only pressure has considerable effect on permeation flux. However, all parameters showed different influence on rejection percent of cobalt ions.