A comparative study for the rejection of nickel ions from waste water by PES, fMWCNTs/PES, TiO2/PES and TiO2-fMWCNTs/PES mixed matrix membranes

In this study, the neat polyethersulfone (PES) membrane and the mixed matrix membranes (MMMs) containing 20 wt. %polyethersulfone (PES) and different amounts of functionalized multi-walled carbon nanotubes (fMWCNTs), TiO2, and TiO2 coated on fMWCNTs were fabricated by wet phase inversion and conventional casting methods. The nickel ions rejection and permeate flux performance were then investigated and compared by these fabricated membranes. The characteristics of the membranes were performed by field emission scanning electron microscopy (FESEM), transmissionelectron microscopy (TEM), and contact angle (CA) measurement. The operational parameters such as polymer concentration, pressure, pH, time and nickel ion concentration for nickel ions rejection and permeability were firstly optimized on the neat PES membrane. The performance of MMMs containing various amounts of nanoparticles was then evaluated and compared under these optimized conditions. The obtained results indicated that the membrane containing 20 wt. % PES, and operational conditions like pressure 15bar, low concentration of nickel, time =30min, and various amounts of pH were the best conditions to achieve the highest rejection percentage of nickel ions and permeate flux. In such operational conditions, PES/fMWCNTs and PES/TiO2 membranes have the highest nickel ion rejection and permeate flux, respectively. Totally the prepared mixed matrix membranes showed that they have higher ability to reject nickel ions from wastewater and a higher permeate flux value compared with the neat PES membrane.