Flux enhancement by argon–oxygen plasma treatment of polyethersulfone membranes

Argon–oxygen (Ar–O2) plasma treatment of polyethersulfone (PES) membranes is carried out to enhance hydrophilicity of the membranes leading to less deposition of solute particles and subsequent flux enhancement. The membranes are exposed to plasma of Ar–O2 mixtures and the effects of exposure time and concentration of oxygen have been studied in detail. The membrane is characterized by Fourier transform infrared (FTIR) spectrum analysis and the hydrophilicity and flux enhancement of the plasma treated membranes are quantified by contact angle measurements, SEM and experiments with polyethylene glycol (PEG) of molecular weight 20,000, in a continuous flow cylindrical cell. The deposition thicknesses of PEG on the membrane surfaces are optically quantified using image analyzing microscopy. The results clearly demonstrate that a plasma treated PES membrane is more hydrophilic and resists fouling leading to significant enhancement of permeate flux.