Hydrophilic modification of PTFE microfiltration flat membrane by crosslinking OCMCS-PEI to enhance anti-fouling property

Abstract

In order to enhance the hydrophilicity and anti-fouling property of polytetrafluoroethylene (PTFE) flat microfiltration membrane, the PTFE flat membrane was modified via cross-linking O-carboxymethyl chitosan (OCMCS) and polyethyleneimine (PEI) with glutaraldehyde (GA). Membrane performance was characterized by Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS), Field Emission Scanning Electron Microscope (FESEM), water contact angle and pure water flux. Results from ATR-FTIR and XPS showed that PEI and OCMCS were introduced into the modified PTFE membranes successfully. The modified PTFE membrane was endowed with excellent hydrophilicity compared with the original membrane by the result of increased pure water flux. Bovine serum albumin (BSA) static adsorption test and dynamic cross-flow fouling experiment results showed that the modified membrane has good anti-fouling ability. The pure water flux and the contact angle of the modified membranes changed with a variation in the time, GA concentration, OCMCS concentration, and OCMCS:PEI (mass ratio). It seemed that the optimal time, the concentration of OCMCS, the mass ratio of OCMCS and PEI, and the concentration of GA were 12 h, 5 g/L, 4:1 and 5 g/L, respectively.