Chemical characterization of ultrafiltration membranes by spectroscopic techniques (original) (raw)

In relation to the complicated problem of membrane fouling, a study of the adsorption mechanism of some foulants on polysulfone ultrafiltration membranes is being made. This report deals with an analysis of the bulk and surface compositions of two of these membranes. Attenuated total reflection Fourier transform infrared (ATR FTIR) measurements can elucidate the type of polysulfone in the bulk of the membranes. DDS GR 61 PP appears to consist of Udel (polyethersulfone + bisphenol A) and Dorr Oliver SlO of Victrex (polyethersulfone). Nevertheless, secondary ion mass spectrometry (SIMS) analysis indicates a fragmentation product of bisphenol A in the surface of the SlO membrane. The detailed atomic composition of both membrane surfaces, as analysed by X-ray photoelectron spectroscopy (XPS) , shows deviations from the calculated bulk composition. This may be due to preferential location of some functional groups at the membrane surface or to an applied coating. Moreover, in contrast to the presumed chemical structure, the element N is detected. By combination with SIMS and Kjeldahl analysis the presence of a C-N product in the surface is demonstrated. Further research with these techniques will be directed towards the mechanisms of interaction of membrane and foulant.