Characterization of commercial RO and UF modified and fouled membranes by means of ATR/FTIR

A simple grafting procedure was developed for surface modification of commercial polyamide reverse osmosis membranes. The modifications were monitored by spectral analysis. This technique was also used for study of membrane hydration. It was established that water interaction with surface functional groups of polyacrylonitrile (PAN) modified membrane produced very strong changes in the regions of C=O and C-O stretching vibrations. Adsorption and pressure experiments using Nahal Taninim feed water have been conducted on modified RO membranes. The membranes have been examined by ATR/FTIR for extent of adsorption of organic contaminants. Comparison with unmodified membranes shows that surface modification of the membranes resulted in drastic decrease in contaminant adsorption for some polymer grafts and increased ease in rinsing the contaminated surface.

We have detected changes in the interaction of water with the membrane surface as a result of grafting. Using surface spectroscopic techniques such as ATR/FTIR, it is also possible to deter-mine the presence of adsorbed foulants on the membrane surface even prior to flux decline.