Thin film composite (TFC) reverse osmosis (RO) membranes are sensitive to oxidizing agents such as chlorine.  In contrast to many reports on the chemical and performance degradations after chlorine exposure, studies on the fundamental physical properties of the polyamide barrier layer (PBL) are scarce.  Here, we applied an AFM-based nano-thermal analysis technique to directly measure the glass transition temperature (Tg) of the PBL on commercial TFC RO membranes, and its evolution upon chlorine treatment.  The results indicate a monotonic decrease of Tg with increasing exposure time at a given chlorine concentration.  Both the degree and the rate of Tg decrease vary significantly with both the chlorine concentration and pH value of the aqueous chlorine solution.  Further, the decrease in PBL Tg correlates well with the reduction in the salt rejection of the membrane, but the magnitude of the correlation is specific to chlorine concentration and pH values.

Correlation between barrier layer T<sub>g</sub> and the permselectivity of a thin-film composite polyamide membrane upon chlorine treatment

244th National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Correlation between barrier layer Tg and the permselectivity of a thin-film composite polyamide membrane upon chlorine treatment

Correlation between barrier layer T_g and the permselectivity of a thin-film composite polyamide membrane upon chlorine treatment