AVS 46th International Symposium
    Applied Surface Science Division Thursday Sessions
       Session AS-ThM

Paper AS-ThM11
Identification of Surface Chemical Functional Groups in Reverse Osmosis Membranes: An X-ray Photoelectron Spectroscopy Study

Thursday, October 28, 1999, 11:40 am, Room 6A

Session: Real World Surface Analysis
Presenter: S.D. Beverly, University of Central Florida
Authors: S.D. Beverly, University of Central Florida
S. Seal, University of Central Florida
S.K. Hong, University of Central Florida
Correspondent: Click to Email
Membrane filtration including reverse osmosis (RO) has emerged as a viable drinking water treatment technology that offers a versatile approach to meeting multiple water quality objectives. Due to fouling and membrane failure, however, wide use of membrane processes for municipal water supplies has not become the reality that it could be. This study is an attempt to identify surface functional groups and chemical changes in surfaces of RO membranes during operation, which would give clues to the nature of the membrane failure. Since the depth of the RO membrane skin layer is less than 50 angstroms, X-ray Photoelectron Spectroscopy (XPS) was chosen to be a practicable analytical tool for this research study. Three commercial RO membranes made of organic polymers of polyamide or cellulose acetate were investigated. These membranes were chosen because of specific characteristics such as chlorine degradation, biological degradation, or fouling resistant coatings. For each membrane, a baseline spectrum was taken and then a sample of the membrane used to treat river water in Tampa, Florida was tested. Each sample was thoroughly rinsed in DI water and allowed to dry before XPS analysis. XPS analysis clearly showed a distinct uptake of chlorine in the polyamide membrane, a probable reason for failure in the drinking water industry. The cellulose acetate membrane showed evidence of amino acids, an indicator of digestion by an unidentified microbe. Based on the findings of this report, future studies are being considered to further investigate chlorine uptake by RO membranes. The studies will include charting chlorine uptake over time and finding limiting factors to chlorine uptake.