New Polyamide Interfacial Composite Membranes for Reverse Osmosis

Reverse osmosis water purification units (ROWPUs) are essential to the Army for providing clean water during combat and humanitarian duties. The Army's ROWPUs are designed to treat any water source encountered in the world, therefore reverse osmosis (RO)membranes must be effective under a wide variety of rigorous feedwater conditions. State-of-the-art polyamide RO membranes used by ROWPUs have low tolerance to disinfectants such as chlorine, a situation which leads to either rapid biofouling or filterelement degradation. The objective of the proposed program is to develop a new polyamide membrane that has significantly enhanced resistance to chlorine degradation and biofouling for use by the DoD and the private sector in ROWPUs. Efforts will also bemade to increase the mechanical integrity of the membrane to resist delamination during filter pressurization/depressurization cycles encountered with intermittent use. The Phase II program will focus its efforts on designing, synthesizing, andcharacterizing new polyamide materials that form semipermeable membranes using standard fabrication procedures. New materials will be incorporated into composite RO filtration membranes and be performance tested. The anticipated results are thedevelopment and production of polyamide composite RO membranes with greatly enhanced performance and longevity for use in spiral wound filter elements.Successful development of RO membranes with superior chlorine tolerance and mechanical stability can save tens of millions of dollars for DoD and industry by significantly reducing the field distribution logistics, equipment down-time, maintenance time,and costs associated with water pre- and post-treatment and frequent replacement of degraded and fouled membranes. RO membranes developed in this program will be fabricated into spiral wound filter elements for immediate use in existing RO filtrationsystems such as the Army's ROWPU field units, industrial water and byproduct recovery systems, public utility water purification/desalination plants, and residential water purification units.