As manned-mission profiles change from short duration, small crew to prolonged larger crew missions, the environmental control and life-support system (ECLSS) changes from an open to a closed system. Therefore, water recycling is a major consideration. Currently, the most cost efficient process for H2O recovery is a reverse-osmosis (RO) filtration system. RO filtration does not require a gas-liquid phase separator in zero gravity and has lower energy consumption than phase change processes. The types of reverse osmosis membranes considered to date have either the hollow-fiber (HF) or dual-layer (DL) membrane. HF membranes suffer from a high fouling rate, low throughput, and lower salt rejection. DL membranes have high-flow throughout but also suffer from a high fouling rate and chemical instability. This project will develop a new semipermeable membrane material that operates at pressures of less than 690 kPa (100 psi), with better flow throughput, and less fouling potential. The RO membrane materials will be produced by laser-initiated in-situ polymerization of pyrrolidone, substituted pyrrolidones, maleimide, and maleic anhydride derivatives. This new semipermeable membrane will allow more efficient energy use on missions requiring closed or partially closed ECLSS.
Potential Commercial Applications:The project is a basic material science, proof-of-concept effort. If successful, it will introduce a new semi-permeable membrane material into the reverse osmosis, high-purity water technology. The material could replace the current RO semi-permeable membranes.
