Membrane technology is a well-known method for separating both gas and liquid streams. With the proven success of membranes in water treatment, membrane technology continues to advance. However, remaining problems include membrane fouling and membrane chemical stability. Reduced fouling would enhance cost-effectiveness by extending operational lifetime and lowering energy requirements.
SRI’s Materials Research Laboratory is developing an advanced hollow-fiber membrane for reverse osmosis that is based on a sulfonated-imidazole (SIM) polymer. It is currently being tested for shipboard desalination of seawater and brackish water. In addition to applications in desalination, membranes are also being explored for other types of water purification, such as to purify water extracted during gas and oil production.
The new SIM membrane is known to have high thermal and mechanical stability, and it is more chlorine-tolerant than currently available reverse osmosis polymer membranes. In addition, the membranes can withstand high pressures, which is important in ensuring functional performance over time. SIM is inexpensive, and the hollow-fiber membranes can be made with very thin selective layers and fabricated in varying dimensions. Ultimately, this technology will allow cost-effective, high-performance desalination of water for a variety of uses.