In a typical RO application, which membrane type is most commonly encountered?

The most commonly encountered membrane type in typical reverse osmosis (RO) applications is the thin film composite membrane. This type of membrane is favored due to its superior performance characteristics, including high rejection rates for a wide range of contaminants and low fouling tendencies. Thin film composite membranes are made up of several layers, typically featuring a polyamide active layer that is responsible for filtration. This design allows for enhanced water permeability and salt rejection compared to other membrane types.

Polysulfone and cellulose acetate membranes, while used in certain applications, do not offer the same level of performance as thin film composites, particularly in high-salinity environments or with challenging water sources. These membranes historically have limitations in terms of flux and chlorine resistance. Polytetrafluoroethylene, although known for its chemical resistance, is not commonly used in standard RO applications due to its higher cost and less efficient filtration compared to thin film composite membranes. Thus, for optimal RO performance and efficiency, thin film composite membranes are the preferred choice in the industry.