Reverse osmosis (RO) is an extremely effective method for treating water, and the RO membrane that you choose is critical to the purity of your water. Note that the RO membrane is the primary filtering media for this fairly straightforward system, and there are different types of membranes depending on the type of water that you are going to filter.
There are RO membranes that are designed for sea water, brackish water, or high-flow commercial applications. Membranes come in different diameters to work with different systems. In fact, most people consider the RO membrane to be the heart of the filtration system. While there are different manufacturing methods for this critical piece, the most common configuration is a spiral wound configuration that uses one of two materials to round out the manufacturing process.
For those who are looking to treat water that has chlorine present, a cellulose tri-acetate or CTA material is the right choice. If chlorine is not a concern, then a thin film composite or material, TFC or TFM, can be the smart choice. The tiny pores of the RO membrane allow treated water to flow through while solids and other microscopic particles are left behind on the film.
The estimated life expectancy of a membrane is about two years, but this can vary depending on the amount of solid particles that are in the water and the frequency of use. While you can clean a reverse osmosis membrane, it is not recommended due to the complexity involved.