There are different types of reverse osmosis (RO) membranes that are designed to purify water to varying degrees based on feed water quality and the client’s requirements.
The most important part of any RO system is the membranes. In a typical RO system, membranes are made of sheets of semi-permeable material designed to let pure water flow through, while keeping back all other impurities. These membranes, typically installed in series to each other, are loaded into single housings, which are then arranged into several parallel flow streams.
Different Types of Reverse Osmosis Membranes
Reverse osmosis membranes can be divided into four different types of RO membranes, namely low-pressure nanofiltration membranes; high-rejection brackish water membranes; seawater membranes; and specialty membranes.
1. Low-pressure nanofiltration membranes
Nanofiltration membranes allow for an average of 90% salt removal as well as high removal rates of high molecular weight ions, pesticides, herbicides, and total organic carbon.
2. High-rejection brackish water membranes
High-rejection brackish water membranes serve as membranes with which to purify groundwater and surface water (such as lakes and rivers) in brackish water reverse osmosis processes.
3. Seawater membranes
Seawater reverse osmosis membranes have high salt rejection rates, enabling water treatment systems to treat water effectively to meet stringent quality requirements.
4. Specialty membranes
There are various specialty reverse osmosis membranes available that are designed to purify water for specific purposes, such as removal of organics or protein.