RO Membrane Element Permeate Carrier: The Heart of Reverse Osmosis Technology

In modern water treatment technology, reverse osmosis (RO) membrane element permeate carrier plays a vital role. RO membrane technology is not only widely used in the fields of seawater desalination, brackish water treatment and pure water preparation, but also plays an irreplaceable role in many industries such as medicine, electronics, chemical industry and food processing.

Reverse osmosis is the reverse process of the natural permeation process of water in nature. This process is based on the selective interception of semipermeable membranes, that is, the solutes and solvents in the solution are separated under pressure. When the same volume of dilute solution and concentrated solution are placed on both sides of a container and blocked by a semipermeable membrane in the middle, the solvent in the dilute solution will naturally pass through the semipermeable membrane and flow to the concentrated solution side until it reaches an osmotic equilibrium state. At this time, if a pressure greater than the osmotic pressure is applied to the concentrated solution side, the flow direction of the solvent will be reversed, and this process is reverse osmosis.

RO membrane elements are the core components of the reverse osmosis system, usually composed of multiple layers of thin films of different materials and structures. The most critical of these membranes is the ultra-thin desalination layer, whose density directly determines the desalination rate of the membrane. Common RO membrane materials include cellulose acetate membrane and composite membrane. Although cellulose acetate membrane was widely used in the early days, it was gradually replaced by composite membranes with better performance due to its limited hydrolysis and pH range.

The main support structure of the composite membrane is polyester non-woven fabric, with a layer of microporous engineering plastic polysulfone on the surface, and the barrier layer is made of highly cross-linked aromatic polyamide. This structure not only improves the chemical and biological stability of the membrane, but also significantly enhances its transmission performance. The composite membrane will not be compressed during operation, so the water production and desalination rate are relatively stable, and the service life is longer.

The permeable carrier in the RO membrane element is a bridge connecting the raw water and the produced water. It is responsible for transporting the purified water after membrane filtration from one side of the membrane to the other side. The performance of the permeable carrier directly affects the overall efficiency of the RO system. High-quality permeable carriers should have the characteristics of high permeability, low resistance, corrosion resistance and long life.

In practical applications, permeable carriers often face challenges such as high temperature, high pressure and complex water quality. Studies have shown that long-term exposure to high temperature and high pressure environments may cause physical deformation of RO membranes, such as membrane compaction and penetration of permeate carriers, which will affect the membrane's permeability and desalination rate. Therefore, when designing and selecting permeate carriers, their materials, structures, and working environments must be fully considered to ensure their long-term stable operation.

With the advancement of science and technology, RO membrane technology is also constantly innovating and developing. By improving membrane materials and manufacturing processes, the membrane's desalination rate and water production can be further improved; by optimizing the structural design of membrane components, the system's energy consumption and operating costs can be reduced; by developing new pretreatment and post-treatment technologies, the membrane's service life can be extended and membrane pollution can be reduced.