Reverse osmosis is mainly divided into the following categories:
One is seawater desalination SWRO membrane, the second is brackish water desalination BWRO membrane, including conventional pressure RO membrane and low pressure LP or low energy LERO membrane two types, the third is household RO membrane, ultra-low pressure is more. Of course, there will also be RO membranes such as low-pollution RO membranes, antioxidant RO membranes, etc., which are still included in the first three categories, but due to the modification of membrane materials, RO membranes with certain specific functions and uses are derived.
The working principle of reverse osmosis membrane: The membrane that is selective to the substance through is called a semi-permeable membrane, and the membrane that can only pass through the solvent but not through the solute is generally called an ideal semi-permeable membrane. When the same volume of dilute solution (such as fresh water) and concentrated solution (such as salt water) are placed on both sides of the semi-permeable membrane, the solvent in the dilute solution will naturally flow through the semi-permeable membrane and spontaneously to the concentrated solution side, this phenomenon is called osmosis. When osmosis reaches equilibrium, the liquid level on the concentrated solution side will be higher than that of the dilute solution, that is, a pressure difference is formed, and this pressure difference is the osmotic pressure. The size of the osmotic pressure depends on the inherent properties of the solution, that is, it is related to the type, concentration and temperature of the concentrated solution and has nothing to do with the properties of the semi-permeable membrane. If a pressure greater than the osmotic pressure is applied on one side of the concentrated solution, the flow direction of the solvent will be opposite to the original direction of penetration and begin to flow from the concentrated solution to the dilute solution side, this process is called reverse osmosis. Reverse osmosis is a reverse migration movement of osmosis, which is a separation method to separate the solute from the solvent in the solution under pressure driven by the selective interception of the semi-permeable membrane. It has been widely used in the purification and concentration of various liquids, among which the most common application example is in the water treatment process, using reverse osmosis technology to remove inorganic ions, bacteria, viruses, organic matter and colloids in raw water to obtain high-quality pure water.
Reverse osmosis membrane has the characteristics of high desalination rate, large water flux, strong anti-pollution, anti-bacterial erosion, etc., because of its special surface structure, surface potential is neutral, good hydrophilicity, unlike the general reverse osmosis membrane is easy to absorb surface active substances, blocked by dirt, so it is a new type of ideal reverse osmosis membrane for various wastewater treatment.
The reverse osmosis membrane process is one of the most advanced, reliable and safe technologies in the water purification industry, and the low pressure reverse osmosis membrane technology solves the problem that drinking water can be filtered and sterile without heating. Low pressure reverse osmosis membrane filtration technology can treat liquid separation with high efficiency and low energy consumption. Compared with traditional methods, it has good treatment effect, and can realize the recycling of wastewater and recovery of useful substances. Reverse osmosis membrane as a new separation technology, membrane separation technology can not only effectively purify wastewater, but also recover some useful substances, and has the characteristics of energy saving, no phase change, simple equipment, easy operation and so on.
