Explain The Working Mode Of The Reverse Osmosis Water Purifier

Reverse osmosis water purifiers are generally installed next to faucets. A membrane that is selective for permeable substances is called a semipermeable membrane. Generally, a membrane that can only pass through solvents but not solutes is called an ideal semipermeable membrane.
When the same volume of dilute solution and concentrated solution are placed on both sides of the semipermeable membrane, with a semipermeable membrane blocking the middle, the solvent in the dilute solution will naturally pass through the semipermeable membrane and flow to the concentrated solution side. The liquid level will be higher than the liquid level of the dilute solution by a certain height, forming a pressure difference and reaching a state of osmotic equilibrium.
This pressure difference is the osmotic pressure. The size of the osmotic pressure depends on the type of concentrated liquid, and the concentration and temperature have nothing to do with the properties of the semipermeable membrane. 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 solution and has nothing to do with the properties of the semipermeable membrane.
If a pressure greater than the osmotic pressure is applied to one side of the solution, the flow direction of the solvent will be opposite to the original osmosis direction and begin to flow from the concentrated solution to the dilute solution side. This process is called reverse osmosis. Through the process of reverse osmosis, water can be moved from a more concentrated solution to a less concentrated solution.
Since inorganic ions, colloidal substances and macromolecular solutes cannot pass through the reverse osmosis membrane, in this process, unnecessary substances are left at one end of the solution with high concentration, and the end with low concentration is the purified liquid obtained.