1.The semi-permeable membrane in the reverse osmosis system allows only certain things to pass.
2.The film is easy to pass through water, but it also prevents many other contaminants from catching them.
3.Water is normal on both sides of the membrane, and the water on both sides has different concentrations of dissolved minerals.
4.Water in a lower concentration solution attempts to dilute a more concentrated solution.
5.The water passes through the membrane from one side of the lower concentration to the more concentrated side.
6.The osmotic pressure caused by the difference of water level (see figure) will counteract the diffusion process of equilibrium.