: Everyone wants to come to know about the reverse osmosis is also familiar, and is currently one of the more industrialized membrane processing technology, in addition to microfiltration, ultrafiltration, nanofiltration and electrodialysis. Since reverse osmosis needs to rely on high pressure and wastewater containing high salinity during the treatment of water, in recent years, a new type of membrane-separation technology driven by concentration, that is, positive osmosis technology, has attracted attention and has become a research hotspot in the field of membrane separation one. What is infiltration? Permeation is also known as penetration, refers to the water or other solvents through the natural or man-made semipermeable membrane, from the low solute concentration side of the transfer to high solute concentration side of the process, is a widespread physical phenomenon in nature. Positive infiltration refers to the process by which water flows from the higher hydrated potential (or lower osmotic pressure) side region to the lower hydrated potential (or higher osmotic pressure) -side region through the selective permeable membrane. Two solutions with different osmotic pressures were placed on the two sides with the selective permeable membrane, one for the feed solution with lower osmotic pressure and the other for the draw solution with the higher osmotic pressure ), Just infiltration is the application of membrane osmotic pressure on both sides of the solution as a driving force, it makes the water spontaneously from the side of the feed liquid through the selection of permeable membrane to drive liquid - side. When an applied pressure (ΔP) less than the aTr is applied to the solution with the higher osmotic pressure, the water will still flow from the source fluid to the drive fluid side, a process called Pressure Damping Infiltration -retardedosmosis, PRO). The driving force of pressure damping penetration is still osmotic pressure, so it is also a positive infiltration process. As early as 1981, Lee et al. Summarized the working principles of Reverse Osmosis (RO), Positive Permeability (FO) and Pressure Reducing and Permeability (PRO) processes. Positive infiltration is different from the pressure-driven membrane separation process, which does not require additional hydraulic pressure as a driving force, and rely on the drawdown and osmotic pressure difference of the feedstock solution to achieve membrane separation spontaneously. The realization of this process requires a few necessary conditions: (1) Permselective membranes and membrane modules that allow water to pass through while retaining other solute molecules or ions; (2) to provide a driving force of the draw solution; (3) The dilution of the draw solution and then concentrated way.