RO Membrane: the gatekeeper of the microscopic world, can it truly achieve water purity?

Reverse osmosis membrane (RO membrane) is a semi-permeable membrane with a special microporous structure that can separate water molecules from the solution under a certain pressure, thereby purifying and concentrating water. Understanding the working principle of reverse osmosis membrane requires in-depth exploration of its microstructure and physical and chemical properties.

Reverse osmosis membranes are usually composed of multiple layers of membranes, the most critical part of which is the semipermeable membrane layer. This semipermeable membrane has a microporous structure, and the size of the micropores is usually at the nanometer level, which is much smaller than the size of water molecules. These micropores are tightly arranged, forming a highly selective barrier that only allows water molecules to pass through, while intercepting solute molecules such as salt ions, organic matter, etc.

The selectivity of a reverse osmosis membrane is at the heart of how it works. This selectivity is achieved through the size and chemistry of the pores in the semipermeable membrane. Since water molecules have smaller molecular size and polarity, they can pass through the micropores more easily, while solute molecules are blocked due to their larger size or chemical mismatch with the membrane. This selectivity allows reverse osmosis membranes to effectively separate water from solutes.

During the reverse osmosis process, a certain amount of pressure needs to be applied to overcome the resistance of water molecules passing through the semipermeable membrane. The greater the pressure, the more water molecules pass through the membrane, thereby achieving separation and concentration of the solution. Typically, a reverse osmosis membrane system uses a high-pressure pump to provide the required pressure to push solution through the membrane.

Through the process of reverse osmosis membrane, water molecules will be gathered on one side of the semi-permeable membrane to form pure water, while solute molecules will be blocked on the other side to form a concentrated solution. This separation effect can be adjusted according to different application requirements, thereby achieving different treatments of the solution, such as purifying seawater, concentrating fruit juice, etc.

Since reverse osmosis membranes are susceptible to contamination and scaling during use, they need to be cleaned and maintained regularly to ensure their normal working performance and service life. Cleaning methods usually include chemical cleaning and physical cleaning, which can effectively remove dirt and sediment on the membrane surface and restore the water permeability of the membrane.

As an efficient and environmentally friendly separation technology, reverse osmosis membrane is widely used in water treatment, food processing, pharmaceutical preparation and other fields. As people's demand for clean water continues to increase, reverse osmosis membrane technology will play an increasingly important role. In the future, with the continuous advancement of technology and the expansion of application fields, reverse osmosis membrane technology will continue to improve its performance and efficiency and make greater contributions to the sustainable development of human society.

Through its unique microporous structure and selective separation characteristics, reverse osmosis membranes achieve efficient separation and concentration of water and solutes, providing important technical support for various industrial processes and daily needs. An in-depth understanding of its working principle will help to better understand its role and advantages in practical applications.