What exactly is an RO membrane? Get a complete overview in 3 minutes!

• What is an RO membrane? 

RO is an abbreviation for Reverse Osmosis. An RO membrane is an artificial semi-permeable membrane with certain properties, made by mimicking biological semi-permeable membranes.

It's like an extremely fine sieve, but its pore size is only 0.0001 micrometers (equivalent to one millionth the thickness of a human hair), which can effectively filter out various impurities, bacteria, viruses, and heavy metals in the water.

• Working principle of RO membrane

RO membranes work on the principle of reverse osmosis technology , which is the opposite of the natural osmosis process.

Under natural conditions, osmosis refers to the process of a low-concentration solution flowing through a semi-permeable membrane to a high-concentration solution. Reverse osmosis, on the other hand, uses external pressure (usually requiring a water pump) to force water molecules in a high-concentration solution to flow through a semi-permeable membrane to the low-concentration side, thereby purifying the water.

This process requires a certain amount of pressure, which is why RO water purifiers need to be plugged in—electricity is mainly used to drive the water pump to generate the necessary pressure.

• What can an RO membrane filter?

RO membranes have extremely high filtration precision and can effectively remove:

Heavy metal ions, such as lead, mercury, cadmium, and chromium, pose a great threat to human health.

Bacteria and viruses: removal rate up to 99.99%, ensuring drinking water safety.

Scale and impurities: Effectively removes calcium and magnesium ions, solving the scale problem.

Organic pollutants: Removal of pesticide residues, chemical pollutants, etc.

Soluble salts: Remove excess sodium, potassium, and other salts from water.

Water filtered through an RO membrane is almost pure water with a smooth taste, making it ideal for direct drinking.

• The Development History of RO Membranes

RO technology was not initially developed for civilian use, but rather for the aerospace field. In the 1960s, NASA developed RO technology to solve the problem of drinking water for astronauts in space.

Later, this technology gradually shifted to civilian use, and was widely applied in fields such as seawater desalination and medical water purification. It wasn't until the last 20 years, with the maturity of the technology and the reduction in costs, that RO technology began to enter ordinary households.