Take you to learn about microfiltration, ultrafiltration, nanofiltration, and reverse osmosis 

Author: Hongjie Water

Ultrafiltration (UF):

The filtration accuracy ranges from 0.001 to 0.1 micrometers, which is one of the high-tech technologies of the 21st century. It is a membrane separation technology using differential pressure, which can filter out harmful substances such as rust, sediment, suspended solids, colloid, bacteria, macromolecular organic substances, and retain some mineral elements beneficial to human body. It is a core component in the production process of mineral water and mountain spring water. The water recovery rate in the ultrafiltration process is over 95%, and it can be easily flushed and backwashed, not easily clogged, and has a relatively long service life. Ultrafiltration does not require power and pressure, and can be filtered solely by the pressure of tap water. It has a large flow rate and low usage cost, making it more suitable for comprehensive purification of household drinking water. Therefore, in the future, the purification of drinking water will mainly rely on ultrafiltration technology, combined with other filtering materials, to achieve a wider treatment range and more comprehensively eliminate pollutants in the water.

Nanofiltration (NF):

The filtration accuracy is between ultrafiltration and reverse osmosis, and the desalination rate is lower than reverse osmosis. It is also a membrane separation technology that requires electricity and pressure, and the water recovery rate is relatively low. That is to say, in the process of using nanofiltration membrane to produce water, nearly 30% of tap water will definitely be wasted. This is not acceptable to ordinary families. Generally used for industrial pure water manufacturing.

Reverse Osmosis (RO):

The filtration accuracy is about 0.0001 micrometers, which is an ultra high precision membrane separation technology developed in the early 1960s in the United States using pressure difference. It can filter out almost all impurities (including harmful and beneficial) in water, and can only allow water molecules to pass through. That is to say, in the process of using reverse osmosis membrane to produce water, nearly 50% or more of the tap water will be wasted. This is not acceptable to ordinary families. It is generally used in the manufacture of purified water and industrial Ultrapure water. Reverse osmosis technology requires pressure and electricity, with a small flow rate and low water utilization rate, making it unsuitable for the purification of large amounts of drinking water.

Microfiltration (MF):

The filtration accuracy is generally between 0.1 and 50 microns. Common types of PP filter elements, activated carbon filter elements, ceramic filter elements, etc. belong to the category of microfiltration, used for simple coarse filtration to filter large particle impurities such as sediment and rust in water, but cannot remove harmful substances such as bacteria in the water. The filter element is usually not cleanable and is a disposable filtering material that needs to be replaced frequently.

① PP cotton core: generally only used for coarse filtration with low requirements to remove large particles such as sediment and rust in water.

② Activated carbon: It can eliminate discoloration and odor in water, but it cannot remove bacteria in the water, and its removal effect on sediment and rust is also poor.

③ Ceramic filter element: The filtration accuracy is only 0.1 micrometers, usually with a small flow rate and difficult to clean.