Difference between MF UF NF and RO

Difference between MF UF NF and RO

[2024-07-25] | By Xiamen Smart Water Technology Co., Ltd. Allen Huang

Water purifiers provide important protection for household drinking water, and among the many parts of water purifiers, the filter element is undoubtedly the most core part. The performance of the filter element directly determines the water quality of the water purifier. There are many types of filter elements on the market. In order to help everyone better understand the types and functions of filter elements, this article will analyze the classification, materials and functions of water purifier filter elements in detail to help you make a wise choice when purchasing a water purifier.

At present, the common water purifiers on the market are mainly composed of PP cotton (primary filtration), activated carbon or other composite adsorption materials (secondary filtration) and membrane materials (core filtration) in multiple stages in series, which are composite water purifiers.

The main filter element refers to the filter element that plays a core filtering role in the water purifier, which determines the final water quality of the water purifier. According to the current development of the water purification industry, we can mainly divide the main filter element into four types: reverse osmosis membrane filter element, nanofiltration membrane filter element, ultrafiltration membrane filter element and nano alumina fiber filter element.

1. Reverse Osmosis Membrane Filter(RO)

The reverse osmosis membrane filter (RO membrane) is the most common and most effective filter in water purifiers. Its filtration accuracy can reach 0.0001 microns, which can effectively remove bacteria, viruses, heavy metal ions and other impurities in water. Reverse osmosis technology relies on a high-pressure pump to force water molecules through a semipermeable membrane, and impurities are intercepted outside the membrane. Due to its excellent filtration ability, the water quality output by RO membrane water purifiers is even better than bottled pure water, making it the first choice for many high-end water purifiers.

2. Nanofiltration Membrane Filter(NF)

The filtration accuracy of the nanofiltration membrane filter (NF membrane) is about 0.001 microns, which is lower than that of the reverse osmosis membrane, but it can still effectively filter most pollutants, including some organic matter and divalent ions such as calcium and magnesium. Compared with the reverse osmosis membrane, the nanofiltration membrane retains some beneficial minerals, making the water quality more natural and taste better. Therefore, the nanofiltration membrane is particularly suitable for application scenarios that have high requirements for water quality but do not require complete removal of minerals.

3. Ultrafiltration membrane filter element(UF)

The filtration accuracy of ultrafiltration membrane filter element (UF membrane) is generally between 0.01-0.1 microns, and it is mainly used to remove suspended matter, bacteria and some viruses in water. Ultrafiltration membrane does not require a pressure pump, so it is widely used in household water purifiers, with the advantages of low cost and low energy consumption. Its disadvantage is that it has poor filtration effect on some soluble organic matter and heavy metal ions, so it is usually used as an auxiliary filtration method.

Combination application of main filter element

When designing a water purifier, based on different needs and cost considerations, a general water purifier will choose one of the technologies as the main filter element. A small number of high-end brands will use a composite technology of two main filter elements to improve the water purification effect. Although a combination of multiple main filter elements can further improve the purification effect, the cost will also increase.

The main function of the auxiliary filter element is to perform preliminary filtration on the water, reduce the entry of large particle pollutants, and protect the main filter element to extend its service life. Common auxiliary filter element materials include PP cotton and activated carbon.

1. PP cotton filter element

The PP cotton filter element is mainly used to intercept large particles in the water. According to different manufacturing processes, PP cotton filter elements are divided into ordinary PP cotton and folded PP cotton. The filtration accuracy of ordinary PP cotton filter elements is generally between 1-5 microns, which is suitable for primary filtration. The folded PP cotton filter element has a higher dirt holding capacity and filtration effect due to the improvement of the manufacturing process, which can better protect the subsequent filter element. Folded PP cotton filter elements are mostly used in high-end water purifiers, while ordinary PP cotton filter elements are widely used in general models of water purifiers.

2. Activated carbon filter element

The activated carbon filter element mainly removes residual chlorine, odor and some organic matter in the water through its adsorption. Activated carbon filter elements can be divided into carbon powder filter elements and sintered carbon rod filter elements.

i. Carbon powder filter element

Early activated carbon filter elements mostly use carbon powder. This filter element has a large surface area and strong adsorption capacity, but it is easy to leak carbon. Therefore, black water will be discharged in the early stage of use, and a large amount of flushing is required.

ii. Sintered carbon rod filter element

Sintered carbon rod filter element has significant advantages over carbon powder filter element. It is sintered by high pressure, which not only enhances the surface area and adsorption capacity of activated carbon, but also has a certain physical filtration effect, while avoiding the secondary pollution problem of carbon powder. Therefore, the new generation of water purifiers mostly use sintered carbon rods as activated carbon filter elements.

When purchasing water purifiers, consumers should focus on the type and quality of the main filter element, as well as the configuration of the auxiliary filter element. The water quality and water supply conditions in each region are different. The filter element should be selected according to the water supply quality and water use scene requirements in the area where you are located. Choose the corresponding combination.

1. Main filter element: reverse osmosis membrane or nanofiltration membrane is preferred as the main filter element. Both filter elements have excellent filtering accuracy and effect, and the water can meet the requirements of direct drinking.

2. Auxiliary filter element: Choose a water purifier with a combination of folded PP cotton and sintered carbon rods. Such a configuration can effectively protect the main filter element and improve the taste of water quality.

3. Understand the needs: Choose the appropriate type of water purifier according to your own water quality and drinking water needs, and do not blindly pursue high-end configurations and ignore actual needs.

The filter element of the water purifier is a key part that determines the performance of the water purifier and the water quality. Understanding the type and function of the filter element can help everyone make a more wise choice. Xiamen Smart Water Tech focuses on core technology to protect healthy drinking water for families.