Knowledge

Microfiltration and Ultrafiltration are both physical filtration that use a membrane to trap contaminants. The size of the pores in the membranes determines how much-dissolved materials, turbidity, and microorganisms are eliminated.

Larger than the membrane holes substances are completely eliminated. Depending on how the refuse layer is built on the membrane, materials that are smaller than the pores are partially eliminated.

filtration

In comparison to nanofiltration and reverse osmosis, microfiltration and ultrafiltration are pressure-dependent techniques that remove dissolved solids and other impurities from water to a lesser extent.

MF and UF are frequently used to prepare industrial process streams for further separation. Such as cleaning various streams for the creation of potable water, treating waste, and meeting effluent regulations.

Additionally, they can carry out other applicable separation processes like refining oil and concentrating proteins like whey. The materials and configurations of these membrane filtration systems vary.

What is microfiltration?

Microfiltration

Microfiltration means the filter membranes with pore size between 0.1~10μm. Microfiltration is able to remove all bacteria.

However, some viruses can be also caught in this process, even if they are smaller than the pore size. Because the viruses may attach themselves to the bacteria.

What is ultrafiltration?

UF

Similar to reverse osmosis, ultrafiltration (UF) is a membrane filtration method that pushes water through a semi-permeable membrane using hydrostatic pressure. The pore size of the ultrafiltration membrane is generally between 0.01~0.1μm. And UF is often used in industries such as dairy, food, and metallurgy.

The common things between MF and UF

It is easy to find out that MF and UF are very alike. Below, we summarize some similarities between MF and UF.

Same working principle

They both utilize the semipermeable membrane to filter out contaminants, that are larger than the pore size.

working principle

Prefiltration for RO system

MF and UF are both often applied as prefiltration for downstream RO systems. They can filter out the contaminants that may cause damage to the expensive RO membranes.

Same configuration

MF and UF can be made into the same size, same shape, and same configuration. Both MF and UF membrane configurations can include hollow fiber, plate & frame, spiral wound, and tubular.

Same material

MF and UF can be made of the same raw materials, such as polypropylene, polysulfone, or even stainless steel. Generally, the polymer is the most popular material for MF and UF, because it has flexibility and chemical properties.

polymer

The difference between MF and UF

Though there are many similarities between MF and UF, they still have a big difference, which is the pore size of the membrane. As we mentioned above, the pore size of the ultrafiltration membrane is much smaller than microfiltration.

And the pore size directly affects the particles that could be removed and also make them suitable for different industries and applications.

The relevant applications of MF and UF

Microfiltration

In general, the bigger pore-sized membrane of MF permits the passage of water, monovalent and multivalent ions, and viruses while obstructing some bacteria and suspended particles.

mf applications

Relevant applications:

  • Cold sterilization of beverages and pharmaceuticals
  • Clearing of fruit juice, wines, and beer
  • Separation of bacteria from water (biological wastewater treatment)
  • Effluent treatment
  • Separation of oil/ water emulsions
  • Prefiltration of water for nanofiltration or Reverse Osmosis
  • Solid-liquid separation for pharmacies or food industries

Ultrafiltration

In contrast, because of its smaller pore size, ultrafiltration is able to filter out everything that microfiltration cannot, including viruses, silica, proteins, plastics, endotoxins, smog, and/or odors. It needs a tiny bit more pressure than MF.

ultrafiltration

Relevant applications:

  • Treating wastewater
  • Separating oil/water emulsions
  • Diafiltration in pharmaceutical biotechnology
  • Chemical process separation and diafiltration
  • Concentrating proteins
  • Clarifying fruit juices
  • Removing pathogens from milk
  • Making cheese

What Brother Filtration can provide in microfiltration and ultrafiltration?

Brother Filtration manufactures not only microfiltration filters but also ultrafiltration membranes. Also, you can find the filter housing and membrane vessels for microfiltration and ultrafiltration at Brother Filtration as well.

Our ultrafiltration products:

Our microfiltration products:

Conclusion

Both microfiltration and ultrafiltration are helpful and useful filtration methods to remove undesired impurities. They are very alike and have many common points. In some cases, using microfiltration is already enough. When higher requirements are asked, it is recommended for ultrafiltration or nanofiltration.

Brother Filtration has years of filtration experience and designs and manufactures all kinds of filter products. Recently, we just launched our new UF vessel, DOW IP-77XP retrofit. We believe that you can find what you want at Brother Filtration. If you want to know more, please feel free to contact us.

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