Ultrafiltration Membranes: The Advantages and Disadvantages

As one of the earlier developed polymer separation membranes, ultrafiltration membrane replaces traditional purification processes such as activated carbon decolorization, resin impurity removal, and crystal extraction, and can achieve the purposes of decolorization, impurity removal, and product classification.

High-quality ultrafiltration membranes have the characteristics of good thermal stability, chemical stability, acid resistance, alkali resistance, microbial erosion resistance, and oxidation resistance. So what are the advantages and disadvantages of UF membranes?

 

Figure 1 Ultrafiltration membrane

1. What is an Ultrafiltration Membrane?

Ultrafiltration membrane is a polymer semipermeable membrane. During the ultrafiltration process, pressure is used as the driving force, and the incoming water containing impurities passes through the ultrafiltration membrane.

Since the pore size of the ultrafiltration membrane is 1 to 100 nm and the filtration precision is in the range of 0.001-0.1 micron, polymer colloids or suspended particles of a certain size will be separated from the solution. For example, particles, colloids, bacteria, proteins, viruses, divalent ions, etc.

2. What are the Advantages of Ultrafiltration Membranes?

(1) Use in a normal temperature environment, the conditions of use are mild and there is no component damage.
(2) No heating is required and no phase change will occur.
(3) No chemical reagents need to be added and there is no pollution. It is a very good energy-saving and environmentally friendly separation technology.
(4) The separation efficiency is very high.
(5) The equipment has low energy consumption and long service life.
(6) Operation and maintenance are very simple, making it easier to control and maintain.

Ultrafiltration System Manufacturer banner

3. Disadvantages of Ultrafiltration Membranes.

Ultrafiltration membranes are a common type of filter membrane product in the field of water treatment, and many users with relevant needs purchase ultrafiltration membranes for use. Issues with the ultrafiltration membrane used to treat the water may arise for these consumers while in use.

We’ll go over the most common problems with ultrafiltration membranes and how to fix them.

Common faults of ultrafiltration membranes in water treatment include:

  • Broken membrane fibers
  • Seal ring leakage
  • Decrease in water production
  • Decrease in water quality

The specific reasons and solutions for these faults are as follows:

1) The fault of broken membrane fibers. 

Broken fibers are a fault that may exist in some hollow fiber ultrafiltration membranes. The reasons that may cause broken fibers include water hammering inside the ultrafiltration membrane, too much system pressure, or damage to the membrane fibers during handling or installation.

For this type of fault, users can solve the problem by repairing or replacing the membrane fibers. They should also develop good usage habits to prevent possible damage to the membrane fibers.

2) The fault of seal ring leakage. 

The seal ring is an important device inside the ultrafiltration membrane to prevent water pollution from entering the produced water.

If the seal ring becomes loose, deformed, or detached, it will cause the seal ring to leak. The reasons for its leakage include too high system pressure or incorrect installation.

If the seal ring of the ultrafiltration membrane leaks, users can solve the problem by reinstalling or replacing the seal ring. However, it should be noted that the seal ring must be installed accurately and securely fixed.

3) The fault of decreased water production.

The decrease in water production of the ultrafiltration membrane is mostly caused by clogging and scaling, which slows down the flow rate and reduces water production. It may also be caused by changes in operating conditions.

This fault, users can solve this by cleaning the ultrafiltration membrane components to restore their flux and adjusting the relevant parameters of the operating conditions.

4) The fault of decreased water quality. 

The main reason for the decrease in water quality produced by the ultrafiltration membrane is clogging seal ring leakage and poor quality of the inlet water. This fault, users can solve this by cleaning the ultrafiltration membrane components, replacing the seal ring, and strengthening the pretreatment.

These are some common faults of ultrafiltration membranes in water treatment and their corresponding solutions:

  • Repairing damaged membrane fibers is a good solution.
  • If the seal ring is leaking, simply replace it.
  • To restore normal water production and quality, it is necessary to clean the ultrafiltration membrane components.

4. How Long Will the Ultrafiltration Membrane Last?

The normal service life of ultrafiltration membranes can reach 5-8 years. Cleaning and maintenance of the membrane during use will affect the service life of the ultrafiltration membrane. Therefore, the better the membrane elements are maintained, the longer their service life will be and the lower the system cost will be. Any improper method during operation will reduce the life of the ultrafiltration membrane system.

If the ultrafiltration membrane can always maintain good flux, it can not only improve production efficiency, but also extend the service life of the membrane, reduce the replacement frequency of the ultrafiltration membrane, and reduce cost investment.

5. How to Maintain Ultrafiltration Membranes?

Using proper methods when operating an ultrafiltration system can effectively maintain the ultrafiltration membrane and extend its life. The following are some suggestions on how to effectively extend the service life of ultrafiltration membranes:

1) It is best to choose an ultrafiltration membrane made of PVDF. It uses hollow fiber membranes with high mechanical strength and superior chemical stability. It has relatively low requirements for incoming water quality and is more durable.
2) Improve the quality of incoming water. Suspended solids in the incoming water will affect the degree of damage to the membrane elements. Therefore, it is best to add an ultrafiltration pre-filter before the ultrafiltration system to reduce the degree of water pollution.
3) Clean the ultrafiltration membrane elements regularly. Including backwash and chemical cleaning. Regular chemical cleaning of membrane elements can reduce the accumulation of contaminants and maintain membrane element performance.

Membrane Cleaning System Applications
4) Regularly test the produced water quality. The produced water quality can intuitively reflect the operating status of the ultrafiltration system.

6. Ultrafiltration Membranes Applications.

As ultrafiltration technology becomes increasingly mature, ultrafiltration systems can be seen in more and more application fields. Ultrafiltration membranes are cheaper than reverse osmosis membranes, so they are the first choice for many companies. Common application areas include:

  • Water production industry
  • Sterile liquid food manufacturing
  • Medical and health applications
  • Applications in the food fermentation industry
  • Dairy Industry Applications
  • Applications in biologics
  • Medical applications
  • Pool water purification
  • Figure 1 Lifespan of Medical Ultrapure Water Equipment

    7. How to Choose Ultrafiltration Membrane?

    There are many types of ultrafiltration membranes on the market, and the quality and uses of ultrafiltration membranes made of different raw materials are also different. How to choose the ultrafiltration membrane that suits you based on different materials and characteristics? We provide answers below.
    The main materials of ultrafiltration membranes are: polyacrylonitrile (PAN), polyethylene plastic (PS), polyvinylidene fluoride
    (PVDF), polyvinyl chloride (PVC), polypropylene (PP).

    1. Polypropylene fluoride (PAN): hydrophilic material, easy to form film. The advantages are that the materials are easily available, the film production cost is low, the processing technology is simple, and the daily output is large.
    The disadvantages are low strength, high brittleness, and weak acid and alkali resistance.

    2. Polystyrene plastic (PS): It has good chemical stability, good acid and alkali resistance, good water permeability, good strength, high-temperature resistance, and good biointegration.
    The disadvantage is that the price of raw materials is very high, and ultrafiltration membranes with very low molecular weight cutoffs can be made. Suitable for special material separation, concentration and purification, and high-temperature resistant applications.

    Figure 11 Ultrafiltration membrane

    3. Polyvinylidene fluoride (PVDF): high elongation, not easy to break, good acid and alkali resistance, strong pollution resistance, chemical cleaning resistance, and resistance to high-concentration residual chlorine solutions. The material cost is relatively high and it is suitable for industrial wastewater treatment applications.

    4. Polyvinyl chloride (PVC): It has good strength and elongation, is not easy to break, has high filtration accuracy, is resistant to strong acids and alkalis, has a long life, and has a wide range of material sources. Low price but poor hydrophilicity. Used in water filtration and industrial water treatment.

    5. Polypropylene (PP): The material price is low, the film-making process is environmentally friendly, low consumption, low cost, has good acid and alkali resistance and is resistant to organic solvents.
    The disadvantages are low filtration precision, easy contamination, difficulty in backwash recovery, high tensile strength, and large membrane area. Used in water filtration and sewage treatment.

     

    UF ultrafiltration membrane has the characteristics of good thermal stability, chemical stability, acid resistance, alkali resistance, microbial erosion resistance, and oxidation resistance, and is widely used. If you are considering purchasing ultrafiltration membranes you can get the best purchasing advice by contacting NEWater.

    The reverse osmosis membranes, seawater desalination membranes, nanofiltration membranes, ultrafiltration membranes, and MBR flat membranes provided by NEWater have the advantages of better cost performance, better quality, and more comprehensive services. Contact us to get the best quote!

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