Ultrafiltration is often used when a water treatment process needs reliable removal of suspended particles, colloids, and microorganisms before a downstream purification stage. However, the membrane material and operating structure still matter because different projects place different demands on chemical resistance, mechanical strength, cleaning, and water utilization.
At Runmo, we use modified polyacrylonitrile (PAN) material for our inside-out ultrafiltration membrane elements. We designed this series around separation performance, oxidation resistance, thermal stability, mechanical properties, and permanent hydrophilicity, while also modifying the material and membrane structure to address its pollution-resistance limitations.
Why Use PAN for Ultrafiltration?
The material of a ultrafiltration membrane influences how the membrane behaves during filtration and maintenance. Our modified PAN membrane combines good oxidation resistance with thermal stability and mechanical strength. Its permanent hydrophilicity is another important characteristic for water-treatment applications.
We also recognize that no membrane material should be evaluated through a single property. The official product information notes that conventional PAN has relatively weaker anti-pollution performance, so we modify both the material and membrane to improve this aspect. This is part of our approach to developing a PAN UF membrane for practical operating conditions rather than focusing on material selection alone.
The membrane filament has high strength, with a breakage rate of less than three thousandths. This mechanical characteristic is relevant to membrane modules that undergo routine operating and cleaning cycles.
Where Is PAN UF Commonly Used?
Pure Water and Boiler Recharge Water
Our PAN ultrafiltration membrane series is listed for pure-water preparation and boiler recharge water applications. In these systems, UF can serve as an important separation stage before additional purification processes.
The role of UF depends on the overall process design. Where reverse osmosis is used downstream, ultrafiltration can act as pretreatment to help control suspended matter and other contaminants entering the RO stage.
Food Processing and Pharmaceutical Manufacturing
Food and pharmaceutical production can require controlled water quality and consistent filtration performance. Our PAN series is officially listed for both food processing and pharmaceutical manufacturing.
For these applications, membrane selection should still be based on the actual feed-water conditions, required capacity, cleaning approach, and downstream process. We do not treat the membrane as an isolated component; its performance needs to fit the complete treatment system.
Full Filtration or Cross-Flow Filtration?
One practical feature of our PAN UF membrane elements is the ability to select between full-volume filtration and cross-flow filtration according to water-quality conditions.
Full-volume filtration can provide advantages in energy use and water utilization. For applications where the feed water is suitable for this operating mode, it can support efficient use of the available water stream.
Cross-flow filtration takes a different approach. A portion of the flow moves across the membrane surface, helping discharge pollutants during operation. This can reduce the frequency of membrane cleaning and help extend membrane-component service life.
For project engineers, the choice should therefore be based on feed-water characteristics rather than selecting one operating mode universally. The appropriate configuration depends on how much fouling is expected and how the system needs to manage concentrated contaminants.
What Makes the Module Structure Relevant?
Our PAN elements use a unique central pipe bracket designed to distribute membrane filaments evenly and maintain smooth water flow. We developed this structure to support reliable operation and help prolong membrane-filament service life.
The system is designed so that water washing and chemical cleaning can be performed under the product’s intended operating conditions without affecting normal membrane use. This is relevant to projects where routine membrane maintenance is part of the operating plan.
Compared with traditional filtration methods, the system offers high automation, a smaller floor area, high filtration accuracy, and unattended operation.. The stated floor-area requirement is approximately half that of traditional filtration methods.
What PAN UF Models Do We Offer?
Our product range includes internal pressure ultrafiltration membrane elements in several formats. The 4-inch and 6-inch product series includes RM-UF-4040, RM-UF-4021, RM-UF-4046, RM-UF-4046 short, and RM-UF-160B. Their membrane areas range from 2 m² to 13.7 m², with published design water yields from 0.1 to 0.8 m³/h at 0.1 MPa and 25°C.
For larger systems, our 8-inch and 10-inch series includes RM-UF-8040, RM-UF-8060, RM-UF-8060L, RM-UF-8060A, and RM-UF-1060(D). Their published membrane areas range from 21 m² to 51 m², with design water yields from 1.2 to 2.5 m³/h under the same stated test conditions. Produced-water turbidity is specified as below 1 NTU.
These figures are reference values under the stated conditions. Actual system output can vary according to feed-water quality, operating conditions, pretreatment, and system configuration.
Why Work With Runmo?
At Runmo, we are Suzhou Runmo Water Treatment Technology Co., Ltd., integrating R&D, manufacturing, and sales of reverse osmosis membrane, ultrafiltration membrane, and polymer membrane technologies. We maintain an independent R&D system and automated production capabilities, with annual production capacity of more than 800,000 membrane products and more than 40 patents. Our products and technical support serve customers in more than 60 countries.
Our membrane portfolio includes PAN and PVDF ultrafiltration, nanofiltration, seawater, brackish-water, and ultra-low-pressure membrane products. This range allows us to evaluate membrane selection according to feed-water conditions and treatment objectives rather than applying the same material to every project.
If you are planning a pure-water, boiler recharge, food-processing, pharmaceutical, or RO pretreatment system, contact Runmo with your feed-water conditions and required capacity. We can help you evaluate the appropriate PAN membrane configuration and filtration mode for your application.
