INTRODUCTION

Ultrafiltration membrane elements are membrane separation products with a sieving function made from polymer materials. Common materials for ultrafiltration membranes include polysulfone, polyethersulfone, polyacrylonitrile, etc., which endow the ultrafiltration membranes with good chemical stability and mechanical strength. They usually appear in the form of hollow fibers or flat sheets. For example, hollow fiber ultrafiltration membrane elements consist of a large number of hollow fiber filaments, and each filament serves as a tiny filtration channel.

The pore size of ultrafiltration membrane elements generally ranges from 0.001 to 0.1 micrometers, enabling them to effectively retain impurities such as suspended solids, colloids, bacteria, and macromolecular organic substances in water while allowing water and small-molecule substances like inorganic salts and small-molecular organic substances to pass through smoothly. They come in a variety of specifications, and appropriate elements with suitable membrane areas and fluxes can be selected according to different water treatment capacities and water quality requirements, and they are widely used in many scenarios ranging from small household water purification devices to large industrial water treatment systems.

WORKING PRINCIPLE

The working principle of ultrafiltration membrane elements is based on the sieving effect, that is, the physical retention mechanism. Driven by a certain pressure, the water to be treated enters from one side of the membrane element. When the water flows through the ultrafiltration membrane, due to the uniformly distributed pores of specific sizes on the membrane, substances larger than the membrane pore size, such as colloidal particles and bacteria, will be retained on the influent side of the membrane and cannot pass through the membrane pores, thus realizing the separation from water. Meanwhile, those small-molecule substances and water molecules whose sizes are smaller than the membrane pore size can smoothly pass through the membrane pores under the driving force of the pressure difference and reach the other side of the membrane to form the filtered product water.

The whole process is just like a fine sieve screening items. However, ultrafiltration membrane elements are screening various components in water, and this sieving effect continuously and efficiently occurs at the microscopic level to achieve the purpose of purifying water quality.

MAIN PERFORMANCE AND CHARACTERISTICS

High-precision Filtration:With a precise pore size range, ultrafiltration membrane elements can accurately retain target impurities. For example, the removal rate of common bacteria like Escherichia coli in water can reach over 99%, and the removal effects on colloids and suspended solids are also remarkable, greatly improving the clarity and purity of water quality.

Good Flux Performance: Under appropriate operating pressures, ultrafiltration membrane elements have considerable water fluxes and can handle a relatively large amount of water within a unit time to meet the water demand of different scales. For instance, some large industrial ultrafiltration membrane elements can treat dozens of cubic meters or even more of raw water per hour, ensuring the continuous water supply in the production process.

Good Chemical Stability:Whether facing acidic or alkaline water quality environments, as long as within the specified pH range, ultrafiltration membrane elements can maintain stable performance and are not easily corroded or damaged. This enables them to be applied to various complex water source treatment scenarios, such as the pretreatment of chemical wastewater and mine wastewater.

Strong Anti-pollution Ability:Their surface properties have been specially treated, so they are relatively less likely to adsorb pollutants in water. Moreover, after being polluted, their fluxes and performances can be restored through relatively conventional cleaning methods, such as chemical cleaning and backwashing, which extends the service lives of membrane elements and reduces the usage costs.

Low Operating Pressure:Compared with other membrane separation technologies like reverse osmosis, ultrafiltration membrane elements usually can work under relatively low pressures. Generally, the operating pressure is between 0.1 and 0.5 MPa, which not only reduces the requirements for supporting equipment such as water pumps but also further saves energy consumption.

APPLICATION FIELDS AND INDUSTRIES

Drinking Water Treatment:In municipal water supply systems, ultrafiltration membrane elements can serve as key equipment in the advanced treatment process to further remove tiny impurities and bacteria remaining in water and improve the quality of drinking water, ensuring that residents can drink healthier and safer water. Meanwhile, they are also widely used in household water purifiers to provide families with high-quality direct drinking water and meet people's pursuit of high-quality domestic water.

Industrial Field:In the electronics industry, the water quality requirements for production water are extremely high. Ultrafiltration membrane elements can remove impurities that may affect the performance of electronic components in water to ensure the smooth progress of the ultrapure water preparation process. In the food and beverage industry, they are used to filter the raw water and the water used in the production process to ensure the hygienic quality and taste of products. For example, in beverage production, they can remove microorganisms and impurities in water to make the quality of beverages more stable. In the pharmaceutical industry, they can be used for the pretreatment of pharmaceutical water to intercept bacteria and macromolecular impurities that may be mixed in, laying the foundation for subsequent more refined water treatment processes and ensuring the safety and effectiveness of drug production.

Wastewater Treatment and Reuse:For industrial wastewater, ultrafiltration membrane elements can be used as a pretreatment method to retain macromolecular organic substances and suspended solids in wastewater, reducing the burden on subsequent treatment processes and improving the overall efficiency of wastewater treatment, making the treated water easier to meet the discharge standards or be recycled. In urban sewage treatment, they can also effectively remove impurities in sewage to facilitate the reuse of sewage and realize the recycling of water resources, alleviating the situation of water resource shortage.

Marine Aquaculture Industry:The marine aquaculture industry has strict requirements for water quality. Ultrafiltration membrane elements can filter out harmful microorganisms and impurities in seawater, creating a good living environment for cultured organisms, reducing the probability of diseases, and improving the survival rate and yield of aquaculture.

SUMMARY

Ultrafiltration membrane elements, with their unique working principles and excellent performance characteristics, have shown strong application value in numerous fields. Whether it is ensuring the safety of people's drinking water or facilitating the development of industries such as industrial production, wastewater treatment, and marine aquaculture, they all play an indispensable role. With the continuous progress of technology, the performance of ultrafiltration membrane elements is expected to be further improved, and their application scope will also continue to expand. They will better serve the protection and utilization of water resources as well as people's demand for high-quality water quality and become an important supporting force for the continuous development of the water treatment field, contributing more to the construction of a healthier and more sustainable water use environment.