Ultrafiltration membrane technology is a membrane permeation separation technology that can purify, separate or concentrate a solution, which is between microfiltration and nanofiltration. Ultrafiltration membrane is an effective barrier for suspended particles and colloidal substances. At the same time, the ultrafiltration membrane can also achieve the effective removal of "two insects, algae, bacteria, viruses and aquatic organisms, so as to achieve the purpose of purification, separation and concentration of the solution." Compared with traditional processes, ultrafiltration membrane technology has the advantages of low energy consumption, low operating pressure, high separation efficiency, large flux and recyclable useful substances in water treatment. It is widely used in drinking water purification, domestic sewage recycling, and oily wastewater. , Pulp wastewater, seawater desalination and other water treatment.
The basic principle of ultrafiltration membrane technology:
Ultrafiltration (UF for short) means that the solvent and some low molecular weight solutes pass through the micropores of the membrane to the other side of the membrane under pressure, while the polymer solutes or other emulsified micelles are trapped to achieve separation from the solution. the goal of. The interception mechanism is mainly sieving, but sometimes the chemical properties of the membrane surface (electrostatic effect of the membrane) also play a role of interception. In ultrafiltration separation, after a certain pressure is applied to the feed liquid, the polymer and colloidal substances are blocked and retained in the pores due to the adsorption of the membrane surface and micropores, and the mechanical sieving effect on the membrane surface is superseded by three methods. The filter membrane prevents water, inorganic salts and low-molecular substances from passing through the membrane.
The molecular weight cut-off range of ultrafiltration membrane technology is about 500-500000, the corresponding pore size is about 0.002-0.1μm, the operating static pressure difference is generally 0.1-0.5MPa, and the diameter of the separated component is about 0.005-10μm.
Features of ultrafiltration membrane technology:
1. The removal efficiency of impurities is high, and the quality of the produced water is much better than traditional methods.
2. Completely eliminate or greatly reduce the use of chemical agents to avoid secondary pollution.
3. The system is easy to automate and has high reliability. It is easy to run, and the facility has only two gears to open and close.
4. It has good chemical stability, acid resistance, alkali resistance and hydrolysis resistance, and can be widely used in various fields.
5. The heat-resistant temperature can reach 140℃, and it can be sterilized by ultra-high temperature steam and ethylene oxide; it can be used in a wide pH range, and it can be used under strong acid, strong alkali and various organic solvents.
6. High filtration, can effectively filter out 99.99% of harmful substances such as colloids, bacteria, suspended solids and so on in the water.
7. The cost is equivalent to that of a conventional water treatment system. Domestic sewage undergoes ultrafiltration to improve the quality of the treated water for reuse. However, because the general technology cannot meet the standard in industrial wastewater, the ultrafiltration technology can fully treat the wastewater.
