Ultra Filtration  Manufacturers, Traders, Suppliers

Ultrafiltration is a technical process in which macromolecular substances are separated and concentrated. A distinction is made between ultrafiltration and microfiltration. This is done by the degree of separation. If particles with a size of 0.5 to 0.1 µm are separated, this is called microfiltration. If particles with a size of 0.1 to 0.01 µm are separated, this is called ultrafiltration. The so-called cut-off, i.e. the exclusion limit, is usually given in the form of the NMWC with the unit Dalton. This is given as the minimum mass of a globular molecule held back by a membrane. In practical application, the NMWC is therefore at least 20% lower than the molecular weight of the molecule to be separated. Based on the flux, which contains the transmembrane flow or the passage rate, further qualitative statements about the filtration are made. The transmembrane flow is proportional to the transmembrane pressure and antiproportional to the membrane resistance. These values are determined by the properties of the membrane used as well as by concentration polarization and possible fouling. The passage rate is related to 1 m² membrane area. Their unit is l/m²h. Further application possibilities result from diafiltration. In this process, the buffers can be replaced in a suspension. The salt concentrations can also be changed in this way. This combines the properties of dialysis with those of ultrafiltration. During this process, solvent is constantly exchanged through the membrane in the retentate. If the inflow and outflow ratio is equal, there is no change in the suspension volume. With the introduction of a new drinking water ordinance and the prescribed limit values for the parameter of turbidity, ultrafiltration is increasingly being used in municipal drinking water treatment. This method is called the dead-end method. The membrane converts the entire quantity of raw water into filtrate. Another important advantage is the sterility of this method. This means that even heavily polluted groundwater can be treated safely after heavy rainfall.