Selection of ultrafiltration membrane package
Selection of filter membrane material
In the separation process of biological products, the selection of membrane materials is very important. It must meet the following requirements: low nonspecific protein adsorption, less DNA binding, high recovery rate, large flux, stable physical and chemical properties and alkali washing resistance. At present, the main materials of commercially available membrane packages are polyvinylidene fluoride, regenerated cellulose and polyethersulfone, but the former two are not alkali resistant and the flux is too small, which seriously limits their application; Polyethersulfone membrane is selected as the membrane coated substrate, which has excellent physicochemical properties, acid and alkali resistance, extremely low protein adsorption and large flux. It is very suitable for the concentration and separation of biological products.
What is ultrafiltration membrane
Based on the principle of pore size, the pore size from 2nm to 0.1um can be called ultrafiltration membrane. Ultrafiltration can separate particularly small colloids and dissolved macromolecules; In any type of device, the performance of ultrafiltration membrane depends on its shape. The ultrafiltration membrane has an asymmetric structure, so that particles larger than the molecular weight intercepted by the membrane are intercepted on the surface of the membrane, and smaller substances are allowed to pass through the lower structure of the membrane. If the surface of the filter membrane is extremely smooth, the interception yield of biomolecules and viruses will increase. Due to the lower structure of the filter membrane, the particles are quickly transferred, separated from the ultrafiltration membrane and layered, and the concentration polarization on the surface of the filter membrane is prevented.
Selection of ultrafiltration membrane package
How to select the appropriate membrane pore size for concentration and separation of ultrafiltration membrane package? According to the industry experience and the characteristics of biological products, the selected membrane pore size is usually 3 to 6 times smaller than the particle size of the material to be intercepted, which can not only ensure a good flow rate, but also ensure a high product recovery rate; In addition, the selection of grid channel is also very important. For the configuration of grid channel, the screen creates soft turbulence in the filtered logistics body, which reduces the fouling of filter membrane to the greatest extent; In the backflow path, the fluid path configuration of the suspension screen has a more open structure, and the performance is better when dealing with viscous or particle dense solutions.
