Ultrafiltration membrane is a kind of micropores filter film with the same pore size and the rated aperture range of 0.01 micron.
With the appropriate pressure on the side of the membrane, the solutes smaller than the pore size can be screened out, and the particles with the molecular weight greater than 500 Dalton (atomic mass unit) and particle size greater than 10 nanometers.
Ultrafiltration membrane is one of the earliest developed polymer separation membranes, and the ultrafiltration device was industrialized in the 1960s.
Ultrafiltration membranes have symmetrical and asymmetric structures.
The former is isotropic, without the cortex, the pores in all directions are the same, belonging to deep filtration;
The latter has a dense surface and mainly refers to the structure of the ground floor, surface layer thickness of 0.1 microns or less, and have ordered micro porous, bottom thickness of 200 ~ 250 microns, belongs to the surface layer filtration.
The ultrafiltration membrane used in industry is usually an asymmetric membrane.
Ultrafiltration membrane material of membrane mainly of cellulose and its derivatives, polycarbonate, polyvinyl chloride (PVC), poly (vinylidene fluoride, polysulfone, polyacrylonitrile, polyamide, polysulfone amide, sulfonated polysulfone, cross-linking of pva, modified acrylic acid polymer, etc
The ultrafiltration membrane is divided into: inorganic film and organic film, and the inorganic membrane is mainly ceramic membrane and metal film.
The organic membrane is mainly made of polymer materials, such as cellulose acetate, aromatic polyamide, polyether sulfone, polyvinylidene fluoride and so on.
According to the different shape of membrane, it can be divided into plate membrane, tubular membrane, capillary membrane, hollow fiber membrane and so on.
The membrane used in household water purifier is basically hollow fiber membrane.
In inorganic film, ceramic ultrafiltration membrane is used in household water purifier.
Ceramic film has a long life and corrosion resistance, but it has a soil flavor and affects the taste.
At the same time ceramic membrane is easy to plug, cleaning is not easy.
The hollow fiber ultrafiltration membrane is widely used in household water purification industry because of its large filling density, large effective membrane area, high pure water flux and easy cleaning.