Ceramic membrane

The ceramic membrane is an asymmetric composite membrane made of ceramic carrier with porosity of 30%~50% and 50nm~15 m and produced by sol-gel process or other processes. The structure of ceramic film used for separation is usually sandwich type: support layer (also called carrier layer), transition layer (also known as intermediate layer), and film layer (also called separation layer). The pore size of the supporting layer is generally 1-20 μ m, and the porosity is 30% - 65%, which is used to increase the mechanical strength of the membrane.

The pore diameter of the intermediate layer is smaller than that of the supporting layer, which is used to prevent the particles from penetrating into the porous support layer during the preparation of the film, with a thickness of about 20-60 μ m and porosity of 30% - 40%. The film has the separation function, with the pore size ranging from 0.8nm to 1 μ m, the thickness of 3-10 μ m, and the pore size is about 3-10 μ M The gap ratio is 40% - 55%. The pore size distribution of the whole film decreases from the support layer to the film layer, forming an asymmetric structure distribution.

According to the pore size, ceramic films can be divided into microfiltration (pore size greater than 50nm), ultrafiltration (pore size 2-50nm), nanofiltration (pore diameter less than 2nm) and other types. When separation, under the action of external force, small molecular substances pass through the membrane, and macromolecular substances are intercepted by the membrane, so as to achieve the purpose of separation, concentration, purification, impurity removal and bacteria removal.