What is the principle of flat ceramic membrane plate?

Flat ceramic membrane plate process is a kind of "cross-flow filtration" type of fluid separation process. The raw material liquid flows at high speed in the membrane tube, and the clarifying osmosis containing small molecular components penetrates the membrane vertically, and the turbid concentrate containing large molecular components is intercepted by the membrane, so that the fluid can be separated, concentrated and purified.

The flat ceramic membrane plate is an asymmetric composite membrane made of ceramic carrier with porosity of 30%-50% and 50nm-15um and produced by sol-gel process or other processes. The structure of ceramic membrane used for separation is usually sandwich: support layer (also known as carrier layer), transition layer (also known as intermediate layer), and membrane layer (also known as separation layer).

The pore size of the supporting layer is generally 1-20um, and the porosity is 30%-65%. Its function is to increase the mechanical strength of the membrane. The pore size of the middle layer is smaller than that of the supporting layer. Its function is to prevent the particles from penetrating into the porous supporting layer during the preparation of the membrane. The thickness of the supporting layer is about 20-60um, and the porosity is 30%-40%. The membrane has separation function. The pore size varies from 0.8nm to 1um, the thickness is about 3 to 10um, and the porosity is 40%~55%. The pore size distribution of the whole membrane decreases gradually from the supporting layer to the membrane layer, forming an asymmetric structure distribution.

According to the pore size, flat ceramic membranes plate can be divided into microfiltration (pore size greater than 50nm), ultrafiltration (pore size 2-50nm), nanofiltration (pore size less than 2nm). When separating, under the action of external force, small molecule substances pass through the membrane and macromolecule substances are intercepted by the membrane, so as to achieve the purposes of separation, concentration, purification, impurity removal and bactericidal removal.