Types of membrane filtration, specifications of microfiltration, ultrafiltration, nanofiltration, an

Membrane filtration technology is used in many industries. Its main method is the separation process through membranes. It is mostly used in mixtures. Membranes can be used to separate inorganic particles in mixtures. Two-phase or multi-phase particles pass through the surface of the membrane under certain conditions, pressure, temperature, etc., and rely on the size of the membrane pore to intercept different phases, so as to realize the separation between different components, and play a role in separation, concentration and For the effect of purification, the pressure difference of the fluid is mostly used as the driving force for sieving and separation. Microfiltration, reverse osmosis, nanofiltration, ultrafiltration, etc., are all separation technologies that use pressure-driven membranes.

Microporous filtration, referred to as MF, can intercept suspended particles larger than 0.1 micron, including particles of this size, fibers and bacteria, etc. Water, gas, and solvent solubles smaller than 0.1 micron can pass through the microfiltration membrane.

Ultrafiltration, referred to as UF, can filter water, solvents, ions and small molecules (relative molecular mass <1000), among which biochemical products, colloids and macromolecules with a relative molecular weight of 1000~300000 will be intercepted by the membrane, and the filtration specification is 0.001~0.1 um.

Nanofiltration, referred to as NF, this type of membrane pore size is between ultrafiltration and reverse osmosis, can filter water, solvents, monovalent salts, etc. , sugar and dyes etc. Filter particles with specifications less than 0.001 um.

Reverse osmosis (RO), which can filter liquids such as water and solvents, and intercept extremely small particles less than 0.0001 umSuspended solids, solutes and monovalent salts, free acids, etc.

The above is a brief introduction to the four microporous membranes. The process of microporous separation using membrane filtration is to use the membrane to select the size of the separated particles under the action of fluid pressure difference, and the particles larger than the membrane pores are separated. At the same time, particles or small molecular solutes that cannot be retained by the die holes can pass through the membrane.