Author: Site Editor Publish Time: 2022-12-19 Origin: Site
Microfiltration membranes are divided into inorganic membranes and organic polymer membranes according to the membrane forming materials, inorganic membranes are divided into ceramic membranes and metal membranes, organic polymer membranes are divided into natural polymer membranes and synthetic polymer membranes; according to the form of membranes are divided into flat membranes, tubular membranes, rolled membranes and hollow fibre membranes; according to the principle of membrane making, the preparation methods of polymer membranes are divided into dissolution method (dry-wet method), stretching pore formation method, phase transformation method, thermogenic phase Dip coating method, irradiation method, surface chemical modification method, nuclear tracing method, power formation method, etc. Inorganic membranes are prepared by sol-gel, sintering and chemical precipitation methods. Filtration membranes are divided into four forms: Microfiltration (MF), Ultrafiltration (UF), Nanofiltration (NF) and Reverse Osmosis (RO) based on the size of the microporous pores.
Microfiltration also uses the sieving mechanism of microfiltration membranes to retain particles between 0.1-1 μm in diameter, such as suspended matter, bacteria, some viruses and large size colloids, under pressure-driven conditions, and is mostly used in water pre-treatment systems.
The membrane used in microfiltration is a microporous membrane with an average pore size of 0.02-10, capable of retaining particles with a diameter of 0.05-10 or macromolecules with a molecular weight of more than 1 million, with an operating differential pressure of 0.01-0.2 MPa. The particles larger than the membrane pores are retained, thus achieving the separation of the particles from the solvent in the raw material. The mechanism of particle retention in the microfiltration process is sieving, and it is the physical structure of the membrane, the shape and size of the pores, that determines the separation effect.
1. Separation efficiency is the most important performance characteristic of microporous membranes, which is controlled by the pore size and pore size distribution of the membrane. As the microporous membrane can achieve a more uniform pore size, so the microfiltration membrane has a higher filtration precision and higher reliability.
2. High surface porosity, generally up to 70%, at least 40 times faster than the same retention capacity of filter paper.
3. The thickness of the microfiltration membrane is small, and the loss caused by the adsorption of the liquid by the filter medium is very small.
4. The polymeric microfiltration membrane is a homogeneous continuum, with no media shedding during filtration and no secondary contamination, resulting in a high purity filtrate.
1. Filtration and de-bacterisation in the pharmaceutical industry.
2. Applications in the food industry (clarification of gelatine, clarification of glucose, clarification of fruit juice, clarification of white wine, recycling of beer dregs, decontamination of white beer, milk degreasing, production of drinking water, etc.).
3. Applications in the paint industry.
4. Applications in the biotechnology industry.
5. Pre-treatment of reverse osmosis and nanofiltration processes.
6. Removal of algae and particulate impurities from surface water in reservoirs, lakes, rivers, etc.
7. Filtration membrane components for household water dispensers.
8. PP, PTFE and other microfiltration membrane also has the function of filtering acidic or alkaline water, and its use PH range is 1-14.
