【Daily Question】Chemical Engineering Principles 106: Filtration Media (July 11)

1. Filter medium: It is a porous material. 2. Requirements for the filtering medium: porosity and low resistance. It has a certain degree of mechanical strength. It has a certain degree of chemical stability.

A porous material used to trap solid particles contained in fluids. Porous, low in resistance, with certain mechanical strength and chemical stability.

What is a filtering medium? What are the requirements for the filtration medium? Various porous materials used during operation to intercept solid particles contained in the fluid and to support the filter cake. Commonly used filtering media in industry include: ① Woven materials, such as filter cloths and filters made by weaving natural or synthetic fibers, metal wires, etc., which are the most widely used filtering media in industrial production. Such materials are inexpensive, easy to clean and replace, and can retain particles with a minimum size of 5–65 μm. Single-filament filters made from fibers such as polyamide, polyester, or polypropylene, which feature uniform texture, corrosion resistance, and fatigue resistance, are gradually replacing other types of fabric filters. ②Porous solids, including plain porcelain, sintered metals or glass, or porous plastic pipes made by bonding plastic powder, etc. The minimum particle size that such materials can retain is 1–3 μm, and they are commonly used to treat suspensions containing a small amount of fine particles. ③Packed media, such as granular materials like sand, gravel, charcoal, and diatomite, or layers of unwoven fibers such as glass wool. It is generally used to treat suspensions with a very low solid content, such as municipal water supply and sugar solutions to be purified. In addition, industrial filter paper can also be used in combination with the aforementioned filtering media to capture small amounts of fine particles in the suspension. In recent years, the production and application of polymer porous membranes have seen significant progress, with them being used for filtering even smaller particles in order to obtain highly clarified liquids. Membranes suitable for filtering particles ranging from 0.1 to 1 μm are called microporous filter membranes ； Membranes suitable for filtering particles ranging from 0.01 to 0.1 μm are called ultrafiltration membranes

Answer: A filtering medium is a porous material that can retain solid particles or liquid droplets using the working medium, thereby achieving separation or purification. Requirements: porosity, low resistance ； It has a certain degree of mechanical strength ； It has a certain degree of chemical stability.

A porous material that allows the working medium to pass through while trapping solid particles or liquid droplets therein to achieve separation and purification is called a filtering medium. The filtration medium is required to have the ability to capture solid particles, as well as good permeability, chemical stability, material properties, and mechanical properties; it is also preferable if it has the capability for slag removal and cleaning/regeneration.

Filter medium: A porous material that allows the working medium to pass through while retaining solid particles or liquid droplets within it, thereby achieving separation or purification purposes, is called a filter medium. Requirements include porosity, low resistance, certain mechanical strength, and certain chemical stability.

Filter medium: A porous substance. Requirements: porosity, low resistance ； It has a certain degree of mechanical strength ； It has a certain degree of chemical stability.

What is a filtering medium? What are the requirements for the filtration medium? Filter medium: A porous substance. Requirements: porosity, low resistance, certain mechanical strength, and certain chemical stability.

Filter medium: A porous substance. Requirements: porosity, low resistance ； It has a certain degree of mechanical strength ； It has a certain degree of chemical stability.

Various porous materials used during operation to intercept solid particles contained in the fluid and to support the filter cake. Commonly used filtering media in industry include: ① Woven materials, such as filter cloths and filters made by weaving natural or synthetic fibers, metal wires, etc., which are the most widely used filtering media in industrial production. Such materials are inexpensive, easy to clean and replace, and can retain particles with a minimum size of 5–65 μm. Single-filament filters made from fibers such as polyamide, polyester, or polypropylene, which feature uniform texture, corrosion resistance, and fatigue resistance, are gradually replacing other types of fabric filters. ②Porous solids, including plain porcelain, sintered metals or glass, or porous plastic pipes made by bonding plastic powder, etc. The minimum particle size that such materials can retain is 1–3 μm, and they are commonly used to treat suspensions containing a small amount of fine particles. ③Packed media, such as granular materials like sand, gravel, charcoal, and diatomite, or layers of unwoven fibers such as glass wool. It is generally used to treat suspensions with a very low solid content, such as municipal water supply and sugar solutions to be purified. In addition, industrial filter paper can also be used in combination with the aforementioned filtering media to capture small amounts of fine particles in the suspension. In recent years, the production and application of polymer porous membranes have seen significant progress, with them being used for filtering even smaller particles in order to obtain highly clarified liquids. Membranes suitable for filtering particles ranging from 0.1 to 1 μm are called microporous filter membranes ； Membranes suitable for filtering particles ranging from 0.01 to 0.1 μm are called ultrafiltration membranes