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The classification of membranes and their applications: Inorganic membranes: The most widely used type is ceramic membranes, which possess advantages such as stable properties, ease of cleaning, ease of disinfection, and resistance to acid and alkali corrosion. It is gaining increasing favor among a wide range of customers. In the application of clarification and sterilization in alcoholic beverages, ceramic membrane technology is highly mature. In addition, ceramic membranes are also widely used in the pharmaceutical industry, mainly for the clarification and filtration of fermentation broths. The excellent oil resistance of ceramic membranes gives them a significant advantage in the wastewater treatment process of the petrochemical industry. Organic membranes: Based on the molecular weight range they can retain, organic membranes can be classified into microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO). 1) Microfiltration: Usually measured by the size of the retained particles. Microfiltration is primarily used to remove larger suspended particles from liquids, and it is commonly employed as a pre-treatment step for ultrafiltration (UF), nanofiltration (NF), or reverse osmosis (RO). 2) Ultrafiltration: Usually measured by the molecular weight of the retentate. It is mainly used to remove small particulate suspended matter and dissolved polymers from liquids. Based on their membrane structure, they can be further divided into three types: spiral-wound, tubular, and hollow fiber membranes. Roll-type membranes generally have a large area but take up little space, and are widely used in the field of concentration and separation of liquid materials, such as the concentration and separation of proteins ； Tubular membranes are generally used in applications where the liquid contains a high amount of particulate solids or has a high viscosity; they feature easy cleaning and relatively low requirements for pretreatment ； Hollow fiber membranes have the advantage of large area and small volume compared to the first two types. The unique structure of hollow fiber membranes also determines their main areas of application. It is mainly used for treating liquids with low viscosity, and is generally not used for concentrating such liquids. Common applications include removing heat sources from pure water, as well as clarifying and sterilizing alcoholic beverages. 3) Nanofiltration: Nanofiltration membranes are primarily used in water treatment to remove pigments, viruses, organic substances, and certain inorganic ions from water. It is widely used in the pharmaceutical industry for the concentration and separation of materials, such as the concentration of amino acids, the removal of pigments, the desalination of dyes, and the concentration and separation of proteins. 4) Reverse osmosis: It is commonly used to produce high-purity water, with typical application areas including the electronics industry, boiler feedwater in thermal power plants, and water for injection in the pharmaceutical industry. Reverse osmosis membranes can remove almost all organic substances and inorganic ions from liquids. It is also commonly used in the field of material concentration. Applications of special membranes: Conventional organic separation membranes are not resistant to organic solvents or strong acids and bases. Therefore, organic membranes used in strong acids and bases or in organic solvent media require membranes made of special materials. Industries such as the recovery of organic solvents and acids and bases all require such membranes for processing. For example, in the printing and dyeing industry, there is alkali recovery from mercerization wastewater, as well as acid and alkali recovery from wastewater generated during the regeneration of ion exchange resins. Currently, this type of membrane is already in use abroad, but it is not yet widespread in China. Advantages of membrane technology applications: no phase change, low energy consumption, small footprint, easy operation, and high efficiency.