Application direction and field of activated carbon products
Alkali-free deodorization (refined dethiol)-refining refining device
Ethylene desalination (refined packing)-ethylene plant
Catalyst carrier (palladium, platinum, rhodium, etc.)-styrene, continuous reformer
Water purification and sewage treatment-advanced treatment of water and sewage
Power plant water quality treatment and protection-boiler device
Chemical catalysts and carriers, gas purification, solvent recovery, and decolorization and purification of oils and fats, etc.
Refining and decolorization of beverages, alcohol, MSG mother liquor and food
Gold extraction——Applicable to gold extraction process by carbon slurry method and heap leaching method
Tail liquid recovery-waste utilization and environmental protection of gold mines
Environmental protection industry
Used for sewage treatment, waste gas and harmful gas treatment, gas purification
Cigarette filter, moisture resistance of wooden floor, taste absorption, automobile gasoline evaporation pollution control, various soaking
Preparation of stain solution.
Application situation of activated carbon material in tap water supply
Activated carbon is a kind of carbon with huge specific surface and porous structure. According to the classification of its raw materials, it can be divided into coal-based activated carbon, woody charcoal, fruit shell charcoal and bone charcoal; according to its form, it can be divided into columnar carbon, crushed carbon, powdered carbon and fiber activated carbon. The main raw materials of activated carbon are organic materials rich in carbon elements, such as coal, wood, and fruit shells, which are activated to form complex pore structures with adsorption capacity. Among the pores, those with a radius greater than 20,000 nm are macropores, those between 150-20000 nm are mesopores, and those less than 150 nm are micropores. The adsorption of activated carbon mainly occurs on these voids and surfaces. A large number of molecules on the pore walls of activated carbon can generate a strong gravitational force to attract impurities in water and air into the pores.
The adsorption of activated carbon can be divided into physical adsorption and chemical adsorption. Physical adsorption mainly occurs in micropores rich in activated carbon and is used to remove impurities in water and air. The molecular diameter of these impurities must be smaller than the pore diameter of activated carbon. Different raw materials and processing techniques result in different micropore structure, specific surface area and pore size of activated carbon, which are suitable for different needs. Activated carbon not only contains carbon element, but also contains functional groups on its surface, and it reacts chemically with the adsorbed substance, so that it often occurs on the surface of activated carbon with the adsorbed substance. Impurities in the medium continue to enter the porous structure of activated carbon through physical adsorption and chemical adsorption, so that the adsorption of activated carbon is saturated and the adsorption effect is reduced. The activated carbon after adsorption saturation needs to be activated and regenerated to restore its adsorption capacity and be reused. The main indicators for evaluating the adsorption performance of activated carbon are methylene blue value, iodine value and caramel adsorption value. The larger the adsorption capacity, the better the adsorption effect.
Activated carbon can be used in air purification and water supply, wastewater treatment, used to separate or collect impurities in air and water media. Granular activated carbon and powdered carbon have the same function and can be used for water treatment. Pellet charcoal is not easy to be lost, and can be regenerated and reused. It is used in water treatment processes with light pollution and continuous operation. Powdered charcoal is not easy to recycle, and it is generally used for one time. It is used in the water treatment process with severe intermittent pollution. The activated carbon of the water treatment particles is generally developed with micropores and mesopores, and should meet three requirements: large adsorption capacity, fast adsorption speed, and good mechanical strength. In addition to the above characteristics, powder activated carbon requires that the smaller the particle size, the better the adsorption effect.
The water plants of the Beijing Water Supply Group, which uses surface water as the source of water, are equipped with a 1.5-meter-deep granular activated carbon filter, with a designed filtration rate of 9.5 meters / hour. Activated carbon filter is an advanced treatment process in water supply treatment, which can effectively remove water color, smell, smell and dissolved organic pollutants, and improve the quality of water supply. Granular activated carbon is regularly backwashed according to the quality of the raw water during use. Generally adopt the form of water flushing, backwashing once every six days, the backwashing strength needs to reach the filter expansion rate of more than 30%. The new carbon is mainly based on physical and chemical adsorption. After a certain period of time, a biofilm is formed on the surface of the carbon, and then it is mainly biodegradable. When the index for evaluating the adsorption effect of activated carbon drops below the relevant standard, or a certain pollutant index penetrates the carbon bed, it must be replaced or regenerated. The new charcoal needs to be soaked for 24-48 hours, and then backwashed to remove impurities such as tar and charcoal in the remaining activated carbon. The number of backwashing and the turbidity of the drainage can be determined according to the purpose of the treated water. The backwashing turbidity of the activated carbon for water treatment can generally be controlled at 2-5NTU.
Powder activated carbon has a good application in the treatment of sudden smell and industrial pollutants in water. During the period from September to November 2005, due to the high content of odors in Miyun Reservoir, Beijing Water Supply Group Ninth Water Plant adopted the technology of adding powdered carbon to the water pipeline to effectively remove the odor. During the period when Songhua River was contaminated by nitrobenzene and benzene, during the period when the polluted water flowed through Harbin from November 26 to 30, under the guidance of the expert group of the Ministry of Construction, Harbin Water Supply and Drainage Group used the technology of the ninth water plant to treat the water in time Nitrobenzene meets water quality requirements.
When using powdered carbon, an adsorption test must be carried out according to the type and concentration of contaminants to be removed to determine the type of activated carbon and the amount of powdered carbon required. Before adding powdered carbon, it should be noted that the carbon powder is first made into a carbon slurry and added to the water in a uniform amount. The longer the contact time, the better the decontamination effect. In the process of using powdered carbon, the following safety issues should also be noted; when the dust concentration reaches a certain percentage, it is easy to explode when exposed to open flames. Therefore, smoking, sparks and open flames are prohibited in the operating room; mixing with oxidants should be avoided; Light, should pay attention to dust pollution when using, the operator must be equipped with dust masks to avoid inhalation into the lungs.