Laser particle size analyzer application in particle size measurement of activated carbon
1, Activated carbon and its application
Activated carbon, also known as active carbon black. Amorphous carbon black powder or granular. Activated carbon main components in addition to carbon and oxygen, hydrogen and other elements. Activated carbon has developed pore structure, specific surface area, adsorption of carbonaceous material selective adsorption ability. Under certain conditions, the liquid or gas of a certain or certain substances for adsorption removal, purification, purification or recycling, so as to achieve product purification and environmental purification (Jiang Jianchun, 2010). Today, the activated carbon has been widely used in various fields of industry, agriculture, national defense, transportation, food, medicine, environmental protection, and the use of activated carbon can be used after the failure of various methods of repeated regeneration.
Activated carbon is mainly charcoal, sawdust, various shells, coal and petroleum coke and other high carbon material as raw material, through carbonization and activation and preparation of porous adsorbent. Activated carbon adsorption is most of the physical adsorption, that is, Fan Dehua adsorption, there are chemical adsorption.
2, Development status and development prospects of activated carbon:
China activated carbon in the history of the application is simply divided into three stages: the first phase is 1940s years ago, China's pharmaceutical industry, the use of activated carbon in the chemical industry, are using imported goods. The second phase since the beginning of 1950s, domestic activated carbon market. Production and application of mutual promotion, activated carbon is rapidly expanding the scope of application. Application of activated carbon in China, not only in the domestic market development, but also into the international market. Third stage 2003- so far; activated carbon used in the decoration of pollution control, dedicated to the adsorption of formaldehyde, benzene, ammonia, radon and other harmful gases and air in the body of the floating bacteria. Currently on the market a large number of domestic activated carbon, activated carbon has been into millions of households, to become environmentally friendly health products.
Traditional activated carbon is mostly used for waste gas treatment. At present, with the high specific area of super activated carbon available, people also try to take it to the human body.
The development and application of activated carbon dust free technology has been a special concern of the industry. However, whether it is with coal as raw material, or in the shell or wood as raw material to produce the amorphous granular activated carbon, cylindrical activated carbon or activated carbon spheres are unable to completely remove the surface adhesion of dust, especially to remove dust on the surface of activated carbon in the prerequisite of attachment of the adsorption characteristics of activated the original carbon. For a long time, the market has been calling for the active carbon dust free technology has not been successfully developed. Therefore, the development of this area also has a certain prospect.
These years, the world's major production of activated carbon in the United States and Japan have focused to the regeneration technology of activated carbon development, activated carbon used once and discarded or recycled has become an important symbol of a country's level of activated carbon industry.
3, Activated carbon adsorption and mesh force
In China has become the world's largest producer and exporter of activated carbon, activated carbon detection method for product evaluation, unified testing standards, quality and international trade dispute disposal, is undoubtedly very important. Most of the current domestic evaluation of activated carbon iodine value and methylene blue value, but in engineering practice, not only need to consider the powder activated carbon adsorption surface area, but also to determine whether the pore size distribution of particles inside the activated carbon powder easy to achieve rapid adsorption, in the process of using powdered activated carbon reached the adsorption equilibrium, in addition need to consider the size of carbon powder, powdered activated carbon adsorption of the small number of small specific surface area, adsorption effect is poor, a large number of large specific surface area, adsorption effect will be better, but too much is possible through mesh filter.
Activated carbon mesh refers to the mesh density, particle size of activated carbon is used to represent the mesh. For example, granular activated carbon, granular activated carbon, granular activated carbon is used to mesh representation.
Mesh more that smaller particles, generally more than 100 mesh activated carbon particles tend to powder, but still smaller particles; mesh, while the larger particles such as activated carbon, activated carbon particles of 8 mesh -12 mesh is very big.
The number refers to the size or thickness of materials. The general is defined in the screen of 1 inches *1 inches within the area of the material through the screen, the screen hole number is defined as the number of. As of 200, that of the material through 1 inches *1 inches with 200 mesh screen. And so on, the larger the number of the mesh, material that the finer grain size; mesh size is smaller, the larger the size of that material. The granularity is particles can be obtained by screen mesh size, with 1 inches (25.4mm) the number of mesh width of the screen mesh representation, so called mesh.
In general, activated carbon per unit volume mesh more air contact area is the largest, adsorption is better. This is a limit, such as bamboo charcoal. Big hole, small number, small contact area. Coconut shell activated carbon, mesh, large contact area, good effect. Coal is refined into the activated carbon can only be used for industrial use. Take 5-10 and 10-24 to the same carbon water purification, the same weight, 10-24 activated carbon contact area, good purifying effect, but his slow velocity, net less water, if installed in the water purification equipment, small particles with small equipment, large particles with large equipment.
Activated carbon mesh can be directly converted by the conversion table size, which can understand the activated carbon particle size. In the national standard of activated carbon, it is clear that the size distribution and the effective particle size range, so it can be seen that the particle size of the activated carbon is one of the testing standards.
4, activated carbon particle size detection
Measurement of particle size many, in recent years, laser particle size most commonly used laboratory detection because of its high testing speed, good repeatability, wide measuring range and other notable features become popular in the world of particle testing instrument. Activated carbon under the microscope to observe a long strip, and a larger particle size, the sample is not easy to reunite. With the extension of ultrasonic time, the particle size becomes smaller, the sample is easy to be broken, it is not easy to ultrasonic for long time, and the data can be saved in one minute. After several tests, the test results are stable. Test reports are as follows:

