Details of activated carbon

Activated carbon is a porous material, which is formed by partial oxidation and erosion of carbon particles. It has a large surface area and strong adsorption capacity. It is often used to adsorb organic matter in gas or liquid.
Activated carbon mainly has three shapes: granules, powders, and fibers
Activated carbon filter elements have four molding methods: winding, sintering, extrusion, boxed, and other variants
Theoretically, the specific surface area: fiber activated carbon> powdered activated carbon> granular activated carbon
The molding method of the filter element has a great influence on the adsorption capacity: activated carbon fiber and powdered activated carbon have a small stacking density, and can only hold far less activated carbon than granular activated carbon in the same space, so it cannot be simply assumed that the effect of a large specific surface area is necessarily good. In theory, the effect of sintered filter elements is better than extrusion, because the high temperature during the sintering process will gradually carbonize the resin binder without blocking the surface of the activated carbon, but in fact, the domestic sintered activated carbon does not reach the corresponding temperature, and the effect is no different from extrusion. Adsorption activated carbon filter element and winding activated carbon filter element, adding organic adhesive in the pulping process, is likely to consume part of the micropores of activated carbon, and its adhesive may not meet the food hygiene standards, from this point of view, it is not as good as sintering and extrusion.
A good activated carbon filter element should be able to penetrate quickly when water drips on its surface. When it is placed in water, a large number of bubbles are released on the surface due to the replacement of the liquid. For household water purifiers, non-food grade adhesives are not used. It seems that the most ideal is the boxed granular carbon filter element, but in fact, because of the short water flow time, the adsorption speed of granular activated carbon is not as good as ideal, and it may not have a good effect. This is why activated carbon is often used in multiple stages in series, which is nothing more than increasing its contact time with water. Based on the above principles, the so-called simple activated carbon masks on the market are very thin and have a low content of activated carbon, and their effects can be imagined.
A good way to use activated carbon is to prepare it into a small box that can be placed in a cup or kettle. After about 10 minutes of adsorption, the effect can be well reflected. . If it is powdered carbon, of course the finer the particle size, the better, because simply looking at it, the larger the surface area, the stronger the adsorption capacity, and the faster the adsorption speed, because according to the analysis of the activated carbon adsorption time period, the key adsorption time is the time for impurities to move from the surface of the activated carbon to the inside, that is, the puncture time, of course, the smaller the particle size, the better. What is required here is the uniformity of the activated carbon, that is, the more uniform the particle size of the activated carbon, the better. Moreover, the filtration of activated carbon mainly relies on itself to filter (filter cake), and no matter how good the activated carbon is, it is inevitable that broken carbon will appear during use.
For physical adsorption, adsorption capacity and adsorption speed are two different things. Low temperature is conducive to adsorption capacity, and high temperature is conducive to adsorption speed. The principle of simple thermal motion, the design to the adsorption efficiency of the specific process, or the user himself to choose.