Help: Formula for calculating the saturated adsorption capacity of activated carbon

This post was last edited by hesonchang214 on 2009-8-8 19:12. A water treatment method that uses activated carbon as an adsorbent to remove dissolved substances from water. Activated carbon is expensive, and when used in large quantities, it is often regenerated and reused. 　　Properties of activated carbon 　Activated carbon is produced by using carbon-containing materials such as wood chips, fruit peels, and lignite, through processes of carbonization and activation. There are two types: powdery (with particle sizes of 10–50 microns) and granular (with particle sizes of 0.4–2.4 millimeters). A common characteristic is porosity and a large specific surface area. The total surface area ranges from 500 to 1,000 m2 per gram. The main performance parameters are adsorption capacity and adsorption rate. The adsorption capacity is the amount of solute that can be adsorbed per unit weight of activated carbon when it reaches adsorption saturation, and it is related to the raw materials, manufacturing process, and regeneration methods. The greater the adsorption capacity, the less activated carbon is required. The adsorption rate refers to the amount of solute that can be adsorbed by a unit weight of activated carbon per unit of time. Due to the selectivity of adsorption, the performance parameters should be determined experimentally. Granular activated carbon must have certain mechanical strength and particle size specifications. 　　Activated carbon continuously adsorbs solutes from water until adsorption equilibrium is reached, at which point the solute concentration no longer changes. At a constant temperature, the curve that shows the relationship between the weight of solute adsorbed per unit weight of activated carbon and the concentration of solute in water at the point of adsorption equilibrium is called an adsorption isotherm. Curves are commonly expressed using the Freundlich equation: X/M = kC1/n, where X represents the amount of solute adsorbed by the activated carbon; M is the weight of the activated carbon used; and C is the concentration of the solute in water at the point of adsorption equilibrium ； k and n are constants determined experimentally. 　　Applications in water treatment Activated carbon was first used to remove odors from domestic water. Swamp water often has an earthy smell, while lake and reservoir water often has a foul odor caused by algae; treating it with activated carbon is the most effective method, and it only needs to be used when such an odor appears. Powdered activated carbon is mostly used, which is directly added to the coagulation sedimentation tank or aeration tank and removed along with the sludge, without being recycled. 　　Activated carbon can remove odor-causing substances and organic compounds from water, such as phenols, benzene, chlorine, pesticides, detergents, and trihalomethanes. In addition, it also has the ability to adsorb ions such as silver, cadmium, chromate, cyanide, antimony, arsenic, bismuth, tin, mercury, lead, and nickel. In water treatment plants, activated carbon adsorption also plays a role in improving water quality. The equipment used is a filter with granular activated carbon as the filter media; its structure and operation are similar to those of a conventional rapid filter. During operation, it must be flushed regularly to remove suspended particles from the carbon layer and prevent excessive head loss (see filtration). The activated carbon filter bed can also be a fluidized bed or a moving bed. Unlike rapid filters, the water flow is from bottom to top. The flow rate in the fluidized bed causes the carbon layer to expand, making blockage less likely. The failed carbon in the moving bed is continuously discharged from the bottom of the tank, while new carbon is continuously added from the top of the tank. 　　Activated carbon regeneration: Granular activated carbon is regenerated once its adsorption capacity is exhausted. The common method used is heating; the spent carbon is dried and then calcined in a regeneration furnace at around 850°C. Granular activated carbon loses about 5–10% of its mass with each regeneration, and its adsorption capacity decreases with each cycle. The regeneration efficiency has a significant impact on the operating costs of activated carbon filters (that is, on the water treatment expenses). 　　To extend the regeneration cycle of activated carbon, the bio-activated carbon method is being developed. Ozone is used as a modifier for organic substances, while activated carbon not only performs an adsorption function but also serves as a carrier for microorganisms, turning the filter bed into a biological bed. The raw water is first treated with ozone to convert the refractory organic substances in it into more readily degradable ones, and then it passes through an activated carbon filter. Due to the properties of activated carbon, bio-bed systems have a very strong ability to absorb organic substances from water, while the ability of microorganisms to degrade these organic substances serves to regenerate the activated carbon.

This post was last edited by li*ch1968 on 2009-10-31 at 19:09. Last month I ordered the latest anti-counterfeiting version of activated carbon in a 1200g package from Taobao, and after recent testing, everything is perfect – the performance is really good! ! ! I recommend everyone use it, after all, the lives and health of us and our families are what matter most! ! ! 　　The shop owner shipped it quickly, and the packaging was great too! ! ! It would be great if that detector could send 2 units, haha~! 　　Visit Taobao by clicking on the URL; there, you can find more detailed information: http://s.click.taobao.com/t_1?i=qvA8k4vyu8xK&p=mm_10027085_0_0&n=11. In fact, activated carbon has a wide range of applications. From enthusiastic shop owners, I learned that it can be used for: 1. Removing harmful gases (such as chemical toxins like formaldehyde) in newly renovated homes; 2. Placing it in wardrobes and bookshelves; 3. Eliminating unpleasant odors from furniture; 4. Using it in cars; 5. Placing it in refrigerators; 6. Deodorizing bathrooms; 7. Keeping it in shoe cabinets; 8. Using it for cleaning pets...