What is activated carbon .Activated carbon is a generic term for.pptx

Activated carbon is a generic term for a family of highly porous carbonaceous materials, none of which can be characterized by a structural formula or by chemical analysis)

1. Activated carbon is a generic term for a family of highly porous carbonaceous materials, none of which can be characterized by a structural formula or by chemical analysis ). The volume of the pores in activated carbons is generally defined as being greater than 0,2 m/g , and the internal surface area is generally larger than 400 m 2 / g as measured by the nitrogen BET method. The width of the pores varies from 3Å several thousand angstroms, and the pores are generally classified for convenience in terms of their diameters : What is activated carbon ?

2. Preparation of activated carbon Activated carbon can be produced from a wide variety of carbonaceous raw materials like nutshells, peat, wood, coir, lignite, coal and petroleum pitch. The choice of raw material has a large influence on the characteristics and performance of the AC, each producing an AC with differing surface areas, total pore volume, pore radius and pore volume distribution. .

3. Carbon Type Total Pore Volume (ml/g) Mean Pore Radius (Angstroms) Surface Area ( m 2 /g) Coconut Shell 0.5 – 0.6 10 – 11 1000-1100 Peat 0.6 – 0.7 11 – 12 1000-1275 Bituminous Coal 0.6 – 0.7 12 – 14 1000-1150 Bituminous Coal 0.7 – 0.8 14 – 16 900-1050 Lignite Coal 0.9 – 1.0 29 – 32 900-1050 Peat 1.1 – 1.2 23 – 26 600-675 Wood 1.4 – 1.8 22 - 26 1200-1600

4. Structure The basic structural unit of activated carbon is closely approximated by the structure of pure graphite. The graphite crystal is composed of layers of fused hexagons held by weak van de Waals forces. The layers are held by carbon–carbon bonds. Activated carbon is a disorganised form of graphite, due to impurities and the method of preparation (activation process).

5. The chemistry of the surface depends on the presence of heteroatoms , mainly oxygen , which form organic functional groups such as carboxylic acids , lactones, phenols , carbonyls , quinones, aldehydes , ethers , anhydrides and even others (Boehm, 1994)

6. Activated carbon is manufactured through two different processes: Physical activation: It is a process by which the carbonised product develops porous structure of molecular dimensions and extended surface area on heat treatment in the temperature range of 800–1000 °C in presence of suitable oxidising gases such as steam, CO2, air. Gasification of the carbonised material with steam and carbon dioxide occurs by the following endothermic reactions :

7. 2) Chemical activation : Chemical activation is another process for the production of activated carbon from tyres . It allows both pyrolysis and activation to be integrated into a single, relatively lower temperature process in the absence of oxygen. Chemical agents such as phosphoric acid, zinc chloride and potassium hydroxide act as dehydrating and stabilizing agents that enhance the development of porous structure in the activated carbon .

8. The activation process creates or increases porosity on the activated carbon surface

9. A PPLICATIONS Activated carbon is utilized by a number of industries for its purification properties. Water Treatment : The biggest application of activated carbon is in the purification of water and potable water treatment. It is used in a variety of water treatment industries, from municipal water supply treatment, wastewater treatment, swimming pools, aquariums and even home filtration systems. Air Purification : Activated carbon is used to control potentially harmful, environmentally damaging or unpleasant odors in a number of environments, including homes, manufacturing facilities and in operating rooms. Food & Beverage : The Food & Beverage industry uses activation as part of various processes, such as the decolorization of sugar, purify organic compounds, chlorine removal, decaffeination and many other practices.

10. Industrial : Activated carbon is used as a catalyst for many industrial applications, gas processing, gas storage and delivery, gold recovery, pharmaceutical purification and many other practices. Medical : Activated carbon can be found in almost every hospital, clinic or doctor’s office in the world. It is used to as a poison treatment, odor control, filtration, respiration masks and wound dressing just to name a few applications. APPLICATIONS

11. The activated carbon which has adsorbent function with micro pore is useful for world environment preservation. The main applications are to help create pleasant environment for living, through improving the water quality, deodorizing, removing soil contaminant and dioxin.

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