TABLE OF CONTENTS Activated carbon is manufactured by heating carbonaceous material, normally coal, wood or coconut shells, under controlled conditions. Initially the material is heated in the absence of air to drive off all volatile substances. It is then activated at high temperatures by further heating it to a high temperature and allowing it to react either with steam, air, and CO 2 or with phosphoric acid. This removes the volatile matter within the pores of the carbon and produces a material with an open porous structure with a high surface area per unit weight of material.
There are two broad classes of activated carbon: gas adsorbent carbon, which has predominantly micropores which allow the entry of gases but permit only limited entry of liquids; and liquid-phase carbons which have a wide distribution of pore sizes and which allow liquid to penetrate the carbon.
Activated carbon comes in two main forms for water treatment: powdered (PAC), which is a finely ground material, and granular (GAC) which comes in a range of grain sizes, typically 0.5 1.5 mm. In water treatment, activated carbon is used to remove dissolved organic chemicals, either by dosing PAC to the water or by passing the water through a bed of GAC.
The properties of activated carbon are defined by several parameters. Table 11.1 lists some of the key properties of activated carbon and summarizes their significance. [1]
| Property | Why important |
|---|---|
| Particle size | Based... |
