ACTIVATED CARBON FROM WASTE MATERIALS

Abstract

Waste materials of various origin, such as domestic waste, agricultural by-product (grain husk), tyre rubber, and the light fraction of shredded interiors of cars ('autoshredder light') were converted into final products of active carbon properties by pyrolysis and subsequent steam activation of the waste. Products were tested using the standard measurements for adsorption of iodine and methylene blue. The porous structure was characterized by small angle X-ray scattering, low-temperature nitrogen adsorption measurements and mercury porosimetry. The extent of gasification (burn-off) on activation, the adsorption characteristics, and the pore-size distribution were found to reflect the composition and the fine structure of the waste used as raw material. High surface area microporous active carbon was obtained from agricultural wastes. The burn-off of the pyrolyzed rubber consisting mainly of chemically resistant carbon black was relatively small and activation resulted in essentially meso- and macroporous carbon. Organics in the domestic waste and in the 'autoshredder light' were converted into high surface area active carbon, however, the mass related adsorption capacity of the products was small due to the high fraction of inert inorganic components in the preparations.