Active carbon from apricot pits.

Active carbons are produced from fossil coals or organic materials rich in carbon, e.g. polymers or different parts of plants. The latter can be a byproduct of the timber industry (e. g. sawdust) or different agricultural by-products, such as straw, seeds or fruit stones. Throughout the world agricultural by-products are used as raw materials in active carbon production (1,2). Especially the use of many kinds of fruit stones have been studied intensively (3-5). Our institute has studied since 1982 the properties of active carbon prepared from the stone of apricot (Armeniaca vulgaris), for Hungary produced large quantities of apricot in the past (6). The kernel of the fruits processed by the canning industry was utilized in the confectionery industry, therefore the shell was available in clean form. The shell of the apricot pit is an ideal raw material for active carbon. The active carbon prepared from this raw material shows a high carbon and low ash content and has a high mechanical strength. The raw material can be milled to optional particle size, therefore, no graining process is needed during the technology. The shell is pyrolyzed and then activated, which results at a burn-off value of ca 50 % a microporous product with high specific surface area. An optimal micro/mesopore ratio can be achieved by setting the activation parameters according to the application.