The production of granular activated carbon from agricultural waste products

[摘要] ENGLISH ABSTRACT:Peach and apricot shells are agricultural waste products. These waste productsaccumulate around canneries and food-processing plants in South Africa. No effort isbeing made to utilise these waste products. This study is the first part of the productdevelopment from these products i.e. peach shell activated carbon and apricot shellactivated carbon. By producing activated carbon from peach and apricot shells thesolid waste problem is addressed, but most of all a profit can be made.But why activated carbon? Activated carbons are unique and versatile adsorbent witha vast amount of adsorption applications. It can be produced via a simple oxidationreaction with steam and the nature of peach and apricot shells are such that it isexpected that activated carbons with good adsorption properties can be produced fromit. The single largest consumer of activated carbon in South Africa is the gold miningindustry that uses imported coconut shell activated carbon for gold adsorption in thegold recovery process. Activated carbon is also used as water purification adsorbents.During this study activated carbons were produced in a fluidized bed reactor atvarious activation conditions: 700 - 900°C, 0.0425 - 0.0629 g steamlg char.min and30 - 60 min. This was done in order to find the optimum activation conditions withinthe activation parameter range. The optimal activated carbons were defined as peachand apricot shell activated carbons that showed good microporous as well asmesoporous character. The optimal activated carbons produced are: peach shellactivated at 875°C, 0.0533 g stearnlg char. min, 60 min and apricot shell activatedcarbon at 850°C, 0.0533 g steamlg char.min, 60min.The possible use of these optimal activated carbons and two other activated carbonsproduced (Peach shell activated carbon 900°C, 0.0425 g steamlg char. min, 60 minand apricot shell activated carbon 900°C, 0.0425 g steamlg char.min, 60min) weretested in gold recovery and water purification. The gold adsorption properties ofpeach and apricot shell activated carbons were found to be better than twocommercial coconut shell activated carbons (Chemquest 650 and GRC 22). Nodefinite conclusions could, however, be drawn about the replacement of coconut shell activated carbon with peach or apricot shell activated carbon, because abrasion testwork and thermal regeneration of the experimental carbons still have to be performed.The experimental activated carbons displayed good phenol adsorption characteristic,although further test work is required.

[发布机构] Stellenbosch University