Preparation and Characterization of Activated Carbons Based on Peanut Shell (Arachis hypogaea) Green Soya Shell (Vigna radiata)

Two activated carbons were prepared based on peanut shell (CAA) and green soya shell (CAS) at 500 C during 6 h after impregnation in soda. Without impregnation in soda, two non-activated carbons were prepared in the same conditions, from peanut shell (CNAA) and green soya shell (CNAS). To compare, we characterized two commercial activated carbons. The first, CACOM 1, was bought in a drug store and the second, CACOM 2 was bought in a shop of chemical products. The ash content of all carbons was lower than 12 %, except CACOM 1 (42 %). The presence of excipients is certainly the reason of the high ash content of CACOM 1. The pH values of all carbons except CACOM 2 changed from 7.35 to 7.73. The pH value of CACOM 2 is 9.24. The determination of the specific surfaces of carbon was carried out according to the model of Langmuir with the molecule of acetic acid. The specific surfaces of CNAA, CNAS, CAA, CAS, CACOM 2 and CACOM 1 are respectively 141.47 m2/g, 194.46 m2/g, 311.15 m2/g, 433.09 m2/g, 514.32 m2/g and 1206, 30 m2/g. The specific surfaces of CAA and CAS are closer than the commercial carbon CACOM 2.