| Popis: |
The objective of this study is to determine the surface functions and the pH at the point of zero charges (pHPCN) of powdered activated carbons (PAC) produced from two biomasses (nucleus shell ofBalanites aegyptiacaand nucleus shell ofZizyphus mauritiana) with a particle size between 60 and 80 µm. The methodology is based on immediate analyzes of the biomasses (ash rate, humidity rate, volatile matter rate and the actual density), the chemical activation of the biomasses by H3PO4and KOH activating agents at concentrations of (5%, 15%, 25%) and (10%, 15%, 20%) respectively, followed by pyrolysis at 400 °C and 600 °C for 2 hours. The CAPs obtained were characterized for their surface chemistry, by Boehm titration and pHPCNmeasurements and for their quantity, by yield calculation. The characterized PACs were compared to a commercial activated carbon. These analyzes reveal that the best PACs were obtained using a concentration of 25% H3PO4 and 10% KOH with a pyrolysis temperature of 400 °C. The surface functions of the PACs produced are acidic with a total absence of basic functions and exceed those of commercial activated carbon (CAC). The pHPCNsof PACs resulting from acid activation are acidic and those resulting from basic activation are neutral and basic. Thus, the pHPCNof the CAC is closer to the pHPCNof the PACs resulting from the impregnation with KOH. These biomasses are potentially promising for the production of PACs. |
