Determination of the surfaces functions and of the pH at the point of zero charges of powdered activated carbons produced from the shells of the nucleus of Balanites aegyptiaca and Zizyphus mauritiana
1 Department of chemistry, Faculty of Science and Technology, Abdou Moumouni University of Niamey, B.P :10662 Niamey, Niger.
2 Department of chemistry, Faculty of Science and Technology, University of Agadez, B.P: 199 Agadez, Niger.
Research Article
World Journal of Advanced Research and Reviews, 2022, 16(03), 893-904
Article DOI: 10.30574/wjarr.2022.16.3.1437
Publication history:
Received on 14 November 2022; revised on 26 December 2022; accepted on 29 December 2022
Abstract:
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 of Balanites aegyptiaca and nucleus shell of Zizyphus 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 H3PO4 and 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 pHPCN measurements 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 pHPCNs of PACs resulting from acid activation are acidic and those resulting from basic activation are neutral and basic. Thus, the pHPCN of the CAC is closer to the pHPCN of the PACs resulting from the impregnation with KOH. These biomasses are potentially promising for the production of PACs.
Keywords:
Powdered activated carbon; Balanites aegyptiaca; Zizyphus mauritiana; Surface functions; pHPCN
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