The BIO4Africa partners are conducting a wide range of research studies. The objective is to investigate the nutritional potential and functional properties of agricultural waste products and the optimal setup and processing steps for bio-based technologies in local contexts. These findings are then used to optimise the pilot trials at our test sites.

Here you can find an overview of the studies that have been published in international journals to date. Click on the images to view the literature.

Omar M. Abdeldayem, Capucine Dupont, David Ferras, Lat Grand Ndiaye, Maria Kennedy. Journal of Analytical and Applied Pyrolysis. Volume 179, 2024. 106459, ISSN 0165-2370.
https://doi.org/10.1016/j.jaap.2024.106459.

Abstract

Although industrial hydrothermal carbonization (HTC) uses wet feedstock, lab-scale studies tend to dry the feedstock under the assumption that the rehydration of the feedstock would restore its original properties. To the best of our knowledge, this assumption has not been thoroughly examined at the lab scale; therefore, its investigation is crucial to prevent any discrepancies that might affect the upscaling of HTC. This research aims to examine the effects of pre-drying biomass by comparing it to the use of wet biomass in HTC experiments, employing three different types of biomass (rejected tomatoes, rejected apples, and digestate). Additionally, the study investigates the influence of stirring on pre-dried and wet biomass under the selected HTC conditions. The results indicate a substantial disparity in studied hydrochar properties when using pre-dried biomass compared to wet biomass. For pre-dried biomass, there is a tendency for an increase in mass yield and solid carbon yield in most examined samples (5–10% dry basis) compared to the wet biomass. Regarding functional groups, wet tomatoes and apples exhibit more pronounced peaks than pre-dried samples. Conversely, digestate shows similar spectra across all examined scenarios. The effect of stirring appears insignificant for most of the studied scenarios; nevertheless, it reduced dehydration and decarboxylation reactions during HTC. 

Philippe Bernard Himbane and Lat Grand Ndiaye. Activation kinetics of biochars from peanut shells, cashew nut shells, and millet stalks under isothermal conditions in CO2 atmosphere. South African Journal of Chemical Engineering. Vol. 49, 2024. Pages 249-257 ISSN 1026-9185. https://doi.org/10.1016/j.sajce.2024.06.004.

Abstract

This study investigates the reactivity kinetics of biochar from biomass. The biochars were obtained by pyrolysing peanut shells, cashew nut shells and millet stalks at 800°C in a fixed bed reactor. The chemical composition of the biochar samples shows that silicon, potassium and magnesium are the major elements in the biochar of peanut shells, while potassium and magnesium are the major elements in the biochar of cashew nut shells and millet stalks. The biochars were activated in a CO2 (200 Nml/min) atmosphere at temperatures 1123 K, 1173 K, and 1223 K under atmospheric pressure. The random pore model (RPM) and a modified random pore model (MRPM) were used to correlate the reactivity profiles versus carbon conversion and to determine the kinetic parameters. It was observed that biochar reactivity increases as the temperature increases, attaining at least three times at 1173 K than those corresponding to 1123 K. Furthermore, the increase in reactivity is more pronounced with millet stalk biochar. It was observed that the RPM model cannot follow the kinetic of the experimental reactivity of all biochar samples. However, a better fitting of the reactivity is obtained using the MRPM model. The activation energies (Ea) are distributed in the range of 98.11–148.46 kJ/mol while the pre-exponential factors (k0) are in the range of 19.31–249.53 s-1. It was observed that, for the MRPM model, the lower activation energy and lower pre-exponential factor were obtained by the cashew nut shell biochar. However, Ea and k0 are well evaluated for peanut shell and millet stalk biochar with a coefficient of determination of 99.76%. The proposed modified random pore model could be used to describe the reactivity of biochar from biomass as well as the reactivity of coal.

Mohammed S, Fatumah N, Abasi K et al. Co-designing sustainable biochar business models with sub-Saharan African communities for inclusive socio-economic transformation. Sci Rep 14, 15802 (2024). https://doi.org/10.1038/s41598-024-66120-y

Abstract

Smallholder farmers in sub-Saharan Africa (SSA) encounter multiple livelihood challenges. Embracing circular bioeconomy principles, particularly considering agricultural and food processing residues, could enable inclusive, locally led, sustainable development pathways within rural communities. Biochar products are one such example of a bio-based material that can be generated using circular principles and deployed for sustainable community development, including among smallholder farmers. This research leverages empirical evidence from four SSA regions to explore the potential of inclusive and sustainable biochar business models, namely: (i) Northern Region, Ghana, (ii) Yamoussoukro, Côte d’Ivoire, (iii) Casamance, Senegal, and (iv) Western Region, Uganda. Co-creation workshops using the Triple-Layered Business Model Canvas framework were carried out in each region with local stakeholders to evaluate the social, ecological, and economic implications of four locally relevant biochar applications: water filtration, biogas purification, soil amendment, and cooking fuel briquettes. Data was analysed at an aggregate level for all regions and applications. The study describes this consolidated biochar business model and examines the implications for SSA communities. The resulting sustainable bio-based business model can guide value chain actors and policymakers in SSA communities towards rural sustainable development with a better understanding of the needs, opportunities, challenges, and impacts of biochar-based value chain development.