Conducted jointly by UL and UAC, this research explores the production of activated carbon from Lophira lanceolata to treat micropollutants.
The Essentials: Conducted jointly by UL and UAC, this research explores the production of activated carbon from Lophira lanceolata to treat micropollutants.
Elie Sogbochi, researcher at LERMAB (Université de Lorraine).
Thesis defended in 2023 at the doctoral school École doctorale SIMPPé - Sciences et ingénierie des molécules, des produits, des procédés, et de l'énergie (Lorraine).
This research is part of a Franco-Beninese joint supervision, ensuring both grounding in the local field context and adherence to international academic standards.
Context and Research Problem
Activated carbons derived from biomass play a major role in treating contaminated water. Their properties, such as high specific surface area and developed porosity, make them effective adsorbents for capturing various micropollutants. The search for sustainable alternatives for producing activated carbon is of growing importance, particularly in regions such as West Africa, where pollution of water resources is an alarming problem. Lophira lanceolata shells, a plant species widely available in this region, represent a potential raw material for producing activated carbon through thermochemical pathways. Using these shells not only valorizes agricultural waste but also addresses environmental challenges related to water management.
Methodology
The production of activated carbon from Lophira lanceolata shells was carried out via pyrolysis, a thermal process that decomposes biomass at high temperature in the absence of oxygen. This process was optimized by impregnating the shells with orthophosphoric acid, an agent that promotes the development of the adsorbent properties of activated carbon.
Pyrolysis conditions were carefully controlled to maximize the specific surface area and porosity of the resulting materials. Additional analyses were carried out to characterize these activated carbons, notably using spectroscopy and microscopy techniques, making it possible to understand the relationship between preparation conditions and adsorbent properties.
The effectiveness of the activated carbons was evaluated through adsorption tests on specific micropollutants, notably methylene blue, phenol, and Congo red. These substances were chosen due to their prevalence in industrial effluents and their potential toxicity to the environment and human health. Adsorption kinetics modelling was also carried out to quantify the performance of the activated carbons.
Key Findings
The results showed that activated carbons produced from Lophira lanceolata shells have favorable physical characteristics, with a high specific surface area and adequate porosity. Optimal pyrolysis and impregnation conditions made it possible to obtain materials with significant adsorption capacity for the targeted micropollutants.
Adsorption tests revealed that the activated carbons can effectively remove methylene blue, phenol, and Congo red from aqueous solutions. The observed adsorption rates exceed those obtained with commercial activated carbons, indicating that materials derived from Lophira lanceolata could constitute a viable and competitive alternative on the market.
Analysis of the results highlighted relatively short adsorption equilibrium times, suggesting rapid kinetics of interaction between the micropollutants and the activated carbons. Kinetic modelling confirmed these observations, identifying the dominant adsorption mechanisms.
Discussion and Outlook
This research on activated carbons derived from Lophira lanceolata illustrates the potential of local resources for producing water treatment materials. The proposed process offers considerable economic and environmental advantages, valorizing agricultural waste while providing sustainable solutions for water purification.
The results pave the way for further studies on optimizing production conditions and evaluating the effectiveness of activated carbons under real-world water treatment conditions. Integrating these materials into existing purification systems also deserves further exploration, as do the challenges related to their implementation at scale.
The implications of this research are numerous, ranging from improved water resource management in West Africa to the creation of economic opportunities in the biomass sector. The valorization of agro-resources through activated carbon production could also contribute to environmental sustainability by reducing dependence on synthetic materials and promoting the use of renewable resources.
Continued work could explore extending this methodology to other types of biomass, as well as evaluating the durability of activated carbons over time and under various environmental conditions. This future research will be essential to maximizing the impact of activated carbons on water quality and developing treatment strategies adapted to local needs.
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Sources and Access
Elie Sogbochi. Élaboration par voies thermochimiques de charbons actifs dérivés de coproduits de Lophira lanceolata : essais d’adsorption de micropolluants de l'eau. Sciences de l'ingénieur [physics]. Université de Lorraine; Université d'Abomey-Calavi (Bénin), 2023. Français. ⟨NNT : 2023LORR0194⟩. ⟨tel-04628680⟩