Potential applications of biochar produced with agroindustrial waste

Abstract

Biochar is a carbonaceous material obtained from the pyrolysis of lignocellulosic residues and has attracted increasing scientific interest due to its versatile physicochemical properties, such as high porosity, structural stability, and the presence of surface functional groups. This thesis investigates the potential application of biochar in three strategic areas: sustainable energy generation, the development of anodes for lithium-ion batteries, and contaminant adsorption in water treatment systems. In the energy context, the performance of biochar produced from agro-industrial residues, including açaí seed and fiber and Brazil nut shell, was evaluated in terms of its energetic properties. The results demonstrated that biochar exhibits a high fixed carbon content and energy efficiency compatible with its use as a renewable solid fuel, indicating its capacity to partially replace fossil sources and contribute to the reduction of greenhouse gas emissions and the environmental impacts associated with the use of conventional fuels. Regarding energy storage, this thesis explored the application of niobiumdoped biochar as an anode material in lithium-ion batteries. Due to its high specific surface area, porous structure, and favorable electrochemical properties, the material exhibited promising performance, with good lithium storage capacity, stability during charge–discharge cycles, and potential to improve the efficiency of more sustainable batteries, establishing itself as a viable alternative to conventional graphite-based anodes. From an environmental perspective, biochar was evaluated as an adsorbent for the removal of organic contaminants from aqueous media. The results demonstrated high efficiency in the adsorption of methylene blue dye, attributed to the combination of the material’s porosity and the presence of surface functional groups, highlighting its potential application in water purification processes and low-cost, low-impact environmental remediation. In an integrated manner, the results of this thesis indicate that biochar represents a multifunctional and strategic material capable of simultaneously contributing to renewable energy generation, the advancement of energy storage technologies, and the mitigation of environmental contamination. By promoting the valorization of agro-industrial residues, this work reinforces the principles of the bioeconomy and circular economy, highlighting the role of biochar in the development of sustainable technological solutions for contemporary environmental and energy challenges.