Characterization and potential applications of lignocellulosic and mineral solid wastes from industries in Minas Gerais, Brazil

The growing generation of solid waste presents an environmental challenge, but it also offers an opportunity to develop sustainable materials with high application potential. Achieving this requires a detailed characterization of industrial residues to understand their properties and guide the development of sustainable technological applications, while minimizing improper environmental disposal. This study examined three lignocellulosic residues, including charcoal mulch, and ten mineral residues from the mining and pulp-processing industries in the state of Minas Gerais, aiming to identify their potential for use in hybrid formulations and functional materials. Physicochemical characterization included Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy coupled with Energy-Dispersive Spectroscopy, and X-ray Diffraction, as well as pH and conductivity measurements of the inorganic aqueous suspensions. Primary fibers stood out due to their crystallinity (55.85%), open fibrillar structure, and high cellulose purity, indicating strong potential for microorganism immobilization and selective adsorption. Among the inorganic residues, silicates exhibited high conductivity and a neutral pH, making them suitable for conductive gels and ionic adsorbents. In contrast, inert materials such as muscovite and sand proved suitable as stabilizing or encapsulating fillers. The presence of metal oxides in samples such as iron-enriched sludge and baghouse dust suggests applicability in ion adsorption and electrocatalytic processes. Overall, the results demonstrate that investigating the composition, crystallinity, and surface reactivity of these residues enabled their classification according to their functional potential, guiding valorization pathways that convert environmental liabilities into valuable resources for biotechnology, remediation, and the circular economy.