Ceramic materials incorporating spent biosorbent biomass

Abstract

Biosorption is a sustainable alternative for the removal of heavy metals from aqueous effluents through the use of agro-industrial wastes as adsorbent materials. However, the final disposal of spent biosorbents represents a limitation for their practical application, particularly when metal recovery is not economically feasible. In this context, the incorporation of contaminated biomass into ceramic matrices emerges as a valorization strategy that enables both waste management and pollutant immobilization.
This work evaluates the manufacture of ceramic bricks incorporating peanut shells previously used as biosorbents for Cu(II), Zn(II) and Ni(II). Contaminated biomasses were incorporated at 10 vol.% into clay matrices, producing formulations with uncontaminated biomass and biomass containing each of the evaluated metals. The samples were uniaxially pressed and sintered at 1000°C. The obtained materials were characterized through physical, mechanical, and environmental tests.
The incorporation of biomass increased the porosity and water absorption of the bricks while maintaining suitable mechanical properties. Leaching tests showed reductions higher than 98% in metal release compared with the original biomass, demonstrating the high efficiency of the thermal process in immobilizing the contaminants. Additionally, ecotoxicological assays revealed a significant reduction in contaminant bioavailability after incorporation into the ceramic matrix.
The results demonstrate that the production of ceramic materials containing spent biosorbents is a viable alternative for agro-industrial waste valorization and the safe management of contaminated biomass.