Sustainable oxygen-functionalized graphitic carbons from agro-waste: Influence of biomass source on atenolol removal

Population growth has intensified concerns regarding agro-industrial residues generation, emerging contaminants, and environmental preservation. A promising strategy to address these challenges is the valorization of agro-industrial waste into functional materials capable of removing contaminants from the environment, particularly through the development of sustainable adsorbents for water remediation. Achieving this goal requires materials with accessible porous surface features and appropriate surface functionalities to enable effective interactions with target pollutants. Given the diversity of agro-industrial residues, rational biomass selection is crucial for optimizing material performance. In this study, functionalized carbon materials were synthesized from coffee grounds, mate tea, banana peel, sugarcane peel, and sugarcane bagasse using a molten salt–assisted method, which is based on a KOH-assisted thermal treatment at 450 °C, that avoids toxic solvents during the carbonization step. The resulting materials were characterized by Raman and FTIR spectroscopies and scanning electron microscopy, and their performance was evaluated for the adsorption of atenolol, a pharmaceutical contaminant of emerging concern. The results demonstrate that the adsorption performance of biomass-derived graphitic-like materials is strongly governed by surface chemistry and morphology. Raw biomasses exhibited faster adsorption kinetics, whereas graphitic-like structures displayed higher maximum adsorption capacities. Materials derived from sugarcane bagasse and banana peel were particularly effective, with sugarcane-based adsorbents showing up to a 350% increase in maximum sorption capacity. This enhancement may be attributed to the retention or enrichment of oxygenated functional groups. These findings underscore the importance of biomass selection for the sustainable design of efficient adsorbents for water remediation. • Agro-waste converted into oxygen-functionalized graphitic carbons • Molten-salt/KOH synthesis provides a scalable route • Surface chemistry and morphology govern atenolol adsorption • Sugarcane-derived carbons showed the highest removal efficiency reaching na improvement of 350% after the KOH termal treatment • Biomass rational selection enhances adsorbent performance