Sustainable carbon materials from biowaste for the removal of organophosphorus pesticides, dyes, and antibiotics

Abstract

This study investigates the potential of spent coffee grounds (SCG) as a precursor for functional carbon materials to remediate diverse pollutants. SCG, a globally abundant biowaste, offers a sustainable resource for addressing environmental challenges while reducing waste. Carbonized at 900 °C and activated using KOH, H₃PO₄, and CO₂, SCG biochars were analyzed for their ability to adsorb organophosphorus pesticides (malathion, chlorpyrifos), organic dyes (methylene blue, rhodamine B), and antibiotics (amoxicillin, ceftriaxone). These pollutants were selected due to their persistence and risks to ecosystems and health. KOH activation significantly enhanced adsorption of dyes and antibiotics by increasing porosity and surface functionality. Langmuir isotherm-derived adsorption capacities at 25 °C showed SCG biochar activated with KOH and CO₂ had the highest efficiency: 17.3 mg g⁻¹ for malathion, 25.6 mg g⁻¹ for chlorpyrifos, 9.7 mg g⁻¹ for methylene blue, 130 mg g⁻¹ for rhodamine B, 9.9 mg g⁻¹ for amoxicillin, and 14.2 mg g⁻¹ for ceftriaxone. The results of this study highlight the potential of SCG valorization to contribute to sustainable environmental management, offering affordable and environmentally friendly strategies to mitigate water pollution.