Sustainable Removal of Chloroquine from Aqueous Solutions Using Microwave-Activated Cassava Biochar Derived from Agricultural Waste
Janaína Oliveira Gonçalves, Bruna Silva de Farias, Estéfani Cardillo Rios, Anelise Christ-Ribeiro, Kamila da Rosa Acosta, Carla Pereira Wenderroschs Gomes, Tito Roberto Sant’Anna Cadaval
Abstract
This study presents a sustainable solution for the removal of the emerging contaminant chloroquine from aqueous solutions, utilizing biochar synthesized from cassava waste through a rapid, single-step microwave activation process. By repurposing cassava waste, a prevalent agricultural by-product, this method aligns with circular economy principles, promoting the sustainable reuse of waste materials. Characterization of the biochar demonstrated a highly porous, crystalline structure optimized for adsorption applications. Adsorption studies demonstrated optimal performance at 45 °C, with a maximum adsorption capacity of 39 mg g−1 in the Langmuir model. Thermodynamic analysis confirmed that the process was spontaneous, endothermic, and consistent with physisorption. Kinetic experiments revealed that 200 rpm agitation provided the most favorable conditions. Notably, the biochar demonstrated substantial reusability, maintaining up to 70% of its adsorption capacity over five desorption cycles. This sustainable adsorbent stands out as a practical, eco-friendly option for removing pharmaceutical contaminants while also corroborating with the beneficial reuse of agricultural by-products.