Alkali activation and carbonization synergy: Unlocking the potential of Auricularia auricula biochar for efficient naproxen adsorption

To effectively eliminate the widely detected naproxen (NPX) pollutant in the aqueous environment, it is essential to explore eco-friendly materials. Recently, biochar as an adsorbent material attracted considerable attention, owing to its unique ability to remove organic pollutants from water. Herein, Auricularia auricula biochar (a-BC-800) was fabricated through alkali treatment of Auricularia auricula biomass for activation, followed by carbonization at 800°C. Characterization via scanning electron microscopy and Brunauer-Emmett-Teller revealed that a-BC-800 possesses a very high specific surface area (SSA) of 1660 m²/g and a complex mesoporous structure properties. The combination of alkali activation and high-temperature carbonization was crucial for enhancing the SSA of the biochar. a-BC-800 exhibited a maximum adsorption capacity of approximately 300 mg/g, outperforming most NPX adsorbent materials reported in the literature. The NPX adsorption process closely aligns with the pseudo-second-order kinetic model and the Freundlich isotherm model. Analysis of the adsorption mechanism revealed that π-π interactions, pore filling, and van der Waals forces were the primary mechanisms responsible for the efficient adsorption of NPX by a-BC-800. This study demonstrates that the combination of high-temperature treatment and alkali activation is an effective strategy for enhancing the adsorption performance of Auricularia auricula biochar for NPX, offering significant potential for the efficient removal of environmental pollutants.