Adsorption of ibuprofen using biomass carbon derived from one-step pyrolysis of ginkgo leaves

Recovering biomass from forestry waste can create low-cost adsorbents for purifying and treating ibuprofen (IBU)-contaminated wastewater, thereby enabling the high-value utilization of this biomass. This study utilized waste from Ginkgo biloba leaves to develop activated biochar with a porous structure that effectively removes IBU from wastewater. The process involved using KOH and urea as activators in a simple one-step carbonization method. Biochar characterization results show that prepared biochar with urea modification results in nitrogen enrichment in biochar in three forms: graphitic nitrogen, pyridine, and pyrrole, which provides additional active sites for ibuprofen adsorption. The biochar's pore volume and specific surface area achieved 0.8631 cm 3 /g and 1424.8840 m 2 /g, respectively. The adsorption performance of the biochar on IBU, cyclic stability, and adsorption kinetics were investigated, and the adsorption mechanism was elaborated by molecular dynamics (MD) kinetic calculation. Thanks to the multi-level porous structure and active sites, biochar exhibits a high removal rate (99.14 %) and large adsorption capacity (160.00 mg/g) of IBU, which remains at 92 % after five adsorption-desorption cycles, indicating good recyclability. The adsorption behavior fits the Langmuir and pseudo-second-order (PSO) models, mainly due to synergistic effects of pore filling, hydrogen bonding, electrostatic interactions, and π-π stacking. MD simulations revealed that modifying Ginkgo biloba leaf biochar with urea enhances the intermolecular forces and the interaction energy between IBU and biochar, thereby improving the adsorption capacity of biochar for IBU. Estimated preparation costs were approximately 0.0003 USD/L for treating 1 L of solution with optimal IBU concentration. This study indicates that Ginkgo biochar may serve as a promising adsorbent for IBU. • Porous structure biochar was created using waste Ginkgo leaves as raw material. • Ginkgo biochar had large pore volume and high specific surface area (1424.8840 m 2 /g). • Biochar exhibited great removal rate (99%) and adsorption capacity (160 mg/g) for IBU. • Adsorption mechanism was linked to π–π stacking, van der Waals force, and H-bonding. • MD simulations show that the van der Waals force mainly drives adsorption energy.