Effective removal of the anticancer drug 5-fluorouracil from water using a sustainable tannin-derived carbon

The antineoplastic drug 5-fluorouracil (5-FU) is widely prescribed for the treatment of gastric, colorectal, and breast cancers but is increasingly detected in aquatic environments due to insufficient removal in conventional wastewater treatment and improper disposal. Its persistence and toxicity raise serious environmental concerns. This study evaluates the adsorption performance of a sustainable micro-mesoporous carbon (TMC) synthesized from tannin via a mechanochemical mesostructuration process. Despite a lower specific surface area compared to commercial activated carbons (CACs), TMC exhibited superior adsorption capacity for 5-FU (q = 0.56 mmol g^-1) at reduced adsorbent dosages. Thermodynamic analyses indicated that the process is spontaneous, endothermic, and enthalpy-driven, with adsorption strongly governed by pH-dependent electrostatic interactions. The high oxygen content of TMC enhanced binding affinity with both 5-FU molecules and water, with endothermicity attributed primarily to solvent desorption (ΔH_{imm H2O-TMC} = 4.8 mJ m^-2 and ΔH_{int 5-FU} = 0.58 mJ m^-2, at pH 4). These findings demonstrate that TMC offers a viable, eco-friendly alternative to petrochemical- or imported biomass-derived CACs, contributing to the mitigation of pharmaceutical pollution while lowering the environmental footprint of adsorbent production and transportation.