Demirdag, EsraDemirel, Mehmet FeritBenek, VeyselDogru, ElifOnal, YunusAlkan, Mehmet HuseyinErol, Kadir2026-04-042026-04-0420251420-3049https://doi.org/10.3390/molecules30122501https://hdl.handle.net/11616/108497Activated carbon is widely recognized as an effective material for removing pollutants, especially pharmaceutical residues, from water. In this study, high-surface-area activated carbon derived from rice husks (RHAC) was synthesized via KOH activation and used for the adsorption of ciprofloxacin, a widely used fluoroquinolone antibiotic. Its adsorption behavior was systematically investigated through batch experiments varying the pH, adsorbent dosage, contact time, initial concentration, and temperature. The RHAC exhibited a high surface area of 1539.7 m(2)/g and achieved a maximum adsorption capacity of 398.4 mgg(-1). The Freundlich isotherm best describes its adsorption equilibrium, suggesting multilayer adsorption on a heterogeneous surface. Kinetic modeling revealed that the adsorption process followed a pseudo second-order model (R-2 = 0.9981), indicating chemisorption as the rate-limiting mechanism. Thermodynamic parameters (Delta H degrees = 6.61 kJ/mol, Delta G degrees < 0) confirmed that the process was endothermic and spontaneous. These findings demonstrate that RHAC is a highly efficient, low-cost, and sustainable adsorbent for removing ciprofloxacin from aqueous environments.eninfo:eu-repo/semantics/openAccessactivated carbonadsorptionantibiotic pollutionciprofloxacinrice huskArticle30124057246710.3390/molecules301225012-s2.0-105009052184Q1WOS:001515824300001Q20000-0002-0761-64360000-0002-8523-69220000-0001-9158-60910000-0002-3080-22960000-0001-6342-6816