BACKGROUND: The removal of antibiotic ampicillin sodium using H2O2 and modified granular activated carbon (GAC) is discussed. Two types of modified activated carbons were used in experiment to catalyze .OH production from H2O2. One was modified with base (NaOH; called B-GAC), the other was modified with Fe(NO3)3 (Fe-GAC) and the nominal Fe metal loading was 5 wt%. In the experiment, pH, contact time, dosage of activated carbon and H2O2 and initial concentration of ampicillin sodium were investigated to determine their influence on the removal efficiency. The stability of Fe-GAC was also evaluated. RESULTS: With an initial ampicillin sodium concentration of 200 mg L-1, 85.(2)% of chemical oxygen demand (COD) and 76.4% of total organic carbon (TOC) can be removed with 8.0 g L-1 of B-GAC and 80 mg L-1 of H2O2 (at pH 5.0). For the Fe- GAC/ H2O2 process, with 5.0 g L-1 of activated carbon and 80mg L-1 of H2O2, COD and TOC removal can be elevated to 91.(2)% and 79.5% (at pH 3.0), respectively. CONCLUSION: The integration of activated carbon and H2O2 treatment was more effective for the removal of ampicillin from aqueous solution than using activated carbon alone. In the process, adsorption played a dominant role and the addition of a small amount of H2O2 accelerated the reaction rate and improved the removal efficiency. pH also greatly affected removal efficiency. (C) 2011 Society of Chemical Industry