The catalytic activity of carbon activated with NH4Cl (NAC) was compared with a standard analytical grade activated carbon (SAC) for ozonation of amoxicillin. The results indicate that the NAC had greater catalytic potential than SAC for degradation and mineralization of amoxicillin by ozonation. Complete degradation and 54.1% mineralization of 50 mg/L amoxicillin was obtained using the catalytic ozonation process with NAC as catalyst (COP/NAC) at a solution pH of 6.8, ozone dosage of 0.8 mg/min, catalyst concentration of 100 mg/L and reaction time of 50 min. The catalytic ozonation process with SAC as the catalyst (COP/SAC) degraded 64.7% of amoxicillin while the single ozonation process (SOP) degraded 22% and COP/SAC mineralized 32.4% of amoxicillin while SOP mineralized 8.3% under similar conditions. The rates of degradation and mineralization of amoxicillin for COP/NAC were 3.2 and 1.8 times, respectively, those for COP/SAC. These findings demonstrate the high catalytic activity of NAC, suggesting it is a promising and efficient material for catalyzing the ozonation of emerging water contaminants. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.