Removal of amoxicillin from contaminated water using NH4Cl-activated carbon: Continuous flow fixed-bed adsorption and catalytic ozonation regeneration

• Amoxicillin removal was investigated by NAC and SAC fixed-bed columns.
• The NAC bed attained a longer service time and better adsorption capacity than the SAC bed.
• The saturated NAC bed was efficiently regenerated with ozonation at 1.4 mg-O3/min for 3 h.
• The regenerated NAC bed preserved its adsorption capacity during repeated cycles.
• The real contaminated water sample was efficiently treated in the NAC-bed column.

This study investigates the elimination of amoxicillin from water by adsorption onto NH4Cl-activated carbon (NAC) and standard activated carbon (SAC) in the fixed-bed columns with ozone-regeneration of the saturated carbon. Breakthrough curves for amoxicillin (AMX) adsorption were determined at various empty bed contact times (EBCTs) ranging from 2 to 10 min. Results determined breakthrough times of 5.5–103 h for the NAC bed and 10–98 h for SAC bed. The breakthrough point adsorption capacity of NAC was much greater than that of SAC at each of the tested EBCTs. Based on the experimental data, the breakthrough point adsorption capacity of NAC increased from 73.3 to 274.1 mg/g and that of SAC increased from around 31.6 to 65.2 mg/g with an increased EBCT from 2 to 10 min. The saturated NAC bed was completely regenerated in situ through a catalytic ozone-regeneration process with an ozone dose of 1.4 mg-O3/min for 3 h and the regenerated NAC demonstrated adsorption behavior similar to that of fresh NAC. The NAC-bed improved the quality of the contaminated real water from background contaminants and completely removed AMX. Therefore, the NAC fixed-bed adsorption and subsequent ozonation presents a promising and efficient process for the removal of AMX as an emerging contaminant from polluted water.