Abstract:The influence of different dissolved organic matter (DOM) on the removal of an antibiotic―sulfamethoxazole (SMZ) during nanofiltration (NF)processes was examined. Commercial humic acid (HA) and tannic acid (TA) as well as sodium alginate (SA) were selected as DOM. DOM used in the study displayed obviously diverse impacts on SMZ removal and flux decline by NF membranes. These impacts seemed to correlate with the hydrophobicity or hydrophilicity of DOM. To better understand the mechanism by which they affect SMZ transport across NF membrane, HA after ozonation was applied to examine. The ozonized HA was much more hydrophilic than HA and it presented a more significant effect on SMZ retention. The findings reported illustrated the complexity of the retention mechanism of SMZ in real water matrix where various DOM co-present, and confirmed the important role of physicochemical properties of DOM and target solute on process efficiency.