Abstract:Eeffects of two kinds algae (Anabaena, Cyclotella) AOM on naproxen (NPX) removal by HL nanofiltration membrane were investigated. In the presence of AOM, NPX removal by NF increased from 63% with only NPX to 64.7% with Cyclotella and 72.7% with Anabaena, and severe fouling occurred with flux decreasing from 99.7% with only NPX to 89.6% with Cyclotella and 86.3% with Anabaena. It was found that medium molecular weight (MW) 1.5~5kDa with two AOM play a significant role in enhancing NPX removal and resulting fouling.They composed mainly of hydrophobic organics, and could adhere closely to NF membrane, forming cake layeron the surface of NF membrane, thus enhanced hydrophobicity of membrane. The hydrophobicity of cake layer was responsible for flux decline and increased NPX removal. The experiment exhibited also that AOM of Anabaena containedmore hydrophobity in 1.5~5.0k Da of MW than that of Cyclotella, thus resulted more severe fouling and higher NPX removal.