KMnO4 pre-oxidation combined with FeCl3 coagulation for UF membrane fouling control

KMnO4 pre-oxidation combined with FeCl3 coagulation for membrane fouling reduction was investigated during ultrafiltration (UF) of water samples from an impacted canal river. 0.5 mg/L KMnO4 oxidation alone showed an obvious effect on the decrease of the total membrane fouling and fouling irreversibility, due to the removal of relevant organic membrane foulants such as biopolymers and humic acids. However, further increase of KMnO4 dosage to 1.0 mg/L showed little enhancing effect on the reduction of membrane fouling. When coupled with FeCl3 coagulation at low dosage (1 mg Fe/L), 0.5 mg/L of KMnO4 pre-oxidation was able to further decrease the total fouling resistance in addition to the 1 mg Fe/L coagulation, which can be attributed to the more effective removal of biopolymers from the water. However, no effect was observed for further reduction of irreversible fouling by the KMnO4 pre-oxidation. As the FeCl3 dosage was increased to 4 mg Fe/L, it was shown that 0.5 mg/L KMnO4 oxidation cannot further decrease the total fouling resistance; whereas the KMnO4 pre-oxidation exhibited a certain effect on the reduction of membrane fouling irreversibility. The results of this work may provide useful information for the application of combined KMnO4 oxidation and FeCl3 coagulation for UF membrane fouling control.