Feasibility study on magnetic enhanced flocculation for mitigating membrane fouling

• Magnetic enhanced flocculation could mitigate membrane fouling dramatically.
• Large and high-density magnetic flocs were helpful for alleviating fouling.
• Uneven and porous cake layer with magnetic seeds exhibited excellent drainage.
• Microcosmic morphology of the foulants was analyzed.

During coagulation/flocculation-membrane filtration (CF-MF) process, membrane fouling was alleviated more significantly through magnetic enhanced flocculation-membrane filtration (MEF-MF) in the presence of ferromagnetic seeds in coagulants. Porous cake layer with flocs of large size was able to alleviate decline rate of membrane flux. Foulant analysis proved that magnetic enhanced flocculation (MEF) pretreatment was more efficient for the reductions of low and mid-molecular weight (MW) organic structures than CF-MF. Biopolymers with high molecular weight were also effectively removed before filtration. Overall, MEF-MF could provide a novel alternative approach to mitigate membrane fouling for surface water treatment.

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