Investigation on the membrane fouling control and mechanism induced by IOM using heat-activated peroxydisulfate pre-oxidation

Membrane fouling induced by intracellular organic matter (IOM) presents a major challenge in the ultrafiltration (UF) of algal-laden water. While extracellular organic matter (EOM) has been widely studied, the role of IOM and its control mechanism remain insufficiently understood. This study systematically investigated the mitigation of IOM-induced UF membrane fouling through heat-activated peroxymonosulfate (PMS) pre-oxidation. The effects of varying PMS dosages (0.2-0.8 mM) on fouling behavior and mechanisms were thoroughly evaluated. The results demonstrated that the IOM released by <i>Chlorella</i> caused severe membrane fouling during UF. Membrane fouling was significantly mitigated after heat-activated PMS pretreatment when the dosage exceeded 0.2 mM, with the optimal performance obtained at the PMS dosage of 0.6 mM. PMS pretreatment effectively removed macro and medium molecular organics in IOM that were primarily responsible for membrane fouling. Moreover, PMS pretreatment influenced the surface morphology and hydrophobicity of the fouling layer. The interaction energy between the membrane and foulants was also changed. The fouling mechanism exhibited a shift in the dominant mode, while the untreated IOM primarily caused cake layer formation, and PMS pre-oxidation altered the fouling behavior toward pore blocking. Collectively, this research proposed a practical strategy to mitigate membrane fouling induced by IOM in the UF of algal-laden water.