Impact of membrane pore morphology on multi-cycle fouling and cleaning of hydrophobic and hydrophilic membranes during MBR operation

Membrane processes

“…Sodium hypochlorite, EDTA, and cationic surfactants were used to remove polymers from the membrane surface. Fan, Xiao, et al (2018) studied the impact of membrane pore morphology on cleaning behavior and fouling, using four different MF membranes with varying hydrophobicity and polymer structure (e.g., particulate-packing vs. nonwoven network). The authors suggested that thin fibrous network-like pore morphology membranes performed better and are less prone to irreversible fouling than porous particulate-packing membranes (e.g., PVDF).…”

Outlining the Roles of Membrane-Foulant and Foulant-Foulant Interactions in Organic Fouling During Microfiltration and Ultrafiltration: A Mini-Review

“…The membrane pore structure (e.g., porosity and pore shape) and surface morphology (e.g., roughness) and the foulant size and morphology can have spatial effects on membrane fouling (Le-Clech et al, 2006;Fu et al, 2008;Xiao et al, 2014a;Kumar and Ismail, 2015;Cai et al, 2018;. The complexity of the pore structure affects fouling in many ways: on the one hand, the filtration flux of a membrane with straight-through pores decreases sharply due to pore blockage, whereas the flux of a membrane with highly interconnected pores decreases mildly due to that the fluid can easily bypass the blocked point Zydney, 1999, 2006); on the other hand, highly crosslinked porous network structures are easier to catch and intercept foulant particles (especially the foulant particles with irregular shapes) and are more likely to suffer internal fouling (Xiao et al, 2014a;Fan et al, 2018). The membrane surface roughness can affect fouling at different scales.…”

“…The spatial effects on the non-covalent interaction are represented by the effect of membrane pore structure and surface roughness on foulant adsorption (Xiao et al, 2014a;Zhao et al, 2015;Fan et al, 2018). Compared with membranes with perforated plate-like (e.g., PCTE) or particulate bed-like morphologies (e.g., PVDF), fibrous mesh-like membranes (e.g., PTFE) are beneficial for reducing hydrophobic adsorption (Xiao et al, 2014a;Fan et al, 2018). This is because thin, fiber-like pore walls provide limited contactable area for the adsorption, and the foulant particles sitting on the fibers are not stable under hydraulic disturbance.…”

“…This is because thin, fiber-like pore walls provide limited contactable area for the adsorption, and the foulant particles sitting on the fibers are not stable under hydraulic disturbance. Moreover, interfacial force calculation suggests that the hydrophobic attractive force of a foulant particle received from a thread-like (or cylindrical) membrane object is weaker than that from a plane-like membrane object at the same distance (Fan et al, 2018). At the micrometer scale, the membrane surface roughness can influence the force balance of a foulant particle sitting on the membrane surface.…”

“…The increased rejection rate would in turn promote concentration polarization above the membrane surface (influencing subsequent foulant transport) (Song and Elimelech, 1995;. The porosity and pore morphology changed by the pore adsorption would vary the local fluid conditions (e.g., local flux) near the pores (Ho and Zydney, 1999), or have a feedback effect on the adsorption by altering the effective area or distance of the interaction (Fan et al, 2018). The non-covalent or covalent adsorption on the membrane surface, as well as the mechanical retention at the pore openings, contributes to the accumulation of foulant concentration on the membrane surface (Xiao et al, 2014b).…”