Quantitative assessment of interfacial interactions with rough membrane surface and its implications for membrane selection and fabrication in a MBR

• Interfacial interactions with rough surface were quantitatively assessed.
• Interactions were significantly affected by roughness scale and foulant size.
• Existence of a critical range of roughness scale for fouling mitigation was revealed.
• Implications for membrane selection and fabrication in MBRs were provided.

The interfacial interactions between a foulant particle and rough membrane surface in a submerged membrane bioreactor (MBR) were quantitatively assessed by using a new-developed method. It was found that the profile of total interaction versus separation distance was complicated. There were an energy barrier and two negative energy ranges in the profile. Further analysis showed that roughness scale significantly affected the strength and properties of interfacial interactions. It was revealed that there existed a critical range of roughness scale within which the total energy in the separation distance ranged from 0 to several nanometers was continually repulsive. Decrease in foulant size would increase the strength of specific interaction energy, but did not change the existence of a critical roughness scale range. These findings suggested the possibility to “tailor” membrane surface morphology for membrane fouling mitigation, and thus gave significant implications for membrane selection and fabrication in MBRs.

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