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Wettability-switchable deep bed filtration for efficient oily wastewater treatment
Song Xichen1, Yan Yaping1, Zhang Tingting1
1School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China.
Journal of Hazardous Materials
|June 25, 2026
Summary
A novel temperature-swing deep-bed filtration process uses dynamic interfacial energy regulation to efficiently purify oily wastewater. This sustainable technology overcomes the attachment-detachment paradox for effective oil removal and recovery.
Area of Science:
- Environmental Engineering
- Materials Science
- Surface Chemistry
Background:
- Deep-bed filtration for oily wastewater is hindered by the
- Attachment-Detachment Paradox
- Traditional backwashing methods fail due to high interfacial energy barriers.
Purpose of the Study:
- To develop a temperature-swing deep-bed filtration process for efficient oily wastewater purification.
- To overcome the interfacial energy barrier using dynamic interfacial energy regulation.
- To establish a sustainable technology for oily wastewater treatment.
Main Methods:
- Utilized a thermo-responsive filter bed with temperature-swing operation (20°C filtration, 40°C backwash).
- Investigated interfacial response mechanisms using extended DLVO (XDLVO) theory, atomic force microscopy (AFM), and molecular dynamics (MD) simulations.
Main Results:
- Achieved >99% filtration efficiency at 20°C.
- Demonstrated >98% spontaneous detachment efficiency during 40°C backwash.
- Elucidated temperature-induced polymer conformational changes governing oil droplet attachment and detachment.
Conclusions:
- The temperature-swing process effectively overcomes interfacial attachment hysteresis for oily wastewater treatment.
- Dynamic interfacial energy regulation provides a low-energy, sustainable solution.
- This methodology offers a general approach for stimuli-responsive interfacial control.
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