Superhydrophilicity and underwater superoleophobicity TiO 2 /Al 2 O 3 composite membrane with ultra low oil adhesion for highly efficient oil-in-water emulsions separation

Dawei Zhang, Gang Wang*, Shudi Zhi, Kaile Xu, Lijing Zhu, Wenwei Li, Zhixiang Zeng, Qunji Xue

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

24 Citations (Scopus)

Abstract

To improve the separation efficiency and decrease fouling of the membranes used in oil-in-water emulsions separation, a superhydrophilic and underwater superoleophobic TiO 2 /Al 2 O 3 composite membrane with ultra low oil adhesion was designed. TiO 2 nanorod arrays were prepared on Al 2 O 3 porous ceramic membrane surface by simple magnetron sputtering and hydrothermal oxidation. The microstructure and surface photosensitivity of TiO 2 nanorod array-coated ceramic membrane can effectively increase the efficiency of oil-water separation and reduce the degree of surface fouling. The layer of TiO 2 nanorod arrays not only reduced the pore size of traditional ceramic membrane (enhanced sieving effect of porous structures) but also endowed its superhydrophilicity (enhanced flux) and underwater superoleophobicity (enhanced oil/water selectivity and antifouling). Based on the superhydrophilicity (water contact angle (WCA) of 0°) and underwater superoleophobicity (oil contact angle (OCA) higher than 150°) of ceramic membrane, oil droplets were blocked by the membrane (oil-water separation efficiency 99.1% under gravity) and water will pass (flux is maintained at 41.8 L/(m 2 h) under gravity). It also has excellent anti-fouling ability due to the ultra-low oil adhesion force (0.084 mN) of the TiO 2 nanorod array-coating after UV irradiation. These features, combined with energy-saving, low-cost and easy-to-scale manufacturing schemes will be of great versatility and practicality in environmental rehabilitation and wastewater purification.

Original languageEnglish
Pages (from-to)157-165
Number of pages9
JournalApplied Surface Science
Volume458
Early online date11 Jul 2018
DOIs
Publication statusPublished - 15 Nov 2018

Keywords

  • Ceramic membrane
  • O/W emulsions separation
  • Superhydrophilicity
  • Titanium dioxide
  • Underwater superoleophobicity

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