Membranes with good mechanical strength, high vapor flux and outstanding anti-wetting properties are essential for membrane distillation (MD) applications. In this work, porous polyvinylidene fluoride (PVDF) tri-bore hollow fiber membranes with super-hydrophobicity are developed to achieve these desired properties. The tri-bore hollow fiber offers better mechanical strength than the conventional single-bore fiber. To improve its anti-wetting properties, Teflon® AF 2400 is coated on the membrane surface. The effects of coating on membrane morphology, performance and anti-wetting properties have been thoroughly investigated. With an optimal coating condition (0.025 wt% of Teflon® AF 2400, 30 s), a super-hydrophobic surface with a contact angle of 151o is achieved. The resultant membrane shows an increase of 109% in liquid entry pressure (LEP) with a slight sacrifice of 21% in flux. Long term direct contact MD tests have confirmed that the Teflon® AF 2400 coated membrane has enhanced stability with an average flux of 21 kg m-2 h-1 and rejection of 99.99% at 60 °° C for desalination application.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors would like to thank Singapore National Research Foundation under its Energy Innovation Research Programme for supporting the project entitled, “Using Cold Energy from Re-gasification of Liquefied Natural Gas (LNG) for Novel Hybrid Seawater Desalination Technologies” (Grant number: R-279-000-456-279). Miss Kangjia Lu would also like to thank Dr. Peng Wang and Miss Dan Hua for their valuable advices and kind support.
ASJC Scopus subject areas
- Filtration and Separation
- General Materials Science
- Physical and Theoretical Chemistry