Superhydrophobic polymer membrane coated by mineralized β-FeOOH nanorods for direct contact membrane distillation

• Published in: Desalination Vol. 500; p. 114889
• Main Authors: Li, Bang, Yun, Yanbin, Wang, Manxiang, Li, Chunli, Yang, Woochul, Li, Jingwei, Liu, Guicheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.03.2021
• Subjects: Anti-fouling polymer membrane; Direct contact membrane distillation; Micro-nano structure; Superhydrophobic surface; β-FeOOH Nanorods; β-FeOOH Nanorods; Anti-fouling polymer membrane; Micro-nano structure; Direct contact membrane distillation; Superhydrophobic surface
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2020.114889

Membrane wetting and fouling represent the foremost concerning issues confining membrane distillation in the treatment of industrial wastewater. This work presents a superhydrophobic poly(vinylidene fluoride) (PVDF) membrane with anti-fouling property, which was derived from the bioinspired adhesive, mineralization and fluorination process for the direct contact membrane distillation (DCMD). The synthesis of membrane was initiated by co-depositing polydopamine/polyethylenimine composite layer onto membrane substrates as “bio-glue” associated with β-FeOOH nanorods as hierarchical structure anchoring to form coordination complexes via the catechol group and Fe3+, then proceeded with the fluorination of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to obtain the superhydrophobic PVDF membrane. Due to the unique micro-nano structure obtained, the resulting PVDF membrane, with a low sliding angle of 5.7° and a high water contact angle of 162°, conforms to the Cassie state. The membrane morphology, wetting behaviour, and anti-fouling performance were systematically characterized. The novel mineralized superhydrophobic membrane exhibited a steady flux and an outstanding salt rejection (99.9%) in treating high salinity and hardness containing-wastewater during 60-h-DCMD test, thus showing great potential for practical application in long-term DCMD. Morphologies, contact angles and normalized fluxes of the pristine and modified PVDF membranes. [Display omitted] •Superhydrophobic membrane with micro-nano-structure were fabricated by β-FeOOH nanorods.•Polydopamine leads to a strong chelation between polymer substrate and metal-seeds.•Superhydrophobic membrane exhibits excellent antifouling and antiwetting properties in DCMD.