Hyper-branched dendritic structure modified PVDF electrospun membranes for air gap membrane distillation

• Published in: Desalination 2020-04, Vol.479, p.114307, Article 114307
• Main Authors: Kebria, Mohammad Reza Shirzad, Rahimpour, Ahmad, Salestan, Saeed Khoshhal, Seyedpour, S. Fatemeh, Jafari, Arman, Banisheykholeslami, Fatemeh, Tavajohi Hassan Kiadeh, Naser
• Format: Article
• Language: English
• Subjects: Anti-fouling properties; Electrospun nanofibrous membrane; Hyper-branched dendritic structure; Membrane distillation
• ISSN: 0011-9164; 1873-4464; 1873-4464
• DOI: 10.1016/j.desal.2019.114307

Dendrimers are a new class of polymeric materials owning unique properties such as hydrophobicity. In this study, hydrophobic hyper-branched dendritic (HB-Den) structures were synthesized via a polycondensation reaction between hydroxyl groups of boehmite and carboxylic groups of nitrilotriacetic acid (NTA) and was used to improve the hydrophobicity of electrospun nanofibrous membranes (ENMs). Effects of the different contents of HB-Den structures on membrane morphology, elemental properties, surface hydrophobicity, desalination performance and antifouling properties were assessed by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), water contact angle measurements and air gap membrane distillation (AGMD) experiments. Digital microscopy images showed monodisperse dendrimers with a tree-like structure. The water contact angle and liquid entry pressure (LEP) increased from around 129.3° and 101 ± 3.1 kPa for a neat PVDF membrane to 138.3° and 121 ± 2.2 kPa upon loading with 0.075 wt% HB-Den structures. FTIR analysis of the HB-Den containing ENMs confirmed the presence of carboxylic groups of NTA on the membrane surface. After desalination experiments, the 0.075 wt% HB-Den ENM showed a stable flux of 10.7 kg/m2 h and 99.9% NaCl rejection over 15 h filtration of a 3.5 g/l NaCl solution. The anti-fouling properties of the ENMs were also enhanced by incorporation of the dendritic structures. The 0.075 wt% HB-Den ENM showed flux recovery of about 94% after 20 h desalination experiment using real seawater as a feed solution. [Display omitted] •HB-Den incorporated modified PVDF membranes were fabricated via electrospinning technique.•Loading of HB-Den structures improved desalination performance of ENMs during.•HB-Den incorporated ENMs showed desirable anti-fouling properties during seawater desalination.