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Step-by-step improvement of mixed-matrix nanofiber membrane with functionalized graphene oxide for desalination via air-gap membrane distillation

Fouladivanda, M ; Sharif University of Technology | 2021

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  1. Type of Document: Article
  2. DOI: 10.1016/j.seppur.2020.117809
  3. Publisher: Elsevier B.V , 2021
  4. Abstract:
  5. A straightforward three-stage method was applied to fabricate a super-hydrophobic mixed-matrix nanofiber membrane using the electrospinning method for desalination purpose. First, a hydrothermal technique was applied to synthesize a super-hydrophobic nano-sheet, called octadecylamine-reduced graphene oxide (ODA-rGO) with a water contact angle of 162°, which was then added to PVDF-HFP dope solution. After, 0.005 wt% LiCl was added to the dope solution to decrease the mean pore size by increasing solution conductivity. Moreover, some membranes were hot-pressed to improve liquid entry pressure (LEP). Eventually, a top-quality nanofiber membrane was synthesized using 0.1 wt% ODA-rGO and 0.005 wt% LiCl, and hot-pressed, named by MLH-0.1. By applying these stepwise improvements, the mean pore size reduced from 1.30 to 0.24 µm and LEP significantly increased from 30.4 to 127.6 kPa, compared to a neat electrospun nanofiber membrane. Finally, MLH-0.1 was tested in the air gap membrane distillation process for desalination of an aqueous solution containing 3.5 wt% NaCl. MLH-0.1 demonstrated the maximum flux of 21.1 kg/m2.h at temperatures of 70℃ and 20℃ for the feed and the permeation sides, respectively, as well as a remarkable and stable salt rejection of 99.99% for 4 days. © 2020 Elsevier B.V
  6. Keywords:
  7. Contact angle ; Desalination ; Distillation ; Distilleries ; Graphene ; Hydrophobicity ; Lithium compounds ; Nanofibers ; Nanosheets ; Pore size ; Reduced Graphene Oxide ; Sodium chloride ; Air gap membrane distillation ; Electrospinning method ; Electrospun nanofibers ; Functionalized graphene ; Hydrothermal techniques ; Increasing solutions ; Three-stage method ; Water contact angle ; Membranes
  8. Source: Separation and Purification Technology ; Volume 256 , 2021 ; 13835866 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S1383586620322838