Login | Register

Development of Durable Anti-Wetting and Anti-Fouling Membranes for Water Production via Membrane Distillation (MD)

Title:

Development of Durable Anti-Wetting and Anti-Fouling Membranes for Water Production via Membrane Distillation (MD)

Chen, Tiantian (2021) Development of Durable Anti-Wetting and Anti-Fouling Membranes for Water Production via Membrane Distillation (MD). PhD thesis, Concordia University.

[thumbnail of Chen_PhD_F2021.pdf]
Text (application/pdf)
Chen_PhD_F2021.pdf - Accepted Version
Restricted to Repository staff only until 15 November 2023.
Available under License Spectrum Terms of Access.
6MB

Abstract

Membrane distillation (MD) has gained a growing interest in seawater desalination, wastewater treatment, and separation of volatile compounds as of late due to its low operating pressure, moderate temperature requirements, and high salt rejection. However, membrane fouling and pore wetting are two major problems that hinder maintaining long-term stable flux and salt rejection of MD when treating various feed solutions. Electrospun nanofiber membranes (ENMs) are promising for MD applications due to the discernable advantages of their high hydrophobicity and porosity. Utilization of micro/nano-particles and surface fluoro-silanization are effective modification methods to enhance anti-fouling and anti-wetting properties of MD membranes. The objective of this doctoral research is to develop effective membranes with durable fouling/wetting resistance for water production by MD. To achieve this goal, a highly hydrophobic poly (vinylidene fluoride­co­hexafluoropropylene)/ reduced graphene oxide (PVDF­HFP/ rGO) flat­sheet membrane was prepared via a facile electrospinning technique. The rGO incorporated membranes exhibited excellent stability and durability with a salt rejection of over 99.97% and an average flux of 20.37 kg/m2h using 60 g/L sodium chloride as the feed solution. To expand the application of conventional MD membranes to treat challenging wastewaters that contain low surface tension contaminants, one simple modification method was applied by utilizing fluoroalkylsilane of low surface energy on the pristine PVDF-HFP/rGO substrate to achieve surface superamphiphobicity (both superhydrophobicity and near-superoleophobicity). The resulting membranes demonstrated superamphiphobicity, confirmed by their wetting resistance evaluated with water and low surface tension liquids. The antiwetting performance of the membrane was tested through desalinating 35 g/L sodium chloride solution in the presence of a surfactant (sodium dodecyl sulfate, SDS) in the direct contact membrane distillation (DCMD) unit. Finally, a highly permeable membrane for membrane distillation applications by employing porous MCM-48 silica as the nanofiller was developed. The addition of hydrophobic MCM-48 nanoparticles was found to significantly increase water vapor transport, with a flux enhancement 87.16% greater than that observed in the pristine PVDF-HFP membrane.

Divisions:Concordia University > Gina Cody School of Engineering and Computer Science > Building, Civil and Environmental Engineering
Item Type:Thesis (PhD)
Authors:Chen, Tiantian
Institution:Concordia University
Degree Name:Ph. D.
Program:Civil Engineering
Date:2 August 2021
Thesis Supervisor(s):Chen, Zhi and An, Chunjiang and Rahaman, Saifur
ID Code:989930
Deposited By: Tiantian Chen
Deposited On:29 Nov 2021 16:34
Last Modified:29 Nov 2021 16:34
All items in Spectrum are protected by copyright, with all rights reserved. The use of items is governed by Spectrum's terms of access.

Repository Staff Only: item control page

Downloads per month over past year

Research related to the current document (at the CORE website)
- Research related to the current document (at the CORE website)
Back to top Back to top