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Home > Past events > Defended Ph.D. since 2015

Ph.D. defense - 15/12/2020

Maria DI VINCENZO defended her Ph.D. thesis on 15 December 2020

 

Development of Reverse Osmosis Membranes incorporating biomimetic Artificial Water Channels

 
 
 
 
in front of the jury composed of:

- M. Mihai BARBOIU - Institut Europeen des Membranes - Université de Montpellier - Directeur de thèse
- M. Pierre AIMAR - Laboratoire de Génie Chimique - CNRS - Rapporteur
- Mme Lidietta GIORNO - Institute on Membrane Technology National Research Council -CNR-ITM - Rapporteur
- M. Alberto TIRAFERRI - Politecnico di Torino - Examinateur
- M. Marc HERAN - Institut Européen des Membranes - Université de Montpellier - Examinateur
- Mme Suzana NUNES - King Abdullah University of Science and Technology - Examinatrice
- Mme Sophie CERNAUX - Institut Européen des Membranes - Université de Montpellier - Co-encadrante de thèse
- Mme Stephanie ROUALDES - Institut Européen des Membranes - Université de Montpellier - Co-encadrante de thèse
 
 

Abstract:

As stressors like population growth, industrial usage, and climate change keep on exacerbating the freshwater demand while depleting our traditional resources, the development of efficacious and low-cost desalination technologies is of paramount importance to address the growing global water shortage in a sustainable way. Within this goal, this thesis presents the rational development of the first biomimetic reverse osmosis (RO) membranes that seamlessly incorporate I-quartet artificial water channels (AWC). Here, innovative bioinspired active layers are synthesized via a streamlined interfacial polymerization approach leading to the formation of robust biomimetic membranes, whose structure presents the same microscale morphology of traditional thin-film composite (TFC) but with a different roughness and nano-structure that seamlessly incorporates sponge-like crystalline assemblies containing selective I-quartet AWCs. The kinetic formation of the layers is thoroughly examined to demonstrate the presence of AWC colloidal nanoparticles, from a close inspection of self-assembled superstructures to the formation of supramolecular sponge-like networks of the hybrid AWC-based membrane material. In the first case study, the resulting membranes are evaluated by cross-flow filtration under high-pressure RO conditions to desalinate substitute ocean water and solutions containing 5.800 ppm or 35.000 ppm NaCl at 18 and 65 bar of applied pressure, respectively. Results demonstrate that bioinspired active layers can enhance the selective water transport through the membrane, achieving a large improvement of 75% and 150% up in water permeance for seawater and brackish water desalination, respectively, while maintaining excellent Å-scale separation performance (observed rejection >99.4%, boron removal >91%). Furthermore, it is estimated that their application to industrial processes would results in a remarkable 12-15% reduction in the energy consumption for desalination. The second case study investigates the best combination between I-quartet AWCs precursors and m-phenylenediamine monomer to fabricate bioinspired hybrid layers that seamlessly incorporate self-aggregated AWC colloidal nanoparticles at the highest density possible. In this case, the perm-selectivity performance is evaluated by cross-flow filtration under low-energy RO conditions (6 to 15 bar) to desalinate brackish and tap water feed streams. As a result, optimized bioinspired layers achieve improvement up to 360% in water permeance (up to 6.9 LMH/bar) with respect to traditional TFC membranes, while maintaining excellent desalination performance (observed NaCl rejection ≥99.3%). This work further demonstrates that AWC-based biomimetic membranes own the potential for improving existing RO processes if their industrial transfer is envisaged and viable. Keywords: biomimetic membranes; artificial water channels; reverse osmosis; water purification; thin-film composite.

 
Keywords: biomimetic membranes ; artificial water channels; inverse osmosis; water purification; thin film.