Kelvinraj NURSIAH
defended his PhD thesis
on 13 december 2023
Artificial Water Channels-based membranes for membrane distillation
Front of the jury:
– M. Suming LI, Directeur de recherche, CNRS, Montpellier – Président du jury
– Mme. Cristina IOJOIU, Directrice de recherche, CNRS, Grenoble – Rapporteur
– Mme. Andréa PASC, Professeur, Université de Lorraine – Rapporteur
– Mme Niculina HADADE, Maître de Conférence, Université de Cluj-Napoca – Examinateur
– M. Mihail Dumitru BARBOIU, Directeur de recherche, CNRS, Montpellier – Directeur de Thèse
– Mme Sophie CERNEAUX, Maître de Conférence, ENSCM, Montpellier – Co-encadrante de Thèse
Abstract:
In this research work, innovative self-supported flat-sheet polyvinylidene fluoride (PVDF) membranes incorporating amphiphilic I-quartet Artificial Water Channels (AWCs) were developed and applied for MD desalination technology. The presence of the AWCs was aimed to increase the amount of water vapor transport within the hydrophobic PVDF pores, thus enhancing water permeability and preserving high selectivity, consequently improving the MD performance. Novel strategies were explored, in which water channels structures contribute to water cluster stabilization and the increase of water vapor within hydrophobic pore structures. As such, two different preparation methods, namely Non-Solvent Induced Phase Separation (NIPS) and Vapor Induced Phase Separation (VIPS), were employed for the fabrication of the PVDF-AWC membranes. The NIPS method yielded the highest performing membranes, with enhanced Pure water permeability (PWP) of 75.3 L.m-2.h-1.bar-1 attained for the optimized PVDF-AWC hybrid membrane prepared using 16 wt.% PVDF (530 000 g.mol-1) and 0.05 wt.% AWCs when compared with its reference membrane characterized by a PWP of 30.6 L.m-2.h-1.bar-1. A 10.6 % increase in MD flux was observed, with an enhanced salt rejection of 95.3 % obtained for the PVDF-AWC membrane compared to 85.2 % for the PVDF reference membranes. The efficacy of the hybrid membranes was further put into evidence through dyes Ultrafiltration (UF). Both the reference (14 wt.%) and PVDF-AWC (14 wt.% and 0.075 wt.%, respectively) membranes showed improved separation performance for binary dyes mixture (Methylene Blue-Methyl Orange), with filtered dye feed permeability of 40 L.m-2.h-1.bar-1 for the former and 84 L.m-2.h-1.bar-1 for the latter. In light of the obtained results, it can be inferred that the NIPS method is better suited for the production of the PVDF-AWC membranes. These findings provide further scope into the development of the latter at a larger scale, keeping in mind that the NIPS method is a simple and
easy method.
