Triple-Layer Nanofiber Membranes for Treating High Salinity Brines Using Direct Contact Membrane Distillation.

Mustafa Al-Furaiji,Jeffrey R Mccutcheon,Jason T Arena,Nieck Benes,Jian Ren,Arian Nijmeijer

doi:10.3390/membranes9050060

Abstract

A composite, three-layered membrane for membrane distillation was prepared from electrospun polyvinylidene fluoride (PVDF) nanofibers supported by commercial polyethersulfone (PES) nanofiber based nonwoven from E.I. duPont de Nemours company (DuPont). The membranes were tested in direct contact membrane distillation (DCMD) using a 5.0 M sodium chloride brine as a feed solution. The triple layer membrane combines the hydrophobicity of PVDF and the robustness of the PES. The triple layer membrane demonstrated excellent performance in DCMD (i.e., relatively high water flux compared to the commercial PVDF membrane and a complete salt rejection of the brine) with mechanical properties imparted by the PES layer. This work is the first to demonstrate the use of a commercially produced nanofiber nonwoven for membrane distillation.

Highlights

Membrane distillation is a thermally driven separation process in which only water vapor molecules transfer across microporous hydrophobic membranes
The thickness was controlled by the amount of the polyvinylidene fluoride (PVDF) polymer that was spun onto the PES layer
Triplelayer layernanofibers nanofibersmembranes membranes with mid-layer were investigated as asaamechanically mechanicallysuperior superioralternative alternativetotosingle singlelayer layer nanofiber nanofiber membranes

Summary

Introduction

Membrane distillation is a thermally driven separation process in which only water vapor molecules transfer across microporous hydrophobic membranes. In direct contact membrane distillation (DCMD), a hot feed solution flows on one side of the hydrophobic membrane while a cold solution (normally DI water) flows on the other side generating the driving force (i.e., vapor pressure) across the membrane. DCMD has been considered as an alternative to traditional distillation to treat highly concentrated solutions and brines due to its low sensitivity towards salinity of the feed solution [1]. These brines may include reverse osmosis reject [2], produced water [3], forward osmosis draw solutions [4] and hypersaline lakes [5]. The high heat loss by conduction across the membrane can reduce the performance of the process

Methods

Results

Conclusion