Functionalization of a Hydrophilic Commercial Membrane Using Inorganic-Organic Polymers Coatings for Membrane Distillation

Lies Eykens,Chris Dotremont,Bart Van Der Bruggen,Klaus Rose,Marjorie Dubreuil,Luc Pinoy,Kristien De Sitter

doi:10.3390/app7060637

Abstract

Membrane distillation is a thermal separation technique using a microporous hydrophobic membrane. One of the concerns with respect to the industrialization of the technique is the development of novel membranes. In this paper, a commercially available hydrophilic polyethersulfone membrane with a suitable structure for membrane distillation was modified using available hydrophobic coatings using ORMOCER® technology to obtain a hydrophobic membrane that can be applied in membrane distillation. The surface modification was performed using a selection of different components, concentrations, and application methods. The resulting membranes can have two hydrophobic surfaces or a hydrophobic and hydrophilic surface depending on the application method. An extensive characterization procedure confirmed the suitability of the coating technique and the obtained membranes for membrane distillation. The surface contact angle of water could be increased from 27° up to 110°, and fluxes comparable to membranes commonly used for membrane distillation were achieved under similar process conditions. A 100 h test demonstrated the stability of the coating and the importance of using sufficiently stable base membranes.

Highlights

Membrane distillation (MD) is a thermal separation technique using a hydrophobic microporous membrane as a contactor between two liquid phases
polyvinylidene fluoride (PVDF) GVHP (Merck Chemicals N.V., Overijse, Belgium) is a hydrophobic membrane commonly used in the membrane distillation literature as a reference for
Hydrophobic commonly usedsynthesized in the membrane distillation literaturemembranes as a reference[37,38,39]

Summary

Introduction

Membrane distillation (MD) is a thermal separation technique using a hydrophobic microporous membrane as a contactor between two liquid phases. The membrane allows vapors (e.g., water vapor) to permeate, whereas the liquid phase including the dissolved components (e.g., salts) is retained by the membrane. A temperature difference induces the driving force and allows vapors to permeate from the hot feed side to the cold permeate side. The technique was initially proposed as an alternative technology for reverse osmosis in seawater desalination. Due to the benefits of very high retentions and less dependence on salinity, it is recently proposed for applications beyond the scope of reverse osmosis. The applications can include but are not limited to desalination and brine

Methods

Results

Conclusion