Modification of Nanofiber Support Layer for Thin Film Composite forward Osmosis Membranes via Layer-by-Layer Polyelectrolyte Deposition

Ralph Rolly Gonzales; Myoung Jun Park; Leonard Tijing; Dong Suk Han; Sherub Phuntsho; Ho Kyong Shon

doi:10.3390/membranes8030070

Modification of Nanofiber Support Layer for Thin Film Composite forward Osmosis Membranes via Layer-by-Layer Polyelectrolyte Deposition

Membranes (Basel). 2018 Aug 25;8(3):70. doi: 10.3390/membranes8030070.

Authors

Ralph Rolly Gonzales¹, Myoung Jun Park², Leonard Tijing³, Dong Suk Han⁴, Sherub Phuntsho⁵, Ho Kyong Shon⁶

Affiliations

¹ Centre for Technology in Water and Wastewater, University of Technology Sydney, 15 Broadway, Ultimo, New South Wales 2007, Australia. RalphRolly.Gonzales@student.uts.edu.au.
² Centre for Technology in Water and Wastewater, University of Technology Sydney, 15 Broadway, Ultimo, New South Wales 2007, Australia. Myoungjun.Park@uts.edu.au.
³ Centre for Technology in Water and Wastewater, University of Technology Sydney, 15 Broadway, Ultimo, New South Wales 2007, Australia. Leonard.Tijing@uts.edu.au.
⁴ Chemical Engineering Program, Texas A&M University at Qatar, Education City PO Box 23874, Doha, Qatar. dong_suk.han@qatar.tamu.edu.
⁵ Centre for Technology in Water and Wastewater, University of Technology Sydney, 15 Broadway, Ultimo, New South Wales 2007, Australia. Sherub.Phuntsho@uts.edu.au.
⁶ Centre for Technology in Water and Wastewater, University of Technology Sydney, 15 Broadway, Ultimo, New South Wales 2007, Australia. Hokyong.Shon-1@uts.edu.au.

Abstract

Electrospun nanofiber-supported thin film composite membranes are among the most promising membranes for seawater desalination via forward osmosis. In this study, a high-performance electrospun polyvinylidenefluoride (PVDF) nanofiber-supported thin film composite (TFC) membrane was successfully fabricated after molecular layer-by-layer polyelectrolyte deposition. Negatively-charged electrospun polyacrylic acid (PAA) nanofibers were deposited on electrospun PVDF nanofibers to form a support layer consisted of PVDF and PAA nanofibers. This resulted to a more hydrophilic support compared to the plain PVDF nanofiber support. The PVDF-PAA nanofiber support then underwent a layer-by-layer deposition of polyethylenimine (PEI) and PAA to form a polyelectrolyte layer on the nanofiber surface prior to interfacial polymerization, which forms the selective polyamide layer of TFC membranes. The resultant PVDF-LbL TFC membrane exhibited enhanced hydrophilicity and porosity, without sacrificing mechanical strength. As a result, it showed high pure water permeability and low structural parameter values of 4.12 L m^-2 h^-1 bar^-1 and 221 µm, respectively, significantly better compared to commercial FO membrane. Layer-by-layer deposition of polyelectrolyte is therefore a useful and practical modification method for fabrication of high performance nanofiber-supported TFC membrane.

Keywords: electrospinning; forward osmosis; layer-by-layer; layered interfacial polymerization; membrane; nanofiber; thin film composite.