(152bo) High Performance Novel Thin Film Speek Composite Membrane for Produced Water Treatment

Produced water (PW) is a prominent waste in the petroleum and gas industry, which has potential to be reused after desalination. Forward osmosis (FO) for desalination emerges as a promising alternative to pressure-driven membrane technologies. In this work, novel sulfonated polyetheretherketone (SPEEK) osmotic thin film composite (TFC) membranes were fabricated by phase inversion process for FO produced water treatment. These membranes were then subjected to heat treatment to avoid delamination of the polymeric layer and to enhance the adhesion between the PE support and the dope casting solution as well as to enhance SPEEK stability. The polymer solution was cast directly onto a hot-pressed polyester backing fabric support layer followed by an interfacial polymerization technique to create the TFC-based membranes. Different TFC-(SPEEK) membrane sets were fabricated based on single and double casting layers. The TFC-SPEEK based membranes morphology, functional group analysis, and hydrophilicity were analysed. The membrane performance was tested using a cross-flow FO testing setup. The effect of salinity variation in synthetic PW and its composition on PW desalination through the forward osmosis process was investigated. To the best of our knowledge, no studies have incorporated SPEEK polymer for creating TFC-based FO membranes with high FO desalination performance,

The optimal TFC-SPEEK based double casting layers showed an ultra-high water flux up to 2660 LMH and very low reverse salt diffusion of 0.18 GMH in FO mode when DI water and 1M NaCl were used as the feed solution and the draw solution, respectively, which is superior to the commercial cellulose triacetate (CTA) and TFC membranes (HTI). In addition, the salts rejection of the optimal membrane was 85.9%,73.6%, 84.5%, 82.9%, 71%, 77.8%, and 72.2% for Na₂SO₄, NaHCO_3, MgCl₂, SrCl₂, CaCl₂, NaCl, and NH₃Cl, respectively. Therefore, it is believed that the increase in water flux is due to the addition of hydrophilic (SPEEK) polymer solution which enhanced membrane overall hydrophilicity, while the change of membrane surface charges due to sulfonic acid groups introduced by SPEEK polymer have enhanced membrane salt rejection performance. The membrane's performance in terms of water permeation flux and mechanical strength has been improved by the heat-pressing of the PE support layer, which resulted in a thin and compact membrane.

These promising results indicate that SPEEK TFC membranes have potential to be used for FO produced water desalination.