Fouling-resistant surface modification of forward osmosis membranes using MoS2-Ag nanofillers

Abstract

The mitigation of organic fouling is a main challenge for forward osmosis (FO) technology. In order to enhance the fouling resistance and desalination efficiency of the FO membrane, various studies have suggested the incorporation of nanomaterials into thin-film composite (TFC) membranes, which are defined as thin-film nanocomposite (TFN) membranes. In this study, we fabricated MoS2-Ag nanofillers by photochemical deposition method and incorporated them into TFC membranes for FO water treatment. After incorporation of MoS2-Ag nanofillers into TFC membranes, we could observe significant change in the surface of membranes. Especially, active layer surface of TFN membrane was smoothened, which was represented by decrease of roughness from 40.09 ± 1.39 nm of TFC membrane to 15.53 ± 0.17 nm of TFN membrane. Furthermore, according to the hydrophilic surface modification, contact angle of membranes was also decreased from 79.0 ± 2.0° of TFC membrane to 52.2 ± 0.7° of TFN membrane. The surface modification of the TFN membrane resulted in improvement of desalination capacity in terms of 35.2% improved water flux. Finally, the resistance to alginate fouling of TFN membrane was realized and it exhibited almost 4 times lower water flux loss than TFC membrane. This study presents that photochemically synthesized nanofillers could modify the surface of TFN membrane, therefore, this technique can be a feasible approach to future membrane-based technologies.