Antifouling Property of Oppositely Charged Titania Nanosheet Assembled on Thin Film Composite Reverse Osmosis Membrane for Highly Concentrated Oily Saline Water Treatment

Abstract

With the blooming of oil and gas industries, oily saline wastewater treatment becomes a viable option to resolve the oily water disposal issue and to provide a source of water for beneficial use. Reverse osmosis (RO) has been touted as a promising technology for oily saline wastewater treatment. However, one great challenge of RO membrane is fouling phenomena, which is caused by the presence of hydrocarbon contents in the oily saline wastewater. This study focuses on the fabrication of antifouling RO membrane for accomplishing simultaneous separation of salt and oil. Thin film nanocomposite (TFN) RO membrane was formed by the layer by layer (LbL) assembly of positively charged TNS (pTNS) and negatively charged TNS (nTNS) on the surface of thin film composite (TFC) membrane. The unique features, rendered by hydrophilic TNS bilayer assembled on TFC membrane in the formation of a hydration layer to enhance the fouling resistance by high concentration oily saline water while maintaining the salt rejection, were discussed in this study. The characterization findings revealed that the surface properties of membrane were improved in terms of surface hydrophilicity, surface roughness, and polyamide(PA) cross-linking. The TFC RO membrane coated with 2-bilayer of TNS achieved >99% and >98% for oil and salt rejection, respectively. During the long-term study, the 2TNS-PA TFN membrane outperformed the pristine TFC membrane by exhibiting high permeability and much lower fouling propensity for low to high concentration of oily saline water concentration (1000 ppm, 5000 ppm and 10,000 ppm) over a 960 min operation. Meanwhile, the average permeability of uncoated TFC membrane could only be recovered by 95.7%, 89.1% and 82.9% for 1000 ppm, 5000 ppm and 10,000 ppm of the oily saline feedwater, respectively. The 2TNS-PA TFN membrane achieved almost 100% flux recovery for three cycles by hydraulic washing.

Antifouling and Flux Enhancement of Reverse Osmosis Membrane by Grafting Poly (3-Sulfopropyl Methacrylate) Brushes

“…The grafting of PSPMK polymer brushes results in a smooth hydrophilic membrane surface [ 47 ]. A pristine PA membrane shows high roughness owing to the presence of ridge and valley-like morphology [ 48 ]. The PA-NH 2 bar corresponds to the attachment of an amine group on the TFC-PA membrane.…”

A Dopamine/Tannic-Acid-Based Co-Deposition Combined with Phytic Acid Modification to Enhance the Anti-Fouling Property of RO Membrane

“…Membrane-based separation technologies, such as ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO), have become more and more popular in the industries of seawater desalination and wastewater treatment in recent years [ 1 , 2 , 3 ]. In particular, RO technology has been applied to various separation and enrichment applications due to its low energy consumption, simple operation, and its environmentally friendly nature [ 4 , 5 , 6 ]. However, the decrease of permeability, caused by membrane fouling during the long-term use of an RO membrane, needs to be solved urgently [ 7 , 8 , 9 , 10 , 11 ].…”

Novel High Flux Poly(m-phenylene isophtalamide)/TiO2 Membranes for Ultrafiltration with Enhanced Antifouling Performance

“…There are only a few works devoted to the application of composite polyamide/TiO 2 in membrane technology, particularly for the preparation of membranes for nanofiltration [ 27 , 28 , 29 , 30 , 31 , 32 ], reverse osmosis [ 33 , 34 , 35 , 36 , 37 , 38 ], pervaporation [ 39 ], and microfiltration [ 40 ]. In [ 27 , 28 , 29 , 30 ], the nanofiltration thin film nanocomposite (TFN) membranes based on PA were subjected to the modification with TiO 2 .…”

“…For reverse osmosis (RO), the modification with TiO 2 of PA membrane was carried out by various approaches: the introduction of fillers into polymer matrix [ 33 ] or the coating of fillers on the surface [ 34 , 35 , 36 , 37 , 38 ]. In [ 33 ], a RO PA membrane was developed by the incorporation of GO and TiO 2 to enhance the salt rejection and filtration performance for purification of drinking water and treatment of wastewater.…”

“…RO membrane modified with both acrylamide and TiO 2 under UV irradiation had enhanced water flux up to 18% with slightly higher rejection and better antifouling properties compared to the pristine membrane. RO TFN PA membrane was also modified by the layer-by-layer (LbL) assembly of positively and negatively charged titanium nanosheets (TNS) on the surface to improve the fouling resistance for high concentration oily saline water and to maintain a high level of salt rejection [ 37 ]. It was demonstrated that the modification improved surface hydrophilicity, roughness, and PA cross-linking.…”