Abstract
The advantages of thin film nanocomposite reverse osmosis (TFN-RO) membranes have been demonstrated by numerous studies within the last decade. This study proposes a facile and novel method to tune the microscale and nanoscale structures, which has good potential to fabricate high-performance TFN-RO membranes. This method involves the addition of alkyl capped silica nanoparticles (alkyl-silica NPs) into the organic phase during interfacial polymerization (IP). We discovered for the first time that the high concentration alkyl-silica NPs in organic solvent isopar-G can limit the diffusion of MPD molecules at the interface, therefore shaping the intrinsic thickness and microstructures of the PA layer. Moreover, the alkyl group modification greatly reduces the NPs agglomeration and increases the compatibility between the NPs and the PA matrix. We further demonstrate that the doping of alkyl-silica NPs impacts the performance of the TFN-RO membrane by affecting intrinsic thickness, higher surface area, hydrophobic plugging effect, and higher surface charge by a series of characterization. At brackish water desalination conditions (2000 ppm NaCl, 1.55 MPa), the optimal brackish water flux was 55.3 L/m2∙h, and the rejection was maintained at 99.6%, or even exceeded this baseline. At seawater desalination conditions (32,000 ppm NaCl, 5.5 MPa), the optimized seawater flux reached 67.7 L/m2∙h, and the rejection was sustained at 99.4%. Moreover, the boron rejection was elevated by 11%, which benefits from a hydrophobic plugging effect of the alkyl groups.
Highlights
Owing to its low energy consumption and efficiency, reverse osmosis (RO) has become the most popular purification methods to provide for clean water needs through membrane-based processes such as desalination, water reclamation, and water detoxification, etc. [1,2,3,4]
The recently established polyamide (PA)-based thin film nanocomposite reverse osmosis (TFN-RO) membranes have proven to be promising by both research and industrial efforts over the past decade [8,9,10,11,12,13,14]
Most thin film nanocomposite (TFN) membranes have been prepared by blending hydrophilic nanoparticles (NPs) with the amine aqueous phase during the interfacial polymerization (IP) step due to the facile synthesis of the nanomaterials and ease of fabrication process
Summary
Owing to its low energy consumption and efficiency, reverse osmosis (RO) has become the most popular purification methods to provide for clean water needs through membrane-based processes such as desalination, water reclamation, and water detoxification, etc. [1,2,3,4]. Most thin film nanocomposite (TFN) membranes have been prepared by blending hydrophilic nanoparticles (NPs) with the amine aqueous phase during the interfacial polymerization (IP) step due to the facile synthesis of the nanomaterials and ease of fabrication process. AgNPs within the PA layer, forming defects at the interface of NPs and polyamide In this case, the incorporation of inorganic NPs allows for the enhancement of surface hydrophilicity and higher water flux, but introduces ion-nonselective voids, which negatively impacts the salt rejection [22]. When NPs are added to the organic phase, the properties of the PA separation layer are enhanced and membranes contain fewer defects, resulting in higher roughness and improved water flux while maintaining salt rejection [9,24]. The performance of the resultant TFN membrane is examined in both brackish water and seawater desalination conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
