scholarly journals Thin Film Composite Forward Osmosis Membrane with Single-Walled Carbon Nanotubes Interlayer for Alleviating Internal Concentration Polarization

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 260 ◽  
Author(s):  
Yuanyuan Tang ◽  
Shan Li ◽  
Jia Xu ◽  
Congjie Gao

This study reported a series of thin film composite (TFC) membranes with single-walled nanotubes (SWCNTs) interlayers for the forward osmosis (FO) application. Pure SWCNTs with ultrahigh length-to-diameter ratio and without any functional group were applied to form an interconnect network interlayer via strong π-π interactions. Compared to the TFC membrane without SWCNTs interlayer, our TFC membrane with optimal SWCNTs interlayer exhibited more than three times the water permeability (A) of 3.3 L m−2h−1bar−1 in RO mode with 500 mg L−1 NaCl as feed solution and nearly three-fold higher FO water flux of 62.8 L m−2 h−1 in FO mode with the deionized water as feed solution and 1 M NaCl as draw solution. Meanwhile, the TFC membrane with SWCNTs interlayer exhibited significantly reduced membrane structure parameters (S) to immensely mitigate the effect of internal concentration polarization (ICP) in support layer with micro-sized pores in favor of higher water flux. It showed that the pure SWCNTs interlayer could be an effective strategy to apply in FO membranes.

2019 ◽  
Vol 1 (1) ◽  
pp. 18-32 ◽  
Author(s):  
Ke Zheng ◽  
Shaoqi Zhou

Abstract In this study, cyanoethyl cellulose (CEC) was used as a membrane material, and polyvinylpyrrolidone (PVP) was used as pore-forming agent to prepare the substrates for the thin-film composite (TFC) forward osmosis (FO) membrane for the first time. The experimental results demonstrate that the properties of the substrates were significantly improved after PVP was added. The scanning electron microscope (SEM) images show that a two-sublayer structure, a fringe-like top sublayer and macrovoids with sponge-like wall bottom sublayer, were formed after the addition of PVP. These improvements contributed to improved membrane performance during FO tests. Meanwhile, after adding PVP, the TFC membranes exhibited good water flux, and excellent specific reverse salt flux. For instance, the TFC-M2 exhibited 9.10/20.67 LMH water flux, 1.35/2.24 gMH reverse salt flux, and 0.15/0.11 g/L specific reverse salt flux in FO/pressure-retarded osmosis mode while using 1 M NaCl as the draw solution and deionized (DI) water as the feed solution.


2014 ◽  
Vol 900 ◽  
pp. 191-196 ◽  
Author(s):  
Ning Ma ◽  
Cao Liu ◽  
Pei Jing Wang ◽  
Chu Yang Tang

Nanocomposite membranes with enhanced performance were investigated for forward osmosis (FO) by incorporation of nanoporous materials. The incorporation of zeolite into both polysulfone (PSf) substrates and polyamide (PA) rejection layer of thin film composite (TFC) membrane (PSf-TFC) could effectively improve FO membrane performance. In the case of zeolite loading into PA layer, the resulted PSf based thin film nanocomposite (PSf-TFN) membrane showed improved but limited water permeability of the rejection layer, corresponding to ~1.76 times water flux higher than PSf-TFC membrane. Significantly, the polysulfone nanocomposite (PSfN) based TFC membrane (PSfN-TFC), which formed by embedding zeolite nanoparticles in PSf substrates, not only enhanced water permeability of the polyamide rejection layer but also reduced internal concentration polarization (ICP) effect, and thus improved FO membrane performance significantly, which corresponding to ~2.50 times water flux higher than PSf-TFC membrane.


2020 ◽  
Vol 13 (2) ◽  
pp. 51-57
Author(s):  
Mustafa Al-Furaiji ◽  
Mohammed Kadhom ◽  
Khairi Kalash ◽  
Basma Waisi ◽  
Noor Albayati

Abstract. The forward osmosis (FO) process has been considered to be a viable option for water desalination in comparison to the traditional processes like reverse osmosis, regarding energy consumption and economical operation. In this work, a polyacrylonitrile (PAN) nanofiber support layer was prepared using the electrospinning process as a modern method. Then, an interfacial polymerization reaction between m-phenylenediamine (MPD) and trimesoyl chloride (TMC) was carried out to generate a polyamide selective thin-film composite (TFC) membrane on the support layer. The TFC membrane was tested in FO mode (feed solution facing the active layer) using the standard methodology and compared to a commercially available cellulose triacetate membrane (CTA). The synthesized membrane showed a high performance in terms of water flux (16 Lm −2 h−1) but traded the salt rejection (4 gm−2 h−1) compared with the commercial CTA membrane (water flux = 13 Lm−2 h−1 and salt rejection = 3 gm−2 h−1) at no applied pressure and room temperature. Scanning electron microscopy (SEM), contact angle, mechanical properties, porosity, and performance characterizations were conducted to examine the membrane.


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