Polyamide nanofilms with linearly-tunable thickness for high performance nanofiltration

Zhu, Cheng‐Ye; Liu, Chang; Yang, Jing; Guo, Bian‐Bian; Li, Haonan; Xu, Zhi‐Kang

doi:10.1016/j.memsci.2021.119142

Cited by 133 publications

(30 citation statements)

References 43 publications

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“…The result showed that TFC VAIP had higher N–C=O/O–C=O ratio (5.53) than TFC TIP membrane (4.57), meaning it had a denser polyamide layer. The vacuum-assisted method can enrich diamine monomers on the mPAN support, which ensures that there are enough diamine monomers to react with TMC, thereby enhancing the cross-linking degree of the resulting polyamide layer [ 42 , 43 ]. A denser structure would be beneficial to the high separation efficiency of the membrane.…”

Section: Resultsmentioning

confidence: 99%

Vacuum-Assisted Interfacial Polymerization Technique for Enhanced Pervaporation Separation Performance of Thin-Film Composite Membranes

et al. 2022

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In this work, thin-film composite polyamide membranes were fabricated using triethylenetetramine (TETA) and trimesoyl chloride (TMC) following the vacuum-assisted interfacial polymerization (VAIP) method for the pervaporation (PV) dehydration of aqueous isopropanol (IPA) solution. The physical and chemical properties as well as separation performance of the TFCVAIP membranes were compared with the membrane prepared using the traditional interfacial polymerization (TIP) technique (TFCTIP). Characterization results showed that the TFCVAIP membrane had a higher crosslinking degree, higher surface roughness, and denser structure than the TFCTIP membrane. As a result, the TFCVAIP membrane exhibited a higher separation performance in 70 wt.% aqueous IPA solution at 25 °C with permeation flux of 1504 ± 169 g∙m−2∙h−1, water concentration in permeate of 99.26 ± 0.53 wt%, and separation factor of 314 (five times higher than TFCTIP). Moreover, the optimization of IP parameters, such as variation of TETA and TMC concentrations as well as polymerization time for the TFCVAIP membrane, was carried out. The optimum condition in fabricating the TFCVAIP membrane was 0.05 wt.% TETA, 0.1 wt% TMC, and 60 s polymerization time.

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Section: Resultsmentioning

confidence: 99%

Vacuum-Assisted Interfacial Polymerization Technique for Enhanced Pervaporation Separation Performance of Thin-Film Composite Membranes

et al. 2022

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“…On the one hand, some additives are introduced into the aqueous phase of an IP system to subtly manipulate the amine diffusion rate from the solution toward the reaction zone at the interface. [117][118][119][120] Excitingly, by virtue of their chemical or physical interaction at a suitable density with amine monomers or incorporation into PA layer, reduced thickness and interesting micro-structures may be achieved simultaneously. Ultrathin Turing structure was discovered by Tan et al after adding polyvinyl alcohol (PVA) into the aqueous solution, which was believed to regulate the polymerization process (Figure 6a) and water permeance of ≈25 L m −2 h −1 bar −1 was reached at the Na 2 SO 4 rejection of 99.6%.…”

Section: Polyamidementioning

confidence: 99%

Ultrathin Membranes for Separations: A New Era Driven by Advanced Nanotechnology

et al. 2022

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“…Creating interlayers between the support and the top PA layer provides an alternative approach for regulating the diffusion rate of the PIP monomers, thereby constructing high-performance NF membranes without functionalizing the supports. − The highly efficient NF membranes have successfully broken the trade-off lines for TFC desalination membranes, but the compatibility of the triple layers is far from satisfactory. In situ incorporation of macromolecules/inorganic salts into the aqueous solutions was considered as an efficient and scalable strategy to confine the diffusion of PIP monomers via hydrogen bonding, reactive complexation, and electrostatic interaction. − However, previous studies mainly focus on the PIP diffusion regulation; the tailored diffusion of TMC and the simultaneous diffusion control of both the PIP and TMC monomers have rarely been reported. Considering the differences in the transport behavior during the IP reaction, it is of great value to explore the role of the simultaneous confined diffusion for the PIP and TMC monomers in the structure and performance of the TFC NF membranes.…”

Section: Introductionmentioning

confidence: 99%

Toward Enhancing Desalination and Heavy Metal Removal of TFC Nanofiltration Membranes: A Cost-Effective Interface Temperature-Regulated Interfacial Polymerization

Cheng

Lai

et al. 2021

ACS Appl. Mater. Interfaces

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Polyamide (PA) chemistry-based nanofiltration (NF) membranes have an important role in the field of seawater desalination and wastewater reclamation. Achieving an ultrathin and defect-free active layer via precisely controlled interfacial polymerization (IP) is an effective routine to improve the separation efficiencies of NF membranes. Herein, the morphologies and chemical structures of the thin-film composite (TFC) NF membranes were accurately regulated by tailoring the interfacial reaction temperature during the IP process. This strategy was achieved by controlling the temperature (−15, 5, 20, 35, and 50°) of the oil-phase solutions. The structural compositions, morphological variations, and separation features of the fabricated NF membranes were studied in detail. In addition, the formation mechanisms of the NF membranes featuring different PAs were also proposed and discussed. The temperature-assisted IP (TAIP) method greatly changed the compositions of the resultant PA membranes. A very smooth and thin PA film was obtained for the NF membranes fabricated at a low interfacial temperature; thus, a high 19.2 L m −2 h −1 bar −1 of water permeance and 97.7% of Na 2 SO 4 rejection were observed. With regard to the NF membranes obtained at a high interfacial temperature, a lower water permeance and higher salt rejection with fewer membrane defects were achieved. Impressively, the high interfacial temperature-assisted NF membranes exhibited uniform coffee-ring-like surface morphologies. The special surface-featured NF membrane showed superior separation for selected heavy metals. Rejections of 93.9%, 97.9%, and 87.7% for Cu 2+ , Mn 2+ , and Cd 2+ were observed with the optimized membrane. Three cycles of fouling tests indicated that NF membranes fabricated at low temperatures exhibited excellent antifouling behavior, whereas a high interface temperature contributed to the formation of NF membranes with high fouling tendency. This study provides an economical, facile, and universal TAIP strategy for tailoring the performances of TFC PA membranes for environmental water treatment.

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Polyamide nanofilms with linearly-tunable thickness for high performance nanofiltration

Cited by 133 publications

References 43 publications

Vacuum-Assisted Interfacial Polymerization Technique for Enhanced Pervaporation Separation Performance of Thin-Film Composite Membranes

Vacuum-Assisted Interfacial Polymerization Technique for Enhanced Pervaporation Separation Performance of Thin-Film Composite Membranes

Ultrathin Membranes for Separations: A New Era Driven by Advanced Nanotechnology

Toward Enhancing Desalination and Heavy Metal Removal of TFC Nanofiltration Membranes: A Cost-Effective Interface Temperature-Regulated Interfacial Polymerization

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