Functional group configuration influences salt transport in desalination membrane materials

Luo, H.; Chang, Kevin; Bahati, Kevin; Geise, Geoffrey M.

doi:10.1016/j.memsci.2019.117295

Cited by 23 publications

(37 citation statements)

References 58 publications

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“…To gain a more fundamental understanding of how MAAc and DMAA affected the membrane water uptake, we examined the state of water in the membranes. Three populations of water molecules are generally observed inside charged polymer membranes“free” water that behaves similarly to bulk water, “bound” or “non-freezable” water that is strongly associated with the polymer or ions, and “weakly bound” water in an intermediate state. ,− For the membranes studied here, the fractions of the total water uptake attributable to bound water ranged from 70 to 98% and were in a similar range to the bound water fractions of other methacrylate-based membranes reported in the literature. , Hence, the majority of the water absorbed by our membranes was strongly associated with the polymer.…”

Section: Resultssupporting

confidence: 71%

“…24,52−54 For the membranes studied here, the fractions of the total water uptake attributable to bound water ranged from 70 to 98% and were in a similar range to the bound water fractions of other methacrylate-based membranes reported in the literature. 24,55 Hence, the majority of the water absorbed by our membranes was strongly associated with the polymer.…”

Section: Anion Exchange Membranes With Non-covalentmentioning

confidence: 96%

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Tunable Anion Exchange Membrane Conductivity and Permselectivity via Non-Covalent, Hydrogen Bond Cross-Linking

Kingsbury

Hegde

Wang

et al. 2021

ACS Appl. Mater. Interfaces

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Ion exchange membranes (IEMs) are a key component of electrochemical processes that purify water, generate clean energy, and treat waste. Most conventional polymer IEMs are covalently cross-linked, which results in a challenging tradeoff relationship between two desirable propertieshigh permselectivity and high conductivityin which one property cannot be changed without negatively affecting the other. In an attempt to overcome this limitation, in this work we synthesized a series of anion exchange membranes containing non-covalent cross-links formed by a hydrogen bond donor (methacrylic acid) and a hydrogen bond acceptor (dimethylacrylamide). We show that these monomers act synergistically to improve both membrane permselectivity and conductivity relative to a control membrane without non-covalent cross-links. Furthermore, we show that the hydrogen bond donor and acceptor loading can be used to tune permselectivity and conductivity relatively independently of one another, escaping the tradeoff observed in conventional membranes.

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Section: Resultssupporting

confidence: 71%

Section: Anion Exchange Membranes With Non-covalentmentioning

confidence: 96%

Tunable Anion Exchange Membrane Conductivity and Permselectivity via Non-Covalent, Hydrogen Bond Cross-Linking

Kingsbury

Hegde

Wang

et al. 2021

ACS Appl. Mater. Interfaces

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“…Compared with other water treatment technologies, such as nanofiltration, reverse osmosis, electrodialysis, the solar evaporation technology using CNFAs is efficient, low cost, energy-saving, and convenient maintenance which makes it unparalleled advantages and potential for seawater desalination and wastewater treatment. [48][49][50][51][52][53] In summary, we assemble SiO 2 nanofibers and CNTs into cellular structured nanofibrous aerogels with vertically aligned vessels and porous vessel walls by the fiber freeze-shaping technology. With this unique cellular architecture, the CNFAs exhibit an excellent salt-resistance with stable and efficient solar desalination even in 20% brine and under 6-sun irradiation, better than current reports.…”

mentioning

confidence: 99%

Cellular Structured CNTs@SiO₂ Nanofibrous Aerogels with Vertically Aligned Vessels for Salt‐Resistant Solar Desalination

et al. 2020

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The emerging solar desalination technology is considered as one of the most promising strategies to ensure water security. However, with the proceeding of solar desalination, salt crystallization on the surface of solar evaporators caused by increasing salinity of seawater will result in a decrease in the evaporation rate. Thus, it is still challenging to fabricate solar evaporators with superior salt resistance. In this work, elastic ceramic‐based nanofibrous aerogels with a cellular architecture are fabricated by the combination of electrospinning and fiber freeze‐shaping technologies, which are composed of vertically aligned vessels and porous vessel walls. Under the action of convection and diffusion promoted by this unique cellular architecture, the aerogels exhibit a superior salt‐resistance without any salt crystals on the surface of aerogels even in 20% brine and under 6‐sun irradiation. Moreover, by virtue of the synergistic effect of the promising structure and light absorbance of carbon nanotubes, aerogels possess a high light absorbance of up to 98% and excellent evaporation performance achieving 1.50 kg m−2 h−1 under 1‐sun irradiation. This work may provide a fascinating avenue for the desalination of seawater in a salt‐resistance and efficient manner.

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“…All changes in membrane flux and rejection rate were consistent with the trade-off effect. Water/salt permeability selectivity as a function of diffusive water permeability for the PA-TFC membrane and the D2/T4-PhA modified membrane is shown in Figure S2 [ 39 , 40 , 41 , 42 ].…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2021

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Reverse osmosis (RO) membranes are widely used in the field of water treatment. However, there are inevitably various fouling problems during long-term use. Surface engineering of RO membranes, such as hydrophilic modification, has attracted broad attention for improving the anti-fouling performance. In this work, we constructed a green biomimetic composite modification layer on the surface of polyamide membranes using a dopamine (DA)/tannic acid (TA) co-deposited layer to bridge the polyamide surface and hydrophilic phytic acids (PhA). The DA/TA interlayer could firmly adhere to the RO membranes, reducing the aggregation of DA and providing abundant phenolic hydroxyl sites to graft PhA. Meanwhile, the anchored PhA molecule bearing six phosphate groups could effectively improve the superficial hydrophilicity. The membranes were characterized by the SEM, AFM, XPS, water contact angle test, and zeta potential test. After surface modification, the hydrophilicity, smoothness, and surface electronegativity were enhanced obviously. The flux and rejection of the virgin membrane were 76.05 L·m−2·h−1 and 97.32%, respectively. While the modified D2/T4-PhA membrane showed decent permeability with a water flux of 57.37 L·m−2·h−1 and a salt rejection of 98.29%. In the dynamic fouling test, the modified RO membranes demonstrated enhanced anti-fouling performance toward serum albumins (BSA), sodium alginates (SA), and dodecyl trimethyl ammonium bromides (DTAB). In addition, the modified membrane showed excellent stability in the 40 h long-term test.

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Functional group configuration influences salt transport in desalination membrane materials

Cited by 23 publications

References 58 publications

Tunable Anion Exchange Membrane Conductivity and Permselectivity via Non-Covalent, Hydrogen Bond Cross-Linking

Tunable Anion Exchange Membrane Conductivity and Permselectivity via Non-Covalent, Hydrogen Bond Cross-Linking

Cellular Structured CNTs@SiO₂ Nanofibrous Aerogels with Vertically Aligned Vessels for Salt‐Resistant Solar Desalination

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

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Functional group configuration influences salt transport in desalination membrane materials

Cited by 23 publications

References 58 publications

Tunable Anion Exchange Membrane Conductivity and Permselectivity via Non-Covalent, Hydrogen Bond Cross-Linking

Tunable Anion Exchange Membrane Conductivity and Permselectivity via Non-Covalent, Hydrogen Bond Cross-Linking

Cellular Structured CNTs@SiO2 Nanofibrous Aerogels with Vertically Aligned Vessels for Salt‐Resistant Solar Desalination

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

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Cellular Structured CNTs@SiO₂ Nanofibrous Aerogels with Vertically Aligned Vessels for Salt‐Resistant Solar Desalination