Electro-nanofiltration membranes with positively charged polyamide layer for cations separation

Sheng, Fangmeng; Hou, Linxiao; Wang, Xiuxia; Irfan, Muhammad; Shehzad, Muhammad A.; Wu, Bin; Ren, Xuemei; Ge, Liang; Xu, Tongwen

doi:10.1016/j.memsci.2019.117453

Cited by 64 publications

(35 citation statements)

References 29 publications

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“…The Mg/Li ratio of the pristine brine could be effectively reduced, yet the loss of lithium resource and production of liquid waste problems remain unresolved. [ 5,9 ] Electrochemical lithium recovery shows good selectivity and recovery yield toward concentrated Mg 2+ /Li + mixtures, [ 3,10,11 ] but it involves high cost of electrochemical setups and relatively poor recycle stability. [ 3,5 ] Reaction‐coupled separation has also been exploited for the recovery of magnesium and lithium resources.…”

Section: Introductionmentioning

confidence: 99%

A Nano‐Heterogeneous Membrane for Efficient Separation of Lithium from High Magnesium/Lithium Ratio Brine

Peng

Zhen

2021

Adv Funct Materials

160

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Lithium extraction from salt lake brines is highly demanded to circumvent the lithium supply shortage. However, polymer nanofiltration membranes suffer from low lithium permeability while nanofluidic devices are hindered by complicated preparation and miniaturized scales despite high permeability. Here, the authors report a facile strategy to prepare positively charged nanofiltration membranes for ultrapermeable and selective separation of lithium ions from concentrated magnesium/lithium mixtures. A new electrolyte monomer (diaminoethimidazole bromide, DAIB) containing bidentate amine groups is designed to modify pristine polyamide composite membranes. Structure characterizations and simulations show that the DAIB modification brings about nano-heterogeneity that not only improves surface hydrophilicity, but also reduces water transport resistance through the ≈100 nm thick separation layer. Water permeance of the modified membrane improves fivefold and is coupled with good stability in 200-h continuous nanofiltration. It exhibits high lithium flux (0.7 mol m −2 h −1) for brines (Mg 2+ /Li + ratio 20) at 6 bar operation pressure.

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Section: Introductionmentioning

confidence: 99%

A Nano‐Heterogeneous Membrane for Efficient Separation of Lithium from High Magnesium/Lithium Ratio Brine

Peng

Zhen

2021

Adv Funct Materials

160

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“…Recently, the group prepared a NF membrane with a positively charged polyamide surface and showed increased Li + /Mg 2+ selectivity compared with ED with a commercial cation‐exchange membrane. [ 112 ] The positive charge excludes the divalent cation Mg 2+ more strongly than Li + and largely contributes to the increased selectivity. More importantly, because the active layer of the NF membrane was not very selective between cations and anions (because it is very thin), the limiting current density in electrodialysis with these NF membranes significantly increased.…”

Section: Nf Membranes With Monovalent/divalent Ion Selectivities In Nmentioning

confidence: 99%

Ion separations with membranes

Tang

Bruening

2020

Journal of Polymer Science

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Ion separations are important for resource recovery, water treatment, and energy production and storage. Techniques such as chemical precipitation, selective adsorption, and solvent extraction are effective, but membranes may separate ions continuously with less waste and lower energy costs. Separation of monovalent and multivalent ions with nanofiltration or electrodialysis membranes already enables water softening and edible salt purification. Similar membranes are attractive as separators in vanadium redox flow batteries. Selective partitioning of divalent counter-ions into ion-exchange membranes even allows transport of these ions against their concentration gradients in salt mixtures. However, separations of ions with the same charge is more challenging. Recent research demonstrated highly selective ion "sieving" at small scales. Separations using electrical potentials and differences in ion electrophoretic mobilities are promising, but relatively unexplored. Carrier-mediated transport affords high selectivity in liquid membranes, but these systems are not very stable, and selective transport via hopping between anchored carriers has proven elusive. Finally, this paper discusses how concentration polarization decreases selectivities in many membrane processes. Although development of selective, inexpensive ion-separation membranes is a work in progress, successes in water softening and edible salt purification suggests that future selective membranes will serve as complementary methods to traditional purification techniques.

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“…Water uptake (WU) and area swelling were measured according to the reported literature [40]. First, the membrane samples (1.5 × 1.5 cm 2 ) were dipped in DI water for 24 h to fully hydrate and weigh as W wet .…”

Section: Characterization Of Zsm-5/pva-based Mmmsmentioning

confidence: 99%

PVA-Based Mixed Matrix Membranes Comprising ZSM-5 for Cations Separation

et al. 2020

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The traditional ion-exchange membranes face the trade-off effect between the ion flux and perm-selectivity, which limits their application for selective ion separation. Herein, we amalgamated various amounts of the ZSM-5 with the polyvinyl alcohol as ions transport pathways to improve the permeability of monovalent cations and exclusively reject the divalent cations. The highest contents of ZSM-5 in the mixed matrix membranes (MMMs) can be extended up to 60 wt% while the MMMs with optimized content (50 wt%) achieved high perm-selectivity of 34.4 and 3.7 for H+/Zn2+ and Li+/Mg2+ systems, respectively. The obtained results are high in comparison with the commercial CSO membrane. The presence of cationic exchange sites in the ZSM-5 initiated the fast transport of proton, while the microporous crystalline morphology restricted the active transport of larger hydrated cations from the solutions. Moreover, the participating sites and porosity of ZSM-5 granted continuous channels for ions electromigration in order to give high limiting current density to the MMMs. The SEM analysis further exhibited that using ZSM-5 as conventional fillers, gave a uniform and homogenous formation to the membranes. However, the optimized amount of fillers and the assortment of a proper dispersion phase are two critical aspects and must be considered to avoid defects and agglomeration of these enhancers during the formation of membranes.

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Electro-nanofiltration membranes with positively charged polyamide layer for cations separation

Cited by 64 publications

References 29 publications

A Nano‐Heterogeneous Membrane for Efficient Separation of Lithium from High Magnesium/Lithium Ratio Brine

A Nano‐Heterogeneous Membrane for Efficient Separation of Lithium from High Magnesium/Lithium Ratio Brine

Ion separations with membranes

PVA-Based Mixed Matrix Membranes Comprising ZSM-5 for Cations Separation

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