Layer-by-layer membrane modification allows scandium recovery by nanofiltration

Remmen, Kirsten; Schäfer, Roman; Hedwig, Sebastian; Wintgens, Thomas; Weßling, Matthias; Lenz, Markus

doi:10.1039/c9ew00509a

Cited by 26 publications

(59 citation statements)

References 42 publications

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“…The PWP values reported here are consistently low relative to the ones of PSS–PDADMAC multilayer membranes in the literature (5–15 L m –2 h –1 bar –1 ). 20 , 29 , 57 − 60 This variation might be due to differences in selective layer thickness and density. On the other hand, MgSO 4 retentions are reasonably comparable; in the literature, best results vary from 60% to more than 90%.…”

Section: Resultsmentioning

confidence: 99%

“… 28 More significantly, membranes coated with PSS–PDADMACshowed stable MgSO 4 retention even at high acid concentrations such as 3 M HCl. 29 Thus, polyelectrolyte multilayer based nanofiltration membranes, especially of PSS and PDADMAC, hold great promise. Unfortunately, the preparation of PEM membranes is time-consuming and laborious.…”

Section: Introductionmentioning

confidence: 99%

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Polyelectrolyte Complex Membranes via Salinity Change Induced Aqueous Phase Separation

Durmaz

Baig

Willott

et al. 2020

ACS Appl. Polym. Mater.

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Polymeric membranes are used on very large scales for drinking water production and kidney dialysis, but they are nearly always prepared by using large quantities of unsustainable and toxic aprotic solvents. In this study, a water-based, sustainable, and simple way of making polymeric membranes is presented without the need for harmful solvents or extreme pH conditions. Membranes were prepared from water-insoluble polyelectrolyte complexes (PECs) via aqueous phase separation (APS). Strong polyelectrolytes (PEs), poly(sodium 4-styrenesulfonate) (PSS), and poly(diallyldimethylammonium chloride) (PDADMAC) were mixed in the presence of excess of salt, thereby preventing complexation. Immersing a thin film of this mixture into a low-salinity bath induces complexation and consequently the precipitation of a solid PEC-based membrane. This approach leads to asymmetric nanofiltration membranes, with thin dense top layers and porous, macrovoid-free support layers. While the PSS molecular weight and the total polymer concentrations of the casting mixture did not significantly affect the membrane structure, they did affect the film formation process, the resulting mechanical stability of the films, and the membrane separation properties. The salt concentration of the coagulation bath has a large effect on membrane structure and allows for control over the thickness of the separation layer. The nanofiltration membranes prepared by APS have a low molecular weight cutoff (<300 Da), a high MgSO 4 retention (∼80%), and good stability even at high pressures (10 bar). PE complexation induced APS is a simple and sustainable way to prepare membranes where membrane structure and performance can be tuned with molecular weight, polymer concentration, and ionic strength.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Polyelectrolyte Complex Membranes via Salinity Change Induced Aqueous Phase Separation

Durmaz

Baig

Willott

et al. 2020

ACS Appl. Polym. Mater.

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“…Membrane processes are promising methods for the separation of pollutants. Membranes obtained by layer deposition can be used for the separation of concerning pollutants from water, such as pharmaceuticals, dyes and metal ions using ultrafiltration (UF), reverse osmosis (RO), or nanofiltration (NF), as demonstrated by many authors [ 202 , 203 , 204 , 205 , 206 , 207 ].…”

Section: Biomedical and Environmental Applications Of Polyelectrolyte Multilayersmentioning

confidence: 99%

Polyelectrolyte Multilayers: An Overview on Fabrication, Properties, and Biomedical and Environmental Applications

Petrila¹,

Bucătariu

Mihai

et al. 2021

Materials

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Polyelectrolyte multilayers are versatile materials that are used in a large number of domains, including biomedical and environmental applications. The fabrication of polyelectrolyte multilayers using the layer-by-layer technique is one of the simplest methods to obtain composite functional materials. The properties of the final material can be easily tuned by changing the deposition conditions and the used building blocks. This review presents the main characteristics of polyelectrolyte multilayers, the fabrication methods currently used, and the factors influencing the layer-by-layer assembly of polyelectrolytes. The last section of this paper presents some of the most important applications of polyelectrolyte multilayers, with a special focus on biomedical and environmental applications.

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“…In the described study, a ceramic membrane coated with three bi-layers was exposed up to a 1 M HCl solution for several hours and was shown to remain stable [13]. We also reported good stability for polymeric LbL membranes in a 1 M HCl solution [27]. In a study by Nehme et al [28], coated capillaries were rinsed with 1 M HCl for 30 min.…”

Section: Introductionmentioning

confidence: 57%

Assessment of Layer-By-Layer Modified Nanofiltration Membrane Stability in Phosphoric Acid

et al. 2020

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Nanofiltration (NF) can enable P recovery from waste streams via retaining multivalent impurities from spent pickling acid. However, with the currently available membranes, an economically feasible process is impossible. Layer-by-layer modified NF membranes are a promising solution for the recovery of P from acidic leachate. LbL membranes show a high level of versatility in terms of fine tuning for ion retention, which is necessary to achieve sufficient phosphorus yields. However, the stability of layer-by-layer modified membranes during phosphoric acid (H3PO4) filtration needs to be further investigated. In our study, we show that a polyethersulfone hollow fiber membrane modified with four or eight bi-layers was stable during immersing and filtering of a 15% H3PO4 solution. A sulfonated polyethersulfone (sPES)-based hollow fiber LbL membrane was only stable during filtration. Thus, we show the importance of applying real process conditions to evaluate membranes. Another important aspect is the influence of the high ionic strength of the feed solution on the membrane. We show that a high ionic strength led to a decrease in Mg retention, which could be increased to 85% by adjusting the process parameters.

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Layer-by-layer membrane modification allows scandium recovery by nanofiltration

Abstract: Layer-by-layer membrane modification yields acid resistant membranes for selective scandium recovery from wastes.

Cited by 26 publications

References 42 publications

Polyelectrolyte Complex Membranes via Salinity Change Induced Aqueous Phase Separation

Polyelectrolyte Complex Membranes via Salinity Change Induced Aqueous Phase Separation

Polyelectrolyte Multilayers: An Overview on Fabrication, Properties, and Biomedical and Environmental Applications

Assessment of Layer-By-Layer Modified Nanofiltration Membrane Stability in Phosphoric Acid

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