The Donnan potential revealed

Göktürk, Pınar Aydoğan; Sujanani, Rahul; Qian, Jin; Wang, Ye; Katz, Lynn E.; Freeman, Benny D.; Crumlin, Ethan J.

doi:10.1038/s41467-022-33592-3

Cited by 51 publications

(35 citation statements)

References 39 publications

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“…Recent advances in AP-XPS instrumentation and methodology have enabled its use to directly quantify the electrochemical polarization and potential of conductive solidliquid interfaces. [37][38][39][40][41][42][43][44][45][46] For a material immersed in liquid, the work required to bring an emitted photoelectron from the surface to the detector depends directly on the degree of interfacial electrochemical potential. 38,39,42,43,47,48 Thus, by monitoring shis in XPS peaks (corresponding to changes in electron binding energies) of components of the solid surface, we aimed to quantify changes in the magnitude of interfacial polarization as a function of solution pH.…”

Section: Resultsmentioning

confidence: 99%

Metal nanoparticles supported on a nonconductive oxide undergo pH-dependent spontaneous polarization

et al. 2023

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Section: Resultsmentioning

confidence: 99%

Metal nanoparticles supported on a nonconductive oxide undergo pH-dependent spontaneous polarization

et al. 2023

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“…Traditional nanofiltration membranes are typically thin-film composites comprising a polyamide selective layer and a polysulfone support layer. – The polyamide layer is conventionally fabricated through interfacial polymerization between trimesoyl chloride and piperazine, and the membrane’s permeability and ion selectivity are dictated by the degree of crosslinking . Consequently, electrostatic potentials form along the membrane–liquid interface during operation, resulting from the ionization of residual carboxyl and amino moieties in polyamide matrix with water. ,– Ion fractionation of the feed solution is achieved through a combination of steric, dielectric and Donnan exclusion mechanisms. ,– In recent demonstrations, the monovalent cation selectivity can be effectively enhanced by up to six times with Donnan potential magnification through active layer functionalization with positive charge centers or surface coatings. – …”

Section: Introductionmentioning

confidence: 99%

Lithium Concentration from Salt-Lake Brine by Donnan-Enhanced Nanofiltration

Foo

Rehman

Bouma

et al. 2023

Environ. Sci. Technol.

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Membranes offer a scalable and cost-effective approach to ion separations for lithium recovery. In the case of salt-lake brines, however, the high feed salinity and low pH of the post-treated feed have an uncertain impact on nanofiltration's selectivity. Here, we adopt experimental and computational approaches to analyze the effect of pH and feed salinity and elucidate key selectivity mechanisms. Our data set comprises over 750 original ion rejection measurements, spanning five salinities and two pH levels, collected using brine solutions that model three saltlake compositions. Our results demonstrate that the Li + /Mg 2+ selectivity of polyamide membranes can be enhanced by 13 times with acid-pretreated feed solutions. This selectivity enhancement is attributed to the amplified Donnan potential from the ionization of carboxyl and amino moieties under low solution pH. As feed salinities increase from 10 to 250 g L −1 , the Li + /Mg 2+ selectivity decreases by ∼43%, a consequence of weakening exclusion mechanisms. Further, our analysis accentuates the importance of measuring separation factors using representative solution compositions to replicate the ion-transport behaviors with salt-lake brine. Consequently, our results reveal that predictions of ion rejection and Li + /Mg 2+ separation factors can be improved by up to 80% when feed solutions with the appropriate Cl − /SO 4 2− molar ratios are used.

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“…It should be noted that the concentrations of external solution were much lower than the ion exchange capacity of the substrate membrane (20 mM equivalent versus about 1.7 M equivalent per [ 37 ]), so an existence of relatively high Donnan potential difference [ 54 ] was expected.…”

Section: Methodsmentioning

confidence: 99%

Short-Term Stability of Electrochemical Properties of Layer-by-Layer Coated Heterogeneous Ion Exchange Membranes

et al. 2022

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Layer-by-layer adsorption allows the creation of versatile functional coatings for ion exchange membranes, but the stability of the coating and resulting properties of modified membranes in their operation is a frequently asked question. This paper examines the changes in voltammetric curves of layer-by-layer coated cation exchange membranes and pH-metry of desalination chamber with a studied membrane and an auxiliary anion exchange membrane after short-term tests, including over-limiting current modes. The practical operation of the membranes did not affect the voltammetric curves, but enhanced the generation of H+ and OH− ions in a system with polyethylenimine modified membrane in Ca2+ containing solution. It is shown that a distinction between the voltammetric curves of the membranes modified and the different polyamines persists during the operation and that, in the case of polyethylenimine, there is an additional zone of growth of potential drop in voltammetric curves and stronger generation of H+ and OH− ions as indicated by pH-metry.

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The Donnan potential revealed

Cited by 51 publications

References 39 publications

Metal nanoparticles supported on a nonconductive oxide undergo pH-dependent spontaneous polarization

Metal nanoparticles supported on a nonconductive oxide undergo pH-dependent spontaneous polarization

Lithium Concentration from Salt-Lake Brine by Donnan-Enhanced Nanofiltration

Short-Term Stability of Electrochemical Properties of Layer-by-Layer Coated Heterogeneous Ion Exchange Membranes

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