Highly efficient monovalent ion transport enabled by ionic crosslinking‐induced nanochannels

Abstract

Charge-governed ion transport is of significant importance to industrial development, and advanced membrane materials with fast and selective ionic transport are essential components. In cell membranes, ionic transport is mainly determined by the charge-governed protein channels, representing an architecture with functional differentiation. Inspired by this, a novel class of membranes was developed by ionically crosslinking sulfonated (poly[ether ether ketone]) and quaternized poly (2,6-dimethyl-1,4-phenylene oxide) to construct the cationic conductive biomimetic nanochannels. Ionic crosslinking was tailored to realize nanophase separation and efficient ion transport mainly based on surface chemistry without altering the scaffold feature of polymeric pore channels. The best-performing ionic crosslinking membrane exhibited a high ionic permeation (2.23 molÁm À2 Áh À1 for K + ) and high cationic selectivity (7.91 for K + /Mg 2+ ), which were comparable with the commercial monovalent cation permselective CIMS membrane, owing to the negligent surface resistance toward monovalent cations but strong positively charged repulsion against divalent cations.

The role of ion‐membrane interactions in fast and selective mono/multivalent ion separation with hierarchical nanochannels

“…A constant current was applied, and the voltage across the membrane was measured using a multimeter (VC890D, Xi'an Beicheng Electronics, China). The area resistance ( R A , Ω cm 2 ) of the newly developed CEM was obtained using the following equation 42 : where U is the applied voltage (mV), U 0 is the applied voltage (mV) between the dilution and concentration chambers without membrane loading, I is the applied current (mA), and A m is the efficient surface area (7.07 cm 2 ) of the membrane.…”

“…A constant current was applied, and the voltage across the membrane was measured using a multimeter (VC890D, Xi'an Beicheng Electronics, China). The area resistance (R A , Ω cm 2 ) of the newly developed CEM was obtained using the following equation 42 :…”

Developmental Progress of Electrodialysis Technologies and Membrane Materials for Extraction of Lithium from Salt Lake Brines

“…Inspired by the electric eel cell membrane structures, Lin et al 176 developed a bioinspired architecture of nanochannels via nanophase separation, as shown in Figure 17c. The ionic cross-linking membranes were fabricated by tuning the contents of two electrolyte ionomers with similar linear molecular structures but opposite chargers.…”

Efficient acid/alkali recovery enabled by only one negatively charged microporous polymer membrane

“…In practice, the membranes used in the recovery of acid and alkali via membrane processes are constrained by the tradeoff between permeability and selectivity. [13][14][15] There are no feasible membranes that could function well in both processes, even though ion exchange membranes with varied polymer architectures, for example, comb-shaped type, 16 side chain type, [17][18][19][20] organic-inorganic hybrid membranes, [21][22][23] and so forth, have been developed. For example, comb-shaped sulfonated poly (ether ether ketone) was employed in electrodialysis-based acid recovery and presented the highest H + flux of 2.41 Â 10 À7 mol cm À2 s À1 and but a very low H + /Fe 2+ selectivity of 32.13.…”

“…In principle, both anion exchange membrane (AEM) and cation exchange membrane (CEM) can be adopted in either process. In practice, the membranes used in the recovery of acid and alkali via membrane processes are constrained by the tradeoff between permeability and selectivity 13–15 . There are no feasible membranes that could function well in both processes, even though ion exchange membranes with varied polymer architectures, for example, comb‐shaped type, 16 side chain type, 17–20 organic–inorganic hybrid membranes, 21–23 and so forth, have been developed.…”