Polymer Inclusion Membranes for Ion Transport and Separation

Polymer inclusion membranes (PIMs) represent a versatile separation technology in which a base polymer—commonly cellulose triacetate or poly(vinyl chloride)—is plasticised and doped with selective ion carriers to facilitate the transport of target ions across the membrane. The fundamental mechanism hinges on a carrier-mediated complexation at the feed interface, diffusion of the carrier–ion complex through the polymer matrix, and subsequent release of the ion into the receiving phase. This approach affords high selectivities and tunable fluxes under mild conditions, offering low energy requirements and minimal chemical consumption compared with conventional liquid–liquid extraction or pressure-driven membrane processes. Recent developments have emphasised the role of membrane morphology and mechanical integrity in governing transport kinetics, while the incorporation of task-specific ionic liquids has extended the applicability of PIMs to a broader spectrum of cationic and anionic species. Owing to their modular design and ease of fabrication, PIMs have emerged as promising platforms for environmental remediation, resource recovery from industrial and electronic waste streams, and targeted removal of toxic and valuable ions in water treatment contexts worldwide.

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Polymer Inclusion Membranes for Ion Transport and Separation publication trend

The graph below shows the total number of articles in polymer inclusion membranes for ion transport and separation across all publications each year (not limited to Nature Index journals).

Technical terms

Polymer Inclusion Membrane (PIM): A composite membrane of a base polymer, plasticiser and an ion carrier that enables selective transport of target ions via a facilitated diffusion mechanism.

Ionic Liquid (IL): A non-volatile, liquid salt composed of organic cations and anions, designed as a multifunctional extractant and plasticiser within PIMs.

Plasticiser: A low-molecular-weight additive that imparts flexibility and enhances diffusion of carrier–ion complexes within the polymer matrix.

Flux: The rate at which ions traverse the membrane surface, typically expressed as amount per unit area per unit time.

Selectivity Coefficient: The ratio of transport rates of two different ions, indicating the preference of a PIM for one ion over another.

References

1. Ionic liquid-based polymer inclusion membranes for metal ions extraction and recovery: Fundamentals, considerations, and prospects. Chemical Engineering Journal (2024).
2. The Influence of the Morphology and Mechanical Properties of Polymer Inclusion Membranes (PIMs) on Zinc Ion Separation from Aqueous Solutions. Polymers (2018).
3. Separation of Zn(II), Cr(III), and Ni(II) Ions Using the Polymer Inclusion Membranes Containing Acetylacetone Derivative as the Carrier. Membranes (2020).
4. Fluoride removal from natural waters by polymer inclusion membranes. Journal of Membrane Science (2022).