Overview of Supported Ionic Liquids: Effect of Specific Surface Area and Pore Structure
Ionic liquids (ILs) are room-temperature molten salts composed entirely of ions—typically an organic cation paired with an inorganic or organic anion. Compared with conventional organic solvents, ILs offer:
✓ Broad liquid-phase windows and thermal/physicochemical stability (often stable below ~300 °C),
✓ Negligible vapor pressure and nonflammability for cleaner operation, even under high vacuum,
✓ Wide solubility ranges that accommodate inorganic/organic compounds and polymers, sometimes with dual roles as medium and catalyst,
✓ Favourable electrochemical behaviour for electrolytes and reaction media, and;
✓ Molecular tunability by varying cation/anion structure.(1,2)
Supported ionic liquids (SILs) are functional ILs immobilized on porous carriers—by physical deposition or chemical anchoring—to form thin IL films within a solid matrix. Confining the IL converts a difficult-to-handle liquid into a solid-like composite that combines the chemical selectivity of the IL with the mass-transfer and mechanical advantages of a porous support. This approach mitigates the high viscosity and separation challenges of neat ILs and simplifies recovery and reuse, which is why SILs have become a focus across adsorption and catalysis. SILs show broad utility in gas and liquid adsorption/separation,(3) function as catalysts or catalyst supports,(4) and provide efficient aqueous-phase removal of heavy-metal ions.(5)
