1. 1 Liquid Membranes Membrane Phase 1 Phase 2

2. 2 Types of LM  Immobilised (ILM) or Supported (SLM)  Emulsion (ELM) Organic liquid & surfactant Receiving phase Porous support liquid  Volumetric or Bulk (VLM)

3. 3 Facilitated Transport A A Facilitated transport Diffusive transport A A AC

4. 4 Carrier Mediated Transport Mobile CarrierFixed Carrier 10 -5 -10 -7 Diffusivities (cm 2 /s) 10 -6 -10 -8 >10 -7 MobileGelFixed

5. 5 A A AC BC B B Types of FT… Reaction A+C AC Uncoupled A A AC Coupled

6. 6 A A AC BC B B Coupled configurations A AC A B B B Counter coupled transport Reaction A+CB AC+B Co-coupled transport

7. 7 FT Mechanism M+M+ H+H+ M+M+ HC MC H+H+ Source phaseLMStrip phase 1) Carrier reacts with solute 2) The complexed carrier diffuses across the membrane 3) Because the adjacent solution is dilute, the solute carrier reaction is reversed, releasing solute 4) The carrier returns across the membrane

8. 8 FT: fast reaction case  Carrier-solute Complex reaction: Flux of solute A: Flux due to diffusion Flux due to complexation K...equilibrium constant k...distribution coefficient

9. 9 Limiting cases Fickean diffusion Diffusion of the complex Total Flux Fickean Flux Damkolher number Intermediate Region C A,0 >>C AC,0 C AC,0 >>C A,0

10. 10 Planar Flat Laboratory Hollow Fiber Industry Spiral wound SLM Geometry

11. 11 Comparing  Flat Sheet  Hollow Fiber Feed and strip solutions mix directly and the integrity of separation is lost. Small leaks do not seriously affect the performance If the membrane liquid is contaminated, it can be easily be replenished. The pressure drop in fibre bundles is larger Can be fabricated easily in the lab

12. 12 Solvent loss Carrier loss Liquid flows evaporation disolution large  p Irreversible side reactions Solvent condensation SLM Problems

13. 13 Stabilization techniques

14. 14 Classical Fields of Applications  Facilitated transport of gases  Oxigen  Carbon Dioxide  Carbon Monoxide  Hydrogen Sulfide  Olefins  Nitric Oxide  Sensor development

15. 15... more Applications  Immobilized Liquid Membranes  Metal ion separations  Control of heavy metals pollutants  Recovery of: copper, uranium and cobalt  Separation of fermentation products  Acetic and citric acid

16. 16...and more  Emulsion Liquid Membranes  Metal ion extraction  Amino acid extraction  Removal of species without chemical carriers

17. 17 Hollow fiber membrane-based enzyme- facilitated separation

18. 18 Emulsifier Fresh emulsion Settler Purified Water Mixer Wastewater Inner Phase Recovered components of the LM Addition of LM components Emulsion reflux Inner Phase Purification using ELM

19. 19 Balance of using LM  Benefits  High fluxes  Very selective separations  Ions can be concentrated  Expensive extractants can be used  Major Limitations  Rupture  Long term stability