1. Alternative Separations
Eli Gronowski
CBE 562

2. Overview
Membranes
Absorbents
Ion-Exchange Resins

3. Membranes Thin films of porous material
Polymer Films
Ceramics
Carbon Fiber
Porous Metal Substrates
Size: < 10 Angstroms to 100+microns

4. Types of Membranes Microporous Membranes Homogeneous Membranes
Separate by pore diameter and particle size
Homogeneous Membranes
Dense film
Separation by pressure, concentration or electrical potential gradient
Separation of similar size particles

5. Types of Membranes Asymmetric Membranes
very thin ( micron) skin layer on a highly porous ( microns) thick substructure
Thin skin acts as the selective membrane

6. Types of Membranes Electrically Charged Membranes Electrodialysis
ions are transported through a membrane from one solution to another under the influence of an electrical potential.
production of potable water from sea or brackish water
ED can be utilised to perform several general types of separations such as separation and concentration of salts, acids and bases from aqueous solutions or the separation and concentration of monovalent ions from multiple charged components or the separation of ionic compounds from uncharged molecules.

7. Microfiltration membrane
Most widely used
Sterile filtration
Pores ( microns)
Material can be selective
Mechanical strength
Temperature resistance
Chemical compatibility
Hydrophobility
MF has a wide array of applications as mentioned below:
Preparation of parenterals and sterile water for pharmaceutical industry Food & beverages (concentration of fruit juices and alcoholic beverages Chemical industry Microelectronics industry Fermentation Laboratory/analytical uses etc.
Polyvinylidene difluoride

8. Hydrophobic membranes
Resists water while simultaneously venting gases
Materials
Polytetrafluoroethylene (PTFE), nylon, glass fibers, polyethersulfone

9. How Does It work Surface Tension Polarity Differences
Only liquids with surface energy lower than that of the membrane can wet out the membrane.
Polarity Differences
Nonpolar membranes tend to resist passage of polar compounds
Polyvinylidene fluoride
Two main principiles

10. Applications Underwater flashlights Auto Industry
Vent hydrogen gas from Batteries
Auto Industry
Vent Heat / Gases
Windshield wiper motors
Halogen headlights

11. Most Popular Applications
Hemodialysis
Reverse osmosis
Micro/Ultra Water Filtration
In hemodialysis, blood flows through a semipermeable cellulose acetate membrane. This membrane separates proteins and cellular constituents in the blood from smaller molecular solutes. The solutes are then
discharged from the apparatus allowing for pure blood to be generated back into the body.

12. Membrane Industry

13. Growth Fueled by Regulations for potable water/wastewater
Industrial recovery/recycling

14. Benefits Separations Require Energy
Distillation
Membranes typically require a lower amount of energy

15. Reduction of Energy Costs
Replace Typical Units Ops
Ethylene
Production
C2 Splitter

16. Membrane Advantages Energy savings
Clean technology with operational ease
Replaces the conventional processes
Filtration
Distillation
Produces high quality products
Greater flexibility in designing systems.

17. Membrane Disadvantages
Membranes are expensive.
Certain solvents can quickly and permanently destroy the membrane.
Certain solids, especially graphite, can permanently foul the membrane surface.

18. Absorbents MOLECULAR SIEVE crystallized synthetic zeolite
Selective, microporous adsorbent
Premium catalyst and catalytic carrier
Ion exchanger.
Contains a network of uniform pores and empty cavities
Zeolite is an inorganic porous material having a highly regular structure of pores and chambers that allows some molecules to pass through, and causes others to be either excluded, or broken down. It is in many ways, the inorganic equivalent of organic enzymes, many of which also have specific sized chambers that trap chemicals within our bodies, holding them where they either break down, or react with specific chemicals.

19. Molecular Sieve

20. Ethanol-Water System

21. Ion Exchange Resin Water Softeners
Ion exchange resins are insoluble polymers that contain acidic or basic functional groups and have the ability to exchange counter-ions within aqueous solutions surrounding them

22. Pharmaceutical Technology
Drug resinate more stable than original drug.
Vitamin B12 (2 months vs 2 Years)
Drug Abuse Control
Reduce the “High”
This technology is still used commercially today, more than 40 years after it was first introduced

23. Future of Separations Advancements in Membrane Tech Chemical Industry
Better Materials
Higher Selectivity, Stability, Throughput
Chemical Industry
Gas Separations
Cryogenic distillation
Selective adsorption

24. References http://www.edmwt.com/membrane.htm
Using Hydrophobic Membranes to Protect Gas Sensors
Clean Technologies and Environmental Policy. Berlin: Apr 2004. Vol. 6, Iss. 2;  pg. 78
Pharmaceutical Technology. Cleveland: 2004.  pg. 20, 5 pgs