ULTRAFILTRATION

ULTRAFILTRATION manual

08.10.2001

After applying the “Troubleshooting-1- for membrane fouling” procedure (see GettingStarted document), proceed with the following sections:

I. WASHING the ULTRAFILTRATION MEMBRANE

1. Be sure the pressure valve is at OFF position (horizontal)

(See Amicon8000_UsersGuide pdf document)

2. Make the gas (N2) inlet connections

3. Remove the orange O-ring from the membrane holder

4. Place the membrane to the membrane holder, the glossy side facing the solution

5. Place the orange O-ring on the membrane

6. Gently fit the O-ring tight via pushing it and sealing the membrane to prevent leakage from the edges

7. Place the membrane holder on the bottom piece

8. Place the cell onto that and tighten it via screwing it to the bottom piece (graduated face seeing the effluent port)

9. Connect the effluent pipe and close it with a paper clips

10. Put 300 mL dI water into the cell to wash out the glycerine and Na-azide (substrates for handling and preservation) covering the surface of the membrane (minimum 5 min)

11. Place the magnetic stirrer vertically, being careful not to scratch the glossy surface of the membrane

12. Place the cap onto the cell and tighten it via pushing down with a twisting motion

13. Be sure that the pressure valve+cell’s graduated face+effluent port be at the opposite site of the gas inlet connection

14. Place the cell into the black stand

15. Put the cell+stand on the magnetic stirrer

16. Turn the pressure valve to ON position (vertical)

17. Turn on the stirrer to give a vortex of 1/3 height of the total height

18. Open the effluent pipe and start collecting the filtrate

19. Immediately, turn on the gas source gradually till reaching to the appropriate filtration pressure

20. While pressure increases in the cell, the cap will slowly rise and touch top of the back stand

21. Continue collecting the filtrate into a clean beaker until 50-20 ml of sample remains in the cell (the amount of remaining sample should be bigger [50 ml] with membranes of higher NMWCO, and can be smaller [20 ml] with membranes of lower NMWCO. The reason for this is to secure the internal pressure of the cell to be maintained properly, and not to loose pressure and cause the buckling and deterioration of the membrane due to the sudden pressure drop inside the cell)

22. Be sure to check the speed of the magnetic stirrer to maintain a vortex of 1/3 of the total depth, at all the times. The total depth decreases during filtration, thus speed of stirrer should be decreased. This is to maintain sample homogenization and to prevent premature polarization of the solutes adjacent to the membrane surface.

23. When 50-20 ml of sample is left in the cell, halt filtration via closing the effluent pipe with the paper clips

24. Immediately, turn the gas source OFF gradually (no change is observed on the scale of the gas gauge)

25. When the main gas valve is totally loosen, release the internal pressure of the cell VERY SLOWLY via turning the black pressure valve from ON to OFF position (from Vertical to Horizontal). The release should be very slow to prevent creating a vacuum and cause the buckling and deterioration of the membrane due to the sudden pressure drop inside the cell. Meanwhile the pressure at the scale of the gas gauge will be zeroed automatically

26. Push the cap down and remove the cell from the black stand

27. Open the cell via pulling the cap up with a twisting motion

28. If needed add more dI water for further membrane wash and continue from Item 11.

Else proceed as follows;

II. SAMPLE FILTRATION

1. Take the stirrer rod and effluent pipe out, wash them with dI water

2. Rinse the cell and the membrane couple of times with dI water

3. Dry the cell interior and the stirrer rod with paper towel. Be sure not to touch the surface of the membrane. Put the stirrer into the cell.

4. Add the sample to be filtered into the cell and continue from Section I, Item 11 to Item 27. Do not forget to waste the first 10-20 mL of filtrate before collecting the aliquot (for measurements) to a clean beaker

5. If needed (especially with membranes of high NMWCO), filtrate some more sample, else; apply Section II, Items 1-2.

6. Rinse the membrane with dI water (either 300 ml or for 30 min) under working pressure

7. Rinse the membrane with 70% EtOH solution (either 300 ml or for 30 min) under working pressure. This is for the sterilization of both the membrane and the cell itself.

8. Unscrew the cell from the membrane holder.

9. Take out the orange O-ring

10. Remove the membrane from the membrane holder VERY CAREFULLY, holding from the edge and AVOIDING scratching the glossy surface

11. Place the membrane vertically in a jar full of 10% EtOH solution. Store at +4^oC in a fridge until next use.

12. Rinse the cell with dI water under some pressure

13. Dry the parts of the cell and place the next membrane for the next filtration

When finished with all, apply the “Troubleshooting-2- for membrane fouling” procedure (see GettingStarted document), for all membrane discs.

Important Notes:

1. The membrane should never be dry: Always leave some sample in the cell before stopping filtration.

2. Pressure release of the cell should be very slow to prevent membrane deterioration: When finished with filtration, release the internal pressure of the cell very slowly

3. When filtering more than one sample subsequently thru the same membrane, rinse the membrane and cell thoroughly with dI water (2x300 ml or minimum 30 min) between samples

4. The AP40, 0.45 and 0.22 m membranes are disposable, thus no need to wash them with 70% EtOH and store them in 10% EtOH solution.

Important parameters:

Filter Type	Filter Size	Max working presssure	Storage	Regeneration
*Filtration*
Millipore AP40, glass fiber	1.2-1.6 m	0.35 atm*	Disposable	Disposable
DuraporeÒ HV, PVDF	0.45 m	0.35 atm*	Disposable	Disposable
DuraporeÒ GV, PVDF	0.22 m	0.35 atm*	Disposable	Disposable
*Ultrafiltration*
Millipore, PL	100 kDa	0.7 atm	in 10 % EtOH, +4^oC	0.1 N NaOH, 30 min
Millipore, PL	30 kDa	3.7 atm	in 10 % EtOH, +4^oC	0.1 N NaOH, 30 min
Millipore, PL	10 kDa	3.7 atm	in 10 % EtOH, +4^oC	0.1 N NaOH, 30 min
Millipore, PL	3 kDa	3.7 atm	in 10 % EtOH, +4^oC	0.1 N NaOH, 30 min
Millipore, PL	1 kDa	3.7 atm	in 10 % EtOH, +4^oC	0.1 N NaOH, 30 min

*No pressure recommendation is available from the manufacturer for these disposable membranes. The value was estimated safely according to the value available for 100 kDa membrane.