I try to do filtration of lysozyme (which has IEP=12) with RC membrane. Rejection at pH 8 shows higher rejection than at pH 12.
Dear Ayu,
Disadvantages of Cellulose Acetate Membranes
• Hydrolysis by acids and alkalies can lead to poor rejection.
• Membrane susceptibility to biodegradation, so a chlorine feed is often required.
• Inferior salt rejection.
• Narrow pH range (4-8).
• Narrow temperature limits (0-35°C).
• Subject to structural compaction and high operating pressures.
• Lower permeability requires higher pressures and resulting operating costs
This kind of membrane is not stable at pH higher than 8 and it might undergo hydrolysis resulting in poor rejection.
http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_0062/0901b80380062296.pdf?filepath=liquidseps/pdfs/noreg/609-00232.pdf&fromPage=GetDoc
Hoping this will be helpful,
Rafik
Thank you for your answeer, Rafik! I compare it with poly ethyl sulfone membrane.. the result is different by increasing pH. I think Regenerated cellulose membrane is different with cellulose acetate membrane.
Dear Ayu,
Do you mean poly ether sulfone?
The cellulose acetate is an ester which is not stable in high or low pHs, whereas the sulfone is much more stable in this range of pH.
Rafik
Yes, I mean poly ether sulfone. Thank you for your answer Rafik!
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