Hello!
Are there any scientific explanation that most of hollow fiber membrane manufacturers for water treatment prefers PES to PSU as main material? Are thee any important physical-chemical PES features?
The preparation of the hollow fiber polymeric membranes is made from different materials, but polyethersulfone (PES) is one of the polymers that has attracted attention because of its excellent chemical resistance, mechanical strength, high stiffness, thermal stability and biological compatibility. Even with all these properties suitable for producing good membranes, there are still problems with hydrophilicity. Therefore, some researchers try to solve this problem by adding inorganic materials to the polymer matrix.
Polysulfones are highly resistant to aqueous mineral acids, bases, and oxidizing agents and are fairly resistant to many non-polar solvents. However, polysulfones are not resistant to low polar solvents, such as esters, ketones, aromatic and chlorinated hydrocarbons.
Regards
PES shows more finger-like pores than PSU, leading to higher affinity to water, higher liquid and solution (aqueous) fluxes, and greater flexibility of the PES membranes as compared to higher (non-polar) gas fluxes and mechanical resistance of PSU membranes. Hence, PES should be more suitable for separations involving the liquid state while PSU should be advantageous for gas separation and the application of higher pressures.
You can check the paper below for more information:
Article Asymmetric polysulfone and polyethersulfone membranes: Effec...
Regards,
K
From point of thermal analysis, PES has not so many advantages compared to PSU but in another hand, PES is intrinsically a little harder and straighter than PSU that can make PES more appropriate than PSU to fabricate hollow fiber membranes.
please check the below data:
Mechanical comparison
Yield Strength: PES= 84.1 to 89.6 Mpa, PSU= 75.5 to 83.3 Mpa
Tensile Strength: PES= 67.6 to 95.2 Mpa, PSU= 94.4 to 104 Mpa
Elongation: PES= 6 to 80%, PSU= 40 to 80%
Hardness (Vickers): PES= 247 to 264 Mpa, PSU= 223 to 245 Mpa
Thermal comparison
Max Service Temperature: PES= 150 to 180 °C, PSU= 147 to 172 °C
Thermal Expansion Coefficient= 9.7e-5 to 1.01e-4 strain/°C, PSU= 5.47e-5 to 5.69e-5 strain/°C
Regards,
PES membranes posses higher physical strength and slightly higher chemical resistance. Membrane fabrication is easier with PES. PES membranes provide higher number of surface pores in comparison with PSf.
By looking at the answers to the topic, I think I found the right people to ask my question.
So, I am using PES membranes (Pall, 100K, macrosep omega) to concentrate vesicles from cell culture media. Can you help me understand how it works? Do molecules above 100K stuck in the membrane after centrifuge, and stay there? Will it be saturated after a while, or can be used many times? How can I keep them intact, if I use them multiple times? Once they are wetted, I was keeping them in PBS, is it the correct way to store them for multiple uses? Or can they be dried? I also used 70%EtoH to sterilize them, according to manufacturer's suggestion. Can I keep them in 70% EtOH for long term, say months?
I appreciate your lecture and answers on this.
Thank you.
Hello, Ahmet Alptekin
You correctly described the mechanism. Therefore, the performance of such membranes will decrease over time. The membranes are best kept wet. A 70% ethanol solution is quite suitable for this and will not have any negative effects on their structure. Since you are working with organic molecules I would suggest storing the membranes in an alkaline ethanol/water solution (pH 11-12) to better clean them from contaminants.
Good day! Here is the list of articles, dedicated to the use of PES membranes:
Article Immersed membranes configuration for the microfiltration of ...
Article Decoloration of sugarcane molasses by tight ultrafiltration:...
Article Fruit juice processing using membrane technology: A review
Article Clarification of Apple Juice Using Polymeric Ultrafiltration...
Article Dead-End Dynamic Ultrafiltration of Juice Expressed from Ele...
https://doi.org/10.1016/B978-0-12-802230-6.00013-8.
https://doi.org/10.1016/j.memsci.2018.03.048
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