White Yeti - 2-2-2013 at 10:58
Pervaporation is a promising new technology with many potential uses in many sectors of industry. It is a process by which liquids permeate through a
selectively permeable membrane into a chamber held under low pressure. The low pressure environment allows the permeate to vaporise; the vapours are
then condensed and collected.
One major promising application of this technology is the continuous extraction of ethanol from fermentation tanks1,2. However this
technology has other potential uses, owing to its ability to break azeotropes and separate mixtures at low temperatures. These include:
-solvent dehydration
-removal of water from esterification reactions
-removal of water from heat sensitive reactions or extractions
This technology is not yet used on a large scale owing to several factors:
-Pervaporation is a "relatively" new technology with the earliest account dating back to 1906.
-Pervaporation membrane development is still in its early stages.
-Pervaporation systems are many times more expensive than present day competing technologies.
In some cases the membranes for this kind of extraction are made of exotic materials. Many successful pervaporation systems consist of membranes
constructed from complex organic polymers (Polyetherimide, Kapton®, PMDA, BPDA) affixed to porous ceramic substrates (zeolites, amorphous silica,
titania, zirconia)3, but other membranes have been constructed from ubiquitous materials such as PVA, nitrile, butadiene rubber, and
styrene butadiene rubber4.
I believe this technology can be developed in an amateur setting and holds significant potential for future development. Replication of results could
lead to more efficient and cheaper ways to break azeotropes and ameliorate yields of small scale organic syntheses.
Literature cited:
[1] http://doc.utwente.nl/67225/1/ethanol.pdf
[2] http://www.nt.ntnu.no/users/skoge/prost/proceedings/ecce6_se...
[3] http://scholarbank.nus.edu.sg/bitstream/handle/10635/23069/Q...
[4] http://www.cheresources.com/content/articles/separation-tech...