NAMS 2002 Workshop - ICOM 2008

Nanofiltration and Reverse Osmosis I - Membranes – 4
Monday July 14, 4:00 PM-4:30 PM, Maui
Engineering Molecular Weight Cut-Off of Organic Solvent Nanofiltration
(OSN) Membranes for Natural Product Fractionation
I. Sereewatthanawut (Speaker), Membrane Extraction Technology Ltd, issara.s@imperial.ac.uk
Y. See Toh, Imperial College London
F. Lim, Membrane Extraction Technology Ltd
A. Boam, Membrane Extraction Technology Ltd
A. Livingston, Imperial College London
In recent decades there has been an increase in consumers’ concerns over the
quality and safety of many products including food, medicines and cosmetics.
Consumer’s preference has strongly moved to products produced from natural
sources as opposed to synthetic sources. As a result of this market demand, the
production of natural products has rapidly expanded and become a global
industry.
The production of natural products mainly involves separation processes. In
general, the most challenging aspect of natural compounds production are the
purification and fractionation steps. Current state-of-the-art technologies for
separation and purification involve the use of either distillation technology (shortpath
or conventional distillation), or conventional preparative liquid
chromatography. In recent years, membrane technology, particularly organic
solvent nanofiltration (OSN), has attracted a great deal of attention as an
alternative molecular separation technology. The main advantage of employing
OSN for purification of natural extracts is that by selecting suitable molecular
weight cut-off (MWCO) membranes, this technology can be used to fractionate
molecules of similar molecular weight (e.g. in the 200 to 1000 Da range) at a
much lower operating temperature compared to conventional processing
operations. In addition to the large saving in energy costs, natural products are
often susceptible to thermal damage and thus the milder operating conditions of
a membrane process can minimize the nutritive value loss from thermal
degradation.
The key aspect of employing this technology in natural product purification is
therefore to tailor and control the MWCO of OSN membranes. This study reports
the successful development of a robust technique for producing OSN
membranes with tuneable molecular weight [1] . We have found that through
careful control of the membrane formation conditions, it is possible to generate a
family of membranes with MWCO in the nanofiltration range, i.e. 200 to 1000 Da.
We have also shown that these membranes can be produced at pilot scale and
used to form spiral wound elements.