Membranes: a quick state-of-the-art · Constant Volume Membrane Purification: Molecule A (product)...
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Membrane Separations for a Sustainable Future Membranes: a quick state-of-the-art Dr Darren Lee Oatley-Radcliffe Chemical Engineering (College of Engineering)
Transcript of Membranes: a quick state-of-the-art · Constant Volume Membrane Purification: Molecule A (product)...
Membrane Separations for a Sustainable Future
Membranes: a quick state-of-the-art
Dr Darren Lee Oatley-Radcliffe
Chemical Engineering (College of Engineering)
Overview
What is a membrane?
How do you make a membrane?
How do I use a membrane?
Questions
About me…
Hold a Ph.D. in membrane technology (nanofiltration)
10 years industrial experience in pharmaceuticals
Now working in research at Swansea University
Membranes is a key theme in my work
Director of a spin out company
What is a membrane ?
According to the International Union of Pure and Applied
Chemistry [IUPAC (1996)], a membrane is
“a structure having lateral dimensions much greater than
thickness, through which mass transfer may occur under a
variety of driving forces”.
a pretty useless description…
IUPAC (1996), Journal of Membrane Science, 120, 149-159.
What is a membrane ?
A membrane is an “advanced” form of filter
There are many different kinds of membranes and processes
Focus on synthetic pressure driven membrane technology
What is a membrane ?
Synthetic membranes come in a variety of shapes and sizes
What is a membrane ?
What is a membrane ?
There are many applications and the field is still growing !
The major sectors include...
Production of drinking water
Production of foods, beverages and juices
Production of fine chemicals
Production of oil, fuels and lubricants
Production of pharma, biopharma and neutraceuticals
Production of gases
Wastewater treatment
Medical applications
What is a membrane ?
At the surface things are quite different
What is a membrane ?
At the surface things are quite different
What is a membrane ?
At the surface things are quite different
Composite membranes
What is a membrane ?
Flat sheets are easy to visualise, tubes are slightly different
What is a membrane ?
Flat sheets are typical for small scale applications
What is a membrane ?
Spirals or tubular are typical for large scale applications
How do I make a membrane ?
For microfilters and large pore membranes
The polymer precipitates to form a solid porous film
Solid
membra
ne
Solvent
out
Non-
Solvent in
How do I make a membrane ?
For small pore or non-porous, phase inversion is used
How do I make a membrane ?
Cut to video
How do I use a membrane ?
Predominantly the liquid phase membrane process are used
industrially for the vast majority of membrane applications
Microfiltration
Ultrafiltration
Nanofiltration
Reverse Osmosis
Filtration – the basics
It is important not to confuse filtration with sieving.
Filtration – the basics
Filtration – the basics
MF SUSPENDED
PARTICLES
UF
NF
SUGARS
DIVALENT SALTS
DISSOCIATED ACIDS
RO
MONOVALENT SALTS
UNDISSOCIATED ACIDS
WATER
MACROMOLECULES
VIRUSES
COLLOIDS
Fouling is a major issue
Atomic Force Microscopy image Bio-colloid of 0.3 m Blocking
MF Membrane Pore
Filtration – the basics
Nanofiltration – Basic principles
Nanofiltration – Basic principles
Size exclusion Charge exclusion Key parameters: Pore size Solute size Charge of membrane Valence of solute
Nanofiltration – Diafiltration to purify mixtures
Constant Volume
Membrane Purification:
Molecule A (product) together
with Impurity B is added as a
batch at start of process
Solvent is added continuously to
make up for solvent permeating
across the membrane, therefore
volume in system is constant
Fresh Solvent
Dilute A
Membrane
MW B ≥ MW A
A A
A
A B
B B B
B A A
A
A
A B
B B B
B A B B B B
B
Nanofiltration – Diafiltration example, separation of dyes
Permeate – Product (yellow dye – MW of 274 g.mol-1) permeates
Retentate – Impurity (blue dye – MW of 826 g.mol-1) retained
Nanofiltration – An industrial example
A valuable pharmaceutical
Stage 5 in the production of zanamivir (Relenza™)
GSK anti-viral for influenza
In these separations, a 1% increase in yield is worth around £100k per annum
Nanofiltration – The basic laboratory study to verify the model
Nanofiltration – The diafiltration process
The drug loss was minimal at < 10% over the entire run
The pyruvate impurity was completely removed
The process was an order of magnitude more efficient than ion exchange
From Physics to Processes – The primary goal
Sequence and
Structure
Process Prediction
Process Plant
V /(mL)
0 5 10 15 20 25 30
t /
V
/(m
in m
L-1
)
0
1
2
3
4
5
6
7
8
9
10
pH 4, +18.84 mV
pH 5, +9.00 mV
pH 6, + 0.82 mV
nanoscale macroscale
Thank you for Listening
