phospholipids
precipitation
a
small
quantity
of
water or and
separation
by centrifugation.
Most
o f the
studies focused
on gum
removal
solvent
mixture 1987; Snape and
Kwiatkowski
and
but only
few studies
were related to
oil
organic
solvent.
The limitation in
case
comes
from low
permeate
flux
as
a consequence
of high The permeate
flux
can
improved
by
optimizing operating parameters
pressure, feed velocity
and
by applications
of tangential flow and suitable membrane
module. In process
application, tangential
or
filtration
is
most used due
to its
ability
to
create
turbulence at
the surface
and minimize concentration
polarization
and
fouling. In
addition, this
can be
well adapted when
it
is
applied
at
different membrane
module
designs.
The
most
common
designs
include flat sheet,
spiral wound,
tubular, and
hollow
fiber. Flat sheet, tubular and
designs
are preferred
for
tangential filtration of
suspensions
containing and
these have intermediate to very
low tendency
to
clog and
exhibit
high fluxes
fort 1994.
The objective
o f this
work
was to
evaluate
different
membranes
under
different operating
for
twin-screw extruder-pressed sun flower
oils
purification.
The performance
of membrane was
characterized with the permeate
flux,
the phosphotipids
rejection but
also
the color
and the
free fatty
acid
removal.
The
influence
operating
conditions pressure,
tern tangential flow
rate
parameters was
with pol
PES
membranes
cassette
with
a
molecular
weight
MWCO
of
10, 30
and
and
a area
of
MATERIALS
AND
METHODS
oils
and sunflower oils were
produced by pressing oleic
sunflower seeds in a 45
twin extruder.
The
of
the oils
extracted
was
presented in
All and
chemicals
were analytical grades that
were obtained
Sigma-Aldrich, and ICS.
Membrane
and Experiments
were conducted using
three PALL-FILTRON with
a
Tek.
Pen
58-65
molecular
weight
cut-off
M o f 10.30
and 50
membranes were in
a
configuration
which
is
of layers
with polyester
them. membranes
have
a
total area
of 0.09
m
2
. The initial
pure water
of
10,
30
and
membranes was
respectively 174, 534
and
540 Table
1. of
crude
Phospholipids
-
2288
sunflower
oil
Color CIE
:
Parameters
blue-yellow
color 77
Value
Experimental
I
Tangential was
conducted
w i
t h
a
diaphragm
pump 1270,
for
the
PALL membranes under
continuous
recycling Figure
The
pressure was
calculated following
+
I. Feed
tank
2. Pump
4
Membrane Pressure
7.
Schematic
flow
diagram of
fi
I feed tank
was
charged 5 liters
sunflower
oil and
regulated
the
desired
of
membrane
and operating
including pressure
and
59
tangential flow
rate
on
were
evaluated
by
comparing permeate
flux,
phospholipids and
free
fatty
acid In
this study, the
membrane calculated
following
relationship:
A
=
-
x where
and
are
phospholipids in
and feed,
respectively. The
were
in glycerol
for
minutes
and
then
overnight in
refined sunflower
oil
to reduce
the
moisture
of
membrane before its
introduction into
module.
To ensure
a
stable permeate
flow,
the
tangential was
operated for 60
minutes
processing the
actual achieving
steady
operation, permeate
samples
were
collected
over certain
Permeate
flow was using
cylinder. To
maintain
the performance
of
the
membrane,
the membrane was cleaned
using
sodium
sulfate after
the
test and
rinsed
with
water.
The
tangential flow
rate
of
membrane
cassette
considering
the feed
to
be completely
open. This is therefore
a rough approximation
since we
should
have
to consider
the
in the
hydrodynamic is
not yet
elucidated and
can
not
be
at
this
time. Analysis
The phosphorus
was
using
the
method Ca 12-55
and
total obtained
by
multiplying phosphorus
content by
free
acids content
was
using the French normalized
method T60 204. The
was
determined
with
a The
values
measured
are presented
as L,
a
and b
corresponding to lightness,
the green-red and
the
blueyellow components,
respectively.
Those
results are the
average
of five consecutive
m ts.
RESULTS AND
Variation
time
was
with membrane
of
1
operating
of
3.0 23°C and
As shown in Figure
2, the permeate
flux did not
decrease with
time. No
term fouling
was
observed.
However, the
permeate flux
was
low compare to
water
permeability of
membrane
74
bar. The steady
state
permeate flux
is
obtained
than 60
minutes,
as
observed
by
Nabi
al.
al.
2001
and
Time
min
Figure
2.
Permeate
flux
as a function
for
membrane of
I Factors
permeate flux
The
results
3
indicate
that the
permeate
flux
increased with the pressure
all
tested.
There no
compaction
of
the
pressure
in
the range
tested
in
this study, hence the flux
rapidly
as
observed by
1 997 and Nabi
At
a
very low
permeate flux is
the
of
concentration is small
and
a
layer
does
not
on
the
membrane As
the
applied pressure
is the
concentration polarization and
o f solutes at the
membrane
increase
as flux
rises. If pressure is
concentration polarization becomes enough for
retained
at
the membrane surface
to
reach the gel concentration
and
form
the secondary layer.
This
is
the
limiting
flux
for
membrane
was
not the
conditions tested in
Transmem
brane
pressure
Figure
3. of
pressure
on permeate
flux
as
function
o f
MWCO of
membranes
and 0.04
58-65
Twin-Screw Pressed..
. . .
. . . . .
.
The permeate
flux
of
the 30
and 50
was
than the
membrane.
The
difference
in pore
size distribution,
as
well the
interaction, the
variation
in
flux. As
MWCO
of 30
and
membranes were
than 10
membrane,
in
the easily
these
membranes.
addition,
the
interaction occurring
between the oil particularly
the
phospholipids, and
the
the
structure
formed
by
oil components at
membrane
surfaces
or
within the
changed of
membrane and
an
increase
in
membrane resistance.
MWCO
of membranes should reduce the and
thus
allows
permeate Figure
4
shows that
an
in
enhanced flux of
30
and
50
membranes
while
the
permeate
o f
10 membrane remained relatively
stable
the
region, the
influence of temperature on permeate
flux
is due to its on
density and viscosity
In-Chul Kim 2002.
also increases
with temperature,
phospholipids
increases.
the the
feed
viscosity
which
increases
the
convective flow rate
and
reduces
polarization
concentration
at membrane
surface,
thus
increasing the permeate flux,
as
described
by
2001
a
and According to
the law,
of
permeate
viscosity
contributes also
to
the permeate
flux. In
this work,
reduction of the feed viscosity is
up to
14
for
an
of
Fw
all
i t
is best to operate the
of
crude sunflower
oils
at the highest consistent
with
limits
of the feed
solution
and
the membrane, for
membrane
of
30
and
30
4 0
Figure
4. Influence
