Permeate pressure effects on selectivity

Research Trends

membranes

contact

membrane

concentration liquids

of

is

ethylene cell,

from

The

and

effective

concentration

glycol is negligible,

compared

the

temperatures

both computer them

values were obtained

unusual

behaviour

appeared

that the lactone

by a difference the

This of the

in

concentration

of the pervaporation

separation

polypropylene

code,

for the permeability

of the

the outside

coefficients

of the boundary

sulfate

(1. Rincirn,

J.M. Ortiz

/. Membrane

of other

literature

de Zgrate,

J.I. Mengual:

chemical

experiments - covering

properties,

low-boilers

with from

at 300°C

aqueous

organophilic

A model,

membranes

estimation

of

trans.membrane

coefficients

(with

a driving

pressure

between

the influence

of the

pressure

on the selectivity

total

membrane

set,

extraction was

containing that

03

selective the

most

was

carried

the

SDS

water-system

having

proved

low-boiler, series on

of

unfilled

module

by using dextran

ultrafiltration

liquid

enhanced

can be achieved namely

were

ultrafiltration

their

angle.

flow,

critical

pore

permeate

earlier to the TCEto the TCE-

wetted

pore

and

the inclined T.-W.

tubular

Membrane

i5

of the of the

53”

in

the

here.

The

about

of natural induced

Cheng,

flux

angle

in tlux is brought

convection

with

up to a certain

inclination

effects

the

system

increases

optimal

combination forced

resistances-in-series

by the

convection

and

by the slug flow in

membrane.

H.-M.

Yeh,

Science 158(1-2)

J.-H.

Wu:

221-234

1.

(1 June

1999). 187-209

(1 June

microfiltration of successive operating

z~; / at constant

(MF) performance.

paid

from

stress,

Z~ at

and /

these successive to

the

Nanoporous

alumina

the

cycles

evolution

of

to skimmed

milk

of trimethylaluminium

vapour

the

Aluminium

conditions.

The

chamber.

in the pores of

reduction

Separation

vapour

in

of the mixture

(water)

and

gas (oxygen)

was performed

unmodified

and modified

membranes

temperature. exhibited

The

CVD-modified

a water/oxygen

the

on the

80%

relative

permeance

at room factor

separation

membranes humidity

with

as

with water

of 6.9 x lo--’ mol/m2sPa.

the maximum

unmodified

nonon the

membrane

separation

high as 71 at 12% relative humidity permeance

the

gases, but not of

condensable

system

hysteresis

vapour.

with

layer. The modification

of non-condensable

condensable

comparison,

The

reaction

a substantial

condensable

vapour

depended

membrane in

permeance

into

(CVD),

oxide was deposited

the y-Al,O, resulted

deposition

by

introduction

water

(0.1 pm

proteins.

layer, on a

was modified

and

of casein

flux which

support,

alternative

membrane

soluble

a-AlzO, vapour

for the separation

ceramic

membranes

4 nm pore y-Al,O,

chemical

of

of the separation.

was applied

a limiting

AII

trans-membrane

selectivity

mean pore diameter)

It and

(A P at constant

AZ’ the

flux. During and

for

cycles of increasing

parameters

This methodology

was used

conditions

ZW; z~, at constant

was

permeability

of

operating

consisted

hydrodynamic

the

In

as the inclination

column

The

enhancement

through

wetted

“cyclic” methodology

crossflow

micelles

ultrafiltration

significantly

angle

slightly.

A. Das, A. Saraf, K.K. Sirkar: _/.

An experimental

showed

flux

two-phase

two-

turbulent

of inclination

permeate

discussed

Crossflow microfiltration skimmed milk

permeation

with

flow, the variation

laminar

solution

gas-liquid

liquid

feed

aqueous

or the

affects gas-liquid

were

membrane

system

dodecyl feed

experiments ceramic

T500

(TCE) as

the

and

flow ratios

In the single, liquid-phase

system,

A sol-gel derived

decreasing

The

in a tubular

system

Science 158( l-2)

evaluate

gas-liquid

angles.

out

gas-slugs

measured

experimental

the

for both

MF using a tubular

feed

inclination

carried

macroporous

to

various

ultrafiltration

1979).

attention

pressure.

and

under

were

surfactant,

Zw the wall-shear

the

discussed

of an inclined

system

phase

on

pore conditions.

Membrane

fluxes

as the tested solution.

a thin

coating

The

has been extended

I. Abou-Nemeh,

permeate

of

applied

,/,

(1 June

flux in tubular

i,< about

pressure,

vapour-liquid

second out

successfully system,

G. Da&n:

column

and ethyl

of the aqueous A

The

for example,

The

and

soluble

211-222

ultrafiltration

pore.

and

E. Boyaval,

Science 158(1-2)

Depending

conditions,

water

cake structure fluxes

performance.

,I) with

operation

hydrophobic

acetate.

studied.

to investigate

constant

membrane

than

of VOCs

a

the fibre bore. The

range

concentration

non-wetted

by

surfactant.

the

molecules,

of the total permeate

characteristic

is ethyl

experiments

two

the silicalite-filled

more

for

(diaceryl

factor of the pervaporation

to be

of small-

used

With

equilibrium

permeate

silicone

separation Moreover,

to

At

acetate).

was independent

each

in order

compounds.

of low-boilers these

in

of the pervaporation

permeants,

pervaporation

the

aroma

for the selective

organic

on

expressed

represent

best-suited

on a plate-

force

was used

a silicalite-filled

of

solutions

transfer

difference

studied

were

from

and SDS concentrations,

a wide

non-wetted

concept -

kinds

based

side of rhe membrane),

of the various

rhe

and

hydrophilic

three

module.

terms of partial

aroma

solutions,

through

and-frame

size

the

Membrane

ultrafiltration

sodium

parameters,

TCE

over

two different

high-boilers

commercial

first.

as

of its

transmission.

Ultrafiltration membranes

microporous

and

because

tl-.ins-membrane

permeation

G. G&an-Guiziou.

The

(PDMS)

was passed through

separation

a wide range of physicoranging

in model binary

over a

1999).

trichloroethylene

contaminant

operating

varied on

four

to very hydrophobic

conducted

the

of VOCs

fibres,

effect on the process

Permeate pressure effects on selectivity

diluted

diameter,

flow-rate,

(1 June

1999).

compounds

protein

model of

the

thi:, ratio.

/. Me&rune

been

silicone

(SDS)

process

155-165

hollow

model

solution

expectations.

Science 158(1-2)

Pervaporation

low

membrane-based

has

high

led to irreversible

to

which

Above

of the deposit, under

then

hydrophobic

plasma-polymerised the

layers. The values

employed

was satisfactory.

1999).

aqueous

process

process

under

pressure,

(I June

hollow-fibre

performance

c.omprcssibility

flux over efficient

(//Tabs).

the

operation

recovery

surfactant-conraining composite pervaporation

to take

those

and

stress

the consolidation

Hollow-fibre membrane-based pervaporation The

ratio of permeation

wall-shear

the

prediction

167-185

(such as thickness,

and made it possible to determine

nature

coefftcient

selectivity

specific

in order

agree with

transfer accurate

rhc

dcpos1:

characteristics

compression

of

.~i)our

m1(.ellcs

at each side of

associations,

in

and

the computer

and with theoretical

the

resulted

and for the heat and mass-transfer

sources,

as it

flux was not induced

compound

I. Souchon,

an

asauml,r~irn\ casem

and structure) a critical

permeate

displayed

pressure

Whatever

an

ywere

y-decalactone.

in partial

membrane.

total

membrane with

membrane-aroma

membrane, obtained

I’DMS

the

The

Science 158(1-2)

the

the effects of

From

on

pressure.

and

selectivities

that

hand,

code was developed account.

dependent

cases.

M. Marin:

pressure

were very important,

into

In both

pressure.

employed and

temperature

polarisation

(S-methylthiobutanoate

range of total permeate

with that of water,

On the other

of

A. Baudot,

is achieved.

since the vapour

experiments.

suggested

alteration

reject the glycol,

result ia expected, ar

observed

aroma

different

show

completely

flow

of PDMS

high-boiling

decalactone).

trans-membrane

water-

using a tangential

experiments

almost

coolant

with

membranes

temperatures.

the

distillation

performed

glycol mixtures,

membranes

used

Membrane

were

various

and

glycol

analysed.

experiments

for

distillation

layer composed

with

compounds highly

Separation of water and glycols In this paper the feasibility of using direct-

(&ctive

I’EBAJ

and

was about a water

In

factor for

11 at vapour

of 2.9 X 1O-’ mol/m*sPa.

Membrane Technology No. 115