Advanced Materials Technologies,
Год журнала:
2024,
Номер
unknown
Опубликована: Дек. 27, 2024
Abstract
Recently,
hollow
fiber
polyelectrolyte
multilayer
membranes
(PEMMs)
have
shown
great
potential
for
removing
organic
micropollutants
from
wastewater
streams.
Currently,
these
PEMMs
are
made
with
the
selective
layer
on
inside
of
fiber.
However,
to
reduce
physical
footprint
PEMM
modules,
it
would
be
beneficial
outside.
This
will
lead
an
increased
surface
area
per
and
enable
use
smaller
mechanically
stronger
fibers,
which
further
increases
membrane
module.
To
prove
that
concept
outer‐skinned
is
feasible,
dry‐jet
wet‐spinning
process
used
fabricate
charged
supports,
they
coated
through
layer‐by‐layer
self‐assembly
form
a
PEMM.
Scanning
electron
microscopy
images
fibers
confirm
existence
asymmetric
structure
outer
skin,
while
fluorescence
imaging
confirms
located
outside
Filtration
experiments
showed
exhibited
nanofiltration
properties
similar
conventional
inner‐skinned
PEMMs.
Overall,
show
3.8x
increase
in
active
volume
ratio
compared
commercial
PEMMs,
clearly
highlighting
benefits
terms
footprint.
Membranes,
Год журнала:
2023,
Номер
13(4), С. 368 - 368
Опубликована: Март 23, 2023
The
increasing
demand
for
nanofiltration
processes
in
drinking
water
treatment,
industrial
separation
and
wastewater
treatment
has
highlighted
several
shortcomings
of
current
state-of-the-art
thin
film
composite
(TFC
NF)
membranes,
including
limitations
chemical
resistance,
fouling
resistance
selectivity.
Polyelectrolyte
multilayer
(PEM)
membranes
provide
a
viable,
industrially
applicable
alternative,
providing
significant
improvements
these
limitations.
Laboratory
experiments
using
artificial
feedwaters
have
demonstrated
selectivity
an
order
magnitude
higher
than
polyamide
NF,
significantly
excellent
(e.g.,
200,000
ppmh
chlorine
stability
over
the
0–14
pH
range).
This
review
provides
brief
overview
various
parameters
that
can
be
modified
during
layer-by-layer
procedure
to
determine
fine-tune
properties
resulting
NF
membrane.
different
adjusted
process
are
presented,
which
used
optimize
Substantial
progress
PEM
membrane
development
is
particularly
improvements,
most
promising
route
seems
asymmetric
offering
breakthrough
active
layer
thickness
organic/salt
selectivity:
average
98%
micropollutant
rejection
coupled
with
NaCl
below
15%.
Advantages
highlighted,
high
selectivity,
wide
range
cleaning
methods.
Additionally,
disadvantages
also
outlined;
while
may
impede
their
use
some
applications,
they
largely
not
restrictive.
effect
realistic
feeds
(wastewaters
challenging
surface
waters)
on
performance
presented:
pilot
studies
conducted
up
12
months
show
stable
values
no
irreversible
fouling.
We
close
our
by
identifying
research
areas
where
further
needed
facilitate
adoption
this
notable
technology.
ACS Applied Polymer Materials,
Год журнала:
2023,
Номер
5(3), С. 2032 - 2042
Опубликована: Фев. 10, 2023
Layer-by-layer
(LbL)
assembly
of
the
alternating
adsorption
oppositely
charged
polyions
is
an
extensively
studied
method
to
produce
nanofiltration
membranes.
In
this
work,
concept
chaotropicity
polycation
and
its
counterion
introduced
in
LbL
field.
general,
more
chaotropic
a
polyion,
lower
effective
charge,
charge
availability,
hydrophilicity.
Here,
researched
for
well-known
PDADMAC
(polydiallyldimethylammonium
chloride)
PAH
(poly(allylamine)
hydrochloride),
synthesized
PAMA
(polyallylmultimethylammonium),
with
two
different
counterions
(I-
Cl-).
Higher
(PDADMAC
>
PAMA-I
PAMA-Cl
PAH)
translates
into
reduced
availability
pronounced
extrinsic
compensation,
resulting
mass
higher
pure
water
permeability.
PAMA-containing
membranes
show
most
interesting
results
series.
Due
molecular
structure,
perfectly
lies
between
PAH.
Overall,
allows
formation
right
balance
intrinsic
compensation
PSS.
Moreover,
modifying
nature
or
Cl-)
tune
density
multilayer
size
exclusion
abilities
compared
(higher
MWCO
MgSO4
retention).
contextualization
polyion
interaction
within
specific
(poly)ion
effects
expands
understanding
influence
polycations
without
ignoring
chemical
functional
groups
their
monomer
units.
Desalination,
Год журнала:
2023,
Номер
574, С. 117246 - 117246
Опубликована: Дек. 21, 2023
Nanofiltration
membranes
produced
with
polyelectrolytes
via
the
layer-by-layer
technique
are
frequently
researched,
but
misunderstood
parameter
is
polyelectrolyte
concentration.
Higher
(PE)
concentrations
known
to
produce
thicker
PE
layers,
its
effect
on
membrane
performance
has
only
been
studied
in
a
limited
fashion,
leading
premature
conclusions.
In
this
work,
two
well-known
strong
polyelectrolytes,
PDADMAC
and
PSS
were
used
prepare
using
coating
solutions
of
0.01,
0.1,
1.0,
2.5
5.0
wt%
different
salt
solution
0.05
1
M,
as
higher
lead
layers.
The
prepared
researched
terms
pure
water
permeability
(PWP),
molecular
weight
cut-off
(MWCO)
retention
salts.
first
bilayer,
coated
M
showed
lower
PWPs
MWCOs
retentions
by
increasing
After
certain
number
bilayers,
MWCO
reach
plateau
for
all
concentrations;
value
was
obtained
earlier
concentration
had
or
comparable
rates,
except
MgCl2,
than
those
salt.
resulted
more
abundant
membrane,
which
promotes
MgCl2
bilayers.
conclusion,
we
found
that
significantly
alters
performance,
after
7
same
size
exclusion
plateaus
reached.
