Environmental Science & Technology,
Год журнала:
2024,
Номер
58(25), С. 11162 - 11174
Опубликована: Июнь 10, 2024
Thermal
treatment
has
emerged
as
a
promising
approach
for
either
the
end-of-life
or
regeneration
of
granular
activated
carbon
(GAC)
contaminated
with
per-
and
polyfluoroalkyl
substances
(PFAS).
However,
its
effectiveness
been
limited
by
requirement
high
temperatures,
generation
products
incomplete
destruction,
necessity
to
scrub
HF
in
flue
gas.
This
study
investigates
use
common
alkali
alkaline-earth
metal
additives
enhance
mineralization
perfluorooctanesulfonate
(PFOS)
adsorbed
onto
GAC.
When
treated
at
800
°C
without
an
additive,
only
49%
PFOS
was
mineralized
HF.
All
tested
demonstrated
improved
mineralization,
Ca(OH)2
had
best
performance,
achieving
efficiency
98%
air
N2.
Its
ability
increase
reaction
rate
shift
byproduct
selectivity
suggests
that
role
may
be
catalytic.
Moreover,
reduced
gas
instead
reacting
additive
form
inorganic
fluorine
(e.g.,
CaF2)
starting
waste
material.
A
hypothesized
mechanism
is
proposed
involves
electron
transfer
from
O2–
defect
sites
CaO
intermediates
formed
during
thermal
decomposition
PFOS.
These
findings
advocate
GAC
disposal
reuse,
potential
reduce
operating
costs
mitigate
environmental
impact
associated
incinerating
PFAS-laden
wastes.
Science,
Год журнала:
2022,
Номер
377(6608), С. 839 - 845
Опубликована: Авг. 18, 2022
Per-
and
polyfluoroalkyl
substances
(PFAS)
are
persistent,
bioaccumulative
pollutants
found
in
water
resources
at
concentrations
harmful
to
human
health.
Whereas
current
PFAS
destruction
strategies
use
nonselective
mechanisms,
we
that
perfluoroalkyl
carboxylic
acids
(PFCAs)
could
be
mineralized
through
a
sodium
hydroxide-mediated
defluorination
pathway.
PFCA
decarboxylation
polar
aprotic
solvents
produced
reactive
ion
intermediates
degraded
fluoride
ions
(78
~100%)
within
24
hours.
The
carbon-containing
products
were
inconsistent
with
oft-proposed
one-carbon-chain
shortening
instead
computationally
identified
pathways
consistent
many
experiments.
Degradation
was
also
observed
for
branched
ether
might
extended
degrade
other
classes
as
methods
activate
their
headgroups
identified.
Environmental Science & Technology,
Год журнала:
2022,
Номер
56(9), С. 5355 - 5370
Опубликована: Апрель 21, 2022
Per-
and
polyfluoroalkyl
substances
(PFASs)
are
fluorinated
organic
chemicals
that
concerning
due
to
their
environmental
persistence
adverse
human
ecological
effects.
Remediation
of
PFAS
contamination
presence
in
consumer
products
have
led
the
production
solid
liquid
waste
streams
containing
high
concentrations
PFASs,
which
require
efficient
cost-effective
treatment
solutions.
PFASs
challenging
defluorinate
by
conventional
advanced
destructive
processes,
physical
separation
processes
produce
(e.g.,
membrane
concentrate,
spent
activated
carbon)
requiring
further
post-treatment.
Incineration
other
thermal
widely
available,
but
use
managing
PFAS-containing
wastes
remains
poorly
understood.
Under
specific
operating
conditions,
is
expected
mineralize
degradation
mechanisms
pathways
unknown.
In
this
review,
we
critically
evaluate
decomposition
mechanisms,
pathways,
byproducts
crucial
design
operation
processes.
We
highlight
analytical
capabilities
challenges
identify
research
gaps
limit
current
understanding
safely
applying
destroy
as
a
viable
end-of-life
process.
Environmental Science & Technology,
Год журнала:
2023,
Номер
57(25), С. 9416 - 9425
Опубликована: Июнь 9, 2023
Electrochemical
oxidation
(EO)
has
been
shown
to
have
the
unique
ability
degrade
perfluorooctanoic
acid
(PFOA),
although
radical
chemistry
involved
in
this
degradation
is
unclear,
particularly
presence
of
chloride
ions
(Cl–).
In
study,
reaction
kinetics,
free
quenching,
electron
spin
resonance,
and
probes
were
used
examine
roles
·OH
reactive
chlorine
species
(RCS,
including
Cl·,
Cl2•–,
ClO·)
EO
PFOA.
Using
NaCl,
PFOA
rates
89.4%–94.9%
defluorination
38.7%–44.1%
achieved
after
480
min
with
concentrations
ranging
from
2.4
240
μM.
The
occurred
via
synergistic
effect
Cl·
rather
than
through
direct
anodic
oxidation.
products
density
functional
theory
(DFT)
calculations
revealed
that
triggered
first
step
reaction,
thus
initial
transfer
was
not
rate-limiting
degradation.
change
Gibbs
energy
caused
by
65.57
kJ
mol–1,
which
more
two
times
lower
·OH.
However,
subsequent
demonstrated
for
time
promising
development
electrochemical
technology
remove
perfluorinated
alkyl
substances
environment.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(19)
Опубликована: Март 1, 2024
Abstract
Perfluoroalkyl
substances
(PFASs)
are
persistent
and
toxic
to
human
health.
It
is
demanding
for
high‐efficient
green
technologies
remove
PFASs
from
water.
In
this
study,
a
novel
PFAS
treatment
technology
was
developed,
utilizing
polytetrafluoroethylene
(PTFE)
particles
(1–5
μm)
as
the
catalyst
low
frequency
ultrasound
(US,
40
kHz,
0.3
W/cm
2
)
activation.
Remarkably,
system
can
induce
near‐complete
defluorination
different
structured
PFASs.
The
underlying
mechanism
relies
on
contact
electrification
between
PTFE
water,
which
induces
cumulative
electrons
surface,
creates
high
surface
voltage
(tens
of
volts).
Such
generate
abundant
reactive
oxygen
species
(ROS,
i.e.,
O
⋅
−
,
HO⋅,
etc.)
strong
interfacial
electrostatic
field
(IEF
10
9
~10
V/m).
Consequently,
IEF
significantly
activates
molecules
reduces
energy
barrier
nucleophilic
reaction.
Simultaneously,
co‐existence
(PTFE*(
e
))
HO⋅
enables
synergetic
reduction
oxidation
its
intermediates,
leading
enhanced
thorough
defluorination.
US/PTFE
method
shows
compelling
advantages
consumption,
zero
chemical
input,
few
harmful
intermediates.
offers
new
promising
solution
effectively
treating
PFAS‐contaminated
drinking
PLoS ONE,
Год журнала:
2025,
Номер
20(1), С. e0317696 - e0317696
Опубликована: Янв. 23, 2025
Previous
studies
have
indicated
the
great
performance
of
electrooxidation
(EO)
to
mineralize
per-
and
polyfluoroalkyl
substances
(PFASs)
in
water,
but
different
anions
presented
wastewater
may
affect
implementation
EO
treatment
field
applications.
This
study
invetigated
perfluorooctane
sulfonate
(PFOS)
perfluorooctanoic
acid
(PFOA),
two
representative
perfluoroalkyl
acids
(PFAAs),
using
porous
Magnéli
phase
titanium
suboxide
anodes
electrolyte
solutions
with
present,
including
NO
3
-
,
SO
4
2-
CO
PO
3-
.
The
experiment
results
indicate
that
enhanced
PFAS
degradation,
while
suppressed
degradation
reactions
its
concentration
higher
than
10
mM.
exhibited
less
impact.
Further
electrochemical
characterizations
radical
quenching
experiments
illustrate
mechanisms
how
impact
performance.
ACS ES&T Engineering,
Год журнала:
2022,
Номер
2(2), С. 198 - 209
Опубликована: Янв. 11, 2022
In
this
study,
we
found
that
thermal
decomposition
of
per-
and
polyfluoroalkyl
substances
(PFAS)
in
soil
was
rapid
at
moderate
temperatures
400–500
°C,
regardless
whether
the
contaminated
by
a
single
PFAS
compound
or
mixture
aqueous
film-forming
foams.
Substantial
degradation
(>99%)
soil,
including
perfluorooctanoic
acid
(PFOA),
perfluorooctane
sulfonate
(PFOS),
short-chain
homologues,
cationic
zwitterionic
precursors,
PFOA
PFOS
alternatives,
occurred
30
min
500
°C
both
sealed
reactor
air
horizontal
under
continuous
flow
N2.
The
effect
initial
level
(0.001–10
μmol/g)
texture
insignificant,
provided
sufficiently
high
temperature
applied.
Furthermore,
study
showed,
for
first
time,
kaolinite
dramatically
decreased
apparent
yield
F
from
heated
>300
likely
due
to
chemisorption
radicals
on
kaolinite.
This
phenomenon
not
observed
when
an
inorganic
fluoride
salt
(NaF)
were
thermally
treated.
Lastly,
various
nonpolar
products
reported
time.
profile
fluorinated
volatiles,
particularly
perfluoroalkenes,
similar
between
these
two
chemicals.
results
support
radical-mediated
pathway
PFAS.
