Environmental Science & Technology Letters,
Journal Year:
2024,
Volume and Issue:
11(11), P. 1254 - 1259
Published: Oct. 18, 2024
A
growing
number
of
recent
studies
have
reported
the
global
environmental
occurrence
bis(perfluoroalkanesulfonyl)imides
(bis-FASIs).
While
shorter-chain
bis-FASIs
such
as
NTf2
(aka
bis(trifluoromethanesulfonyl)imide
or
bistriflimide)
are
often
tied
to
battery
and
energy
sectors,
aqueous
film-forming
foams
may
be
potential
sources
longer-chain
bis-FASIs.
As
remediation
technologies
for
destruction
these
persistent
per-
polyfluoroalkyl
substances
(PFAS)
urgently
needed
but
not
yet
been
identified,
we
investigated
effectiveness
incineration
using
quantum
chemical
calculations.
At
temperatures
around
600
°C,
parent
readily
decompose
through
carbon–sulfur
bond
cleavage
a
minor
extent
nitrogen–sulfur
cleavage.
However,
mineralization
released
perfluoroalkyl
substituent
HF
CO2
only
proceeds
at
>900
°C.
Temperature
requirements
slightly
increase
with
chain
length
due
time
required
break
additional
C–C
bonds.
Under
conditions
≥1000
°C
typical
secondary
combustion
units
in
hazardous
waste
incinerators,
complete
thermal
is
viable
given
all
other
process
variables
optimized.
The
same
true
treatment
operating
lower
gas-phase
unless
catalytic
effects
activation
barriers.
Integrated Environmental Assessment and Management,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 6, 2025
Abstract
Perfluoroalkyl
and
polyfluoroalkyl
substances
(PFAS)
herbicides
are
important
persistent
contaminants
that
require
specific
management.
A
variety
of
is
stored
in
fluorinated
containers
the
form
aquatic
solutions.
In
such
environments,
simultaneous
release
PFAS
takes
place.
Nature-based
solutions,
as
use
clay
materials
possible
sorbents,
attractive
for
immobilization
environmental
protection.
Nanotubular
minerals,
halloysite
imogolite,
sufficient
sorbents
herbicides.
Due
to
their
structural
morphology,
could
be
efficient
this
study,
potential
sorption
a
short
chain
PFAS,
perfluorobutanoic
acid
(PFBA),
sorbent
PFBA,
(atrazine
diuron)
were
investigated.
Forcefield
calculations
used
classical
molecular
simulation
study.
Different
distributions,
arrangements,
ratios
investigated
molecules
complete
energy
characterization
systems.
Both
minerals
created
stable
complexes
with
PFBA
well
both
herbicide
molecules.
Halloysite
mineral
led
similar
total
energies
system
sorbed
alone,
or
pollutants.
contrast,
imogolite
lower
showed
relatively
higher
when
interacting
PFBA.
The
pollutants
presented
moderate
energies.
Electrostatic
interactions
dominant
all
complexes.
Environmental Science & Technology Letters,
Journal Year:
2025,
Volume and Issue:
12(2), P. 230 - 236
Published: Feb. 3, 2025
Per-
and
polyfluoroalkyl
substances
(PFAS)
are
persistent
environmental
contaminants
found
in
groundwater
sources
a
wide
variety
of
consumer
products.
In
recent
years,
electrochemical
approaches
for
the
degradation
these
harmful
have
garnered
significant
amount
attention
due
to
their
efficiency
chemical-free
modular
nature.
However,
processes
occur
open,
highly
non-equilibrium
systems,
detailed
understanding
PFAS
mechanisms
promising
technologies
is
still
its
infancy.
To
shed
mechanistic
insight
into
complex
processes,
we
present
first
constant-electrode
potential
(CEP)
quantum
calculations
on
electrified
surfaces.
These
advanced
CEP
provide
new
details
about
intricate
electronic
that
during
presence
an
bias,
which
cannot
be
gleaned
from
conventional
density
functional
theory
calculations.
We
complement
our
with
large-scale
ab
initio
molecular
dynamics
simulations
bias
time
scales
Taken
together,
CEP-based
critical
reaction
open
can
used
prescreen
candidate
material
surfaces
optimal
conditions
remediating
other
contaminants.
Cyanuric
acid
(CA),
a
triazine-ring
compound
commonly
used
as
stabilizer
for
free
chlorine
to
enhance
disinfection,
often
persists
in
wastewater
the
production
of
chlorinated
cyanurates
(Cl-CAs),
posing
challenges
treatment.
This
study
demonstrates
that
conventional
advanced
oxidation
processes
(UV/H2O2
and
UV/peroxydisulfate)
are
ineffective
degrading
CA,
while
UV/sulfite
system
successfully
achieves
its
breakdown.
Hydrated
electrons
(eaq-)
were
identified
primary
reactive
species
responsible
cleaving
stable
triazine
ring,
with
minimal
contributions
from
SO3•-
H•.
The
pH
value
influences
both
activity
eaq-
degradability
CA
by
altering
structure;
lower
increases
electron-deficient
regions
dihydrogen
enhancing
susceptibility
nucleophilic
attack
eaq-.
high
concentrations
Cl-
can
inhibit
removal,
likely
due
formation
react
sulfite
suppress
production.
Effective
degradation
was
also
demonstrated
real
wastewater,
highlighting
sustainable
solution
water
These
findings
offer
valuable
insights
into
transformation
present
effective
approaches
eliminating
emerging
contaminants
context
extensive
use
disinfectants.
Accounts of Chemical Research,
Journal Year:
2023,
Volume and Issue:
57(1), P. 153 - 163
Published: Dec. 15, 2023
ConspectusAlkanes
play
a
pivotal
role
in
industrial,
environmental,
and
biological
processes.
They
are
characterized
by
their
carbon–carbon
single-bond
structure,
remarkable
stability,
conformational
diversity.
Fluorination
of
such
compounds
imparts
unique
physicochemical
properties
that
often
enhance
pharmacokinetic
profiles,
metabolic
receptor
interactions
while
keeping
beneficial
properties.
However,
per-
polyfluoroalkyl
substances
(PFAS)
show
persistent
presence
the
environment
potential
adverse
health
effects,
which
propelled
them
to
forefront
global
environmental
discussions.
Alkyl
also
prototypical
for
stereoelectronic
(SE)
effects
widely
applied
chemistry.
Substituents
typically
described
as
electron-density-donating/withdrawing
and/or
responsible
sterically
interacting
with
reagents
or
strategic
groups
molecule.
That
alkane
branching
can
result
higher
stability
compared
less-branched
isomers
has
been
investigated
detail
testing
quantum
chemical
methods,
particular
density
functional
theory
(DFT).
Alkane
results
spatially
compact
structures
close
intramolecular
contacts
so
at
specific
size
detailed
balance
attractive
London
dispersion
covalent
versus
repulsive
Pauli
exchange
shifts
new,
chemically
unfragile
situations.
This
may
lead
dissociation
room
temperature
opens
central
question:
what
is
smallest
crowed
cannot
be
made
synthetically?
In
this
Account,
we
try
shed
light
on
interplay
among
various
(free)
energy
components
crowded
(fluoro)alkane
dissociation.
context,
homolytic
cleavage
C–C
bond
series
model
alkanes
increasing
tert-butyl
(tBu),
adamantyl
(Ad),
[1.1.1]propellanyl
(Prop)
substituents
investigated.
Reference
energies
calculated
PNO-LCCSD(T)-F12b
level
used
benchmark
performance
contemporary
DFT
functionals.
line
previous
conclusions,
application
corrections
functionals
mandatory.
For
structures,
accurate
description
midrange
correlation
specifically
van
der
Waals
interactions,
crucial,
observed
density-dependent
VV10
correction
superior
D4
although
asymptotic
region
better
latter.
The
best
available
dispersion-inclusive
systematic
reasonably
small
residual
errors
safely
large
systems
(>100
atoms),
coupled
cluster
methods
basis
sets
not
computationally
feasible
anymore.
qualitatively
correct
predictions
synthetic
accessibility
under
equilibrium
conditions
(free
energy),
inclusion
thermostatistical
(entropy)
contributions
essential.
According
our
results,
tetra-tert-butylmethane
(C17tBu)
largest
most
system
positive
free
should
synthesizable.
difference
between
hydrogenated
perfluorinated
originates
from
increase
steric
repulsion
substituents,
compensated
same
extent
orbital
interactions.
A
sometimes-assumed
similar
demand
fluorine
hydrogen
atoms
corroborated
investigations
systems.
Perfluorination
found
substantially
decrease
thermal
rendering
hexamethylethane
(C8tBuF)
last
potentially
stable
representative.
