Environmental Science & Technology,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 8, 2025
Ocean
alkalinity
enhancement
(OAE)
based
on
enhanced
weathering
of
olivine
(EWO)
is
a
promising
marine
carbon
dioxide
removal
(mCDR)
technique.
Previous
research
primarily
focuses
the
toxicological
effects
potentially
toxic
metals
(PTMs)
released
from
olivine.
In
this
Perspective,
we
explore
overlooked
impacts
EWO
environmental
media
in
two
scenarios:
applied
to
beaches/shallow
continental
shelves
and
offshore
dispersion
by
vessels.
We
analyze
potential
migration
pathways
iron
PTMs
(e.g.,
nickel
chromium)
after
their
release,
interactions
with
manganese
oxides
sediments,
causing
secondary
contamination.
Additionally,
propose
mitigation
strategies
prevent
PTM
concentrations
exceeding
local
quality
standards,
including
use
alkalization
equipment
control
levels.
This
Perspective
underscores
need
for
thorough
assessments
prior
large-scale
implementation
ensure
sustainability
efficacy
mCDR
efforts.
Water,
Год журнала:
2025,
Номер
17(2), С. 261 - 261
Опубликована: Янв. 17, 2025
Mn2+
is
a
prevalent
contaminant
in
groundwater.
In
this
study,
manganese
oxides
(MnOx)
were
prepared
via
redox
method
to
remove
from
water.
The
effects
of
the
drying
operation
preparation
process,
including
heat
at
20–120
°C
with
different
times
and
freeze
methods,
on
structural
properties,
removal
performance
mechanisms
investigated.
results
indicate
that
conditions
can
significantly
affect
stability
MnOx.
MnOx
dried
50
for
12
h
exhibited
best
efficiency
stability,
an
adsorption
capacity
125.7
mg/g
efficacy
95.1%
after
six
reuse
cycles.
pathway
experiments
revealed
sample
had
superior
catalytic
oxidation
abilities
Mn2+,
while
other
samples
removed
by
primarily
relying
process.
investigation
structure
excessive
led
shrinkage
oxide
particles,
reduction
surface
voids,
decrease
hydroxyl
groups.
Conversely,
insufficient
time
or
temperatures
resulted
high
water
content
MnOx,
which
occupied
active
sites.
XPS
analysis
indicated
relied
Mn(III)
adsorbed
oxygen
With
inadequate
drying,
large
amount
Mn(II)
remained
surface,
over-drying
conversion
Mn(IV),
reducing
activity
resulting
low
stability.
Toxics,
Год журнала:
2025,
Номер
13(4), С. 262 - 262
Опубликована: Март 31, 2025
Current
research
focuses
more
on
redox
of
toxic
Cr(VI),
with
less
attention
to
Cr(III)
changes
in
flooded
soil.
First,
the
structure
acid
birnessite
and
cryptomelane
was
characterized
by
X-ray
diffraction
(XRD),
scanning
electron
microscopy
(SEM),
photoelectron
spectroscopy
(XPS)
other
test
methods.
This
study
investigated
farmland
soil
Yuxi,
Yunnan
Province,
under
flooding
stress
induced
addition
two
distinct
concentrations
manganese
oxides.
Throughout
experiment,
key
physicochemical
properties
soil—including
pH,
potential
(Eh),
Cr(VI)
concentration,
chromium
speciation—were
systematically
measured
analyzed.
Structural
characterization
demonstrated
morphological
surface
area
properties.
Specifically,
birnessite,
petal-like
stacked
spheres,
has
a
specific
103.76
m2/g,
while
cryptomelane,
strip-shaped,
an
95.92
m2/g.
The
submergence
experiment
yielded
following
phenomena:
(1)
During
60-day
amended
0.5%
or
1%
exhibited
increase
Eh
compared
control
group.
(2)
At
end
period,
concentration
treated
increased
2.4
times
In
addition,
after
60
days,
exceeded
5
mg/L
soils
oxide
added
them.
evaluates
how
oxides
oxidize
Cr(III),
aiding
assessing
their
environmental
risks
long-term
impacts
metal
transformation.
findings
help
predict
behavior
farm
guide
remediation
strategies.
Abstract
The
present
study
demonstrates
a
treatment
approach
that
utilizes
flower-shaped
tin
oxide
nanoparticles
for
the
removal
of
cadmium
from
synthetic
wastewater
by
adsorption.
Tin
were
synthesized
using
simple
and
eco-friendly
method
employed
ions
wastewater.
nanoflowers
successfully
characterized
Fourier
Transform
Infrared
Spectroscopy,
X-Ray
Diffraction
Analysis,
Scanning
Electron
Microscope
Brunauer-Emmett-Teller
(BET)
surface
area
analysis.
batch
adsorption
process
was
optimized
response
methods
to
investigate
influential
parameters
process.
Optimal
efficacy
achieved
at
pH
value
9.0,
mixing
time
20
min,
an
adsorbent
amount
15
mg.
results
indicated
maximum
efficiency
99.14
±
0.10%
Cd(II)ions
in
domestic
equilibrium
elucidated
Langmuir,
Freundlich,
Sips
Toth
isotherm
models
nonlinear
regression.
In
addition,
error
functions
such
as
Chi-square
(X2),
Average
Relative
Error
(ARE),
Root
Mean
Squared
(RMSE)
HYBRID
used
test
validity
models.
model,
with
R2
0.9894,
accurately
matched
experimental
data
capacity
57.12
mg
g-1
Cd(II)
calculated
respectively.
sorption
kinetics
well
pseudo-second-order
kinetic
model.
demonstrated
onto
SnO2
is
influenced
both
monolayer
multi-site
interactions.
These
findings
indicate
are
suitable
removing
aqueous
solutions
processes.
Environmental Science & Technology,
Год журнала:
2025,
Номер
unknown
Опубликована: Апрель 7, 2025
Natural
manganese
(Mn)-rich
nodules
effectively
sequester
cadmium
(Cd)
in
soils
and
influence
on
the
geochemical
cycling
of
soil
Cd,
yet
microscale
understanding
their
enrichment
mechanisms
remains
limited.
From
a
regional
survey
1448
rhizosphere
soil-rice
sample
pairs
karst
areas
Guangxi,
China,
we
identified
characterized
Mn-rich
from
representative
sites
to
investigate
role
Cd
sequestration.
Using
chemical
extractions
combined
with
laser
ablation-inductively
coupled
plasma-mass
spectrometry
(LA-ICP-MS)
X-ray
photoelectron
spectroscopy
(XPS),
revealed
that
Mn
oxides
serve
as
primary
carriers
nodules,
accounting
for
approximately
63.6%
total
dominating
through
binding
Cd-O
Cd-OH
bonds
characteristic
inner-sphere
surface
complexation
structural
incorporation.
The
stability
these
interactions
was
confirmed
by
pH-dependent
experiments,
showing
<5.0%
release
even
at
pH
=
3.0.
high
Mn(III)
mass
ratios
(36.0%-40.0%)
facilitated
stable
complexation,
resulting
increased
retention.
These
study
findings
reveal
exceptional
sequestration
capacity
natural
provide
insights
concentrations
low
availabilities
karst,
which
can
aid
developing
strategies
managing
Cd-polluted
soils.
