Implementation of Electro-Fenton technology for environmental … · Fenton reaction The presence...
Transcript of Implementation of Electro-Fenton technology for environmental … · Fenton reaction The presence...
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Implementation of Electro-Fenton technology for environmental remediation:
application for soil and water restoration Marta Pazos and M. Ángeles Sanromán
2nd Summer School on Environmental Applications of AOPsPorto
July 10-14, 2017
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• Green Chemistry
• Applied Biotechnology
• Environmental Technology
Research lines
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1. Introduction
2. Electro-Fenton for effluent treatment
3. Electro-Fenton for soil remediation
4. Conclusions
Implementation of Electro-Fenton technology for environmental remediation:
application for soil and water restoration
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I
EMERGING POLLUTANTS
PESTICIDES
DRUGS PCP
INDUSTRIALADDITIVES
FLAME RETARDANT
IONIC LIQUIDS
FOOD ADDITIVES
SURFACTANTS/ DISINFECTANT
STEROLS/ HORMONES
New chemicals without regulatory status and which impact on environment and human health are poorly understood
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·OHFenton based process
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Environmental problem
TREATMENT REQUIRED
PROBLEM OF GREAT ENVIRONMENTAL IMPACT
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Fe2+ + H2O2 → Fe3+ + •OH + HO-
Constant addition of Fe2+
Constant addition of H2O2 Generation of Fe-complexes
Fe-sludge formation
Fenton’s Reaction
CO2 + H2O …
Organic compounds
H+
HYBRID PROCESSES
(1894) Henry John Horstman Fenton
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CathodeAnode
Power supply
ElectrochemicalProcess
Fe2+
H2O2
Fe2+H2O2
HO•
FentonProcess
HYBRID PROCESSES
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Fe2+
H2O2
Fe2+H2O2
HO•
CathodeAnode
Powersupply
FentonProcess
ElectrochemicalProcess Electro-Fenton
Process
O2 + 2 H+ + 2 e‐ → H2O2Fe3+ + e‐ → Fe2+In situ generation H2O2
Fe2+ regeneration
No Fe-sludge
CathodeAnode
Fe3+
Fe2+
O2
H2O2
Fe2+
Powersupply
Air
HYBRID PROCESSES
Fe-complexes
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Fe2+
H2O2
Fe2+H2O2
HO•
CathodeAnode
Powersupply
Cathode Anode
Fe3+
Fe2+
O2
H2O2
Fe2+
Powersupply
Aeration
Photo-electro Fenton
O2 + 2 H+ + 2 e‐ → H2O2Fe3+ + e‐ → Fe2+
H2O2 + hv→ 2 ⦁OHFe3+ + hv→ Fe2+
FentonProcess
ElectrochemicalProcess
Photolysis
HYBRID PROCESSES
In situ generation H2O2Fe2+ regeneration
No Fe-sludge
No Fe-complex
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1. Introduction
2. Electro-Fenton for effluent treatment
3. Electro-Fenton for soil remediation
4. Conclusions
Implementation of Electro-Fenton technology for environmental remediation:
application for soil and water restoration
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Scarce reactor designs suitable for industrial scaleContinuous treatment of high volumes ( Fe release)
·OHFenton
DRAWBACKS
INDUSTRIALUSE
POA
GOOD RESULTSLAB SCALE
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HETEROGENEOUSCATALYST
REACTOR DESIGN
Fe3+Fe2+
O2H2O2
Fe2+
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STIRRED TANK REACTOR
REACTOR DESIGN
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ActivedCarbon
Nickel
GraphitePTFE
Boron‐DopedDiamond(BDD)
ANODIC MATERIAL
CATHODIC MATERIAL
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0
20
40
60
80
100
0 50 100 150 200
Deg
rada
tion (%
)
Time (minutes)
Fe3+Fe3+
Fe2+Fe2+
O2O2
H2O2
Air
+ →OH●Graphite sheet
cathode BDD anodeO2O2
H2O2
Power supply
Fe3+Fe3+
Fe2+Fe2++ →OH●
100 mg/L Pirimicarb82% removal 3h
PESTICIDES
Pirimicarb
GraphiteBDD
ENHANCEMENTSARE NECESSARY
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STIRRED TANK REACTOR FLUIDIZED REACTORREACTOR DESIGN
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Diez, Sanromán, Pazos (2017) Environ Sci Pollut Res (2017) 24:1137–1151
Graphite+PTFE
PESTICIDESSequential fluidized reactor
New electrodes Graphite-PTFE
UV LED radiation
ENHANCEMENTS
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Diez, Sanromán, Pazos (2017) Environ Sci Pollut Res (2017) 24:1137–1151
c
PESTICIDES
Graphite+PTFE
80% removal 1.5 h
98% removal 1.5 h
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Huge amount of effluents is generated
Request to design processes that permit their remediation in
continuous mode
H2O2
Fe
HETEROGENEOUSCATALYST
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How to avoid Fe release due to the flow system?
Fe
Fe Fe
Fe Fe
Immobilisation on different supports
HETEROGENEOUSCATALYST
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Adequate support
Environ‐mentally friendly
Inexpensive
Fe Retention
ALGINATE
SEPIOLITE
KAOLINITE ACRYLAMIDE
ACTIVATEDCARBON
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Fe-Alginate
Fe-Sepiolite
Fe entrapment
Fe adsorption
Iglesias, Rosales, Pazos, Sanromán Environ Sci Pollut Res (2013) 20:2252–2261Iglesias, Fernández de Dios, Pazos, Sanromán Environ Sci Pollut Res Int (2013) 20:5983‐93
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Homogenous Electro‐Fenton
Heterogeneous Electro‐Fenton
Fe2+
Fe‐AlginateFe‐Sepiolite
Iglesias, Fernández de Dios, Pazos, Sanromán Environ Sci Pollut Res Int (2013) 20:5983‐93Iglesias, Rosales, Pazos, Sanromán Environ Sci Pollut Res (2013) 20:2252–2261
• Fast removal in heterogeneous• Two stage process ads‐degradation
REACTIVE BLACK 5 DYE
REACTIVE BLACK 5 DYE
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Homogenous Electro‐Fenton
Heterogeneous Electro‐Fenton
Fe2+
Fe‐AlginateFe‐Sepiolite
No adsorption after the process
Initial Final
Iglesias, Fernández de Dios, Pazos, Sanromán Environ Sci Pollut Res Int (2013) 20:5983‐93Iglesias, Rosales, Pazos, Sanromán Environ Sci Pollut Res (2013) 20:2252–2261
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Time(h)
0 20 40 60 80 100 120 140
Dec
olou
risat
ion
(%)
0
20
40
60
80
100
=2.5 h =4 h =12.5 h=6 h
Airlift reactor 1.5 L Graphite electrodes
Reactor design equation
Kinetic model: First orderHydrodynamic model: Stirred flow reactor
Applicability of these catalysts to operate in continuous mode
Iglesias, Rosales, Pazos, Sanromán Environ Sci Pollut Res (2013) 20:2252–2261
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1. Introduction
2. Electro-Fenton for effluent treatment
3. Electro-Fenton for soil remediation
4. Conclusions
Implementation of Electro-Fenton technology for environmental remediation:
application for soil and water restoration
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Cathode(-)
Anode(+)
V/A+ _
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+ +
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+
+
++
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+
+ +
+
+
+
+
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--
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--
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+
+
+--
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+
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+
+
++
+
+
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+ +
+
+
++
+
+
+
+
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--
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--
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+
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+ --
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-----
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POSITIVE SPECIES
NEGATIVE SPECIES
ELECTROMIGRATION
The principle of Electro‐Remediation relies upon the application of a low‐intensity direct current through the soil
between a couple of inert electrodes
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Cathode(-)
Anode(+)
V/A+ _
ELECTRO-OSMOSIS
IN SITU SOIL REMEDIATION
Transport of charged and uncharged species
to the cathode chamber
+
+-
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+ +
+
+
+
+
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--
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-+
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-Ø
Ø ØØ
ØØ
Ø
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Inorganic cations: heavy metals
Inorganic anions: sulphate, nitrates…
VALIDATED
Low solubility
Strongly attached to soil
POOR RESULTS ORGANICS
Electrokinetic remediation
IN SITU degradation by Fenton reagentSOLUTION
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Cathode(-)
Anode(+)
V+ _
Fe
FeFe
Fe Fe
Fe
Fe
Fe
Fe
Fe+2 + H2O2 → Fe+3 + OH∙ + OH‐
R + OH∙ → CO2+ H2O
H2O2
H2O2
H2O2
Electrokinetic-Fenton Organic polllutant
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• 0.1 M Na2SO4• pH 3• 10 % H2O2
Experimental conditions
Electrodes Graphite bars
Electrochemical Field 30 V
Time 3 days
Fe contaminated clay 3000 ppm
Electrokinetic-Fenton
FLUXING SOLUTION
Popescu, Rosales, …, Pazos, Lazar, Sanromán Process Saf Environ Protec (2017) 108:99‐107
RHODAMINE B DYE
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t = 0 d
t = 1.5 d
t = 1 d
t = 2.5 d
• Transportation of the H2O2through the soil
• In situ degradation of pollutant
H2O2
∙OH
∙OH
∙OH
Electro Kinetic cells (EK)
Electrokinetic-Fenton
Popescu, Rosales, …, Pazos, Lazar, Sanromán Process Saf Environ Protec (2017) 108:99‐107
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Cathodic chamber
• 0.1 M Na2SO4• pH 3• 10 % H2O2
¿ citric acid ?
Experimental conditions
Electrodes Graphite bars
Electrochemical Field 30 V
Time 27 days
Fe naturally 33594 ppm• Pyrimetanil• Phenanthrene• Anthracene• Fluoranthene• Benzo[a] anthracene• Pyrene
Electrokinetic-Fenton
Bocos, Fernández, Pazos, Sanromán Chemosphere (2015) 125:168‐174
FLUXING SOLUTION
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Pollutant
PY PH AN FL PYRE BZ[A]
Deg
rada
tion
(%)
0
20
40
60
80
100
Treatment without complexing agentTreatment with citric acid
Electrokinetic-Fenton
Bocos, Fernández, Pazos, Sanromán Chemosphere (2015) 125:168‐174
50%
80%
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GI (%)
0 20 40 60 80 100
Polluted Soil
Decontaminated Soil enhanced by pH control at 5
Commercial substrate
Decontaminated Soil
• Phytotoxicity assays withLolium perenne
Electrokinetic-Fenton
Bocos, Fernández, Pazos, Sanromán Chemosphere (2015) 125:168‐174
GERMINATION INDEX
A
B
C
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The electrokinetic phenomenon can be used to produce in situ Fenton reactionThe presence of complexing agents enhances the treatment
Electro-Fenton in soils
The optimization of operational conditions and reactor design are necessaryHeterogeneous catalyst useful for the treatment of continuous flow
Electro-Fenton in aquatic environment
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Thank to PhD student Aida DíezPhD student Marius Popespu
Thank to my former studentsPhD BocosPhD IglesiasPhD Rosales