Novel Activation Technologies for Sodium Persulfate In Situ Chemical Oxidation

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Abigayle Dixon
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1 Novel Activation Technologies for Sodium Persulfate In Situ Chemical Oxidation Frank Sessa FMC Corporation Philadelphia, PA Dalbir Sethi FMC Corporation Philadelphia, PA Jean Pare ChemCo Quebec, CA

2 Persulfate Oxidation Chemistry Simplified Reaction Persulfate + CoC CO2 + H2O Na 2 S 2 O 8 Strong Oxidizer kinetically slow Persulfate anion: S 2 O H + + 2e - 2HSO 4-2 E 0 = 2.12 v Sulfate radical: need to activate SO e - SO 4-2 E 0 = ~ 2.6 v In Comparison: H 2 O 2 OH - MnO - 4 E 0 = 1.8 v E 0 = 2.7 v E 0 = 1.7 v

3 Conventional Persulfate Activation Heat S 2 O heat 2 SO 4 Compounds with > 90% Decomposition Treat with Persulfate 20 ºC 35 ºC 45 ºC Toluene Ethylbenzene Xylene 1,1-DCE 1,2-Dichlorobenzene 1,3-Dichlorobeneze 1,2,4-Trichlorobenzene Benzene Chlorobenzene 1,2-DCE PCE TCE 1,1-DCA 1,2-DCA MTBE Vinyl Chloride Carbon Tetrachloride 1,1,1-TCA Chloroform Methylene Chloride Aqueous solutions - lab data; 72 hour Advantage: will oxidize all compounds of concern given enough thermal input Disadvantage: may be costly to apply in field applications

4 Conventional Persulfate Activation Transition Metal Catalysis S 2 O M +2 M +3 + SO SO 4 Advantage: BTEX Chlorinated Ethenes Chlorobenzenes MTBE concentration (ppm) chorinated ethanes chlorinated methanes chlorinated ethenes BTEX Chlorobenzenes Oxygenates Aqueous Room temp 100 mg Fe / L 2.5% persulfate 21 days control ph 8 persulfate + ph 8 persulfate + ph 2 Disadvantage: precipitation of Fe(OH)3 reduces availability of catalyst

5 Targets for Novel Technologies: Easy to apply in a variety of subsurface conditions Transportable in a groundwater system Increased reactivity of persulfate with a broad range of organic contaminants Chelated metal catalysts Hydrogen peroxide activation High ph activation

6 Chelated Metal Catalysts enhance solubility and transportability in groundwater M +2 Chelant combinations of di- or tri- valent metals with chelants Examples: Fe (II) Fe (III) EDTA Citrate Catechol Polyphosphate Glycolic acid NTA THQ

7 Chelated Metal Catalysts chorinated ethanes chlorinated methanes chlorinated ethenes BTEX Chlorobenzenes Oxygenates Control Persulfate + ph 2 Persulfate + ph 8 ph 8 Aqueous Room temp 100 mg Fe / L 2.5% persulfate 21 days Advantages: improved performance at neutral ph s on chlorinated ethenes, BTEX, chlorobenzenes and oxygenates Disadvantages: not effective on chlorinated ethanes or methanes

8 Hydrogen Peroxide Activation S 2 O H 2 O 2 SO 4 + 2OH* multi-radical attack removal of SOD by peroxide Degradation of Contaminants with Persulfate + Peroxide Contaminant (mg/l) Time 0 Day 8 1,1-DCE TCE 2.8 Non Detectable Room temp Aqueous soln 2 g persulfate 8 ml 12.5% H2O2 100 g of solution 1,1-DCA 1.1 Non Detectable 1,1,-TCA Data from ORIN RT

9 Hydrogen Peroxide Activation Oxidation of M GP Residuals T=0 T=14 Cont rol T = 14 Persulf at e data from ERM 1, Total Target VOCs TOTAL Target SV OCs DCPD 400 g soil from MGP site 1.08 L distilled water 1.5 g / L sodium persulfate 120 ml of 50% peroxide VOC s: BTEX, styrene SVOC s: 3 5 ring PAHs DCPD: dicyclopentadiene

10 Hydrogen Peroxide Activation Decomposition of Contaminants by Persulfate + Peroxide concentration (ppb) 16,000 14,000 12,000 10,000 8,000 6,000 4,000 2,000 1,1,1-TCA CT Benzene TCE Room temp 300 ml water 150 g soil (KMnO4 SOD 9 13 g / kg) 5 g/l sodium persulfate 50 g 17.5% peroxide Day Advantages: broad applicability including chlorinated ethanes and methanes

11 Alkaline Activation ph > 10 Effect of KOH Ratio on Persulfate Reactivity 90,000 80,000 70,000 60,000 50,000 40,000 30,000 20,000 Ethenes Ethanes Methanes BTEX Cl-Benzene Oxygenates 10,000 0 Cntrl Mole Ratio KOH:Per s Room temperature Aqueous solutions 7 days Analyzed by GC-MS 25 g/l sodium persulfate KOH as ph modifier

12 Alkaline Activation Decomposition of Contaminants by Alkaline Activation concentration (ppb) 16,000 14,000 12,000 10,000 8,000 6,000 4,000 2,000 0 ph drifted down, added additional KOH Day 1,1,1-TCA CT Benzene TCE Room temp 300 ml water 150 g soil (KMnO4 SOD 9 13 g / kg) 5 g/l sodium persulfate 0.01 mol / L KOH Advantages: broad applicability including chlorinated ethanes and methanes

13 Selection of Activation Technology Efficacy Matrix Technology BTEX chlorinated ethenes chlorinated ethanes MTBE PCB 1,4-dioxane Un-activated Sodium Persulfate Y N N N N N Sodium Persulfate + Fe(II) Y Y N Y? Y Sodium Persulfate + Heat Y Y Y Y Y Y Persulfate with Chelated Metals Y Y N Y? Y Persulfate with Hydrogen Peroxide Activation Y Y Y Y? Y Persulfate with Alkaline Activation Y Y Y Y Y Y

14 Selection of Activation Technology Are Contaminants Only BTEX? Yes Evaluate Persulfate Alone Mild Oxidation No Only BTEX & MTBE? Yes Evaluate Persulfate Klozur EDTA Chelant Fe - Strong Oxidation No Are there CVOCs? Yes Are CVOCs Cl-Ethanes Cl-Methanes? No (e.g., PAHs, Styrene 1,4-Dioxane, etc.) No (Ethenes & benzenes) Steam Available & Usable? No Permeable Soils? No Yes Yes Evaluate Heated 1. Klozur Persulfate Peroxide Persulfate 2. Kolzur -Peroxide Alkaline Alkaline 3. heated Persulfate persulfate Evaluate 1. Klozur Peroxide 2. Klozur Alkaline Evaluate Alkaline Klozur Persulfate Alkaline Aggressive Oxidation Yes

15 Acknowledgements Richard Brown Linda Osborne Scott Steffl Larry Kinsman ERM FMC FMC Orin RT

Advances in Persulfate ISCO Remediation. Scott Steffl FMC Corporation

Advances in Persulfate ISCO Remediation Scott Steffl FMC Corporation Agenda Activated Persulfate Overview New Activation Methods On Site Persulfate Measurement Kits What is In-Situ Chemical Oxidation?