catalytic destruction of chlorinated solvents in soil vapor

Catalytic Destruction of Chlorinated Solvents in Soil Vapor

Student: Jagoda Vojvodic

Mentor: Eric Betterton

University of Arizona Space Grant

Superfund

• Federal government’s program to clean up hazardous waste sites from a priority list of 1246

• Common contaminants:- Trichloroethylene (TCE)- Tetrachloroethylene (PCE)

Priority List of Hazardous Substances

1 Arsenic

2 Lead

3 Mercury

4 Vinyl Chloride

5 POLYCHLORINATED BIPHENYLS

6 Benzene

7 Cadmium

8 POLYCYCLIC AROMATIC HYDROCARBONS

9 BENZO(A)PYRENE

10 BENZO(B)FLUORANTHENE

11 CHLOROFORM

12 DDT, P,P'-

13 AROCLOR 1254

14 AROCLOR 1260

15 DIBENZO(A,H)ANTHRACENE

16 *TRICHLOROETHYLENE

Motivation

• Pose risk to the human and ecological health from groundwater contamination

• Current remedies with activated carbon are too expensive and do not destroy the contaminant

Propane as reductant

• Economic alternative to using Hydrogen in conversion of PCE

• Concentrated on experiments of propane conversion under various conditions

HClCOOHCPCE

HClCOOHPCE

2283

222

Lab Process Flow DiagramPCE + reductant + O2 CO2 + H20 + HCl

Cross section of reactor

Propane Conversion dataVarying amount of oxygen from 5% to 40%

1% Propane Exps, Jan 2008

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

400 425 450 475 500 525 550 575 600

Pro

pane

Rem

oval

5%

10%

12%

20%

40%

Varying propane concentration,oxygen concentration constant

10%, 88%N2

0

10

20

30

40

50

60

70

80

90

100

340 390 440 490 540 590 640 690

Catalyst Temperature

%R

em

oval

1.00%

0.50%

2.00%

Propane effect on PCE conversion

Conclusion

• Can destroy the chlorinated solvents using a Pt/Rh catalyst effectively

• Need 1.5% Propane to destroy 500ppm of PCE at 440 C

Price Comparison

At >1% Propane, we can destroy 1lb of PCE using:

Propane: $5

Hydrogen: $100

Acknowledgements

NASA Space Grant

Susan Brew

Eric Betterton, Eduardo Saez, Robert Arnold, Brian Barbaris

Erik Rupp, Marty Willinger, Suzanne Richards, Desiree Polson