DECHLORONATION OF TRICHLOROETHYLENE USING

ZEROVALENT IRON

July 27, 2000

The University of Oklahoma

Research Experience for Undergraduates (REU)

by: Matthew Jefferson

ACKNOWLEDGMENTS

• National Science Foundation

• OU CEES

• REU Professor:

– Dr. Elizabeth Butler

• Graduate Students:

– Meera Subramanim

– Maria Leonor Támara

OVERVIEW

• Background

• Research Question

• Materials and Methods

• Procedure

• Results

• Conclusion/ Recommendations

BACKGROUND

• Remediation– Passive Treatment

– Replacement Reaction

• Why Do We Care?

RESEARCH QESTION

• How do different types of iron affect the dechlorination by-products of trichloroethylene (TCE)?

METHODS AND MATERIALS

• Shimazu Gas Chromatograph

GAS CHROMATOGRAPH

METHODS AND MATERIALS

• Shimazu Gas Chromatograph

• Three Irons

METHODS AND MATERIALS

• Shimazu Gas Chromatograph

• Three Irons

• Chlorinated Compounds

TESTING PROCEDURE

• Dechloronation Experiment– Sample Preparation

• Irons

• Tris Buffer

• TCE Spike Solution

• Anaerobic Conditions

– Platform Shaker

Vial Cap

Tris-buffer

Iron

6 mL Vial

PLATFORM SHAKER

TESTING PROCEDURE

• Dechlorination Experiment– Sampling Procedure

• Liquid• Gas

• QA/QC– GC Accuracy– Mixing vs. Time

PLATFORM MIXING

MIXING EXPERIMENT

Mixing Time vs. Concentraion of TCE

6.00E-07

7.00E-07

8.00E-07

9.00E-07

1.00E-06

1.10E-06

0 10 20 30 40

Time (min)

Con

c (M

)

EXPERIMENTAL RESULTS

• Duration

• General Trends/Observations– Dechlorination– First Order Rate Law

Rates for Fisher Electrolytic

y = 1.992E-05e-8.745E-03x

R2 = 8.915E-01

0

0.000003

0.000006

0.000009

0.000012

0.000015

0.000018

0.000021

0 100 200 300 400 500 600

Time (hrs)

Con

c. o

f TC

E (M

)

Fisher Electrolytic Blank Rate Law

Rates for Peerless Iron

y = 8.573E-06e-4.063E-03x

R2 = 3.444E-01

0.000E+00

3.000E-06

6.000E-06

9.000E-06

1.200E-05

1.500E-05

1.800E-05

2.100E-05

0 100 200 300 400 500 600

Time (hrs)

Con

c. o

f TC

E (M

)

Peerless Iron Blank Rate Law

Rates for Fisher Filings

0.000E+00

3.000E-06

6.000E-06

9.000E-06

1.200E-05

1.500E-05

1.800E-05

2.100E-05

0 100 200 300 400 500 600

Time (hrs)

Con

c. o

f TC

E (M

)

Fisher Filings Blank

EXPERIMENTAL RESULTS

• Duration

• General Trends/Observations– Dechlorination– First Order Rate Law

• Problems– Preliminary Data– GC Calibration

• Reaction by-products• Experimental Data

Rates for Fisher Filings

0.000E+00

3.000E-06

6.000E-06

9.000E-06

1.200E-05

1.500E-05

1.800E-05

2.100E-05

0 100 200 300 400 500 600

Time (hrs)

Con

c. o

f TC

E (M

)

Fisher Filings Blank

IN SUMMARY...

• Inconclusive

• More Research– Reproducibility– Fix problems– Reaction by-products– Controlling the reaction

QUESTIONS?