(157f) Catalytic Treatment of Water Contaminated with Chlorinated Hydrocarbons

Umit. S. Ozkan^1*, Hyuntae Sohn¹, Gokhan Celik¹, Seval Gunduz¹, Saurabh A. Ailawar¹, Paul Edmiston²

¹The Ohio State University, Columbus, Ohio 43210 (United States)

²The College of Wooster, Wooster, Ohio, 44691 (United States)

^*ozkan.1@osu.edu

Contamination of groundwater by chlorinated compounds such as trichloroethylene (TCE) is an environmental concern due to their high level of toxicity and potential impact on drinking water [1]. It is estimated that TCE is present above permissible levels in 9-34% of drinking water sources in the U.S [2]. Thus, development of a remediation system to remove chlorinated compounds from groundwater has become imperative. Existing remediation techniques for treatment of contaminated water are not efficient or feasible due to low rates of remediation, high energy inputs, and media regeneration/replacement cost. [3, 4]. Although hydrodechlorination (HDC) appears to be an efficient way of groundwater remediation, it suffers kinetically due to low concentration of contaminants and catalyst deactivation due to anionic groundwater constituents [5, 6].

The focus of this study is the use of a new class of materials, namely swellable organically-modified silicates (SOMS) as a catalyst scaffold for HDC reactions. SOMS are absorptive, swellable when contacted with organics and extremely hydrophobic [7-9]. Organometallic precursors used for catalyst synthesis facilitate deposition of the active metal inside the pores. The absorptive and hydrophobic nature of SOMS will guide the organics toward the active sites and repel water and anionic poisons. When used as catalyst scaffolds, SOMS can have potential to resolve the issues involved in HDC of TCE.

In this study, the catalytic activity and poison resistance of Pd-incorporated SOMS have been investigated for HDC of TCE. In addition to continuous flow and batch reactor experiments, a wide array of characterization techniques including N₂ physisorption, laser Raman and infrared spectroscopy, solid-state nuclear magnetic resonance (NMR), temperature programmed studies with mass spectrometer, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometer (ICP-OES), X-ray absorption fine structure (XAFS) and transmission electron microscopy (TEM) has been used for a better understanding of the nature of these materials.

References

[1] R.E. Doherty, Environmental Forensics 1 (2000) 69-81.

[2] C. Wu, J. Schaum, Environmental Health Perspectives 108 (2000) 359-363.

[3] A. Elola, E. Díaz, S. Ordoñez, Environmental science & technology 43 (2009) 1999-2004.

[4] H.H. Russell, J.E. Matthews, G.W. Sewell, TCE removal from contaminated soil and ground water. Ground water issue, Environ. Protect. Agency, 1992, p. 12 pp.

[5] N. Munakata, M. Reinhard, Applied Catalysis B: Environmental 75 (2007) 1-10.

[6] G.V. Lowry, M. Reinhard, Environmental Science & Technology 35 (2001) 696-702.

[7] C.M. Burkett, P.L. Edmiston, Journal of Non-Crystalline Solids 351 (2005) 3174-3178.

[8] C.M. Burkett, L.A. Underwood, R.S. Volzer, J.A. Baughman, P.L. Edmiston, Chemistry of Materials 20 (2008) 1312-1321.

[9] P.L. Edmiston, L.A. Underwood, Separation and Purification Technology 66 (2009) 532-540.