Grantee Research Project Results

Heterogeneous Catalyst Deactivation and Regeneration in Water Treatment Systems

EPA Grant Number: F07F20358
Title: Heterogeneous Catalyst Deactivation and Regeneration in Water Treatment Systems
Investigators: Paul, Tias
Institution: University of Illinois Urbana-Champaign
EPA Project Officer: Lee, Sonja
Project Period: August 1, 2007 through August 1, 2010
RFA: STAR Graduate Fellowships (2007) RFA Text |  Recipients Lists
Research Category: Safer Chemicals , Fellowship - Environmental , Academic Fellowships

Objective:

The quality of our nation's drinking water sources is being threatened due to contamination with xenobiotic compounds. Although many of the contaminants are present at trace levels, chronic exposure may still pose long-term human health risks. To safeguard the public from potential health risks, it is important to develop new technologies to more efficiently target the degradation of toxic micropollutants during drinking water treatment. Heterogeneous catalysts have shown great promise in laboratory studies for degrading a wide range of contaminants that are poorly treated using conventional technologies. However, before these catalysts can be applied in large scale applications, we need to gain a better understanding of the long-term stability of these materials during use in complex natural water systems. This project will address one of the main obstacles to widespread implementation of heterogeneous catalytic technologies for water treatment: catalyst deactivation by aqueous chemical species.

The specific objectives of this project are to:

1. Identify aqueous chemical species that contribute to catalyst deactivation
2. Gain a molecular-level understanding of the mechanisms contributing to catalyst deactivation
3. Develop simple and effective procedures for restoring catalyst activity

Approach:

This project will be performed using a model reductive catalyst, palladium metal, and a model advanced oxidation catalyst, titanium dioxide photocatalyst. The deactivation of the catalysts will be observed by performing kinetics experiments in the presence of a range of potential foulants. The initial hypothesis is that compounds that complex strongly with the active sites on the catalyst surface will result in significant catalyst deactivation. To test this hypothesis, the catalysts utilized in the kinetics experiments will subsequently be examined by ATR-FTIR and other surface specific spectroscopic techniques. Specific regeneration methods will be developed to target the mechanism(s) of deactivation observed during the spectroscopic studies.

Expected Results:

The results of this study will yield both a fundamental understanding of catalyst deactivation mechanisms and also practical strategies for increasing catalyst efficiency and stability during long-term catalysis operations.

Supplemental Keywords:

heterogeneous catalysis, drinking water treatment, photocatalysis, catalyst fouling, catalyst poisoning, catalyst regeneration, noble metal catalysts,

Progress and Final Reports:

2008

2009

Final