The advanced oxidation processes
such as photocatalysis, radiolysis and sonolysis are useful for
undesirable organics from air and water. For example, organic materials
such as hydrocarbons, haloaromatics, phenols, halogenated biphenyls,
textile dyes have been successfully mineralized in TiO2
slurries. In aqueous solutions the photogenerated holes at TiO2
particles are scavenged by surface hydroxyl groups to generate .OH
radicals which then oxidize the dissolved organics.
We are currently comparing
different oxidative processes inorder to understand the role of .OH
radicals. One of the disadvantages of semiconductor slurry based
system is the high degree of recombination between photogenerated
carriers within the individual particles. This is usually overcome by
electrons with a sacrificial electron acceptor such as dissolved oxygen
so that the holes can participate in the oxidation of the organics.
scavenging of electrons becomes a limiting factor in controlling the
oxidation of organics.
The use of an anodic bias to
the charge carriers obviates the need for oxygen as an electron
and makes it possible to carry out the photocatalytic reaction in
conditions. The electrochemically assisted photocatalysis also
provides an unique opportunity
to separate the anodic and cathodic processes and thereby isolate the
reactions occurring in photocatalytic systems.
understand the role of hydroxyl radical in the oxidative
transformation of organic compounds that are considered toxic in
- To develop new
methodologies (e.g., combining sonolysis and photocatalysis) to
improve the rate of degradation and control the fate of reaction
pathways leading to mineralization.
- To develop smart materials that
simulaneously detect and destroy organic contaminants ( e.g. ZnO based
out selective hydroxyl radical and elctron transfer induced
oxidation using radiolytic methods and identify reaction
intermediates using pulse radiolysis
reaction products and computation calculations to
establish reaction pathways.
- Comapre and contrast the merits of photocatalysis,
and radiolysis for their effectiveness in the mineralization of
organic contaminants and humic substances
Profs. K. Vinodgopal and Julie Peller;
(Indiana Univ. Northwest), Prof. Patricia Morris (Center
for Environmental Engineering Science & Technology, Notre Dame),
Prof. Kevin O'Shea (Florida International University), Prof. Papa
Constantineau (Greece) and Dr. David Kreller (U. Notre Dame), who
contribute to the success of our environmental research.
Progress So Far
- Demonstrated the effectiveness of Electrochemically
- Introduced the concept of visible light induced
degradation of textile azo dyes on titania surface
- Established the role of hydroxyl radical and direct
electron transfer in TiO2 assisted photocatalysts
- Demonstrated the synergy of combining sonolysis and
photocatalysis and minimize the toxic impact of intermediates
- Introduced the concept of "Sense & Shoot"
simultaneous detection and degradtion of organic contaminants using
Contributions with highest citations
U., Gray, K. A. and Kamat, P. V., Radiolytic and TiO2
assisted photocatalytic degradation of 4-chlorophenol. A
comparative study. J. Phys. Chem., 1994, 98, 6343-6351.
K. and Kamat, P. V., Electrochemically assisted photocatalysis using
nanocrystalline semiconductor films. Solar Energy Mater. Solar Cells,
1995, 38, 401-410.
K. and Kamat, P. V., Enhanced rates of photocatalytic degradation of an
azo dye using SnO2/TiO2 coupled
semiconductor thin films. Environ. Sci.
Technol., 1995, 29, 841-845.
K., Wynkoop, D. and Kamat, P. V., Environmental Photochemistry on
semiconductor surfaces: A photosensitization approach for the
degradation of a textile azo dye, Acid Orange 7. Environ. Sci.
Technol., 1996, 30, 1660-1666.
J., Wiest, O. and Kamat, P. V., Synergy of combining sonolysis
and photocatalysis in the degradation and mineralization of chlorinated
aromatic compounds. Environ. Sci. Technol., 2003, 37, 1926-1932.
Kamat, P. V.,
Huehn, R. and Nicolaescu, R., A Sense and Shoot Approach for
Photocatalytic Degradation of Organic Contaminants in Water. J. Phys.
Chem. B, 2002, 106, 788-794.
Wiest, O. and Kamat, P. V., Radical induced oxidative transformations
of Quinoline. J. Phys. Chem. A, 2003, 107, 427-433.
Peller, J., Wiest, O.
and Kamat, P. V., Hydroxyl Radical's Role in the Remediation of a
Common Herbicide, 2,4-Dichlorophenoxyacetic acid (2,4-D). J. Phys.
Chem. B, 2004, 108, 10925-10933
Daily InScights: Fighting
Toxins With Radiation
Radiation, Minerals, Toxic Waste could be cleanup boon
Also featuredin Nature Science
American and ALCHEMIST
Cited as one of the major developments of the year 2001 in the National
Nanotechnolgy Initiative and its Implementation Plan (see page 29
and 41) submitted by National Science and Technology Council, Committee
on Technology Subcommittee on Nanoscale Science, Engineering and
Technology. Detailed Technical Report Associated with the
Report to the President's FY 2003 Budget
December 16, 2004 issue of the Journal of Physical Chemistry A
Peller, J., Wiest, O. and Kamat, P. V.,
Hydroxyl Radical's Role in the Remediation of a Common Herbicide,
2,4-Dichlorophenoxyacetic acid (2,4-D) -Feature Article. J. Phys. Chem.
A, 2004, 108, 10925-10933.
March 31 issue of the The Journal
of Physical Chemistry A, 2005, issue
Mechanistic Pathways of the
Hydroxyl Radical Reactions of Quinoline. 1. Identification,
Distribution, and Yields of Hydroxylated Products A. Roxana Nicolaescu, Olaf Wiest, and Prashant V.
Kamat J. Phys. Chem. A, 109, 2005,
2822 - 2828
Mechanistic Pathways of the
Hydroxyl Radical Reactions of Quinoline. 2. Computational Analysis of
Hydroxyl Radical Attack at C Atoms A.
Roxana Nicolaescu, Olaf Wiest, and Prashant V. Kamat J. Phys. Chem. A, 109, 2005, 2829 - 2835