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Abstract for the section ICES302: AlChe - Physio-Chemical Life Support
Process Development at the 43 nd International Conference on Environmental
Systems (ICES)
Title: Visible Light Responsive Catalysts Using Quantum Dot-Modified Ti0 2 for
Air and Water Purification
Authors: Janelle L. Coutts 1 , Lanfang H. Levine 2 , Jeffrey T. Richards 3 , Paul E. Hintze 4 , Christian
A. Clausen 5
Authors:
Janelle L. Coutts, Lanfang H. Levine, Jeffrey T. Richards - Engineering Services Contract -
Team QNA, Kennedy Space Center, FL 32899
Paul Hintze - NASA Materials Science Division, NE-L, Kennedy Space Center, FL 32899
Christian Clausen - Department of Chemistry, University of Central Florida, Orlando, FL 32816
Abstract:
The method of photocatalysis utilizing titanium dioxide, Ti0 2 , as the catalyst has been widely
studied for trace contaminant control for both air and water applications because of its low
energy consumption and use of a regenerable catalyst. Titanium dioxide requires ultraviolet light
for activation due to its band gap energy of 3.2 eV. Traditionally, Hg-vapor fluorescent light
sources are used in PCO reactors and are a setback for the technology for space application due
to the possibility of Hg contamination. The development of a visible light responsive (VLR)
Ti0 2 -based catalyst could lead to the use of solar energy in the visible region (-45% of the solar
spectrum lies in the visible region; > 400 nm) or highly efficient LEDs (with wavelengths > 400
nm) to make PCO approaches more efficient, economical, and safe. Though VLR catalyst
development has been an active area of research for the past two decades, there are few
commercially available VLR catalysts; those that are available still have poor activity in the
visible region compared to that in the UV region. Thus, this study was aimed at the further
development of VLR catalysts by a new method - coupling of quantum dots (QD) of a narrow
band gap semiconductor (e.g., CdS, CdSe, PbS, ZnSe, etc.) to the Ti0 2 by two preparation
methods: 1) photodeposition and 2) mechanical alloying using a high-speed ball mill. A library
of catalysts was developed and screened for gas and aqueous phase applications, using ethanol
and 4-chlorophenol as the target contaminants, respectively. Both target compounds are well
studied in photocatalytic systems serve as model contaminants for this research. Synthesized
catalysts were compared in terms of preparation method, type of quantum dots, and dosage of
quantum dots.
'Scientist II, Craig Technologies (a teammate of ESC-Team QNA), Mail Code: ESC-24,
Kennedy Space Center, FL 32899
2 Senior Research Chemist, Enterprise Advisory Services, Inc. (a teammate of ESC-Team QNA),
Mail Code: ESC-24, Kennedy Space Center, FL 32899 and AIAA senior member
3 Research Scientist, Stinger Ghaffarian Technologies (a teammate of ESC-Team QNA), Mail
Code: ESC-24, Kennedy Space Center, FL 32899
4 Chemist, NASA Materials Science Division, NE-L, Mail Code: NE-L6, Kennedy Space Center,
FL 32899
5 Professor of Chemistry, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL
32816
Bio:
Janelle Coutts is a Scientist II with Craig Technologies at Kennedy Space Center under the
Engineering Services Contract. In 2008, she earned a bachelor’s degree in Chemistry at the
University of Central Florida in Orlando, and is currently in her 5 lh year of the Materials
Chemistry Ph.D. program at the same university. For the past three years, she has worked as part
of the Analytical and Biological Capabilities Lab with the Advanced Life Support Group at
KSC, focusing on air revitalization and photocatalytic oxidation of volatile organic compounds.
Janelle has also focused on research involving environmental remediation of hazardous
chemicals in some of her graduate research with the Industrial Chemistry Lab at UCF, while her
main dissertation research focuses on her KSC work.