Laboratory and Field Studies of Photocatalytic Nox and O3 Removal by Coatings on Concrete
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TECHNICAL REPORT 0-6636-1 TxDOT PROJECT NUMBER 0-6636 Laboratory and Field Studies of Photocatalytic NOx and O3 Removal by Coatings on Concrete Neil Crain Maria Juenger Clement Cros Alexandra Terpeluk Lisa Burris Elena McDonald-Buller David Sullivan Yosuke Kimura Jarett Spinhirne Michael Rung December 2016; Published March 2017 http://library.ctr.utexas.edu/ctr-publications/0-6636-1.pdf Technical Report Documentation Page 1. Report No. 2. Government 3. Recipient’s Catalog No. FHWA/TX-17/0-6636-1 Accession No. 4. Title and Subtitle 5. Report Date Laboratory and Field Studies of Photocatalytic NOx and O3 December 2016; Published March 2017 Removal by Coatings on Concrete 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Neil Crain, Maria Juenger, Clement Cros, Alexandra Terpeluk, 0-6636-1 Lisa Burris, Elena McDonald-Buller, David Sullivan, Yosuke Kimura, Jarett Spinhirne 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Center for Transportation Research 11. Contract or Grant No. The University of Texas at Austin 0-6636 1616 Guadalupe Street, Suite 4.202 Austin, TX 78701 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Texas Department of Transportation Technical Report, 09/01/2010–12/31/2016 Research and Technology Implementation Office 14. Sponsoring Agency Code P.O. Box 5080 Austin, TX 78763-5080 15. Supplementary Notes Project performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration. 16. Abstract This project involved thorough testing of titanium dioxide (TiO2)-containing commercial photocatalytic coatings applied to portland cement concrete for highway applications, focusing on the use of these coatings as an abatement method for atmospheric nitrogen oxide (NOx) and ozone (O3). The study consisted of four parts: laboratory chamber testing; outdoor exposure studies; modeling; and field application. Full-factorial experiments in laboratory chambers designed to examine the impact of variables such as temperature, relative humidity, time, and pollutant concentrations on NOx and O3 removal by the coatings demonstrated that a commercial stucco was the best performer of the four original materials tested. After one and two years of outdoor, roadside exposure, the NOx removal capacity of the stucco decreased significantly, but could be improved by soap and water washing. A Comprehensive Air Quality Model with extensions (CAMx) for the Houston-Galveston-Brazoria and Dallas-Fort Worth areas showed the potential of the stucco to reduce average ozone concentrations if large areas of highway structures are coated. Testing at a field site in north Austin, however, showed no conclusive difference between air quality in areas with coated and uncoated highway barriers. Therefore, while photocatalytic concrete coatings have promise for improving air quality, the data from this project suggest that such improvements may not be significant enough to be measured experimentally in common roadway configurations such as the site tested for this study. 17. Key Words 18. Distribution Statement Nitrogen Oxides, Nitric Oxide, Ozone, Photocatalytic No restrictions. This document is available to the Materials, Titanium Dioxide, Anatase public through the National Technical Information Service, Springfield, Virginia 22161; www.ntis.gov. 19. Security Classif. (of report) 20. Security Classif. (of this page) 21. No. of pages 22. Price Unclassified Unclassified 344 Form DOT F 1700.7 (8-72) Reproduction of completed page authorized Laboratory and Field Studies of Photocatalytic NOx and O3 Removal by Coatings on Concrete Neil Crain Maria Juenger Clement Cros Alexandra Terpeluk Lisa Burris Elena McDonald-Buller David Sullivan Yosuke Kimura Jarett Spinhirne Michael Rung CTR Technical Report: 0-6636-1 Report Date: December 2016; Published March 2017 Project: 0-6636 Project Title: Photocatalytic NOx/HRVOC/O3 Removal in Transportation Applications Sponsoring Agency: Texas Department of Transportation Performing Agency: Center for Transportation Research at The University of Texas at Austin Project performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration. Center for Transportation Research The University of Texas at Austin 1616 Guadalupe, Suite 4.202 Austin, TX 78701 http://ctr.utexas.edu/ Disclaimers Author's Disclaimer: The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official view or policies of the Federal Highway Administration or the Texas Department of Transportation (TxDOT). This report does not constitute a standard, specification, or regulation. Patent Disclaimer: There was no invention or discovery conceived or first actually reduced to practice in the course of or under this contract, including any art, method, process, machine manufacture, design or composition of matter, or any new useful improvement thereof, or any variety of plant, which is or may be patentable under the patent laws of the United States of America or any foreign country. Notice: The United States Government and the State of Texas do not endorse products or manufacturers. If trade or manufacturers' names appear herein, it is solely because they are considered essential to the object of this report. Engineering Disclaimer NOT INTENDED FOR CONSTRUCTION, BIDDING, OR PERMIT PURPOSES. Research Supervisor: Dr. Maria Juenger iv Acknowledgments The researchers would like to thank the Texas Department of Transportation for supporting this work, particularly the efforts of project managers Duncan Stewart and Wade Odell. The project advisors on the project management committee provided very useful guidance: Pat Henry, Jackie Ploch, Clifton Coward, Lisa Lukefahr, and Andy Naranjo. We also appreciate the advice of technical contacts Mark Sather and Ruben Casso from the Environmental Protection Agency, Doug Boyer from the Texas Commission on Environmental Quality, and Christopher Klaus from the North Central Texas Council of Governments. The field site and outdoor exposure sites would not have been successful without the help of the TxDOT North Austin District office, especially Jamie Witten, Joseph Carrizales and Lowell Choate, Terry McCoy, Erica Ramirez, Wayne Rehborg, and James Wilhem. Cyril Durrenberger was the senior technical advisor for this project and a good friend. Cyril spent much of his adult life working for the state of Texas trying to improve environmental quality and the life of everyday Texans. Unfortunately, Cyril passed away in April of this year. Cyril will be missed not only at UT but also throughout the state he loved. v Table of Contents Chapter 1. Executive Summary ....................................................................................................1 Chapter 2. Literature Review .......................................................................................................4 2.1 Introduction ............................................................................................................................4 2.2 Titanium dioxide photocatalysts ............................................................................................4 2.3 Photocatalysis on titanium dioxide ........................................................................................5 2.4 TiO2 application methods ......................................................................................................5 2.5 Laboratory scale photocatalytic oxidation research ...............................................................7 2.5.1 Nitrogen oxides removal .................................................................................................7 2.5.2 VOC removal ................................................................................................................11 2.6 Substrate/TiO2 interactions and durability of photocatalytic specimens .............................13 2.6.1 Effect of substrate properties on photocatalysis ...........................................................13 2.6.2 Effect of concrete properties on photocatalysis ............................................................14 2.6.3 Effect of TiO2 on substrate properties...........................................................................15 2.6.4 Durability of photocatalytic specimens.........................................................................15 2.7 Self-cleaning properties of photocatalytic specimens .........................................................16 2.8 Pilot scale and field tests of photocatalytic pollution reduction ..........................................17 Chapter 3. Materials and Testing for Laboratory and Outdoor Exposure Studies ..............20 3.1 Concrete samples and coatings preparation .........................................................................20 3.1.1 Description of concrete samples ...................................................................................20 3.1.2 Concrete slab preparation .............................................................................................22 3.1.3 Coatings ........................................................................................................................23 3.2 Methods for characterization of concrete and coatings .......................................................27 3.2.1 X-ray diffraction ...........................................................................................................27