Gas-phase photocatalytic oxidation: Cost comparison with other air pollution control technologies

Turchi, Craig; Wolfrum, Edward J.; Miller, Ryszard

doi:10.2172/10194943

Cited by 3 publications

(3 citation statements)

References 3 publications

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“…The most common VOC emission control methods [3,4] include carbon adsorption, incineration, catalytic oxidation, biofiltration and photocatalytic oxidation (PCO) using titanium dioxide (TiO 2 ), which has gained much attention in the treatment of air and water pollutants, especially in low-concentration, low-flow-rate, and room-temperature applications. Examples of such applications are process vent treatment, soil vapor extraction, air stripping, indoor air purification, pathogen inactivation, and ground water decontamination [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Oxidation of PCE and Butyraldehyde over Titania Modified with Perovskite Optical Crystal BaTiO₃

Vajifdar¹,

Chen²,

Gossage³

et al. 2007

Chem Eng & Technol

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Photocatalysis utilizes near-UV or visible light to break down organic pollutants into innocuous compounds at room temperatures. This paper introduces the use of semiconducting optical crystals as an additive to a photocatalyst. The perovskite optical material BaTiO 3 (band gap of 3.7-3.8 eV) is found to increase VOC destruction when black light is used. The best composition found is 0.1 wt % BaTiO 3 with the balance being TiO 2 . This photocatalyst increases tetrachloroethylene (PCE) conversion by 12 % to 32 % for space times between 1.4 and 17.2 seconds and inlet concentrations of 40 to 130 ppm with a 4 W black light. The average enhancement is approximately 25 %. For butyraldehyde conversion the maximum enhancement is 20 % at 130 ppm in 3.6 seconds. The UV/VIS spectroscopy data indicate a lower absorbance with the additive. The reaction parameters studied are space velocity, inlet concentration and light source. Oxidation by-products are identified using a GCMS.

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Section: Introductionmentioning

confidence: 99%

Photocatalytic Oxidation of PCE and Butyraldehyde over Titania Modified with Perovskite Optical Crystal BaTiO₃

Vajifdar¹,

Chen²,

Gossage³

et al. 2007

Chem Eng & Technol

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“…Common scavengers such as humic substances and bicarbonate ions increase treatment costs for the technology. 13 Turchi and coworkers 14 found that by air stripping the volatile contaminants from the water stream, the regulated compounds at many contaminated sites could be transferred to the air, leaving the radical scavengers behind. The water can then be safely discharged, depending on stripper efficiency, and the air effectively treated with PCO.…”

Section: Introductionmentioning

confidence: 99%

Pilot-Scale Demonstration of an Innovative Treatment for Vapor Emissions

Watt

Magrini

Carlson

et al. 1999

Journal of the Air & Waste Management Association

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Researchers from the National Renewable Energy Laboratory recently conducted a pilot-scale study at McClellan Air Force Base (AFB) in Sacramento, CA. The objective of the test was to determine the effectiveness of an ambient-temperature, solar-powered photocatalytic oxidation treatment unit for destroying emissions of chlorinated organic compounds from an air stripper. This paper reports test results and discusses applications and limitations of the technology.A 10-standard-cubic-foot-per-minute (SCFM) (28.3 L/min) slip stream of air from an air stripper at Operative Unit 29-31 at McClellan AFB was passed through a reactor that contained a lightweight, perforated, inert support coated with photoactive titanium dioxide. The reactor faced south and was tilted at a 45° angle from vertical so that the light-activated catalyst received most of the available sunlight. An online portable gas chromatograph with two identical columns simultaneously analyzed the volatile organic compounds contained in the reactor inlet and outlet air streams. Summa canister grab samples of the inlet and outlet were also collected and sent to a certified laboratory for U.S. Environmental IMPLICATIONS Current destructive technologies, such as biofiltration and incineration, for treating air contaminated with chlorinated ethylenes are less than ideal. Sensitivity to upsets and toxicity to microorganisms make biofiltration difficult to apply. Incineration requires considerable energy input to fully oxidize these recalcitrant compounds. This paper describes an ambient temperature process that can destroy trichloroethylene from the off-gas of an air stripper. The system uses the ultraviolet portion of the solar spectrum to activate a photocatalyst and destroy contaminants. The solar-driven process may provide a costeffective treatment system for remote applications and for applications where public perception takes precedence over the speed of cleanup. Alternatively, a lamp-driven process can be used for continuous operation.Protection Agency Method TO-14 analysis and verification of our field analyses.Three weeks of testing demonstrated that the treatment system's destruction and removal efficiencies (DREs) are greater than 95% at 10 SCFM with UV intensities at or greater than 1.5 milliwatts/square centimeter (mW/cm 2 ). DREs greater than 95% at 20 SCFM were obtained under conditions where UV irradiation measured at or greater than 2 mW/cm 2 . In Sacramento, this provided 6 hours of operation per clear or nearly clear day in April. A solar tracking system could extend operating time. The air stream also contained trace amounts of benzene. We observed no loss of system performance during testing.

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“…Also shown in the figure is the predicted range of application for PCO. This range is based on laboratory data, pilot-sc a le tests, and engineering assumptions [2]. Although the predicted range of application for PCO is less accurate than the information from commercially operating systems, it is sufficient to identify potential markets for cohnn ercialization of photocatalysis.…”

Section: Introductionmentioning

confidence: 99%

Overview of solar detoxification activities in the United States

Mehos¹,

Williams²,

Turchi³

1994

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has been investigating a process that uses solar energy to destroy hazardous. wastes in air and water. The process, photocatalytic oxidation, uses ultraviolet light in conjunction with the semiconductor titanium dioxide to generate highly reactive hydroxyl radicals. Early research and development aativities have demonstrated that photocatalysis may be cost effective for some applications. The Department of Energy is currently working to establish a commercial industry that uses solar energy to destroy hazardous wastes in air, water, and soil. To achieve this objective, NREL and Sandia are bringing together environmental firms, solar manufacturers, and organizations that have waste or remediation problems.

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Gas-phase photocatalytic oxidation: Cost comparison with other air pollution control technologies

Abstract: This report was prepared as an account of work sponsored by an agency of the United 9tates gov�rnn1e[)�.

Cited by 3 publications

References 3 publications

Photocatalytic Oxidation of PCE and Butyraldehyde over Titania Modified with Perovskite Optical Crystal BaTiO₃

Photocatalytic Oxidation of PCE and Butyraldehyde over Titania Modified with Perovskite Optical Crystal BaTiO₃

Pilot-Scale Demonstration of an Innovative Treatment for Vapor Emissions

Overview of solar detoxification activities in the United States

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Gas-phase photocatalytic oxidation: Cost comparison with other air pollution control technologies

Abstract: This report was prepared as an account of work sponsored by an agency of the United 9tates gov�rnn1e[)�.

Cited by 3 publications

References 3 publications

Photocatalytic Oxidation of PCE and Butyraldehyde over Titania Modified with Perovskite Optical Crystal BaTiO3

Photocatalytic Oxidation of PCE and Butyraldehyde over Titania Modified with Perovskite Optical Crystal BaTiO3

Pilot-Scale Demonstration of an Innovative Treatment for Vapor Emissions

Overview of solar detoxification activities in the United States

Contact Info

Product

Resources

About

Photocatalytic Oxidation of PCE and Butyraldehyde over Titania Modified with Perovskite Optical Crystal BaTiO₃

Photocatalytic Oxidation of PCE and Butyraldehyde over Titania Modified with Perovskite Optical Crystal BaTiO₃