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Title: Photocatalyzed oxidation of ethanol and acetaldehyde in humidified air

Abstract

Photocatalysis is considered as a potential air treatment and purification technology. Photocatalyzed oxidation of ethanol and acetaldehyde in humidified air was carried out to establish a first complete kinetic model for a photocatalyzed multispecies network. Two photocatalysts were examined in a batch, recirculation reactor, near-UV illuminated TiO{sub 2} (anatase) coated (i) on the surface of a nonporous quartz glass plate and (ii) on a porous ceramic honeycomb monolith. The former contained only illuminated (active) surfaces, the latter consisted of substantial {open_quotes}dark{close_quotes} surfaces coated with a thin layer of illuminated (active) catalyst. Ethanol was photooxidized to acetaldehyde and formaldehyde intermediates, and eventually to carbon dioxide and water products. The catalyst and monolith surfaces adsorbed appreciable fractions of the trace ethanol, acetaldehyde, formaldehyde, carbon dioxide and water present. Ethanol, acetaldehyde, and carbon dioxide adsorption isotherms were measured on both catalysts; the formaldehyde adsorption isotherms were assumed identical to those of acetaldehyde. On the fully illuminated glass plate reactor, all four species were accounted for, and closure of a transient carbon mass balance was demonstrated. Completion of a transient carbon mass balance on the monolith reactor required inclusion of additional reaction intermediates (acetic and formic acids), which appear to reversibly accumulate on onlymore » the dark surfaces. The ethanol and acetaldehyde photocatalyzed oxidation kinetic networks were modeled using Langmuir-Hinshelwood rate forms combined with adsorption isotherms for reactant, intermediates, and product CO{sub 2}. For both the quartz plate and monolith catalysts, satisfactory kinetic models were developed to predict the entire time course of ethanol and acetaldehyde multicomponent batch conversions. 43 refs., 16 figs.« less

Authors:
;  [1]
  1. North Carolina State Univ. Raleigh, NC (United States)
Publication Date:
OSTI Identifier:
263709
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis
Additional Journal Information:
Journal Volume: 158; Journal Issue: 2; Other Information: PBD: Feb 1996
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 54 ENVIRONMENTAL SCIENCES; ETHANOL; OXIDATION; ACETALDEHYDE; TITANIUM OXIDES; CATALYTIC EFFECTS; QUARTZ; CERAMICS; CATALYSTS; REACTION INTERMEDIATES; PHOTOCHEMICAL REACTIONS; AIR; HUMIDITY; CHEMICAL REACTION KINETICS; SORPTIVE PROPERTIES; CATALYST SUPPORTS; ADSORPTION

Citation Formats

Sauer, M L, and Ollis, D F. Photocatalyzed oxidation of ethanol and acetaldehyde in humidified air. United States: N. p., 1996. Web. doi:10.1006/jcat.1996.0055.
Sauer, M L, & Ollis, D F. Photocatalyzed oxidation of ethanol and acetaldehyde in humidified air. United States. doi:10.1006/jcat.1996.0055.
Sauer, M L, and Ollis, D F. Thu . "Photocatalyzed oxidation of ethanol and acetaldehyde in humidified air". United States. doi:10.1006/jcat.1996.0055.
@article{osti_263709,
title = {Photocatalyzed oxidation of ethanol and acetaldehyde in humidified air},
author = {Sauer, M L and Ollis, D F},
abstractNote = {Photocatalysis is considered as a potential air treatment and purification technology. Photocatalyzed oxidation of ethanol and acetaldehyde in humidified air was carried out to establish a first complete kinetic model for a photocatalyzed multispecies network. Two photocatalysts were examined in a batch, recirculation reactor, near-UV illuminated TiO{sub 2} (anatase) coated (i) on the surface of a nonporous quartz glass plate and (ii) on a porous ceramic honeycomb monolith. The former contained only illuminated (active) surfaces, the latter consisted of substantial {open_quotes}dark{close_quotes} surfaces coated with a thin layer of illuminated (active) catalyst. Ethanol was photooxidized to acetaldehyde and formaldehyde intermediates, and eventually to carbon dioxide and water products. The catalyst and monolith surfaces adsorbed appreciable fractions of the trace ethanol, acetaldehyde, formaldehyde, carbon dioxide and water present. Ethanol, acetaldehyde, and carbon dioxide adsorption isotherms were measured on both catalysts; the formaldehyde adsorption isotherms were assumed identical to those of acetaldehyde. On the fully illuminated glass plate reactor, all four species were accounted for, and closure of a transient carbon mass balance was demonstrated. Completion of a transient carbon mass balance on the monolith reactor required inclusion of additional reaction intermediates (acetic and formic acids), which appear to reversibly accumulate on only the dark surfaces. The ethanol and acetaldehyde photocatalyzed oxidation kinetic networks were modeled using Langmuir-Hinshelwood rate forms combined with adsorption isotherms for reactant, intermediates, and product CO{sub 2}. For both the quartz plate and monolith catalysts, satisfactory kinetic models were developed to predict the entire time course of ethanol and acetaldehyde multicomponent batch conversions. 43 refs., 16 figs.},
doi = {10.1006/jcat.1996.0055},
journal = {Journal of Catalysis},
number = 2,
volume = 158,
place = {United States},
year = {1996},
month = {2}
}