Kinetics
and Product Formation during the Photooxidation
of Butanol on Atmospheric Mineral Dust
Milena Ponczek
Christian George
10.1021/acs.est.7b06306.s001
https://acs.figshare.com/articles/journal_contribution/Kinetics_and_Product_Formation_during_the_Photooxidation_of_Butanol_on_Atmospheric_Mineral_Dust/6122003
Mineral
dust particles have photochemical properties that can promote
heterogeneous reactions on their surfaces and therefore alter atmospheric
composition. Even though dust photocatalytic nature has received significant
attention recently, most studies have focused on inorganic trace gases.
Here, we investigated how light changes the chemical interactions
between butanol and Arizona test dust, a proxy for mineral dust, under
atmospheric conditions. Butanol uptake kinetics were measured, exploring
the effects of UV light irradiation intensity (0–1.4 mW/cm<sup>2</sup>), relative humidity (0–10%), temperature (283–298
K), and butanol initial concentration (20–55 ppb). The composition
of the gas phase was monitored by a high-resolution proton-transfer-reaction
mass spectrometer (PTR-ToF-MS) operating in H<sub>3</sub>O<sup>+</sup> mode. Water was observed to play a significant role, initially reducing
heterogeneous processing of butanol but enhancing reaction rates once
it evaporated. Gas phase products were identified, showing that surface
reactions of adsorbed butanol led to the emission of a variety of
carbonyl containing compounds. Under actinic light these compounds
will photolyze and produce hydroxyl radicals, changing dust processing
from a sink of VOC into a source of reactive compounds.
2018-03-29 00:00:00
reactive compounds
Butanol uptake kinetics
reaction rates
hydroxyl radicals
dust processing
Product Formation
light changes
H 3 O
VOC
UV
gas phase
Atmospheric Mineral Dust Mineral dust particles
Arizona test dust
chemical interactions
butanol
surface reactions
proton-transfer-reaction mass spectrometer
gas phase products
actinic light
mineral dust
dust photocatalytic nature
trace gases