Ozonation of isoproturon adsorbed on silica particles under atmospheric conditions

Pflieger, Maryline; Grgić, Irena; Kitanovski, Zoran

doi:10.1016/j.atmosenv.2012.07.021

Cited by 8 publications

(6 citation statements)

References 37 publications

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“…It is difficult to choose between these two models because the L-R model is actually a special case of the L-H model. Hence, both models seem to adequately describe the kinetic pattern of the pesticides under study in agreement with literature reports (Pflieger et al [14][15][16]). …”

Section: Kinetics Studysupporting

confidence: 89%

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Heterogeneous oxidation of pesticides on the aerosol condensed phase

Socorro

2015

WIT Transactions on Ecology and the Environment

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Pesticides are widely used all over the world. It is known that they exhibit adverse health effects and environmental risks due to their physico-chemical properties and their extensive use, which is growing every year. They are distributed in the atmosphere, an important vector of dissemination, over long distances away from the target area. The partitioning of pesticides between the gas and particulate phases influences their atmospheric fate. Most of the pesticides are semi-volatile compounds, emphasizing the importance of assessing their heterogeneous reactivity towards atmospheric oxidants. The photolysis processing and heterogeneous reactivity towards O3 and OH, was evaluated of eight commonly used pesticides adsorbed in silica particles. Silica particles are present in airborne mineral dust in atmospheric aerosols, and heterogeneous reactions can be different in the presence of these mineral particles. Depending on their origin and conditioning, aerosol particles containing pesticides can have complex and highly porous microstructures, which are influenced by electric charge effects and interaction with water vapour. Therefore, the kinetic experiments and consecutive product studies were performed at atmospherically relevant relative humidity (RH) of 55%. The identification of surface-bound products was performed using GC-(QqQ)-MS/MS and the gas-phase products were monitored on-line by PTRToF-MS. The obtained results will allow a better understanding of the impact of pesticides and their degradation products on human health, and to make recommendations in order to reduce population exposure to the pesticide plume and the pollution by phyto-sanitary products on the regional scale, which constitutes a necessary step in the development of environmental strategies.

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Section: Kinetics Studysupporting

confidence: 89%

“…Both kinetic patterns were used for this purpose: Langmuir-Rideal (L-R) mechanism (Palm et al [12,13]; Pflieger et al [14][15][16]; Yang et al [17]) and Langmuir-Hinshelwood (L-H) mechanism (Pflieger et al [14][15][16]). , reporting the difficulty of modeling by L-H mechanism (Socorro et al [11]).…”

Section: Kinetics Studymentioning

confidence: 99%

Heterogeneous oxidation of pesticides on the aerosol condensed phase

Socorro

2015

WIT Transactions on Ecology and the Environment

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“…In addition, when an organic compound is adsorbed on particle surfaces, many factors, which are not considered in gaseous phase, can influence its reactivity such as the nature of the particles or the quantity of organic adsorbed on the surface. The effects of the particles on the reactivity have often been observed in previous studies dealing with the degradation of adsorbed PAH and pesticides. − In fact, the particle surface can directly and/or indirectly act as an inhibitor of the reactivity.…”

Section: Resultsmentioning

confidence: 88%

“…Several parameters can influence heterogeneous kinetics such as the concentration on the solid support, the number of organic compounds simultaneously adsorbed as well as the physicochemical characteristics of the solid support. − Oxidation kinetics are commonly studied using a reference compound, whose kinetic rate constant (toward OH radicals) is well-known. The determination of the radical concentration is then not required.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Oxidation of Terbuthylazine by “Dark” OH Radicals under Simulated Atmospheric Conditions in a Flow Tube

Pflieger

Monod

Wortham

2013

Environ. Sci. Technol.

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In order to investigate the heterogeneous oxidation kinetics of the herbicide terbuthylazine (TERB), a stable and reproducible generation system of "dark" hydroxyl radical in the gas phase was developed and optimized using a PTR-MS. TERB was adsorbed on silica particles, which were coated on the walls of a flow tube. The hydroxyl radical was produced in the dark through the ozonolysis of 2,3-dimethyl-2-butene (DMB). The radical concentration was determined applying two different methods of calculation based on the monitoring of (i) a gaseous compound used as a tracer, m-xylene; (ii) one of the OH radical precursors, DMB. The obtained gaseous OH radical concentration in the reactor was (9.0 ± 4.0) × 10(7) radical cm(-3). Exposing TERB to the oxidant for 1-14 h, a heterogeneous kinetic constant of kOH = (1.5 ± 0.8) × 10(-13) cm(3) molecule(-1) s(-1) was found at 26 °C and RH < 1%. As a result, the heterogeneous oxidation of TERB by OH radicals seems to be much slower (by a factor of 63) when the organic compound is present in the particulate phase than when it reacts in homogeneous gas phase.

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“…0% RH is an unrealistic value as water is always present in the atmosphere. However, most studies of the heterogeneous reactivity of pesticides toward ozone were carried out closer to 0% RH (Pflieger et al, 2009(Pflieger et al, , 2011(Pflieger et al, , 2012Segal-Rosenheimer et al, 2011). From the analysis of water adsorption on the surface of mineral oxides, Goodman et al (2001) have shown that the number of water layers is approximately one monolayer at 20% RH, two to three adsorbed water layers at 50% RH, and three to four at 85% RH.…”

Section: Heterogeneous Ozonolysismentioning

confidence: 99%

Heterogeneous atmospheric degradation of pesticides by ozone: Influence of relative humidity and particle type

Mattei

Wortham

Quivet

2018

Science of The Total Environment

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In the atmosphere pesticides can be adsorbed on the surface of particles, depending on their physico-chemical properties. They can react with atmospheric oxidants such as ozone but parameters influencing the degradation kinetics are not clear enough. In this study the heterogeneous ozonolysis of eight commonly used pesticides (i.e., difenoconazole, tetraconazole, cyprodinil, fipronil, oxadiazon, pendimethalin, deltamethrin, and permethrin) adsorbed on hydrophobic and hydrophilic silicas, and Arizona dust at relative humidity ranging from 0% to 80% was investigated. Under experimental conditions, only cyprodinil, deltamethrin, permethrin and pendimethalin were degraded by ozone. Second-order kinetic constants calculated for the pesticides degraded by ozone ranged from (4.7 ± 0.4) × 10 cm molecule s (pendimethalin, hydrophobic silica, 55% RH) to (2.3 ± 0.4) × 10 cm molecule s (cyprodinil, Arizona dust, 0% RH). Results obtained can contribute to a better understanding of the atmospheric fate of pesticides in the particulate phase and show the importance of taking humidity and particle type into account for the determination of pesticides atmospheric half-lives.

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Ozonation of isoproturon adsorbed on silica particles under atmospheric conditions

Cited by 8 publications

References 37 publications

Heterogeneous oxidation of pesticides on the aerosol condensed phase

Heterogeneous oxidation of pesticides on the aerosol condensed phase

Heterogeneous Oxidation of Terbuthylazine by “Dark” OH Radicals under Simulated Atmospheric Conditions in a Flow Tube

Heterogeneous atmospheric degradation of pesticides by ozone: Influence of relative humidity and particle type

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