Photocatalytic degradation of sulfamethoxazole using TiO2 in simulated seawater: Evidence for direct formation of reactive halogen species and halogenated by-products

2020 ◽  
Vol 736 ◽  
pp. 139605 ◽  
Author(s):  
Oriol Porcar-Santos ◽  
Alberto Cruz-Alcalde ◽  
Núria López-Vinent ◽  
Dimitrios Zanganas ◽  
Carme Sans
Keyword(s):  
Photocatalytic Degradation ◽  
Direct Formation ◽  
Reactive Halogen Species ◽  
Halogen Species ◽  
Simulated Seawater ◽  
By Products

scholarly journals Chemical interactions between ship-originated air pollutants and ocean-emitted halogens

2021 ◽  
Author(s):  
Qinyi Li ◽  
Alba Badia ◽  
Rafael P. Fernandez ◽  
Anoop S. Mahajan ◽  
Ana Isabel López-Noreña ◽  
...  
Keyword(s):  
Air Pollutants ◽  
Atmospheric Composition ◽  
Chemical Transformations ◽  
Chemical Interactions ◽  
China Sea ◽  
Reactive Halogen Species ◽  
The Impact ◽  
Surface Increase ◽  
Halogen Species

<p>Ocean-going ships supply products from one region to another and contribute to the world’s economy. Ship exhaust contains many air pollutants and results in significant changes in marine atmospheric composition. The role of Reactive Halogen Species (RHS) in the troposphere has received increasing recognition and oceans are the largest contributors to their atmospheric burden. However, the impact of shipping emissions on RHS and that of RHS on ship-originated air pollutants have not been studied in detail. Here, an updated WRF-Chem model is utilized to explore the chemical interactions between ship emissions and oceanic RHS over the East Asia seas in summer. The emissions and resulting chemical transformations from shipping activities increase the level of NO and NO<sub>2</sub> at the surface, increase O<sub>3</sub> in the South China Sea, but decrease O<sub>3</sub> in the East China Sea. Such changes in pollutants result in remarkable changes in the levels of RHS as well as in their partitioning. The abundant RHS, in turn, reshape the loadings of air pollutants and those of the oxidants with marked patterns along the ship tracks. We, therefore, suggest that these important chemical interactions of ship-originated emissions with RHS should be considered in the environmental policy assessments of the role of shipping emissions in air quality and climate.</p>

Reduced formation of undesirable by-products from photocatalytic degradation of trichloroethylene

2005 ◽  
Vol 61 (3-4) ◽  
pp. 346-351 ◽  
Author(s):  
Toshifumi Tanimura ◽  
Atsushi Yoshida ◽  
Suzuko Yamazaki
Keyword(s):  
Photocatalytic Degradation ◽  
By Products

scholarly journals A chemical probe technique for the determination of reactive halogen species in aqueous solution: Part 2 – chloride solutions and mixed bromide/chloride solutions

2006 ◽  
Vol 6 (1) ◽  
pp. 941-979 ◽  
Author(s):  
C. Anastasio ◽  
B. M. Matthew
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Method Development ◽  
Companion Paper ◽  
Chemical Probe ◽  
Chloride Solutions ◽  
Reactive Halogen Species ◽  
A New Technique ◽  
Halogen Species

Abstract. Although reactive halogen species (X*=X●, ●X2−, X2 and HOX, where X=Br, Cl, or I) are important environmental oxidants, relatively little is known about their kinetics in condensed phases such as seawater and sea-salt particles. Here we describe a new technique to determine reactive chlorine and bromine species in aqueous solutions by using allyl alcohol (CH2=CHCH2OH) as a chemical probe. This probe is combined with competition kinetics in order to determine steady state concentrations of X*(aq). In some cases the technique also can be used to determine the rates of formation and lifetimes of X* in aqueous solution. In a companion paper we reported the results of our method development for aqueous solutions containing only bromide (Br−). In this paper, we discuss method development for solutions containing chloride (Cl−) alone, and for solutions containing both bromide and chloride.

scholarly journals Quantification of the depletion of ozone in the plume of Mount Etna

2014 ◽  
Vol 14 (16) ◽  
pp. 23639-23680 ◽  
Author(s):  
L. Surl ◽  
D. Donohoue ◽  
A. Aiuppa ◽  
N. Bobrowski ◽  
R. von Glasow
Keyword(s):  
Strong Dependence ◽  
Source Region ◽  
Mount Etna ◽  
Volcanic Plumes ◽  
Processing Times ◽  
Atmospheric Processing ◽  
Constant Rate ◽  
Halogen Chemistry ◽  
Reactive Halogen Species ◽  
Halogen Species

Abstract. Volcanoes are an important source of inorganic halogen species into the atmosphere. Chemical processing of these species generates oxidised, highly reactive, halogen species which catalyse considerable O3 destruction within volcanic plumes. A campaign of ground-based in situ O3, SO2 and meteorology measurements was undertaken at the summit of Mount Etna volcano in July–August 2012. At the same time, spectroscopic measurements were made of BrO and SO2 columns in the plume downwind. Depletions of O3 were seen at all in-plume measurement locations, with average O3 depletions ranging from 11–35 nmol mol−1 (15–45%). Atmospheric processing times of the plume were estimated to be between 1 and 4 min. A 1-D numerical model of early plume evolution was also used. It was found that in the early plume O3 was destroyed at an approximately constant rate relative to an inert plume tracer. This is ascribed to reactive halogen chemistry, and the data suggests the majority of the reactive halogen that destroys O3 in the early plume is generated within the crater, including a substantial proportion generated in a high-temperature "effective source region" immediately after emission. The model could approximately reproduce the main measured features of the O3 chemistry. Model results show a strong dependence of the near-vent bromine chemistry on the presence or absence of volcanic NOx emissions and suggest that near-vent O3 measurements can be used as a qualitative indicator of NOx emission.

scholarly journals Reactive bromine in the low troposphere of Antarctica: estimations at two research sites

2018 ◽  
Vol 18 (12) ◽  
pp. 8549-8570 ◽  
Author(s):  
Cristina Prados-Roman ◽  
Laura Gómez-Martín ◽  
Olga Puentedura ◽  
Mónica Navarro-Comas ◽  
Javier Iglesias ◽  
...  
Keyword(s):  
Arctic Region ◽  
The Arctic ◽  
Trace Gas ◽  
Optical Absorption Spectroscopy ◽  
Ancillary Data ◽  
Reactive Halogen Species ◽  
The Subject ◽  
The Antarctic ◽  
Halogen Species ◽  
The Arctic Region

Abstract. For decades, reactive halogen species (RHSs) have been the subject of detailed scientific research due to their influence on the oxidizing capacity of the atmosphere and on the climate. From the RHSs, those containing bromine are of particular interest in the polar troposphere as a result of their link to ozone-depletion events (ODEs) and to the perturbation of the cycle of toxic mercury, for example. Given its remoteness and related limited accessibility compared to the Arctic region, the RHSs in the Antarctic troposphere are still poorly characterized. This work presents ground-based observations of tropospheric BrO from two different Antarctic locations: Marambio Base (64∘13′ S, 56∘37′ W) and Belgrano II Base (77∘52′ S, 34∘7′ W) during the sunlit period of 2015. By means of MAX-DOAS (Multi-axis Differential Optical Absorption Spectroscopy) measurements of BrO performed from the two research sites, the seasonal variation in this reactive trace gas is described along with its vertical and geographical distribution in the Antarctic environment. Results show an overall vertical profile of BrO mixing ratio decreasing with altitude, with a median value of 1.6 pmol mol−1 in the lowest layers of the troposphere. Additionally, observations show that the polar sunrise triggers a geographical heterogeneous increase in bromine content in the Antarctic troposphere yielding a maximum BrO at Marambio (26 pmol mol−1), amounting to 3-fold the values observed at Belgrano at dawn. Data presented herein are combined with previous studies and ancillary data to update and expand our knowledge of the geographical and vertical distribution of BrO in the Antarctic troposphere, revealing Marambio as one of the locations with the highest BrO reported so far in Antarctica. Furthermore, the observations gathered during 2015 serve as a proxy to investigate the budget of reactive bromine (BrOx = Br + BrO) and the bromine-mediated ozone loss rate in the Antarctic troposphere.

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