Application of the EPR spin-trapping technique for the investigation of the reactions of carbonate, bicarbonate, and phosphate anions with hydroxyl radicals generated by the photolysis of H2O2

Chemosphere ◽  
1992 ◽  
Vol 25 (12) ◽  
pp. 1769-1782 ◽  
Author(s):  
Jan Kochany ◽  
Ewa Lipczynska-Kochany
Keyword(s):  
Hydroxyl Radicals ◽  
Spin Trapping ◽  
Phosphate Anions ◽  
Epr Spin Trapping ◽  
Spin Trapping Technique

Photoredox Reactions of Iodo Iron(III) Complexes Containing Tetradentate Ligands

2001 ◽  
Vol 66 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Jozef Šima ◽  
Dáša Lauková ◽  
Vlasta Brezová
Keyword(s):  
Schiff Bases ◽  
Spin Trapping ◽  
Molar Ratio ◽  
Oh Radicals ◽  
Solvated Electrons ◽  
Open Chain ◽  
Tetradentate Ligands ◽  
Visible Irradiation ◽  
Epr Spin Trapping ◽  
Spin Trapping Technique

Photoredox reactions occurring in irradiated methanolic solutions of trans-[FeIII(R,R'-salen)(CH3OH)I], where R,R'-salen2- are N,N'-ethylenebis(R,R'-salicylideneiminato), tetradentate open-chain N2O2-Schiff bases with R,R' = H, 5-Cl, 5-Br, 3,5-di-Br, 3,5-di-(CH3), 3-OCH3, 5-OCH3, have been investigated and their mechanism proposed. The complexes are redox-stable in the dark. Ultraviolet and/or visible irradiation of methanolic solution of the complexes induces photoreduction of Fe(III) to Fe(II). Depending on the composition of the irradiated solutions, •CH2OH radicals or solvated electrons were identified by the EPR spin trapping technique. The final product of the photooxidation coupled with the photoreduction of Fe(III) is formaldehyde and the molar ratio of Fe(II) and CH2O is close to 2 : 1. The efficiency of the photoredox process is strongly wavelength-dependent and influenced by the peripheral groups R,R' of the tetradentate ligands.

Photodynamic action of C-phycocyanins obtained from marine and fresh water cyanobacterial cultures: A comparative study using EPR spin trapping technique

2006 ◽  
Vol 40 (8) ◽  
pp. 821-825 ◽  
Author(s):  
Bibbin Tom Paul ◽  
Anamika Patel ◽  
Govindan Sadasivam Selvam ◽  
Sandhya Mishra ◽  
Pushpita Kumar Ghosh ◽  
...  
Keyword(s):  
Comparative Study ◽  
Fresh Water ◽  
Spin Trapping ◽  
Photodynamic Action ◽  
Epr Spin Trapping ◽  
Spin Trapping Technique

scholarly journals Fused-Ring Derivatives of Quinoxalines: Spectroscopic Characterization and Photoinduced Processes Investigated by EPR Spin Trapping Technique

Molecules ◽  
2014 ◽  
Vol 19 (8) ◽  
pp. 12078-12098 ◽  
Author(s):  
Zuzana Barbieriková ◽  
Dana Dvoranová ◽  
Maroš Bella ◽  
Viktor Milata ◽  
Adriana Czímerová ◽  
...  
Keyword(s):  
Spectroscopic Characterization ◽  
Spin Trapping ◽  
Fused Ring ◽  
Epr Spin Trapping ◽  
Derivatives Of ◽  
Spin Trapping Technique ◽  
Photoinduced Processes

Photodegradation of 4-chloronitrobenzene in the presence of aqueous titania suspensions in different gas atmospheres

2011 ◽  
Vol 64 (7) ◽  
pp. 1466-1472 ◽  
Author(s):  
Miaomiao Ye ◽  
Tuqiao Zhang ◽  
Zhiwei Zhu ◽  
Yan Zhang ◽  
Yiping Zhang
Keyword(s):  
Spin Trapping ◽  
Photocatalytic Efficiency ◽  
Liquid Chromatography Mass Spectrometry ◽  
Paramagnetic Resonance ◽  
Mineralization Processes ◽  
Degussa P25 ◽  
Epr Spin Trapping ◽  
Electron Paramagnetic ◽  
Nitrate Anions ◽  
Spin Trapping Technique

The photocatalytic degradation of 4-chloronitrobenzene (4-CNB) was carried out using Degussa P25 TiO2 as photocatalyst in three different gas atmospheres: nitrogen, oxygen, and ozone. The total organic carbon (TOC) and inorganic anions including chloride, nitrite, and nitrate anions were measured to monitor the mineralization processes, while the degradation of 4-CNB and the formation of intermediates were followed by liquid chromatography–mass spectrometry (LC/MS). Results showed that the photocatalytic efficiency followed the order of TiO2/UV/N2 < TiO2/UV/O2 < TiO2/UV/O3, which was further proved by evaluating the reaction activities using electron paramagnetic resonance (EPR) spin trapping technique. Chlorine atom, nitro group and hydrogen atom of the benzene ring could be displaced by hydroxyl radical (•OH) leading to the formation of chloride, nitrite (III) anions and a variety of phenols, then the nitrite (III) anions were further oxidized to nitrate (V) anions. 4-Nitrophenol and 5-chloro-2-nitrophenol were identified and quantified in both of the TiO2/UV/N2 and TiO2/UV/O2 processes while no aromatic intermediates were monitored in the process of TiO2/UV/O3.

The photodegradation of model quinolone carboxylates in aqueous media

2014 ◽  
Vol 7 (1) ◽  
pp. 1-8
Author(s):  
Miroslava Bobeničová ◽  
Andrea Čaklóšová ◽  
Dana Dvoranová
Keyword(s):  
Titanium Dioxide ◽  
Hydroxyl Radicals ◽  
Aqueous Media ◽  
Spin Trapping ◽  
Alkaline Media ◽  
Uva Irradiation ◽  
Epr Spin Trapping ◽  
Photoinduced Processes

Abstract This work was focused on the study of photoinduced processes of quinolone carboxylates in the presence of titanium dioxide in an alkaline media. UVA irradiation without/with titanium dioxide caused the decomposition of molecules, with higher efficiency of degradation in the presence of titanium dioxide. EPR spin trapping experiments proved that investigated quinolone carboxylates behave as the efficient scavengers of hydroxyl radicals produced upon irradiation of aerated alkaline titanium dioxide systems.

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