Abstract
Generation of hydroxyl radicals, one of the major active species in ozonation of water was directly observed with a spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-1-pyrrolineN-oxide (DMPO) as a spin-trapping reagent. Hydroxyl radical were trapped with DMPO as a stable radical, DMPO-OH. Eighty μM of ozone produced 1.08 x 10 -6 M of DMPO-OH, indicating that 1.4% of OH is trapped with DMPO. Generation rate of DMPO-OH was determined by ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance OH generation during ozonation of water. Ozonation of 2,3-, 2,5-, 2,6-dichlorophenol gave an ESR spectra of triplet lines whose peak height ratio were 1:2:1. ESR parameters of the triplet lines agreed with those of the corresponding dichloro-psemiquinone radical. Ozonation of 2,4,5- and 2,4,6-trichlorophenol gave the same spectra as those of 2,5- and 2,6-dichlorophenol, respectively, indicating that a chlorine group in p-position is substituted with a hydroxy group during ozonation. Amounts of the radical increased in an ozone-concentration dependent manner and were inhibited by addition of hydroxyl radical scavengers. These results suggest that p-semiquinone radicals are generated from the chlorophenols by hydroxyl radicals during ozonation. The p-semiquinone radicals were at least partly responsible for enhancements of DMPO-OH generation.
| Original language | English |
|---|---|
| Pages (from-to) | 147-154 |
| Number of pages | 8 |
| Journal | Water Science and Technology |
| Volume | 38 |
| Issue number | 6 pt 5 |
| DOIs | |
| Publication status | Published - Jan 1 1998 |
| Event | Proceedings of the 1998 19th Biennial Conference of the International Association on Water Quality. Part 5 (of 10) - Vancouver, Can Duration: Jun 21 1998 → Jun 26 1998 |
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All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Water Science and Technology
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Enhancement of hydroxyl radical generation by phenols and their reaction intermediates during ozonation. / Utsumi, Hideo; Han, Sang Kuk; Ichikawa, Kazuhiro.
In: Water Science and Technology, Vol. 38, No. 6 pt 5, 01.01.1998, p. 147-154.Research output: Contribution to journal › Conference article
}
TY - JOUR
T1 - Enhancement of hydroxyl radical generation by phenols and their reaction intermediates during ozonation
AU - Utsumi, Hideo
AU - Han, Sang Kuk
AU - Ichikawa, Kazuhiro
PY - 1998/1/1
Y1 - 1998/1/1
N2 - Generation of hydroxyl radicals, one of the major active species in ozonation of water was directly observed with a spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-1-pyrrolineN-oxide (DMPO) as a spin-trapping reagent. Hydroxyl radical were trapped with DMPO as a stable radical, DMPO-OH. Eighty μM of ozone produced 1.08 x 10 -6 M of DMPO-OH, indicating that 1.4% of OH is trapped with DMPO. Generation rate of DMPO-OH was determined by ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance OH generation during ozonation of water. Ozonation of 2,3-, 2,5-, 2,6-dichlorophenol gave an ESR spectra of triplet lines whose peak height ratio were 1:2:1. ESR parameters of the triplet lines agreed with those of the corresponding dichloro-psemiquinone radical. Ozonation of 2,4,5- and 2,4,6-trichlorophenol gave the same spectra as those of 2,5- and 2,6-dichlorophenol, respectively, indicating that a chlorine group in p-position is substituted with a hydroxy group during ozonation. Amounts of the radical increased in an ozone-concentration dependent manner and were inhibited by addition of hydroxyl radical scavengers. These results suggest that p-semiquinone radicals are generated from the chlorophenols by hydroxyl radicals during ozonation. The p-semiquinone radicals were at least partly responsible for enhancements of DMPO-OH generation.
AB - Generation of hydroxyl radicals, one of the major active species in ozonation of water was directly observed with a spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-1-pyrrolineN-oxide (DMPO) as a spin-trapping reagent. Hydroxyl radical were trapped with DMPO as a stable radical, DMPO-OH. Eighty μM of ozone produced 1.08 x 10 -6 M of DMPO-OH, indicating that 1.4% of OH is trapped with DMPO. Generation rate of DMPO-OH was determined by ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance OH generation during ozonation of water. Ozonation of 2,3-, 2,5-, 2,6-dichlorophenol gave an ESR spectra of triplet lines whose peak height ratio were 1:2:1. ESR parameters of the triplet lines agreed with those of the corresponding dichloro-psemiquinone radical. Ozonation of 2,4,5- and 2,4,6-trichlorophenol gave the same spectra as those of 2,5- and 2,6-dichlorophenol, respectively, indicating that a chlorine group in p-position is substituted with a hydroxy group during ozonation. Amounts of the radical increased in an ozone-concentration dependent manner and were inhibited by addition of hydroxyl radical scavengers. These results suggest that p-semiquinone radicals are generated from the chlorophenols by hydroxyl radicals during ozonation. The p-semiquinone radicals were at least partly responsible for enhancements of DMPO-OH generation.
UR - http://www.scopus.com/inward/record.url?scp=0031764681&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031764681&partnerID=8YFLogxK
U2 - 10.1016/S0273-1223(98)00576-9
DO - 10.1016/S0273-1223(98)00576-9
M3 - Conference article
AN - SCOPUS:0031764681
VL - 38
SP - 147
EP - 154
JO - Water Science and Technology
JF - Water Science and Technology
SN - 0273-1223
IS - 6 pt 5
ER -