Determination of Hydroxyl Radical Generated During Ozonation of Water Containing Organic Substances by Spin Trapping ESR Technique

摘要

Generation of hydroxyl radical, one of the major active species in ozonation of water was directly observed with spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-pyrrolidine-1-oxyl (DMPO) as a spin-trapping reagent. Hydroxyl radical was trapped with DMPO as a stable radical, DMPO-OH. Eighty uM of ozone produced 1.08 ×10~(-6) M of DMPO-OH, indicating that 1.4 % of ·OH is trapped with DMPO if · OH is produced stoichiometrically from ozone. Humic acid suppressed DMPO-OH generation in a dose-dependent manner. Generation rate of DMPO-OH was determined with 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.