We studied to determine quantitatively the radical species generated from humic acid (HA) solutions by irradiation(>400 nm). The formation of radical species from HA solutions was investigated with ESR spectroscopy. We gave ESR spectrum with g-value 2.0048 and line width 0.559mT, coincided with those of the semiquinone radical. 0.1 mg/L HA solution generated the radicals of 1.2×10-6M, increased with increasing HA concentration. Also, pH and ionic strength effect of the amount of the semiquinone radical generate from HA solution. In this study, we have found that the singlet oxygen affects the semiquinone radicals generation in HA solution.

• 한상국(목포해양대학교 해양시스템공학부 해양환경공학전공) | Sang-Kuk Han Corresponding Author