1. a Department of Environmental Science and Engineering, Kwangju Institute of Science and Technology (K-JIST), 1 Oryong-dong, Buk-gu, Kwangju 500-712, Korea.
2. b Department of Environmental Science and Engineering, Kwangju Institute of Science and Technology (K-JIST), 1 Oryong-dong, Buk-gu, Kwangju 500-712, Korea. Email: hcchoi@kjist.ac.kr. Tel. 82-62-970-2441. Fax. 82-62-970-2434.
3. c Department of Chemical Engineering, Korea Advanced Institute of Science and Technology (KAIST) 305-701, Taejun Yusung-gu, Gusung-dong, 373-1, Korea