1. Central Research Institute of Chemical Technology, Samsung Advanced Institute of Technology, 103-21 Moonji-dong, Yusong-gu, Daejeon 305-380, Korea
2. Division of Chemical Engineering, Korea Institute of Science and Technology, 39-1 Hawolkok-dong, Seongbuk-ku, Seoul 136-791, Korea
3. Department of Environmental Engineering, Chungbuk National University, San 48 Gaishin-dong, Cheongju 360-763, Korea