1. Institute for Tropical Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi 122300, Vietnam
2. Department of Chemistry, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi 122000, Vietnam
3. Department of Civil and Environmental Engineering, Sloan 101, PO Box 642910, Washington State University, Pullman, WA 99164-2910, USA