1. School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
2. School of Biosystems Engineering and Food Science; Zhejiang University; 866 Yuhangtang Road Hangzhou 310058 P. R. China
3. Nanyang Environment and Water Research Institute; Interdisciplinary Graduate School; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
4. Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; 21 Nanyang Link Singapore 637371 Singapore