(d) (e) (d) (e) (f) (g) (f) (g) Fig.2 SEM micrographs of (a) dried water hyacinth, (b, c, d, e) water hyacinth treated hydrothermally at 160, 180, 200 and 220°C for 8 hours, (f and g) water hyacinth treated hydrothermally 180°C for 4 and 12 hours 148 Proceedings of the International Conference on Climate Change, Biodiversity and Ecosystem Services for the (g) (f) (e) (d) (c) (b) (a) Sustainable Development Goals (SDGs): Policy and Practice 27-29 June 2016, Cha-am, Phetchaburi, Thailand (g) (f) (e) (d) (c) (b) (a) Fig.3 FT-IRspectra of (a) dried water hyacinth, (b to e) hydrothermally treated water hyacinth at temperature 160, 180, 200 and 220°C for 8 hours, (f and g) hydrothermally treated water hyacinth at temperature 180°C for 4 and 12 treatment of dried water hyacinth powder could hours lead to conversion of cellulosic content due to the hydrolysis reaction 7. Sevilla and Fuerters reported that the hydrolysis of cellulose and hemicelluloses at a specific temperature above 210°C would result in formation of gas, liquid and solid products 9. Meanwhile, other previous works confirming the formation hydrogen, glucose and carbon are available elsewhere 10, 12. In this work, only the solid product which is called ‘hydro-char’ would be further analyzed and discussed. For confirmation of the existence of functional groups attaching on the surface of hydrothermally treated water hyacinth powder or hydro-char, FT-IR analyses of those solid products were carried out. FT-IR spectra of carbonaceous samples depicted in Fig.3 clearly suggest that functional groups of hydro- char are different from those of originally dried water hyacinth. Distinctive bands at wave number of 3700-3000 cm-1 are attributed – OH stretching vibration 9, 10. The 3500-2850 cm-1 bands were attributed to the presence of – CH vibration whereas the 1700 cm-1 band would suggest the presence of C=O group on the surface of each sample. The appearance of the 1650 and 1200-950 cm-1bands would confirm the presence of C=C in aromatic ring of lignin and C-O in ester or ether, respectively 10. Based on comparison of these FT-IR spectra, it could be noted that an increase in the treating temperature and treating time could result in drastic change in the presence of functional groups on the surface of hydro- char samples. With an ultimate purpose for usage as electrode materials, all of hydro-char were further carbonized for removing un-desired contents of hydrogen, oxygen and other constituents. Because of the removal of some impurities, the carbonized hydro-char would possess a higher content of carbon with a higher purity and
Proceedings of International Conference on Climate Change, Biodiversity and Ecosystem Services for the Sustainable Development Goals : Policy and Practice 27-29 June 2016 at the Sirindhorn International Environmental Park, Cha-am, Phetchaburi, Thailand
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