Fredi Kurniawan, Michael Wongso, Aning Ayucitra, Felycia Edi Soetaredjo, Artik Elisa Angkawijaya, Yi-Hsu Ju, Suryadi Ismadji
In this study, water hyacinth was hydrolyzed to sugars with dilute sulphuric acid (0.25. M) under subcritical water conditions (P= 20. bar, T= 130. °C) for 2. h. The sugar solution was then carbonized under subcritical conditions to produce carbon microsphere. The subcritical water carbonization was conducted at 40. bar and various temperatures (160-200. °C) and times (6-10. h). The highest yield of carbon microspheres was 0.1019. g/g dry water hyacinth at the temperature of 200. °C for 10. h. The carbon microsphere was activated using a combination of chemical (KOH solution) and physical (microwave) treatments to increase the specific surface area and porosity of carbon microsphere. Electrocapacitive study of carbon microspheres showed that the carbon microsphere activated at impregnation ratio of 1:1 and microwave power of 630. W has the highest specific capacitance and excellent electrochemical stability. © 2014 Taiwan Institute of Chemical Engineers.
Department of Chemical Engineering, Widya Mandala Surabaya Catholic University, Kalijudan 37, Surabaya, 60114, Indonesia; Department of Chemical Engineering, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Road, Taipei, 106-07, Taiwan