Delignification, Carbonization Temperature and Carbonization Time Effects on the Hydrothermal Conversion of Salacca...

Hydrochar from the hydrothermal treatment of biomass is considered as a potential precursor for activated carbons (AC) which has been widely utilized not only for adsorbents but also for energy storage application. The advantages of hydrochar from hydrothermal treatment include its high Oxygenated Functional Group (OFG) and high porosity. The authors have been working on the biomass conversion for energy storage application. In our study, salacca peel was used as a biomass source. In previous research for the preparation of AC, conventional carbonization and activation methods were used, resulting in a high surface area of AC. In the current research, the authors investigated the biomass conversion in hydrothermal conditions. Water at a subcritical condition (with temperatures of 200, 225 and 250 °C and at a pressure of 50 MPa) and carbonization time of 4, 5 or 6 hours, with or without delignification, were critical in the research to investigate the conversion of salacca peel into hydrochar. The produced hydrochar from 225 °C, 5 h was chemically activated and compared to commercially-AC. The hydrochar and AC were then used as electrodes for the supercapacitor, and capacitance was measured by cyclic voltammetry (CV). The results showed that the capacitance of hydrochar was higher than that of AC while ACs from salacca peel exhibited much higher levels of capacitance compared to commercially-AC.