Hans Kristianto

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

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.

Preparation of Orange Peel Based Activated Carbons as Cathodes in Lithium Ion Capacitors

In this work, activated carbon was prepared from Indonesian local orange peel using ZnCl2 activation method at various chemical ratios. The structural and morphological characteristics of orange peel based activated carbons were investigated using scanning electron microscope (SEM), Brunaeuer-Emmett-Teller surface analyzer. The highest surface area was estimated as 1200 m2g-1, obtained by the mass ratio of 1:2 (biomass : ZnCl2). The obtained carbon samples were then tested as cathodes in Lithium Ion Capacitors. Electrochemical measurement was examined by half cell configuration, using 1 M LiPF6 in EC/EMC/DMC solution (1:1:1 v/v) as electrolyte and Li metal as reference electrode. From cyclic voltammetry (CV) test, it was shown that orange peel based activated carbon demonstrated a stable electrochemical characteristics, with specific capacitance of 56 Fg-1 measured at scan rate of 1 mVs-1 under cut-off voltages between 2.5 and 4 V.

Adsorption of Cu (II) from Aqueous Solution by Salacca Peel Based Activated Carbons

In n 687.67 mg Cu(II)/g activated carbon. The kinetic study showed that the copper adsorption on the SPAC followed the pseudo-second order model. The results of this study indicated that SPAC was an effective adsorbent for removing copper ions from aqueous solutions.

The Potency of Indonesia Native Plants as Natural Coagulant: a Mini Review

Indonesia is a tropical country which is known for its high variety of natural resources. However, there is limited access to clean water, thus forcing people in rural areas to use turbid water. Furthermore, some of water sources in Indonesia are already polluted by heavy metals with high biological oxygen demand (BOD) and chemical oxygen demand (COD) value. Simple and easy water purification methods are needed to overcome this situation. Coagulation and flocculation are widely used method to treat water. However, chemical coagulants (alum, ferrum, PAC, etc.) are not easily obtained and could cause some health problems if treated water is consumed. Natural coagulants have a good potential to solve these problems. Various possible plant-based natural coagulants which are abundant in Indonesia are highlighted in this paper. Fruit wastes and inedible legumes are suggested to be used as natural coagulant as there are no food competition presents. Further research is needed especially to scale up laboratory scale research that has been done in these years; thus, it can be applied to solve clean water scarcity problem.

The effect of activated carbon support surface modification on characteristics of carbon nanospheres prepared by deposition precipitation of Fe-catalyst

In this study the effect of activated carbon support modification to synthesis of CNSs was observed. Modification of activated carbon was done by using nitric acid. The effect of modification was analyzed from its FTIR spectra. The Fe catalysts were deposited on to the support by using urea deposition precipitation method at various initial catalysts concentration. CNSs was synthesized by utilizing cooking palm oil as renewable carbon source, and pyrolized at 700°C for 1 hour under nitrogen atmosphere. The products obtained then analyzed using SEM-EDS, TEM, XRD, and Raman spectroscopy. The modification of activated carbon support had increased the oxygen functional group. This increase resulted on increase of metal catalysts deposited on activated carbon surface. Peak of C (100) was observed, while ID/IG of samples were obtained around 0.9, which is commonly obtained for CNSs. High catalysts loading on modified activated carbon support caused decomposition of CNSs and formation carbon onion.

Structural and preliminary electrochemical characteristics of palm oil based carbon nanospheres as anode materials in lithium ion batteries

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