Ratna Frida Susanti

Non-oxidative thermal degradation of amines: GCMS/FTIR spectra analysis and molecular modeling

ABSTRACT Aqueous amino solvents, such as monoethanolamine (ETA/MEA), methyl diethanolamine (MDEA) or amine blends, are the most widely used solvents in commercial CO2 or acid gas separation applications. These commercial solvents have various disadvantages, such as the possibilities of the solvent to be degraded. This research examines the impact of non-oxidative thermal degradations on the performance of the CO2 absorption and the degradation mechanism of amine solvents. The impact of degradation was conducted by measuring the CO2 solubility of solvent that had been heated to 120°C for 2 h. Although the performance of CO2 absorption was not significantly reduced, the degradation of amines was found. Supported by Fourier Transform Infrared (FTIR) and Gas Chromatography/Mass Spectrometer result, the suspected products of non-oxidative thermal degradation of MDEA were MEA and acetone.

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.

Chapter 6 – Supercritical Water Gasification for Hydrogen Production: Current Status and Prospective of High-Temperature Operation

Supercritical water gasification (SCWG) is considered to be one of the potential reforming approaches for hydrogen production as a clean and renewable energy carrier. Various feedstocks—renewable and nonrenewable—can be effectively reformed in supercritical water. This chapter reviews the current status and prospective of the SCWG of liquid-type feedstocks such as methanol, ethanol, glycerol, petroleum-based hydrocarbons, and model biomass compounds such as glucose and lignin. To gain better understanding on the thermodynamic and the hydrogen production mechanism in supercritical water, the hydrogen gas yield of each feedstock reformed under different conditions are compared with the theoretical equilibrium yield calculated by the Gibbs free energy minimization. This review attempts to present the potential, some challenges, and research outlooks of the SCWG of liquid-type feedstocks.

The effect of filler addition and oven temperature to the antioxidant quality in the drying of Physalis angulata leaf extract obtained by subcritical water extraction

In traditional medicine, Physalis angulata which is well known as ceplukan in Indonesia, has been utilized to cure several diseases by conventional extraction in hot water. The investigation of the Swietenia mahagoni extract activity in modern medicine typically utilized organic solvents such as ethanol, methanol, chloroform and hexane in extraction. In this research, subcritical water was used as a solvent instead of organic solvent to extract the Pysalis angulata leaf part. The focus of this research was the investigation of extract drying condition in the presence of filler to preserve the quality of antioxidant in Swietenia mahagoni extract. Filler, which is inert, was added to the extract during drying to help absorb the water while protect the extract from exposure in heat during drying. The effects of filler types, concentrations and oven drying temperatures were investigated to the antioxidant quality covering total phenol and antioxidant activity. Aerosil and microcrystalline cellulose (MCC) were utilized as fillers with concentration was varied from 0-30 wt% for MCC and 0-15 wt% for aerosil. The oven drying temperature was varied from 40-60 oC. The results showed that compare to extract dried without filler, total phenol and antioxidant activity were improved upon addition of filler. The higher the concentration of filler, the better the antioxidant; however it was limited by the homogeneity of filler in the extract. Both of the variables (oven temperature and concentration) played an important role in the improvement of extract quality of Swietenia mahagoni leaf. It was related to the drying time which can be minimized to protect the deterioration of extract from heat. In addition, filler help to provide the powder form of extract instead of the typical extract form which is sticky and oily.

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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