Materials Science Forum Vol. 964

Abstract: Nyamplung (Calophyllum inophyllum) is a multi-functional plant which is spread widely over the coast of Indonesia. Its seed produces a high content of oil, but its utilization is still limited. It is because C. inophyllum seed oil contains toxic compounds. Therefore, C. inophyllum seed oil has been used as a biodiesel raw material for many years. It was reported that C. inophyllum seed oil contains wax, but its percentage remains unknown. Wax has been used in cosmetics, pharmaceuticals, foods, and coatings industries as oil binder, water repellent, scratch resistance, and dispersion medium. In this work, wax was separated from C. inophyllum seed oil by solvent crystallization with and without separating non-polar lipid fraction (NPLF) from crude oil. Non-polar lipid fraction was separated by batch-wise solvent extraction using petroleum ether to methanol mass ratio of 3:1 (w/w) for eight stages. After eight stages, non-polar lipid fraction was collected for further separation by solvent crystallization method. The ratios of non-polar lipid fraction to acetone were 1:10, 1:20, and 1:40 (w/v). Then, the isolated wax was analyzed by gas chromatography. It was found that wax (purity of 40% and yield of 0.35%) was successfully isolated by separating non-polar lipid fraction from crude oil (batch wise solvent extraction for eight stages) and followed by solvent crystallization (non-polar lipid fraction to acetone ratio of 1:40 (w/v)).

Abstract: Inhibitor is a chemical compound which commonly used to control corrosion in a tank or a pipelines. Organic inhibitor recently developed because of the availability and the ability to act like commercial inhibitor. The performance of mixed inhibitor was studied on St 41 carbon steel immersed in NaCl solution containing CO₂ gas. Research parameter used were pH 4 and 6, rotation speed of 150 and 250 rpm, with mixed inhibitor volume ratio of 1 (imidazoline) : 2 (paracetamol), 1:1, also 2:1. The Weight loss measurement, isotherm adsorption calculation, FTIR, and XRD measurement have also been done. Based on weight loss test, the highest inhibitor efficiency was 61.412 % at pH 6, 150 rpm, with inhibitor volume ratio of 2:1, adsorption isotherm calculation indicate the adsorption mechanism of the mixed inhibitor is physical adsorption. Tafel test result showed the tendency of inhibitor worked anodically. The FTIR spectrum result found functional group of N-H from the inhibitor precipitated on the metal surface after ten days of immersion Based on the EIS result, there was an increase value of polarization resistance value and decrease on CPE (constant phase element) value. While X – ray diffraction (XRD) result from the volume ratio of 1:2 confirm the CO₂ corrosion product FeCO₃ and Fe₂O₃ formed on metal surface. With volume ratio of 2:1 mixed inhibitor, it was confirmed that iron nitride (Fe₂₄N₁₀) compound was formed on steel surface because of the chemisorption reaction between Fe and nitrogen atom from pyridine at the imidazoline inhibitor. The inhibition mechanism was physisorption for entire parameters, based on calculation of Langmuir adsorption theorem.

Abstract: Nitrogen –doped carbon material using non-precious metal was developed as catalyst fuel cell (PEMFC). In the PEMFC, the cathode reaction occurs three times slower than anode reaction. Oxygen reduction reaction (ORR) in the cathode has major limit performance. Pt/C was used as high-cost catalyst materials but many researchers concerned to improve cathode catalyst performance using high-performance and low-cost materials. Nitrogen based active sites on carbon has important role for oxygen reduction reactions process. In this study, compositions of carbon for Fe-N-C were investigated to understand the electrochemical properties and morphological analysis. Urea and PVP as nitrogen (N) source was mixed with graphite (Gt). The ratio of Gt and N were 1:1, 3:1, and 1:3. The mixture was added to FeCl₃.6H₂O dissolved in ethanol to produce Fe-N/C catalyst. Subsequently powder was introduced to the furnace for the pyrolysis. The catalyst products were analyzed using Potentiostat to show the electrochemical properties of catalyst, X-Ray Diffractometer (XRD) was used to know the compound or phases after catalyst syntheses, Scanning Electron Microscope – Energy Dispersive X-Ray (SEM-EDX) was used to identify the morphology and the chemical compositions of catalyst. As a result, Fe – Gt : N = 1:3 catalyst had the greatest electrochemical properties which is identified by large area of CV curve. This catalyst also had the highest current density for reduction reaction. The presence of Fe₂O₃ and FeS caused the degreasing of catalytic activity. As conclusions of this research, carbon composition had the important rule to improve the ORR activity.

Abstract: Indonesia has abundant resources or raw materials, especially the iron sand raw materials. But, the iron sand processing in Indonesia is still low. Even though, the steel demand in Indonesia is still high. So, the iron sand processing product as raw materials in steelmaking is the solution of it. In this research, the study was conducted by using the variation of briquette dimension of mixture of iron sand and iron ore in Direct Reduction process. The aim of this research is to study the effect of briquette dimension on Fe content and degree of metallization of the Direct Reduced Iron (DRI). First, the iron sand and iron ore were crushed and shieved until pass the 50 mesh standar size. Then, iron sand and iron ore were mixed and briquetted based on the variation of dimension. There are three variations of briquette dimension. Then, the briquettes was reduced at 1250°C for 12 hours. The reduced briquettes then were analyzed using XRD, XRF and degree metallization calculation. The result showed that the dimension of briquette affect the Fe content and the degree metallization of DRI. The dimension of briquette will affect the reductor gas flow in the crucible, so the rate and direction of reduction process of iron oxide will be affected too. The best briquette is Briquette B (7.9 cm for inside diameter, 15.1 cm for outer diameter and 19.5 cm for the height), with 75.02% for Fe total content and 66.52% for degree of metallization. This was due to The briquette B has the most evenly diffused dimension either vertically and horizontally.

Abstract: Bamboo is an interesting renewable material. Bamboo was used as a source to produced carbon black. This study was using Petung Bamboo (Dendrocalamus asper) and Ori Bamboo (Bambusa arundinacea) as a source of carbon. Carbon black was formed from bamboo through carbonization heat treatment at low temperature in air atmosphere (without inert gas). Carbonization heat treatment was done through gradual heating. The achieved bamboo carbon black was examined. In air atmosphere, bamboo carbon black was formed through slow heating at 300 °C and burned at rapid heating. The yield of bamboo carbon from Petung Bamboo was higher than Ori Bamboo. X-ray diffraction (XRD) results showed amorphous structure of the carbon. Scanning Electron Microscopy (SEM) observation showed that bamboo carbon has fiber and cell structure containing pore. BET results showed that surface area increased with increasing carbonization temperature. Bamboo carbon has high calorie value. Thermogravimetric Analysis (TGA) results showed that degradation temperature increased with increasing carbonization temperature.

Abstract: Biogas which consists of methane (CH₄) and carbon dioxide (CO₂) could explode when diluted to a certain degree with air in the presence of ignition source. The maximum explosion overpressure (P_max), the maximum rate of pressure rise (dP/dt)_max, flammability limits, and deflagration index are the most important explosion severities parameters to characterize the risk of explosion. In this research paper, the effect of equivalence ratio (ER) of biogas/air mixtures and the effect of CO₂ concentrations presence in biogas were studied in a 20 L spherical vessel. The values of P_max and (dP/dt)_max of biogas/air mixtures were more severe at ER 1.2. At various CO₂ content, P_max and (dP/dt)_max of biogas/air mixtures were the least affected at 45% vol/vol of CO₂. On the other hand, deflagration index (K_G) of biogas/air mixtures trend was the most severe at 35% vol/vol of CO₂ content despite the lowest P_max and (dP/dt)_max at 45% vol/vol of CO₂ content. The lowest values in P_max and (dP/dt)_max were due to the diffusivity properties of CH₄ that had surpassed the CO₂ suppression effect. Furthermore, the presence of CO₂ in biogas/air mixtures had increased the upper flammability limit and lower flammability limit of biogas.

Abstract: Investigation of Fe K-edge X-Ray Absorption Near Edge Spectroscopy (XANES) spectra of Fe₃O₄ (FeO.Fe₂O₃) from natural source compared with the Fe₃O₄ standard is presented. The natural Fe₃O₄ powder was prepared from ironstone of Tanah Laut, Kalimantan Selatan by co-precipitation method. XANES measurements in transmission mode were performed at the Synchrotron Light Research Institute (SLRI), Nakhon Ratchasima, Thailand. XRD phase analysis confirms that the synthesized Fe₃O₄ powder is a single phase, but it cannot determine the proportion of Fe₂O₃ and FeO in the structure. TEM measurement confirms that the particle size of natural Fe₃O₄ about 10 nm. Qualitative analysis of the pre-edge XANES data revealed that the absorbing atom in the XAS measurement is Fe³⁺. Meanwhile, the absorption edge (E₀) values of natural and standard Fe₃O₄ powders were 7126.44 eV and 7125.02 eV, respectively. The proportion was then acquired using XANES data analysis through Linear Combination Fitting (LCF). It was found that the natural Fe₃O₄ sample consisted of 98 wt. % Fe₂O₃ and 2 wt.% FeO, while the standard Fe₃O₄ powder consisted of 96 wt. % Fe₂O₃ and 4 wt. % FeO. The mechanism of the absorption in both samples is also described and compared.

Abstract: This study has been successfully synthesized Nickel (Ni)-doped olivine-type LiNi_xFe_1-xPO₄/C with x= 0, 0.01, 0.02, 0.03 as cathode materials, using the solid-state reaction method was in order to investigate the effect on the structure and morphology. The precursor material of ion Ferro (Fe) is used natural material from ironstone of Tanah Laut Kalimantan Indonesian which combined with proanalis materials. The X-Ray Diffraction (XRD) patterns on the structure magnetite iron have shown that single phase of Fe₃O₄ and the patterns of structure LiNi_xFe_1-xPO₄/C indicated that doping Ni²⁺ have shown the orthorhombic structure with space group Pnma for all LiNi_xFe_1-xPO₄/C samples. Base on Rietveld method by Rietica software, the formation of phase resulted in olivine structure except at the concentration x = 0.02 and 0.03 have a second phase, that is nasicon structure with a smaller percentage than olivine structure. The general condition, coating carbon on LiNi_xFe_1-xPO₄/C particles by solid state reaction can be perfect which demonstrate the homogeneous existence of carbon on the surface of LiNi_xFe_1-xPO₄/C particles shown by images Scanning Electron Microscopy (SEM). The increased doping of Ni ions causing the Fe ions to decrease base on Energy Dispersive X-Ray Spectroscopy (EDS) observations.

Abstract: The synthesis of Fe₂TiO₅ powders has been successfully performed by making use of Fe₂O₃ and TiO₂ powders. The Fe₂O₃ powder was obtained from local ironstone in Tanah Laut, South Kalimantan, while the TiO₂ powder was a commercial product. The Fe₂O₃ powder was obtained from the local ironstone through coprecipitation method on pH 5, followed by calcination at 800 °C for 1 hour. The synthesis of Fe₂TiO₅ powder was done by mixing the raw powders using Planetary Ball Mill method for 5 hours. Thermogravimetric dan Differential Thermal Analysis (TG-DTA) was performed to estimate the calcination temperature. The milled mixtures were then calcined at temperatures of 700 – 1100 °C. X-Ray Diffraction (XRD) data showed that Fe₂TiO₅ formation started at 800 °C with a weight fraction of 3.60 wt%. The XRD data also showed that at 1100 °C the Fe₂TiO₅ formation has completed. The crystallite size of Fe₂TiO₅ powders was 50 and 66 nm after calcination at 900 and 1100 °C, respectively.