Anggoro Tri Mursito

Use of FTIR combined with forms of water to study the changes in hydrogen bonds during low-temperature heating of lignite

ABSTRACT The changes in the hydrogen bonds (HBs) of three types of Indonesian lignite during low-temperature heating were investigated. The amount of water loss was determined by weighing the samples before and after heating in an oven. The changes in the number of the different types of HBs were determined using Fourier transform infrared spectroscopy coupled with types of water in lignite. The number of peak positions and absorption bands in each spectrum was determined by curve-fitting analysis with a Gaussian function. The quantified integrated area of aromatic hydrogen atoms was used to accurately investigate the changes in the HBs. The results show that at low temperatures (T ≤ 50°C), free water is mainly removed, and the HBs broken are those between free water molecules. However, at medium temperatures (50 <T ≤ 100°C), bound water is mainly removed. The number of HBs significantly changes because of the breaking of bound water molecule HBs and bound water cluster–carboxyl group HBs, and the formation of nonfreezable moisture HBs. At high temperatures (100 <T < 125°C), nonfreezable moisture can be released. The number of HBs changes as a result of competition between the removal of nonfreezable moisture and the increase in the number of carboxyl groups. At higher temperatures (T ≥ 125°C), the moisture remaining in lignite is thermal decomposition moisture. In addition, the rate of decomposition of carboxyl groups is higher than the rate of generation, which means that the number of HBs markedly decreases at higher temperatures.

Hydrothermal Treatment of Hokkaido Peat - An Application of FTIR and 13C NMR Spectroscopy on Examining of Artificial Coalification Process and Development

There have been great changes in attitude toward the use of peat as an energy source since World War II (WEC, 2001). In Japan, peatland covers over 2500 km2 and accounts for a total energy resource of approximately 1.99 GJ.1010 (Spedding, 1988). Peatland in Japan is widely distributed throughout Hokkaido, which is the northernmost area of the country’s four main islands. Although peatland also exists in other regions, its distribution is extremely localized. Peatland is distributed over an area of approximately 2000 km2 in Hokkaido (Noto, 1991), which is equivalent to approximately 6% of the flat area on this island. Peatland is also widespread in the northeastern part of Sapporo, which is the largest city in Hokkaido. Peatland in Japan is often lacustrine peat, which is formed when lakes and marshes become filled with dead plants from their surrounding areas and are then transformed into land. This type of peat is characterized by the spongy formation of plant fiber. In the peatland of Hokkaido, peat usually accumulates to a thickness of three to five meters on the ground surface, while the soft clay layer underlying is the peat is often over 20 meters thick. In some areas, a sand layer exists between the peat and the clay layers.

Formation Mechanism of Titanium Silicon Carbide: The Effect of Different Composition of Starting Materials

Titanium silicon carbide (Ti3SiC2) is a kind of ceramic that has physical property value similar with metal. Ti3SiC2 has been synthesized through various methods based on solid state reaction. Although Ti3SiC2 has been synthesized through various methods by using various starting materials consisting titanium (Ti), silicon (Si), and carbon (C) the mechanism of Ti3SiC2 formation through sintering has not fully understood. The aim of this research is to reveal the mechanism happening during sintering. Two composition of starting material was used, 2Ti/2Si/3TiC and 5Ti/2Si/3C. The analysis through XRD and SEM-EDS shows that the formation of intermediate phases, TiC and Ti5Si3, takes place prior to the formation of Ti3SiC2. In other words, Ti3SiC2 can only be formed through solid state reaction between TiC and Ti5Si3. Since TiC has already available in the system 2Ti/2Si/3TiC, the phase purity of Ti3SiC2 in 2Ti/2Si/3TiC is always higher than that of 5Ti/2Si/3C.

Potential Application of Silica Mineral from Dieng Mountain in Agriculture Sector to Control the Release Rate of Fertilizer Elements

Silica mineral, which comes along with geothermal fluid in Dieng, is a product of erosion, decomposition and dissolution of silicon oxide based mineral, which is followed by precipitation to form silica mineral. This silica cell structure is non crystalline, and it contains 85,60 % silicon oxide, 6.49 volatile elements, and also other oxide elements. Among the direct potential application of this silica is as raw material in slow release fertilizer. Silica in compacted slow release fertilizer is able control the release rate of fertilizer elements. Two type of slow release fertilizer has been made by using silica as the matrix in these slow release fertilizer. The first type is the mixing of ordinary solid fertilizer with Dieng silica, whereas the second one is the mixing of disposal leach water with Dieng silica. The release test shows that both of these modified fertilizers have slow release fertilizer characteristic. The release rate of fertilizer elements (magnesium, potassium, ammonium, and phosphate) can be significantly reduced. The addition of kaolin in the first type of slow release fertilizer makes the release rate of fertilizer elements can be more slowed down. Meanwhile in the second type of slow release fertilizer, the release rate is determined by ratio of silica/hydrogel. The lowest release rate is achieved by sample that has highest ratio of silica/hydrogel.