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Guna meningkatkan nilai ekonomi dari konsentrat zirkon lokal dari Pulau Bangka, Cermet Ni-YSZ disintesis dari zirkonia yang sebelumnya telah disintesis dari konsentrat zirkon lokal. Cermet Ni-YSZ disintesis dengan menggunakan metode solid state reaction. Analisis XRD yang dilengkapi dengan refinement Le Bail telah dilakukan untuk menganalisis struktur kristal dan parameter sel dari material. YSZ dipreparasi dengan melakukan doping 8% mol yttrium oxide kedalam zirkonia dan kemudian disinter pada suhu 1250 oC selama 3 jam. ada penambahan doping 8% mol yttria memungkikan transfomasi fasa dari zirkonia dari tetragonal menjadi struktur kubik. Sementara itu, cermet Ni-YSZ memiliki fasa kristalin, Ni dengan struktur kubik dan YSZ dengan struktur kubik. analisis sem dari material-material tesebut menunjukan bahwa adanya penambahan Ni kedalam YSZ memungkinan morfologi menjadi lebih kasar dengan ukuran butir besar yang disebabkan adanya agglomerasi Ni terhadap YSZ. cermet Ni-YSZ memiliki konduktivitas tertinggi pada komposisi Ni:YSZ 20:80.

This research synthesized a cermet Ni-YSZ, in which the YSZ (yttria stabilized-zirconia) was synthesized from the local zircon sand, ZrSiO4, as a side product of tin mining plant in Bangka island, Indonesia. The synthesized YSZ in this research is zirconia, ZrO2 doped by 8 % mol of yttrium dioxide. The synthesis used solid state reaction method and the result was characterized its crystal structure and its cell parameters by XRD analysis equipped with Le Bail refinement, surface morphology analysis, and an impedance analysis to understand its ionic conductivity. The cermet Ni-YSZ was synthesized at a various composition of Ni:YSZ i.e., 20:80, 30:70, and 40:60 (b/b). The analysis shows that Ni-YSZ is in two phases of Ni and YSZ without any presence of a third phase. It indicates that there was no solid state reaction between Ni and YSZ during synthesis. In this Ni-YSZ cermet, the Ni phase in a cubic structure, and the YSZ is also in a cubic structure. Morphological study shows that the addition of Ni to YSZ allows the morphology to become more roughness with larger grain size. This research found that the Ni-YSZ 20:80 has highest ionic conductivity.

A Research on CdS synthesis in reverse microemulsion of Igepal CO-720 system has been conducted at various weight ratio of water to surfactant. Igepal CO-720 naturally forms oil in water (o/w) emulsion type due to its high HLB (Hydrophilic -Lipophilic Balance) value. Therefore, in this research the Igepal CO-720 system was inversed into water in oil (w/o) system before it was used as microreactor for CdS synthesis. As comparison, a system of AOT (Aerosol OT; sodium bis (2-ethylhexyl) sulfosuccinate) which is naturally w/o system was also used as microreactor for CdS synthesis. The prepared CdS was analyzed by X-ray diffraction for crystal identification, scanning electron microscope for morphological analysis, UV-Vis for absorption edge determination and photoelectrochemical testing for photoactivity. The results show that the Igepal CO -720 system can be inverted into w/o system and can be used as microreactor for CdS synthesis. The prepared CdS is in nanosize with the average diameter of 2.517 ± 0.014 nm and the average gap energy of 3.805 ± 0.178 eV. The prepared CdS in Igepal CO-720 system has less regular form in comparison with morphology of the prepared CdS in AOT system. As the ω values decreases the particle diameter decreases, the gap energy increases and the % IPCE increases. It indicates that high surfactant concentration allows small size micelles formation and produced smaller CdS particle that has high surface area and therefore provide higher photocatalytic activity which was indicated by high value of its % IPCE.

Soda ash (NaOH) has been used in bioethanol production in the second step destillation to increase the purity up to 90%. The destillation process will produce waste water with a high sodium content. The soda ash itself serve as an electrolyte to modify the colligative properties of the water-ethanol mixture allowing the disappearance of azeotropic point. This research aims to study the replacement of NaOH with KOH, in which the kalium is a nutrient to maintain soil fertility. This research study the thermodynamics properties, vapor-liquid equilibrium, colligative properties and also its azeotropic point in the destillation of water-ethanol mixture when KOH and NaOH were used as the additive. A model of water-ethanol mixture at a various composition of 0-100 weight % of ethanol was used. The electrolyte addition was 0.1 mol electrolyte/total weight of ethanol-water. The result shows that the addition of electrolyte into ethanol-water mixture eliminate the azeotropic point and allows the ethanol molecules to separate from water. The enthalpy of mixing between water-ethanol is 239.601 kJ/mol. It becomes 259.796 kJ/mol and 264.793 kJ/mol after the addition of NaOH and KOH, respectively. It confirming the endothermic mixing process due to different polarity between water and ethanol. The presence of electrolyte even reduce more their molecular interaction. However, the change to irregularity result a high positive entropy values that result the negative Gibbs free energy. It confirms the spontaneity of mixing. The vaporization enthalpy, Hvap, of water-ethanol mixture is 76.229 kJ/mol and it becomes 235.366 kJ/mol and 126.189 kJ/mol after the addition of NaOH and KOH. It indicates that the presence of electrolyte inhibites vaporization of water as the major component and allowing ethanol molecules to vapor producing more high purity ethanol.