Papers by Author: Masayoshi Fuji

Abstract: Horse manure, organic waste from livestock, has been used for the production of nitrogen-doped porous carbons (NPC) which could be applied as functional material. The variety of different NH₄OH solution concentrations (0.5, 1, 1.5, 2 M) were introduced in hydrothermal treatment as activating agent. Also, the nitrogen precursor was served. Horse manure derived NPC were characterized through varied physicochemical properties including NPC yields, FTIR, SEM, XPS and N₂ sorption analyzer to characterize specific properties such as elemental composition on surface, surface functional bonding, physical morphology, and porosity of NPC. In addition, the incorporation of nitrogen dopant into the carbon was intended to further enhance the electrochemical performance.

Abstract: Waste lignin (WL) from the pulp mill and paper was studied for its potential application to prepare the nanoporous carbon with high porosity via carbonization assisted acid activation. The effect of acid activation such as HNO₃, HCl, H₂SO₄, and H₃PO₄ on lignin transformation to nanoporous carbon investigated. The physicochemical properties of nanoporous carbon were comprehensively characterized through N₂ sorption, Scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR), respectively. N₂ sorption revealed that the condition using 5% vol of phosphoric acid activation at carbonization temperature of 700°C for 2 h exhibited the highly porous structure of carbon nanoparticles with a total pore volume of 0.035 cm³/g. With the properly selecting process variables of waste lignin development could be producing high porosity nanoporous carbon.

Abstract: Monometallic catalysts have been prepared on nano-porous carbon support materials by way of hydrothermal carbonization of Cattail (genus Typha) leaves. The catalysts are for synthesis of biodiesel fuel. This research studied the effect of hydrothermal temperature (at 160-200 °C), reaction time (4-24 h) and the presence of KOH on the activated porosity of a carbon support. Then the type of loaded metal catalyst (Mn, Fe, Co, Ni, Cu and Pb), placed on the carbon support by an impregnation method, was investigated. This led to partial hydrogenation catalytic activity forming biodiesel. The carbonization temperature was studied in the range 500-900 °C for 2 hours. The samples were characterized by scanning electron microscopy, nitrogen sorption, fourier transform infrared spectroscopy and X-ray diffraction. The results indicated that the hydrothermal process at 200 °C for 12 hours exhibited the highest surface area, porosity and pore volume. This led to an appropriate distribution of metal on the carbon support surface.

Abstract: Zeolite A and zeolite X was successfully synthesized from natural kaolin from Lampang province using calcination and two-step method of hydrothermal under the optimum conditions. Firstly, metakaolin was achieved by calcining the kaolin at 700 °C for 2 h. Secondly, hydrothermal experiments can be separated into two steps, the high temperature and short time of hydrothermal, metakaolin was mixed with NaOH to form hydrous sodium aluminosilicate, which was dissolved in dilute HCl. After the filtration, adjusted with deionized water to pH = 7 to form an amorphous aluminosilicate gel. Low temperature and longtime of hydrothermal, aluminosilicate gel was mixed with NaOH to form zeolite A and zeolite X. The optimum conditions for synthesis zeolite A is the high temperature and short time of hydrothermal with NaOH 8 M at 200 °C for 3 h and low temperature and longtime of hydrothermal with NaOH 1 M at 90 °C for 72 h. The optimum conditions for synthesis zeolite X is the high temperature and short time of hydrothermal with NaOH 8 M at 200 °C for 3 h and low temperature and longtime hydrothermal was NaOH 1 M at 90 °C for 120 h. The characterization of zeolite A and zeolite X were examined by x-ray diffraction (XRD), scanning electron microscopy (SEM), and infrared spectroscopy (FT-IR). Keywords: Zeolite A, zeolite X, Kaolin, Hydrothermal, Kaolin

Abstract: Waste lignin (WL) obtained from paper mills, was studied for its potential application in preparing carbon nanoparticles (CNPs) with high porosity. This was done by impregnation of 0, 5, 10 and 20% concentrations of phosphoric acid under various carbonization temperatures (600, 700, 800 and 900°C). The physicochemical properties of CNPs were characterized through nitrogen sorption, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Fourier transforms infrared spectroscopy (FTIR). Nitrogen sorption revealed that the condition using 10% concentration of phosphoric acid treatment at a carbonization temperature of 700°C formed carbon nanoparticles with a highly porous structure (Surface area 27.65 m²/g and pore volume 0.07 cm³/g). Additionally, in order to high surface area, porosity and concentrated carbon nanoparticle.

Abstract: Layered clay has been of great interest because of their nano-sized layer structure and hence intercalation and ion-exchange capacity to be used as a host material of composite with polymers and/or metals. In this study, smectite as a silicate-layered clay was easily exfoliated and dispersed into purified water, and was deposited onto a cupper plate for which dc voltage ranging from + 1.0 V to + 6.0 V was applied with respect to a counter platinum plate electrode. The cupper plate was pre-treated by chemical and chemical mechanical polishing (CP and CMP) prior to the electrophoretic deposition (EPD). The surface roughness of the substrate as well as the smectite film formed was characterized by an atomic force microscope (AFM). The thickness of smectite layer was estimated using an X-ray fluorescence (XRF) analysis as well as a scanning electron microscope (SEM) observation. The layer thickness can be described as a function of operational parameters such as applied voltage and operating time. Smooth smectite film with thickness ranging from 100 nm to 10 μm has been successfully fabricated onto the CMP cupper plate by the EPD method in this study.

Abstract: Nobel metal particles with nanometer size have attracted keen interest because of, for example, their high catalytic activity to be applied for industrial applications. In this study, nano-sized gold particles were deposited onto a graphite carbon plate by two approaches: 1) electrophoresis of colloidal gold nanoparticles, 2) electrolysis of chlorauric acid. For former case, commercially-available gold nanoparticle and anionic mercapto ligand-stabilized gold nanoparticles, synthesized by citric acid reduction of chlorauric acid, were used. Size and morphology of the gold particles deposited were characterized by scanning electron microscopy. Electrolytic deposition resulted in larger gold particles around tens to hundreds nm in size. Electrophoretic deposition accomplished particle sizes smaller than 15 nm, which basically reflected the size of colloidal gold particles used.

Abstract: This study investigates the phase compositions in gelcast dense alumina and porous alumina that were sintered in an inert atmosphere. Both materials were gelcasted using identical slurry composition except for adding surfactant to slurry intended for porous shaping. The resulting gelcasted samples were dried and then sintered in argon gas at 1700oC. The X-ray photoelectron analysis was used for identifying the phase compositions in sintered samples, which was supported with TG/DTA and electrical measurements. Results showed that, in addition to alumina and carbon phases, the dense sample yielded Al4C3 and Al, while porous sample yielded aluminum oxycarbides. The formation of these phases reduced the carbon content through different chemical reactions to a limited extent because they formed a protective layer on alumina grains, which prevented the direct contact between alumina and carbon. Subsequent measured electrical resistivities of dense and porous alumina were, respectively, 0.20 and 0.32 ,-cm, indicating that the carbon networks are preserved in both materials.

Abstract: In this study, we propose a new process to fabricate electrically conductive alumina by gelcasting and reduction sintering. The process used the conventional gelcasting method except for varying amounts of monomer at 2.8, 5.5, and 8.0 wt.% relative to the weight of the slurry. In the plastic mould, the slurry was under in situ solidification for 3 hrs at 25oC to achieve gelation. The freshly gelled bodies were demolded, carefully dried, and then sintered at 1100oC, 1300oC, and 1550oC in nitrogen atmosphere. The holding times at 1100oC and 1300oC was 2 hours, while at 1550oC were 2, 4, and 6 hrs. The sintered alumina body was characterized by electrical property, X-ray diffraction, and scanning electron microscopy. Results showed that monomer additions and sintering schedule significantly affect in lowering electrical resistance. The low value was 3.6×106 +cm at 8.0wt.% monomer addition and sintering at 1550oC for 2 hrs. The effect of physical properties on electrical conductivity and the corresponding reaction mechanism were discussed in details.

Abstract: Hollow calcium carbonate (CaCO3) particles were synthesized by bubbling CO2 in the solution of calcium chloride (CaCl2) with the presence of ammonia at room temperature. In this method, CO2 bubble, besides as reactant, has an important role as a template for forming hollow particles. The precipitation was carried out by controlling the precipitation condition, such as pH, flow rate and additives. Hollow calcium carbonate particles were precipitated with the major crystal phase of vaterite. An interesting finding is that magnesium ion (Mg2+) can suppress the transformation of vaterite to calcite by inhibiting the growth of the calcite.