KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
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Volume 40, Issue 2
Displaying 1-13 of 13 articles from this issue
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Editorial Note
Particle Engineering
  • A New Method of Particle Powder Formation from Aqueous Solutions using the Joule–Thomson Effect of High-Density Carbon Dioxide
    Keita Akimoto, Masaki Ota, Yoshiyuki Sato, Hiroshi Inomata
    Article type: Research Paper
    2014 Volume 40 Issue 2 Pages 79-83
    Published: March 20, 2014
    Released on J-STAGE: March 20, 2014
    DOIhttps://doi.org/10.1252/kakoronbunshu.40.79
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    A new spray-drying process of nanoparticle-dispersed aqueous solutions was proposed to produce metal/metal oxide fine-particle powder with controlled particle aggregation, in which high-density carbon dioxide is used as both an aqueous colloid dispersing solvent and a compressible fluid for spraying. An experimental setup was built based on the proposed idea and verified with aqueous solutions of 8-nm zirconia particles. The aqueous colloidal content was set to be more than 10 wt% from the viewpoint of practical production. This is an extremely high content in the high-density CO2 phase from the viewpoint of thermodynamic stability and leads to colloid aggregation within a short time, followed by phase separation. The proposed idea focuses on the time scale of such unstable colloids and requires the colloids in CO2 media to be sprayed via a nozzle within the short time before colloid aggregation begins. In addition, the sprayed colloids could be broken down into small droplets and frozen due to Joule–Thomson expansion of high-density CO2. The results showed that powders made of nanoparticles contained in frozen droplets could be generated with controlled particle aggregation.
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Separation Engineering
  • Morphology-Controlled Synthesis of Electrospun Nanofibers and Their Application for Aerosol Filtration
    Takashi Ogi, Hitomi Ono, Li Bao, Hitoshi Niinuma, Kikuo Okuyama
    Article type: Research Paper
    2014 Volume 40 Issue 2 Pages 84-89
    Published: March 20, 2014
    Released on J-STAGE: March 20, 2014
    DOIhttps://doi.org/10.1252/kakoronbunshu.40.84
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    Polyacrylonitrile (PAN) nanofibers with various morphological structures were produced by electrospinning by controlling the physicochemical properties (viscosity, surface tension, and electrical conductivity) in the precursor solution. Quantitative evaluation showed that fiber morphology was strongly influenced by precursor viscosity, and the viscosity thresholds affecting fiber morphology (ribbon-like, straight, spindle-like beaded, and beaded) were clarified. Using a monodisperse aerosol, the air filtration performance of filters made with these fibers was evaluated based on quality factors. Filters composed of beaded fiber showed the best quality in the air filtration test.
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  • Effect of Ionic Strength, Temperature on Equilibrium and Kinetics of Arsenic Adsorption using Magnetite
    Kaoru Ohe, Tatsuya Oshima, Yoshinari Baba
    Article type: Research Paper
    2014 Volume 40 Issue 2 Pages 90-97
    Published: March 20, 2014
    Released on J-STAGE: March 20, 2014
    DOIhttps://doi.org/10.1252/kakoronbunshu.40.90
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    Effect of ionic strength and temperature on the equilibrium and kinetics of arsenic adsorption on magnetite prepared by precipitation were investigated. The adsorption of As(III) was independent of ionic strength. After the adsorption of As(III), the zeta potential decreased and the point of zero charge (PZC) of the magnetite shifted to the acidic side. The adsorption of As(III) was considered to be the result of inner-sphere complex formation because of the endothermic reaction and the positive entropy change in the As(III) adsorption reaction. The adsorption of As(V) increased with increasing ionic strength at higher pH than the PZC, and a shift of the PZC was observed after the adsorption of As(V). The exothermic reaction and the positive entropy change of the reaction indicated that the As(V) adsorption occurred by the mechanism of outer- and inner-sphere complex formation. The presence of phosphate and silicate greatly decreased the adsorption of As(III) and As(V). The rate-controlling step in the adsorption of As(III) and As(V) was found to be the intraparticle diffusion process, since the kinetics of As(III) and As(V) adsorptions can be explained by the Dünwald–Wagner equation.
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  • Preparation of Activated Carbon with High Surface Area using Biomass Wastes and Its Application to Methane Storage Technology
    Akihiro Yamashita, Junpei Shikada, Tatsuya Oshima, Yoshinari Baba
    Article type: Research Paper
    2014 Volume 40 Issue 2 Pages 98-103
    Published: March 20, 2014
    Released on J-STAGE: March 20, 2014
    DOIhttps://doi.org/10.1252/kakoronbunshu.40.98
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    Methane gas is an alternative fuel to petroleum. However, the two conventional methods of storing methane, as liquefied natural gas (LNG) and compressed natural gas (CNG), involve a high degree of risk in terms of safety. To develop a high-safety and low-cost method of storing methane gas, we examined its adsorption on activated carbons newly prepared from biomass wastes, bamboo and crab shell, by chemical activation with K2CO3. The activated carbons prepared from the mixture of bamboo and crab shell exhibited the maximum specific surface area of 2,654 m2 g-1 as measured by the nitrogen gas adsorption method. The adsorption isotherms of methane gas at 25°C were measured using the newly prepared activated carbons. The adsorption capacities of methane gas on the activated carbons at 25°C were one and a half times as much as those of commercially available activated carbon. The adsorption results revealed that the adsorption capacities of methane gas on activated carbons were particularly influenced by their micropore volume.
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Chemical Reaction Engineering
  • Removal of Decamethylcyclopentasiloxane by Metal Oxide
    Shuichi Kanno, Tooru Kawasaki, Hirofumi Matsubara, Kenji Hara, Atsushi ...
    Article type: Research Paper
    2014 Volume 40 Issue 2 Pages 104-111
    Published: March 20, 2014
    Released on J-STAGE: March 20, 2014
    DOIhttps://doi.org/10.1252/kakoronbunshu.40.104
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    In a hydrogen oxidation reaction over Pt/Al2O3 catalyst in the presence of oxygen and highly-concentrated steam, the volatile small molecule siloxane (decamethylcyclopentasiloxane, D5) in the reactant gas was adsorbed on the catalyst surface and the hydrogen oxidation rate was decreased. To keep high catalyst activity, the reactant gas was introduced into the catalyst after passage through a metal-oxide remover. From the analysis of time courses of hydrogen concentration in the gas passed through the catalyst, it was revealed that several removers were able to remove D5 in the reactant gas and inhibit the decrease of hydrogen oxidation rate. ZrO2, SBA-15 and MCM-41 showed particularly high D5 removal activity. Furthermore, Zr-SBA-15 and Ti-SBA-15, in which Zorn and Ti were incorporated in a Si–O mesoporous frame, had new acidic sites and improved the D5 removal activity over that of SBA-15. In a D5 removal test with Zr-SBA-15 coated honeycomb, unreacted D5 and CH4 were detected in the gas passed through the honeycomb. Carbon balance, calculated form D5 introduced into the honeycomb and the unreacted D5 and CH4, was nearly 100%, and it was confirmed that D5 was hydrolyzed. From the Arrhenius plot, the hydrolysis reaction was a first-order reaction for D5 concentration.
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  • Selective Recovery of Rare Earth Elements from Spent Abrasive Material by Chlorination
    Takahiro Kato, Katsuyasu Sugawara
    Article type: Research Paper
    2014 Volume 40 Issue 2 Pages 112-118
    Published: March 20, 2014
    Released on J-STAGE: March 20, 2014
    DOIhttps://doi.org/10.1252/kakoronbunshu.40.112
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    Cerium oxide based abrasive material is widely used for polishing optical glass, glass circuit board etc. Rare earth elements contained in spent abrasive material are now disposed of without recycling. In order to develop a selective recovery process of rare earth elements from spent abrasive material, the chlorination behaviors of rare earth elements Ce, La and Pr and coexisting elements Al, Fe and Si were investigated.
    The chemical forms of rare earth elements contained in the sample of spent abrasive material were estimated to be CeO2, LaOF and PrOF. When the sample was heated to 1100°C in a chlorine gas stream, Ce, La and Pr did not volatilize but remained in the solid phase. Fe, Al and Si were released to the gas phase at the temperatures above 700, 800 and 900°C, respectively. When the sample with added carbon was heated in a chlorine gas stream, the coexisting elements began to volatilize from 400°C in the order of Fe, Si and Al. All of Fe and Si, and 85% of Al were released to the gas phase in the course of heating to 800°C. Ce, La and Pr were released gradually with the increase of temperature above 800°C, and the release reached from 10 to 20% at 1100°C. The experimental results of the carbon-added sample heated at the temperatures from 600 to 800°C in a chlorine gas stream for 1 h indicated that the treatment temperature of 700°C was appropriate to obtain the rare earth elements without any volatile loss and to lower the contents of impurities in the solid residue.
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Biochemical Food and Medical Engineering
  • Filtration and Recovery of Extracellular Polysaccharides from Culture Broth of Polianthes tuberosa Callus—Investigation of Operational Guidelines with a View toward Industrial Scale Operation—
    Koji Mine, Goro Ujita, Masahito Taya
    Article type: Note
    2014 Volume 40 Issue 2 Pages 119-124
    Published: March 20, 2014
    Released on J-STAGE: March 20, 2014
    DOIhttps://doi.org/10.1252/kakoronbunshu.40.119
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    The separation of calli and recovery of extracellular polysaccharides (TPS) by filtration from culture broth of Polianthes tuberosa was studied. In the dead-end filtration operated under a constant pressure with a laboratory-scale instrument, the formation of a filter aid precoat layer improved the optical transmittance of the filtrate. Filtration resistance of the precoat layer increased in proportion to the amount of filter aids in the precoat layer in the range of 0.48–2.7 kg/m2. Average specific filtration resistance of the cake layer was almost constant when the ratio of filter aid to callus concentration in feed slurry was 60–89. A filtration test with a bench-scale filter press was performed in a dead-end mode at a constant feed flow rate, based on the operational guidelines and running conditions determined in the laboratory-scale filtration tests. As a result, desirable filtration performance was achieved, giving a filtrate of over 95% optical transmittance associated with TPS recovery of almost 100%, up to a determined treatment volume of 0.22 m3/m2.
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Materials Engineering and Interfacial Phenomena
  • Enhancement of Water Dispersibility of Quercetin by Complexation with Casein
    Tatsuya Oshima, Yukari Masuda, Takaya Haranomura, Asuka Inada, Yoshina ...
    Article type: Research Paper
    2014 Volume 40 Issue 2 Pages 125-130
    Published: March 20, 2014
    Released on J-STAGE: March 20, 2014
    DOIhttps://doi.org/10.1252/kakoronbunshu.40.125
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    The flavonoid quercetin (Que) is believed to act as an antioxidant as well as a scavenger for free radicals. However, the oral bioavailability of Que is insufficient due to its low aqueous solubility. In the present study, a complex of Que and milk casein (Cas) was prepared to enhance the water dispersibility of Que. The complex (Que–Cas) was prepared by mixing an ethanol solution of Que and an aqueous solution of Cas, followed by evaporation of ethanol in vacuo and lyophilization. The water dispersibility of Que–Cas increased as the quantity of Cas in the complex increased. The zeta potential of Que–Cas suggests that Cas dominates the surface charge of Que–Cas. The particle size of Que–Cas in aqueous media was polydisperse and 90–120 nm or larger, suggesting that Que–Cas was present as a hydrocolloidal material. Characterization of Que–Cas using X-ray diffraction as well as fluorescence quenching of Que showed that Que was incorporated in the hydrocolloid in an amorphous state.
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  • New Micromachining Technique for Unworkable Sapphire by Highly Coalesced Ion Implantation and Eximer Laser Irradiation
    Shintaro Ishiyama, Hironori Ohba, Syunya Yamamoto, Takahisa Shobu
    Article type: Research Paper
    2014 Volume 40 Issue 2 Pages 131-136
    Published: March 20, 2014
    Released on J-STAGE: March 20, 2014
    DOIhttps://doi.org/10.1252/kakoronbunshu.40.131
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    It was found that 0.3–3 MeV H2+-implanted sapphire exhibits singular optical absorption of ultraviolet light at a wavelength of about 200 nm. Using this property, a new micromachining technique for unworkable sapphire was demonstrated by using highly coalesced ion implantation and eximer laser irradiation. When sapphire implanted with 0.3 MeV H2+ up to 1.3×1017 ions/cm2 was irradiated with ArF laser at 3.4 J/cm2 in a single shot, a rectangular microgroove of 1 µm in depth, 80 µm in width and 7 mm in length was observed on the surface of the ion-implanted sapphire. However, with implantation of over 1.3×1017 ions/cm2, remarkable blistering was observed on the surface of the sapphire.
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  • Characteristic Evaluation of Lead-Free Sealing Glasses Composed of V2O5–MnO2–KPO3–CuO
    Shohei Kubo, Seigo Goto, Ryosuke Iwata, Yoshihiro Kouhara, Takayuki Ta ...
    Article type: Research Paper
    2014 Volume 40 Issue 2 Pages 137-142
    Published: March 20, 2014
    Released on J-STAGE: March 20, 2014
    DOIhttps://doi.org/10.1252/kakoronbunshu.40.137
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    Lead-free sealing glasses possessing low melting temperature, high water durability, low thermal expansion coefficient, and high fluidity are desirable for sealing processes in the ceramics and electronics fields. In this paper, novel sealing glasses composed of metal and non-metal oxides (V2O5, MnO2 and KPO3) were developed, and their thermal properties, water durability, structure by X-ray or FT-IR analysis, fluidity by flow-button test, lightness by the Munsell value, sealing properties, and bonding strength by tension test were examined in detail. The glasses with low melting point and high fluidity were composed of 40 mol% V2O5–10 mol% MnO2–50 mol% KPO3, 30 mol% V2O5–20 mol% MnO2–50 mol% KPO3, or 30 mol% V2O5–10 mol% MnO2–60 mol% KPO3. However, these glasses with high phosphorus content had poor water durability, which could be improved considerably by the addition of CuO. The thermal expansion coefficients of the glasses were much higher than that of a soda lime glass (7–8×10-6°C-1) and were lowered to the level of a soda lime glass by the addition of a low thermal expansion ceramic filler (Zr2(WO4)(PO4)2, ZWP). Glass composed of 40 mol% V2O5–10 mol% MnO2–50 mol% KPO3 containing 20 wt% ZWP had an excellent sealing property comparable to commercial lead glass.
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General Research and Others
Erratum
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