著者

笹木 圭子

出版者

一般社団法人 日本鉱物科学会

雑誌

鉱物学雜誌 (ISSN:04541146)

巻号頁・発行日

vol.27, no.2, pp.93-103, 1998-05-11 (Released:2009-08-11)

参考文献数

60

被引用文献数

6 6

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Pyrite dissolution at ambient temperatures is one of the important reactions in biogeochemical processes. It is related to the formation of acid mine drainage, where iron- and sulfur- oxidizing bacteria often grow actively and play an important role in pyrite weathering. In this article experimental studies on the oxidation of pyrite are reviewed, including pretreatment method to obtain the well-defined surface of pyrite particles, the mechanisms of pyrite oxidation by both bacteria and oxidizing agents (Fe(III) ions and oxygen), and suppressing factors of the reactions. Microbially mediated dissolution of pyrite in acidic environments proceeds mainly by the indirect contact mechanism of the iron-oxidizing bacteria, Thiobacillus ferrooxidans, that is, the bacteria mainly take part in the oxidation of Fe(II) ions to Fe(III) ions. Therefore, to suppress the weathering the reaction of pyrite with Fe(III) ions must be inhibited. In addition to the reduction and complexation of Fe(III) ions, masking of active sites on the pyrite surface by the preferential adsorption of other species is the most important factor. Based on the experimental studies, utilization of natural organic acids involved in botanical wastes is proposed for remediation and prevention of damage caused by acid mine drainage due to pyrite weathering.

著者

笹木 圭子 PAWAR RADHESHYAM

出版者

九州大学

雑誌

特別研究員奨励費

巻号頁・発行日

2017-11-10

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有機金属構造体(MOF)は、中心金属とリンカーの組み合わせによって、高分子のような連続構造をとり、比表面積が高く、安定なだけではなく、中心金属やリンカーの特性により、さまざまな機能を付与でき、吸着材や触媒など機能性化学物質として、近年最も注目されている。なかでもガスフィルターとしての用途が最も実用化に近いといわれ、とくにCO2吸着剤としての開発研究が盛んである。しかし、本研究では、あまり研究例のない水溶液溶媒でのMOFの活用、とくに有害水溶性物質の光分解、光触媒機能による還元、陰イオンの吸着除去を目指して、水溶液中でのMOF合成法を開発および最適化し、合成したMOFの特性化、応用までを行った。ソルボサーマル法に代わる水溶媒での合成法の開発では、超音波法、マイクロ波法を試み、モジュレーターおよびリンカーの選択、モジュレーター量、、周波数、官能基の導入など300を超える実験条件をこなし、アプリケーションにおける反応効率の向上をめざした。さらに、MOFと粘土鉱物により複合体を合成し、可視光域で水溶液中での色素物質の分解、Cr(VI)の還元に機能する光触媒効率を評価した。本申請課題の中心であるMOF/粘土鉱物複合体による色素分子ローダミンBの光触媒分解では、MOFとしてZr6O4(OH)4(ABDC)6 (ABDC = 2-aminobenzene-1,4-dicarboxylic acid)を合成し、粘土として針状結晶のセピオライトを選び、複合材料の最適混合比を認めた。合成MOFは2.83 eV のバンドギャップをもつ可視光触媒で、光励起電子はセピオライトの導電帯に移り、スーパーオキシドラジカルを生成し、色素分子を酸化分解する機構を提唱した。このように、粘土鉱物は単なる支持体ではなく、光触媒反応の電子輸送にかかわっていることを示した。成果は国際学術誌4編にまとめられた。

著者

林 良和 郭 柄霖 平島 剛 伊藤 竜也 中村 壮志 笹木 圭子

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.135, no.7, pp.63-70, 2019-07-31 (Released:2019-07-31)

参考文献数

23

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Removal of borate in mine drainages by co-precipitation with hydroxyapatite (HAp) was developed from a laboratory scale to a pilot scale. Weakly acidic initial pH facilitated to enhance dissolution of Ca(OH)2 and decrease the dissolved carbonate concentration, leading to efficient immobilization of borate and arsenate. The NH4H2PO4 lowered best the equilibrium B concentration among different phosphate sources, avoiding the lattice strain of HAp. The added molar ratio of P/Ca significantly influenced the decreasing behavior of the B concentration, showing the optimal value of 0.3. In case of P/Ca larger than 0.30, the excess concentration of PO43- was probably adsorbed on Ca(OH)2 particles to prevent the dissolution, resulting in inhibiting the formation of HAp. In case of P/Ca smaller than 0.30, the production of HAp was limited, leading to less immobilized borate. All the optimized conditions as above were applied to the pilot scale with a 250 L reactor, where borate concentration was effectively reduced in also both batch and continuous tests.

著者

船津 貴弘 平島 美和 笹木 圭子

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.8, pp.110-116, 2018-08-31 (Released:2018-08-28)

参考文献数

2

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An Advanced Graduate Program in Global Strategy for Green Asia (GA) is a component project of the "Program for Leading Graduate Schools" which is supported by the Japan Society for the Promotion of Science (JSPS) and started in 2013. The concept of a “Green Asia” is a bold ideal. Some of the most challenging global environmental conditions now exist in Asia. Many developing countries face the difficult task of raising millions of citizens from poverty. Consequently, environmental concerns are often overlooked. The key to this complex issue is scientific innovation and a transfer of knowledge from technologically advanced to less advanced nations. This educational program aims to cultivate leaders in science and technology who are able to contribute to the realization of an Asia where ecology and economic growth can coexist. Only 20 exceptional students including 10 Japanese and 10 international are allowed to enroll in the GA program each year. This elite group are taught in a bespoke educational environment, also benefitting from the vast collective resources and shared facilities of KU. The students are offered a financial support in order attract the premium candidates and to maximize the available study time by avoiding the need for part time jobs. The students of the Green Asia Education Program follow a stage gate system. This system comprises of six stages, Research Laboratory Rotation, Practice School, Coursework, International Seminar, Internship and the Green Asia Seminar. All activities described above are carried out in English in order to educate international and multicultural sense. Through these program, the students acquire five abilities, which are research, global perspective, leadership, practice and system landscape. In addition, applied skills such as expansion, analysis and upstream thinking skill are also trained by various activities, especially, practice school and international internship. As first batch students had finished this program in March 2017, we introduce the GA program and how the program is managed and carried out in order to make this program better.

著者

井上 聡大 羅 武輝 森山 紗好 平島 剛 島田 英樹 笹木 圭子

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.133, no.10, pp.235-240, 2017-10-01 (Released:2017-10-14)

参考文献数

28

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Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident produced much amount of radioactively contaminated water at the Great East Japan Earthquake. 137Cs and 90Sr have been focused to remove from the contaminated water using zeolite types of adsorbents. Other radionuclides have been treated and removed separately by Advanced Liquid Processing System (ALPS), where resin is used to immobilize anions. However, these kinds of spent-adsorbents are not suitable for long-terms burying because of its instability, and the representative anionic radionuclides (129I, 36Cl, 99mTc and 79Se) have quite long half-life (105-107 years). Montmorillonite (Mt) is an useful adsorbent because of its high chemical stability and large cationic exchange capacity. In the present work, surfactant modified Mt (OMt) has been developed using hexadecylpyridium chloride for adsorption of ClO4-, which is a surrogate of 99mTcO4-. For stabilization of spent-OMt, cement solidification was examined with varying the ratio of spent-OMt content. To evaluate its chemical and physical stability, soaking and compressive strength tests were conducted. As a result, it was revealed by FTIR and 29Si-NMR that with increase in OMt contents, the linkage of calcium silicate hydrate was more developed.

著者

笹木 圭子

出版者

The Japan Society for Analytical Chemistry

雑誌

分析化学 (ISSN:05251931)

巻号頁・発行日

vol.61, no.1, pp.69-69, 2011

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[Additions]「分析化学」第60巻第12号にて,印刷会社のミスにより下記の誤りがございましたので,お詫びするとともに訂正いたします(PDF参照).

著者

笹木 圭子 小林 弘幸 恒川 昌美

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.117, no.9, pp.747-752, 2001-09-25

被引用文献数

4

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Aragonite-type of light calcium carbonate was synthesized by the successive reaction using calcined-hydrous scallop shells and calcined lime stones in the aqueous system with Mg²⁺ ions under the CO₂ bubbling. In order to obtain the high aspect ratios of aragonite, the reaction temperature and concentrations of Ca²⁺ ions in the 2nd step were important. The aspect ratio of aragonite increased when the reaction temperature was higher in the 2nd step than in the 1st step of the successive reaction. When the smaller amounts of calcium source were added in the 2nd step than in the 1st step, and the reaction temperature was lower in the 2nd step than in the 1st step, large particles of aragonite were produced with no smooth surfaces. The successive reaction was useful to extend the variety of morphologies in aragonite.

著者

笹木 圭子 本郷 大 恒川 昌美

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.114, no.10, pp.709-713, 1998-09-25

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Aragonite-type calcium carbonate was synthesized from calcined scallop shell using carbonates of orthorohombic structure (such as SrCO3) as seeds, by bubbling CO2 at ambient temperature. The products were examined by FTIR, SEM, EPMA, and XRD. The addition of SrCO3 increased aragonite content in the products, but BaCO3 and PbCO3 did not play the role of seed crystals due to the difference of their lattice parameters to those of aragonite, whereas lattice parameters of SrCO3 are the most similar to them. With increasing SrCO3 -addition, formation of aragonite was accelerated to a limit in the amount. Light calcium carbonate rich in aragonite was formed in agglegates consisting of needle-like crystals with large specific surface areas.

著者

笹木 圭子 本郷 大 恒川 昌美

出版者

一般社団法人 資源・素材学会

雑誌

資源と素材 (ISSN:09161740)

巻号頁・発行日

vol.114, no.10, pp.709-713, 1998-08-25 (Released:1999-10-01)

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Aragonite-type calcium carbonate was synthesized from calcined scallop shell using carbonates of orthorohombic structure (such as SrCO3) as seeds, by bubbling CO2 at ambient temperature. The products were examined by FTIR, SEM, EPMA, and XRD. The addition of SrCO3 increased aragonite content in the products, but BaCO3 and PbCO3 did not play the role of seed crystals due to the difference of their lattice parameters to those of aragonite, whereas lattice parameters of SrCO3 are the most similar to them. With increasing SrCO3 -addition, formation of aragonite was accelerated to a limit in the amount. Light calcium carbonate rich in aragonite was formed in agglegates consisting of needle-like crystals with large specific surface areas.

著者

笹木 圭子 小林 弘幸 恒川 昌美

出版者

一般社団法人 資源・素材学会

雑誌

資源と素材 (ISSN:09161740)

巻号頁・発行日

vol.117, no.9, pp.747-752, 2001 (Released:2006-01-08)

参考文献数

10

被引用文献数

3 4

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Aragonite-type of light calcium carbonate was synthesized by the successive reaction using calcined-hydrous scallop shells and calcined lime stones in the aqueous system with Mg2+ ions under the CO2 bubbling. In order to obtain the high aspect ratios of aragonite, the reaction temperature and concentrations of Ca2+ ions in the 2nd step were important. The aspect ratio of aragonite increased when the reaction temperature was higher in the 2nd step than in the 1st step of the successive reaction. When the smaller amounts of calcium source were added in the 2nd step than in the 1st step, and the reaction temperature was lower in the 2nd step than in the 1st step, large particles of aragonite were produced with no smooth surfaces. The successive reaction was useful to extend the variety of morphologies in aragonite.