Kyushu University Academic Staff Educational and Research Activities Database
List of Presentations
Keiko Sasaki Last modified date:2019.06.13

Professor / Resources System Engineering / Department of Earth Resources Engineering / Faculty of Engineering


Presentations
1. Tain Quanzhi, Keiko Sasaki, Synthesis and Characterization of Zeolite A from Coal Fly Ash for Stabilization of Cs+ and Sr2+, 平成30年度 資源・素材学会 秋季大会              , 2018.09.
2. Li Zhang, Srinivasarao Kancharla, Keiko Sasaki, Adsorption of perchlorate on synthesized gemini surfactants with different chain lengths, 平成30年度 資源・素材学会 秋季大会              , 2018.09.
3. Radheshyam R Pawar and Keiko Sasaki, Modulated water-based synthesisof Zr-fumarate MOFs for high-efficiency treatment of selenite and selenate from the aqueous solutions, ACS PACCON 2019, 2019.02.
4. Chitiphon Chuaicham, Keiko Sasaki, Surface Plasmon Resonance Enhanced Visible-Light-Driven Photocatalytic Degradation of Rhodamine B by Sepiolite/Carbon Nitride/Pd Nanoparticles Composites, ACS PACCON 2019, 2019.02.
5. Kancharla Srinivasarao, Keiko Sasaki, Covalently functionalized graphene oxide for the recovery of palladium from spent nuclear fuel, ICEAn 2018, 2018.08.
6. Keiko Sasaki, Binglin Guo, Reduction of selenate in ettringite by calcination, Goldschmidt 2018, 2018.08.
7. Binglin Guo, Keiko Sasaki, Confinement of iodide and iodate in ettringite: the plausible mechanism for various inorganic anions selective incorporation, Goldschmidt 2018, 2018.08.
8. Binglin Guo, Keiko Sasaki, Immobilization of iodine and selenium as radionuclide surrogates in cement related materials , PACCON 2019, 2019.02, The confinement of radionuclides or hazardous elements is an important issue for preventing environmental contamination and helping to maintain safe ecosystems for living organisms. Among the radioactive isotopes, the 129I and 79Se isotope are considered as remarkable environmental risk related to nuclear waste storage and/or disposal because of their relatively long half-life (1.57×107 years and 2.95×105, respectively) and high mobility in soil and aqueous system. Since radioactive isotopes are a relatively emergent contaminant and nuclear wastes are usually immobilized in cement, immobilization of I and Se species to cementitious materials is of great interest. As a major and active component in hydrated cement, ettringite is assumed to play a role in immobilization of toxic anions because of its ion-exchange ability. The present talk will display the immobilization mechanisms and properties of iodine and selenium as radionuclide surrogates in ettringite. In addition, the stability of ettringite after uptake toxic anions is also discussed. After accumulation of radionuclides from a contaminated source, ettringite should be stabilized before landfilling for long time storage. An investigation into developing the alternative method to stabilize hazardous wastes by using industrial byproduct/wastes to synthesis glass-ceramics can be also conducted..
9. Shingo Nakama, Quanzhi Tian, Binglin Guo, Niko Dian Pahlevi, Zhaochu Hu, Keiko Sasaki, Suppression mechanism of anionic pollutants released from fly ash by Ca additives, 米国化学会, 2018.03.
10. Chitiphon Chuaicham, Keiko Sasaki, Effects of precursors on the photocatalytic activities of graphitic carbon nitride in hexavalent chromium reduction and rhodamine B degradation under visible light irradiation, 米国化学会, 2018.03.
11. Keiko Sasaki, Suitable matrix for stabilizing anionic radionuclides toward long term storage
, 1st Diversity Symposium for Women Scientist in KU –STEM- , 2018.03.
12. Yuta Kamura, Paulmanickam Koilraj, Tsuyoshi Hirajima, Keiko Sasaki, Simultaneous adsorption mechanism of 79SeO42- and 90Sr2+ on the layered double hydroxide/graphene oxide composite

, CINEST 2016, 2017.12.
13. Niko Dian PAHLEVI1, Binglin GUO1, Tsuyoshi HIRAJIMA1, and Keiko SASAKI, Affecting Factors to the Phase Matrix to Immobilize Selenate in Hydrothermal Co-Precipitation with Sodalite/Cancrinite


, CINEST 2017, 2017.12.
14. Keiko Sasaki, How to find suitable matrix for stabilization of anionic radionuclides toward long term storage?, Penn State Short Seminar, 2017.11.
15. Kojo Twum Konadu, Keiko Sasaki, Kwadwo Osseo-Asare, Takashi Kaneta, Effect of lignin degrading enzymes on the decomposition of large aromatic hydrocarbons using coronene as a surrogate for powdered activated carbon, International Biohydrometallurgy Symposium, 2017.09.
16. Yuta Kamura, Paulmanickam Koilraj, Tsuyoshi Hirajima, Keiko Sasaki, Synthesis of layered double hydroxide/different carbon material composites
for simultaneous adsorption of 79SeO42- and 90Sr2+

, EARTH 2017, 2017.09.
17. Yoshikazu HAYASHI*, Binglin GUO, Tsuyoshi HIRAJIMA, Keiko SASAKI , Immobilization of borate from the discharged water in mining activity by co-precipitation with hydroxyapatite
, EARTH 2017, 2017.09.
18. Shingo Nakama, Binglin Guo, Tsuyoshi Hirajima, Keiko Sasaki, Suppression of anionic pollutants released from fly ash by different Ca additives


, EARTH 2017, 2017.09.
19. Niko Dian Pahlevi, Binglin Guo, Tsuyoshi Hirajima, Keiko Sasaki, Immobilization Process of Selenate in Cancrinite by Hydrothermal Method

, EARTH 2017, 2017.09.
20. Keiko Sasaki, Yoshikazu Hayashi, Binglin Guo, Immobilization of borate and arsenate from geothermal waters by co-precipitation with hydroxyapatite, Goldschmidt 2017, 2017.08.
21. Niko Dian Pahlevi, Binglin Guo, Tsuyoshi Hirajima Keiko Sasaki , Immobilization Mechanism of Selenate in Cancrinite by Hydrothermal Method
, 資源・素材学会 九州支部例会, 2017.06.
22. Wuhui Luo, Sasaki Keiko, Synergistic adsorption of Sr2+ and ClO4− on alginate-encapsulated organo-montmorillonite, Hybrid Materials 2017, 2017.03.
23. Paulmanickam Koilraj, Keiko Sasaki, Multifunctional bio-molecules: A precipitant and anion controlling agent on the synthesis of layered double hydroxides and their arsenate adsorption, Hybrid Materials 2017, 2017.03, Arginine is an important biomolecule, which are widely used as ingredients in food and pharmaceuticals industries [1]. Recently, amino acids are utilized for the synthesis of simple metal oxides and/or metal hydroxides, which showed remarkable electronic and adsorption properties. However, the challenges are the preparation of mixed metal hydroxides or layered double hydroxide (LDHs) using these biomolecules [2]. At present, we have synthesised LDHs using multifunctional amino acids as precipitant and labile anion controlling agent and used for the remediation of aqueous arsenate.
Synthesis of MgAl-LDHs (Mg/Al atomic ratio of 3.0) with controlled labile anion was synthesised by hydrothermal method at 100-150 oC using arginine. Thus prepared materials were utilized for the remediation of aqueous arsenate.
PXRD showed that pure nitrate containing LDHs was obtained at lower temperature due to water hydrolysis. Conversely, at higher temperature LDHs showed carbonate as interlayer anion due to the decomposition amino acid into NH4+ and CO2 which act as precipitant and interlayer anion respectively. Arsenate adsorption studies indicated that the adsorption density is directly related to the amount of labile nitrate present in the interlayer and showed maximum of 1.657 mmol/g for LDH synthesised at 100oC. The mechanism of LDH formation and arsenate adsorption was elucidated by different physicochemical analyses.
In conclusion, for the first time MgAl LDHs with different composition of interlayer anion were synthesised by hydrothermal method using amino acid as precipitant and anion controlling agent without any external base. The products obtained at the end of synthesis are LDH and arginine cation. The LDHs obtained here are used as adsorbent and the arginine cation could be used as chemical intermediates with zero waste disposal promising its superiority..
24. Yuta Kamura, Paulmanickam Koilraj, Keiko Sasaki, Carbon-dot/layered double hydroxide nanocomposite for the co-immobilization of strontium and selenate , CINEST 2016, 2016.12, sStrontium (Sr2+) and anionic sselenate (SeO42-) are the by-products of nuclear reaction. Co-immobilization of these ions are highly desired for total remediation of radioactive waste water. Carbonaceous nanomaterials are received great attention in the field of water remediation and pollution control in recent years. However, the handling of these nanomaterials are very challenging due to increase in the bio-availability and toxicity. At present, Mg2Al-NO3 layered double hydroxides (LDHs) was synthesized and modified using carbon nano-dots. Thus prepared materials were characterized through different physicochemical analyses such as PXRD, FT-IR, Zeta potential and TEM. Strontium and selenate adsorption on Mg2Al-NO3-LDH/C-dot composites showed that the strontium immobilization capacities were increased with increase in the amount of carbon-dot. The mechanism of Sr2+ adsorption on these composites occurs via co-ordination with –COO- group of carbon-dot, while SeO42- occurs through ion-exchange of nitrate present in the interlayer galleries of LDH. These results promising the use carbon-dot/LDH composite materials for the total remediation of both anionic and cationic radioactive nuclides from waste water.

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25. Sasaki Keiko, Bioleaching of Cu from enargite using thermoacidophilic iron-oxidizing archaeon, Acidianus brierleyi: Spectroscopic study for stabilizing As, Copper 2016, 2016.11.
26. Sasaki Keiko, Wuhui Luo, GRINDING EFFECTS OF MONTMORILLONITE AND ILLITE ON FOLLOWING MODIFICATION BY DIOCTADECYL DIMETHYL AMMONIUM CHLORIDE AND ITS APPLICATION IN PERCHLORATE REMOVAL, Asian Clay 2016, 2016.11.
27. Qianqian Yu, Keiko Sasaki, BIOTEMPLATED SYNTHESIS OF A LITHIUM ION-SIEVE DERIVED FROM BIOGENIC MN OXIDE
, Asian Clay 2016, 2016.11, Microbial oxidation is a primary pathway for the Mn oxides formation in nature. Its unique structural properties provide potential for materials scientists to fabricate new functionalized materials. Using Mn oxidizing fungus Paraconiothyrium sp. WL-2 as a bio-oxidizer as well as a bio-template, a special lithium ion sieve with microtube morphology was prepared by calcination. The poorly crystalline Mn oxide facilitates the formation of well crystalline lithium ion sieve at a relatively lower temperature. The effect of calcination temperature was studied by using in situ X-ray diffraction (XRD), Rietveld analysis, X-ray absorption fine structure (XAFS) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). We found that changes of calcination temperature affected the crystal structure (e.g. contents of the spinel phase), the morphology, as well as the chemical composition (e.g. the average oxidation state of Mn) of the product. And the sorption capacity of lithium ion sieve is related with the content of Mn(III) in spinel phase. The optimized sample shows lithium adsorption capacity which is more than twice higher than particulate materials..
28. Sasaki Keiko, NATURAL ATTENUATION OF ARSENATE-CONTAMINATED RIVER IMPACTED BY ACID MINE DRAINAGES: CHARACTERIZATION OF SUSPENDED PARTICULATE MATTERS , ICHMET 2016, 2016.09.
29. Binglin Guo, Keiko Sasaki, Tsuyoshi Hirajima, COORDINATION CHEMISTRY OF SELENATE IN ETTRINGITE, ICHMET 2016, 2016.09, Introduction
Selenium often occurs in association with sulfide minerals by replacement with sulfur, and its toxicity is known as being associated with a number of specific diseases such as nail abnormalities and changes in peripheral nerves. Selenite (SeO32–) and selenite (SeO42–)are much more mobile and toxic in ecosystems. Furthermore, the high mobility of radionuclide 79Se in aqueous environments can pose the terrible threat because most minerals' surfaces are negatively charged in earth crust and it has a long half life time around 2.95×105 years.
Ettringite, which is one of calcium aluminum hydroxysulfates with several crystal water molecules, often occurs in some alkaline environments like cements. It has a general composition of A6B2(C)3(OH)12•26H2O, where A is Ca2+, Sr2+, Cd2+, Co2+; B is Cr3+, Al3+, Fe3+, Mn4+, Si4+; and C is some anions such as SO42– and SeO42– (Gougar et al., 1996). The unit cell of the crystal consists of columns of {Ca6[Al(OH)6]2・24H2O]}6+ with the inter-column spaces occupied by 3 moles of divalent anions (C) and 2 moles of H2O, which hold columns together through electrostatic force. It has been proved by the bond valence theory that AsO43– is complexed with some functional groups on the surface of columns in ettringite (Myneni et al., 1998). Thus, there are two possibilities in incorporations of oxoanions in ettringite, which are the substitution of intercolumn oxoanions or the coordination of oxoanions with functional group on ettringite. This should affect to the chemical stability of anionic species, which are sometimes pollutants in ettringite.
It is not yet clear whether SeO42– is sorbed through inner-sphere complexation or outer-sphere complexation in ettringite. In other word, the bonding Ca(Al)-O-Se-O3 should be created through covalent bond while the bonding H•••••O-Se-O3 should be formed in the later through electrostatic force. In the present work, ettringite containing different concentrations of selenate was characterized by Fourier Transform infrared spectroscopy (FTIR) and bond valence theory to figure out the sorption mechanism of selenate in ettringite.
Methods
Ettringite was synthesized with the stoichiometric amounts of Ca(OH)2 and Al2(SO4)3 with different concentrations of Na2SeO4 (0.5–20mM) in ultrapure water. All solutions were prepared by deionized water and reagent-grade chemicals. The mixture were covered with parafilm to avoid getting CO2 and stirred using a magnetic stirrer at room temperature for 120 min. Then the pH of supernatant was recorded and suspension was filtered by membrane filter for determination of remaining Ca, Al, Se and S concentrations using inductively coupled plasma optical emission spectrometry(ICP-OES).The precipitates were examined by using scanning electron microscope (SEM), X-ray diffraction (XRD), and FTIR. Bond valence theory(Brown et al.,1985)was also applied to calculate the coordination numbers of O atoms in SeO42–assurface functional groups of ettringite.

Results
Changes of water chemistry during immobilization of SeO42– in ettringite were monitored until the equilibrium by determination using ICP-OES. Based on the results of XRD for the solid residues, there is no other phases than ettringite with increase in SeO42–concentrations. Moreover, SEM image has shown needle-like crystals, which are characteristic to ettringite. These results suggest that immobilized SeO42- were completely substituted into inter column spaces in ettringite structure. Furthermore, as shown XRD results, with increasing the amount of immobilized SeO42-in ettringite, the cell parameters a and c also increased.
In ettringite, there are several types of –OH groups including ≡Ca-OH2, ≡Al-OH and ≡Ca2-OH, which produce board FTIR peaks to assign to the stretching vibration mode of O-H around 3200 to 3560 cm-1. Incorporation of SeO42-into the columns of ettringite perturbed the –OH stretching vibration. With increasing the amount of immobilized SeO42– in ettringite, the intensities of–OH stretching peaks decreased in the range of 3250 to 3400 cm-1 which is assigned to the –OH stretching vibration of ≡Ca-OH2.This indicates that SeO42-interacted with H2O which is coordinated to Ca. Based on the structure of ettringite, ≡Ca-OH2, ≡Al-OH and ≡Ca2-OH sites are arranged in the column surfaces, where≡Ca-OH2 is the most dominant sites. According to the bond valence theory, Se-O has1.62 valence units (v.u.) and O-H does about 0.78 v.u. Ligand exchange to such as ≡Ca-OH-SeO3 does not happen, because Se-O-H bond has been already saturated (Brown et al.,1985). Similar characteristic of AsO43- has been also demonstrated (Myneni et al., 1998). In ettringite, SeO42– can be only interacted with these function groups through the formation of inner-sphere complexes of ≡Ca-O-SeO3. It is supposed that the significant change in –OH vibrations may result from the SeO42– sorption in ettringite and the formation of inner-sphere complexes.
Conclusions
The ettringite shows promising application in immobilization of large concentrations of SeO42– in aqueous environments. In the present work, the mechanism of SeO42– by co-precipitation with ettringite was discussed. According to the FTIR spectra, the peak intensity in –OH stretching mode vibration significantly decreased with increasing the amount of immobilized SeO42– in ettringite. Furthermore, based on the XRD patterns, sorption of SeO42– increased the cell parameters a and c of ettringite. EXAFS and TG-DTA analysis would exemplify this assumption.
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30. Wuhui Luo, Keiko Sasaki, ADSORPTION CHARACTERISTICS OF HAZARDOUS INORGANIC OXOANIONS ON ORGANOHDPy-MODIFIED -MONTMORILLONITE, ICHMECT 2016, 2016.09, Introduction
Adsorption of individual anions on organo-montmorillonite (OMt) was has been well investigated in previous studies (Bagherifam et al., 2014; Choung et al., 2014). In those studies different amounts of organic modifier with variable structures were usedapplied, resulting in no criterion for comparing the selectivity of anions to OMt. A systematic study in terms of adsorption of six anions on three surfactant-modified bentonites was has been conducted (Behnsen and Riebe, 2008). Their results showed the relationship between affinity and hydration energy of the anions. Besides, the amount of released organic modifier may be associated with the species of target anions. Compared with poorly hydrated anions of smaller size, a fully hydrated anion of larger size would be less able to penetrate into the head group region of a cationic surfactant for effective neutralization of the bilayer (Leontidis et al., 2002). As a result, the original counter ion would be readily replaced with those poorly hydrated anions to form tight binding and to minimize the repulsive force, inhibiting the dissociation of adsorbed surfactant back into the bulk aqueous solution (Li et al., 1997). Thus, to compareit is of great significance to evaluate the adsorption characteristic of inorganic different oxoanions, which include hazardous heavy metals and are often mobile in environments, on OMt is of great significance.
Methods
10 g of Mt with a cation exchange capacity (CEC) of 111.4 meq/100g was dispersed in 500 mL deionized water at room temperature for 2 h. Separately, 44.56 mmol of HDPy-Cl, corresponding to four times the CEC of Mt, was dissolved in 500 mL deionized water. The HDPy-Cl solution was then slowly added into the Mt suspension and the mixture was vigorously stirred for 24 h. The obtained solid was separated by centrifugation, freeze-dried, ground, and sieved.
1.0 mmol/L Na2MoO4, Na2SO4, NaClO4, NaReO4, NaI, KIO3, NaBrO3, NaNO3, Na2SeO3, Na2SeO4, Na2CrO4, Na2WO4, NaVO3, and KH2AsO4 were separately prepared, without pH adjustment. Forty mg HDPy/Mt was dispersed in 50 mL target anion-bearing solution and then shaken at 25 °C for 24 h. The pH and Eh of solutions before and after adsorption were measured. After the mixture was filtered through a 0.45-μm filter, the obtained solution was provided to determine the residual anion concentration in equilibrium using ion chromatography (Dionex ICS-2100, Sunnyvale, CA, USA), and inductively coupled plasma atomic emission spectroscopy (ICP-AES, Seiko Instruments, Chiba, Japan). The amount of released HDPy was determined by UV-vis spectroscopy (UV-2450, Shimadzu, Tokyo, Japan) at 258 nm. The solid was dried and supplied for X-ray diffraction (XRD) measurement to investigate changes in interlayer space.
Results and Discussion
Based on pH and Eh values before and after adsorption, chemical speciation of all anions was not expected to change during adsorption on HDPy/Mt. Among the selected anions, with the exception of IO3, H2AsO4, and CrO42, monovalent anions showed higher adsorption capacities and selectivities on HDPy/Mt than divalent anions. Besides, higher adsorption capacities normally corresponded to the lower amounts of HDPy release as support by the negligible HDPy release after adsorption of monovalent anions. Release of HDPy led to the decrease of interlayer distance as proved by XRD patterns. The released HDPy presented in different forms in solution, which depends on anion species. After adsorption of the anions showing high affinity to HDPy/Mt, HDPy were slightly released in form of HDPy-target anion such as HDPy-NO3, whereas significantly released in form of HDPy-Cl for poorly selective anions which are mainly highly hydrated divalent anions. Hydration of counter ion (Cl) was the driving force of ion exchange, which accounted for the adsorption of inorganic anions on HDPy/Mt. Desorption-adsorption made partial contribution to adsorption of several anions. Dehydration of anions with stronger hydration shells consumed more energy to intercalate into HDPy/Mt and resulted in the decrease of selectivity. Moreover, the increase of dielectric constant of organic-like interlayer phase derived from HDPy release was another key factor influencing adsorption of anions on HDPy/Mt.
Conclusions
Monovalent anions normally showed higher adsorption capacities and selectivities and led to lower HDPy release on HDPy/Mt than divalent anions, because of the higher energy consumption for dehydration of divalent anions. Hydration of counter ion (Cl) was the driving force of anions adsorption on HDPy/Mt. Selectivity of HDPy/Mt to anions depended not only on the change in anionic size in different phases (from r1 in aqueous solution to r2 in the organic solvent-like OMt), but also variation of dielectric constant after HDPy release.
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31. Binglin Guo, Keiko Sasaki, Removal of selenate by co-precipitate with ettringite in aqueous solution, Goldschmidt 2016, 2016.06, Selenium can be toxicant with high concentrations in aqueous solutions. and 79Se isotope is also one of the radionuclides present in high-level nuclear wastes with long half life periods. Because of negative surface charge of the most minerals in earth crust. S, selenate is quite mobile in ground waters.
Ettringite (Ca6Al2(SO4)3(OH)12•26H2O) is known as one of products formed in an early stage during hydration of Portland cement and can also occur naturally. The structure of ettringite consists consisting of column parts ({consisting of {Ca6[Al(OH)6]2・24H2O]} 6+) and channel parts (including tetrahedral SO42- and H2O). It has been reported that Ca2+, Al3+ and SO42- can be replaced with nuclide species. Selenate can also be partly and fully substituted with sulfate.
In the present work, we have investigated in on immobilization of selenate by co-precipitation with ettringite. , resulting in different types of ettringite by mixing stoichiometric amounts of Ca(OH)2 and Al2(SO4)3, AlCl3 with Na2SeO4 in ultrapure water. Using Ca(OH)2 and AlCl3 as Ca and Al sources, selenate was substituted with sulfate in ettringite, giving providing the highest concentration of Se in the solid residues. The potential stability of selenate-substituted ettringite has been assessed by exposing in aqueous solution under the different pHs. It is was found that more than 90% of selenate was immobilized in the structure of ettringite under the initial pH value from 5 to 11.This suggests that selenate can be effectively immobilized in the structure of ettringite in wide range of pH.
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32. Keiko Sasaki, Application of iron-oxidizing archeaon to biohydrometallurgy of enargite, Goldschmidt 2016, 2016.06, Microbial oxidation of Fe2+ and reduced sulfur species is a basic reaction to dissolve sulfides in biohydrometallurgy. Although chalcopyrite (CuFeS2) is known as a main Cu resource, arsenic-bearing copper sulfides like enargite (Cu3AsS4) are often accompanied in deep copper ore deposits. To recover Cu even from arsenic-bearing coper sulfides, arsenic immobilization should be considered. Acidianus brierleyi, which is an iron-oxidizing hyperthermophilic archeaon, was applied to bioleaching of enargite at 70˚C in the presence of Fe2+ ions as an energy source in a lab scale to find the optimal condition and elucidate the mechanism under the optimal condition. By controling Fe2+ concentrations and pulp density of enargite, 91% of Cu recovery with immobilizing 94% of arsenic species was concurrently achieved. According to the comprehensive interpretation of XANES As K-edge, XRD, and SEM-EDX, the main storage of arsenic was scorodite (FeAsO4), which is in the most ideal form because of high stability and high density of arsenic. Although the released species from enargite is arsenite and A. brierleyi does not oxidize arsenite into arsenate, arsenic was mainly immobilized as scorodite under the optimized condition. Based on spectroscopic and microscopic observation of not only bulk reaction but also interface reaction involving biological tissues, the reaction mechanism is discussed..
33. Kojo Konadu, Sasaki Keiko, Kwadwo Osseo-Asare, Grace OFORI-SARPONG, Activated carbon as surrogate for carbonaceous matter in gold ores: degradation via enzyme treatment, International Conference of the African Materials Research Society , 2015.12.
34. Xiangchun LIU, Tsuyoshi Hirajima, Moriyasu Nonaka, Sasaki Keiko, Effect of Hydrothermal Treatment Assisted with Mechanical Expression on Pore Structure of Loy Yang Lignite, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
35. Masahito TANAKA, Tsuyoshi Hirajima, Sasaki Keiko, Kazuhiro HATANO, Atsuko OHATA, Naoko Okibe, Crystallization of Biogenic Scorodite (FeAsO4·2H2O) from Acidic Wastewaters Containing Diluted Concentrations of Highly Toxic Arsenite, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
36. Yuken FUKANO, Tsuyoshi Hirajima, Sasaki Keiko, Naoko Okibe, Mechanism of Indirect Chemical Oxidation of Highly Toxic As(III), in The Presence of Carbon Fiber via Direct Microbial Fe(II) Oxidation, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
37. Yusei MASAKI, Tsuyoshi Hirajima, Sasaki Keiko, Hajime Miki, Naoko Okibe, Bioleaching of Highly Refractory Chalcopyrite in The Presence of Silver Catalyst, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
38. Keishi OYAMA, Tsuyoshi Hirajima, Sasaki Keiko, Hajime Miki, Naoko Okibe, Selective Bioleaching of Enargite (Cu3AsS4) over Pyrite (FeS2) for Cu Recovery, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
39. Daisuke NAKAYAMA, Tsuyoshi Hirajima, Sasaki Keiko, Naoko Okibe, Investigating Factors Affecting The Size and Distribution of Bio-Pd(0) Nanoparticles, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
40. Akinobu IGUCHI, Hajime Miki, Tsuyoshi Hirajima, Sasaki Keiko, Effect of Silver Addition in Potential Controlled Solution on Dissolution Rate of Enargite, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
41. Shugo NAGATO, Tsuyoshi Hirajima, Sasaki Keiko, Effect of Al3+ Additives on Fluoride Removal by (Co-)Precipitation as Apatites, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
42. Hidekazu MATSUOKA, Tsuyoshi Hirajima, Sasaki Keiko, Hajime Miki, Various Surface Treatment Techniques of Molybdenite and Chalcopyrite, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
43. Kenta TOSHIYUKI, Tsuyoshi Hirajima, Sasaki Keiko, Co-Precipitation of Boron with Hydroxyapatite Using Various Ca Sources, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
44. Santisak KITJANUKIT, Tsuyoshi Hirajima, Sasaki Keiko, Naoko Okibe, Application of Fe(II)-Oxidizing and Fe(III)-Reducing Abilities of The Thermo-Acidophilic Archaeon, Sulfolobus Tokodaii for Bioleaching of Waste Printed Circuit Boards (WPCB) and Formation of Pd(0)-Nanoparticles, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
45. Yu TAKAKI, Paulmanickam KOILRAJ, Tsuyoshi Hirajima, Sasaki Keiko, Delaminated Layered Double Hydroxide Nanosheets for Arsenate Immobilization, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
46. Katsutoshi TSUTSUMI, Tsuyoshi Hirajima, Sasaki Keiko, Naoko Okibe, Effect of Fe(III)-Reducing Microbes on Organic Acid Leaching of Nickel Laterite, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
47. Takahiro MATSUMOTO, Tsuyoshi Hirajima, Sasaki Keiko, Naoko Okibe, Formation of Pt(0) Nanoparticles Using the Extremely Acidophilic Fe(III)-Reducing Bacteria, International Symposium on Earth Science and Technology 2015 (CINEST), 2015.12.
48. Yusei MASAKI, Tsuyoshi Hirajima, Sasaki Keiko, Naoko Okibe, Current Situation of Heavy Metal-Pollution in Developing Country, International Forum for Green Asia 2015, 2015.11.
49. Masahito TANAKA, Tsuyoshi Hirajima, Sasaki Keiko, Naoko Okibe, Microbial Population Structure Analysis of Tsukahara Hot Spring in Oita and Search for Effective Microbes for Biomining and Bioremediation, International Forum for Green Asia 2015, 2015.11.
50. Wuhui Luo, Tsuyoshi Hirajima, Sasaki Keiko, Adsorption of Perchlorate on Slurry-like Modified Montmorillonite by Hexadecylpyridinium Chloride, The 6th Asian Conference on Colloid and Interface Science (ACCIS 2015), 2015.11.
51. KOILRAJ PAULMANICKAM, Sasaki Keiko, Amino acid anchored layered double hydroxide nanosheets and their Co2+ cation sorption behavior, The 6th Asian Conference on Colloid and Interface Science (ACCIS 2015), 2015.11.
52. Tsuyoshi Hirajima, Osamu ICHIKAWA, G.P.W. SUYANTARA, Hajime Miki, Sasaki Keiko, Ahmed Mohamed Elmahdy Ahmed MOHAMED, Seawater Divalent Cations (MgCl2 and CaCl2) Effect on the Flotation of Molybdenite and Chalcopyrite, Flotation ‘15, 2015.11.
53. Tsuyoshi Hirajima, Hidekazu MATSUOKA, Hajime Miki, Ahmed Mohamed Elmahdy Ahmed MOHAMED, Sasaki Keiko, Study of Selective Flotation of Chalcopyrite and Molybdenite with Various Oxidation, Flotation ‘15, 2015.11.
54. Widi Astuti, Tsuyoshi Hirajima, Sasaki Keiko, Naoko Okibe, Utilization of Metabolic Citric Acid from Aspergillus niger Using Corn Starch in the Nickel Leaching of Indonesian Saprolitic Ore, 19th International Biohydrometallurgy Symposium 2015 (IBS 2015), 2015.10.
55. Sasaki Keiko, (invited) Spectroscopic and microscopic investigation in biohydrometallurgy , International Biohydrometallurgy Symposium 2015 (IBS 2015), 2015.10.
56. Kojo Konadu, Sasaki Keiko, Kwadwo Osseo-Asare, Bio-modification of carbonaceous matters in gold ore: Model experiments using powdered activated charcoal and cell-free extracts of Phanerochaete chrysosporium, 19th International Biohydrometallurgy Symposium 2015, 2015.10.
57. Naoko Okibe, Masahito Tanaka, Sasaki Keiko, Tsuyoshi Hirajima, Effect of Cu(II) on bio-scorodite crystallization using Acidianus brierleyi, International Biohydrometallurgy Symposium 2015, 2015.10.
58. Sasaki Keiko, Spectroscopic and Microscopic Investigation for Biohydrometallurgy, 21st International Biohydrometallurgy Symposium (IBS 2015), 2015.10.
59. Yusei MASAKI, Microbial Community Structure Analysis of Blood Pond Hell Hot Spring in Japan and Search for Metal-reducing Microbes, 21st International Biohydrometallurgy Symposium (IBS 2015), 2015.10.
60. Sasaki Keiko, Bio-modification of carbonaceous matters in gold ore: Model experiments using powdered activated charcoal and cell-free extracts of Phanerochaete chrysosporium, 21st International Biohydrometallurgy Symposium (IBS 2015), 2015.10.
61. Yu Takaki, Xinhong Qiu, Tsuyoshi Hirajima, Sasaki Keiko, Removal mechanism of arsenate by hydrocalumite depending on arsenate concentration, EUROCLAY 2015, 2015.07.
62. Wuhui Luo, Sasaki Keiko, Synthesis of surfactant-modified montmorillonites for adsorption of perchlorate, EUROCLAY 2015, 2015.07.
63. Akihiro Inoue, Wuhui Luo, Sasaki Keiko, Sequential Modification of Montmorillonite Using DDAC and BDOAC for Adsorption of Perchlorate, International Symposium Zeolite and Microporous Crystals 2015 (ZMPC 2015), 2015.07.
64. Paulmanickam KOILRAJ, Sasaki Keiko, Fe3O4@MgAl-NO3 Layered Double Hydroxide as Magnetically Separable Phosphate Sorbent From Aqueous Solution, International Symposium on Zeolite and Microporous Crystals 2015(ZMPC2015), 2015.07.
65. Yu TAKAKI, Paulmanickam KOILRAJ, Tsuyoshi Hirajima, Sasaki Keiko, Adsorption Characteristic of Arsenate on Delaminated Layered Double Hydroxides, Euroclay2015, 2015.07.
66. Akihiro INOUE, Wuhui LUO, KWADWO OSSEO-ASARE, Tsuyoshi Hirajima, Sasaki Keiko, Sequential Modification of Montmorillonite Using DDAC and BDOAC for Adsorption of Perchlorate, International Symposium on Zeolite and Microporous Crystals 2015(ZMPC2015), 2015.06.
67. Xinhong Qiu, Sasaki Keiko, Synthesis of layered double hydroxide intercalated with gluconate for removal of boron species, 4th International Conference on Multifunctional Hybride and Nanomaterials (Hybride Materials 2015), 2015.03.
68. Wuhui Luo, Sasaki Keiko, Evaluation of BDTAC, DDAC and BDOAC-modified montmorillonites for perchlorate removal, Hybride Materials 2015, 2015.03.
69. KOILRAJ PAULMANICKAM, Sasaki Keiko, Srinivasan KANNAN, Amino acid assisted solvothermal synthesis of layered double hydroxides, Hybride Materials 2015, 2015.03.
70. Sasaki Keiko, Biohydrometallurgy of enargite: A spectroscopic investigation of bioleaching by thermoacidophilic iron-oxidizing archaeon, Acidianus brierleyi , IGO-2015, 2015.01.
71. Akinobu IGUCHI, Hajime MIKI, Tsuyoshi HIRAJIMA, Keiko SASAKI, Mitsuru SAWADA, The Effect of Solution Potential and Silver Ion Addition on Dissolution Rate of Enargite, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
72. Yu TAKAKI, Xinhong QIU, Tsuyoshi HIRAJIMA, Keiko SASAKI, Sorption Mechanism of Arsenate onto Tri-Metallic Hydrocalumite, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
73. Mutia Dewi YUNIATI, Tsuyoshi HIRAJIMA, Hajime MIKI, Keiko SASAKI, Silica Covering Layer on the Chalcopyrite Surface: Electrochemical Behaviors and Depression Effect on Copper-Molybdenum Flotation, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
74. Akihiro INOUE, Wuhui LUO, Tsuyoshi HIRAJIMA, Keiko SASAKI, Sequential Modification of Montmorillonite Using DDAC and BDOAC for Removal of Perchlorate: Effect of DDAC Dosage, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
75. Takahiro MATSUMOTO, Tsuyoshi HIRAJIMA, Keiko SASAKI, Naoko OKIBE, Microbial Synthesis of Platinum Nanoparticles Using Extremely Acidophilic Iron-Reducing Bacteria, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
76. Yusei MASAKI, Katsutoshi TSUTSUMI, Tsuyoshi HIRAJIMA, Keiko SASAKI, Naoko OKIBE, Microbial Community Structure Analysis of Chinoike-Jigoku (Blood-Pond Hell) Hot Spring and Search for Useful Microorganisms Applicable to Bioremediation of Heavy Metals, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
77. Kenta TOSHIYUKI, Keiko IDETA, Jin MIYAWAKI, Dabo Ismaila,Tsuyoshi HIRAJIMA, Keiko SASAKI, Mechanism of Boric Acid/Borate Removal in Co-Precipitation with Hydroxyapatite and Evaluation of Maximum Sorption Density, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
78. Daisuke NAKAYAMA, Tsuyoshi HIRAJIMA, Keiko SASAKI, Naoko OKIBE, Formation of Bio-Pd(0) Nanoparticles Using Fe(III)-Reducing, Extremely Acidophilic Bacteria, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
79. Hidekazu MATSUOKA, Tsuyoshi HIRAJIMA, Keiko SASAKI, Hajime MIKI, Mitsuru SAWADA, Electrochemical Treatment of Molybdenite and Chalcopyrite, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
80. Widi ASTUTI, Tsuyoshi HIRAJIMA, KeikoSASAKI, Naoko OKIBE, Effect of Leaching Reagent on the Atmospheric Dissolution of Indonesian Saprolitic Ore, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
81. Shiori MORISHITA, Tsuyoshi HIRAJIMA, Keiko SASAKI, Naoko OKIBE, Effect of Cu(II) on Microbial Scorodite Crystallization from As(III)-Containing Copper Refinery Waste-Waters, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
82. Mari YOSHIDA, Xinhong QIU, Tsuyoshi HIRAJIMA, Keiko SASAKI, Comparison of Mg-Al and Mg-Fe Types of Ldhs Synthesized from Calcined Dolomite in Arsenate Sorption, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
83. Masahito TANAKA, Yuta YAMAJI, Yuken FUKANO, Tsuyoshi HIRAJIMA, Keiko SASAKI, Mitsuru SAWADA, Naoko OKIBE, Biooxidation of Alaskan Refractory Gold Ore Concentrates, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
84. Yuken FUKANO, Tsuyoshi HIRAJIMA, Keiko SASAKI, Naoko OKIBE, Arsenite Removal Using Acidophilic Fe(II)-Oxidizing Bacteria in the Presence of Carbon Fiber, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
85. Sasaki Keiko, Sequential modification of montmorillonite using DDAC and BDOAC for removal of perchlorate: Effect of DDAC dosage
, CINEST 2014, 2014.12.
86. Shugo NAGATO, Kenta TOSHIYUKI, Takeshi KAWASHIMA, Tsuyoshi Hirajima, Sasaki Keiko, Enhancement in precipitation rate of fluoroapatite by Mg2+ additives: Advanced utilization of hydrate of calcined dolomite in water treatment, International Symposium on Earth Science and Technology 2014 (CINEST), 2014.12.
87. Hajime MIKI, Tsuyoshi HIRAJIMA, Mutia Dewi YUNIATI, Keiko SASAKI, Suppression of Pyrite and Arsenopyrite Oxidation by Silica Coating: Electrochemical aspects and the mechanism, XXVII International Mineral Processing Congress (IMPC 2014), 2014.10.
88. Himawan PETRUS, Tsuyoshi HIRAJIMA, Keiko SASAKI, Hideyuki OKAMOTO, Separation Mechanism of Tennantite and Chalcopyrite with Flotation after Oxidation Using Oxygen, XXVII International Mineral Processing Congress (IMPC 2014), 2014.10.
89. Tsuyoshi HIRAJIMA, Masanori MORI, Osamu ICHIKAWA, Keiko SASAKI, Hajime MIKI, Mitsuru SAWADA, Selective Flotation of Chalcopyrite and Molybdenite by Surface Oxidation , XXVII International Mineral Processing Congress (IMPC 2014), 2014.10.
90. アストゥティウィディ, 平島剛, 笹木圭子, 沖部奈緒子, 特性評価およびスラウェシ島(インドネシア)からのサプロライトラテライトの大気クエン酸浸出:ミネラル溶出挙動への洞察, 平成26年度資源・素材関係学協会合同秋季大会, 2014.09.
91. Luo Wuhui, 笹木圭子, 平島剛, ベンジルオクタデシルアンモニウムクロリドにより修飾されたモンモリロナイトの特性評価およびその過塩素酸イオン除去への応用, 平成26年度資源・素材関係学協会合同秋季大会, 2014.09.
92. Yuniati Mutia Dewi, 平島剛, 三木一, 笹木圭子, シリカコーティングによる黄鉄鉱の酸化抑制の検証に関する電気化学インピーダンス法の有用性, 平成26年度資源・素材関係学協会合同秋季大会, 2014.09.
93. Naoko Okibe, Masahito Tanaka, Mitsuru Sawada, Keiko Sasaki, Tsuyoshi Hirajima, Biooxidation of Alaskan refractory gold ore concentrates, Biohydrometallurgy `14, 2014.06.
94. Widi ASTUTI, Tsuyoshi HIRAJIMA, Keiko SASAKI, Naoko OKIBE, 大気圧下でのクエン酸によってハルマヘラ島 ( インドネシア) からの
低グレード褐鉄鉱鉱石のニッケル抽出, 一般社団法人資源・素材学会 平成26年度春季大会, 2014.03.
95. Mutia Dewi YUNIATI, Tsuyoshi HIRAJIMA, Hajime MIKI, Keiko SASAKI, シリカコーティングによる硫化鉱の酸化挙動, 一般社団法人資源・素材学会 平成26年度春季大会, 2014.03.
96. Keiko Sasaki, Qianqain Yu, Synthesis of biogenic Mn oxide and its engineering application to Li ion sieve, 247th American Chemical Society, 2014.03.
97. Osamu ICHIKAWA, Tsuyoshi HIRAJIMA, Masanori MORI, Keiko SASAKI, Hajime MIKI, Mitsuru SAWADA, XPS and AFM Analysis of Plasma Oxidized Chalcopyrite and Molybdenite for New Selective Flotation Technique, International Conference on Biological, Civil and Environmental Engineering (BCEE-2014), 2014.03.
98. Mari YOSHIDA, Xinhong QIU, Tsuyoshi HIRAJIMA, Keiko SASAKI, Synthesis of Layered Double Hydroxides Derived from Dolomite Using Microwaving Assisted Hydrothermal Treatment for Removal of Arsenate, International Conference on Biological, Civil and Environmental Engineering (BCEE-2014), 2014.03.
99. Masahito TANAKA, Mitsuru SAWADA, Keiko SASAKI, Tsuyoshi HIRAJIMA, Naoko OKIBE, Biooxidation of Refractory Gold Ore Concentrates using Moderately Thermophilic, Acidophilic Bacteria, International Conference on Biological, Civil and Environmental Engineering (BCEE-2014), 2014.03.
100. Naoki Higashidani, Takashi Kaneta, Nobuyuki Takeyasu, Naoko Okibe, Keiko Sasaki, Speciation of Arsenic by ICP-OES Coupled with Flow Injection Pretreatment Using an Anion Exchange Mini-Column, Asianalysis 2013, 2013.08.
101. YU QIANQIAN, Emiko MORIOKA, Adrian WRIGHT, Keiko Sasaki, Structure Analysis of Lithium Ion Sieve from Biogenic Mn Oxide, 資源・素材学会春季大会, 2012.03.
102. YU QIANQIAN, Emiko MORIOKA, Adrian WRIGHT, Keiko Sasaki, Synthesis and Structure Refinement of Lithium Manganese Oxide Spinel from Biogenic Mn Oxide, 化学系学協会北海道冬季研究会 , 2012.02.
103. Xinhong QIU, Sayo MORIYAMA, Keiko Sasaki, Effect of pH on the Sorption of Borate onto MgO, 化学系学協会北海道冬季研究会 , 2012.02.
104. Keiko Sasaki, Characteristics of Hydrothermally-Upgraded Peat and Its Application for Fuel Based Combustion, 10th International Symposium on East Asian Resources Recycling Technology, 2009.11.
105. Microbiological influence on mineralization of manganese precipitaes in the Sanbe Hot
Spring, Shimane Prefecture.
106. Sorption of heavy metal ions to biogenic minerals produced by Mn-oxidizing microorganisms.
107. Development of permeable reactive barrier technology in North America.