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| 1.
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Habibullah, M. ; Rahman, Ismail M. M. ; Uddin, M. Ashraf ; Iwakabe, Koichi ; Azam, Anisul ; Hasegawa, Hiroshi
概要:
Densities and viscosities of the binary systems of phenylmethanol with 2-butanone were measured for the entire compositi
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on range at T = (303.15, 308.15, 313.15, 318.15, and 323.15) K and at the atmospheric pressure. The excess molar volumes were derived from the experimental data and were fitted with the Redlich-Kister equation to obtain their coefficients and standard deviations. The Grunberg-Nissan equation was used to correlate the viscosity data. Furthermore, kinematic viscosities were compared with those predicted by the UNIFAC-VISCO model. The cause of relatively large deviations between the experimental and predicted kinematic viscosities was explored by comparing the combinatorial and residual terms of the UNIFAC-VISCO model. © 2011 American Chemical Society.
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| 2.
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Rahman, Ismail M. M. ; Furusho, Yoshiaki ; Begum, Zinnat A. ; Sabarudin, Akhmad ; Motomizu, Shoji ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
A simple flow-based method was developed for the simultaneous separation of certain transition metal ions (Co, Ni, Cu, Z
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n, Cd) from aqueous systems, which ions show ecotoxic effects when present at elevated concentrations. A silica-gel-bonded macrocycle system, commonly known as molecular recognition technology (MRT) gel, was used for solid phase extraction (SPE) of the target analytes. The collection behavior of the MRT-SPE system was studied based on pH. Fortified deionized water samples containing 250 μg L-1 of each of the elements were treated at the flow rate of 1 mL min-1. The collected analytes were then eluted by 3 M HNO3 and analyzed using inductively coupled plasma spectrometry. Detection limits of the proposed technique were in the range of 0.004-0.040 μg L-1 for the studied metal ions. The validity of this separation technique was checked with spiked 'real' water samples, which produced satisfactory recoveries of 96-102%. The non-destructive nature and highly selective ion-extraction capability of the SPE material are the most important aspects of the proposed method and they are the main focus of this paper. © 2011 © Versita Warsaw and Springer-Verlag Wien.
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| 3.
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Hasegawa, Hiroshi ; Rahman, Ismail M. M. ; Nakano, Masayoshi ; Begum, Zinnat A. ; Egawa, Yuji ; Maki, Teruya ; Furusho, Yoshiaki ; Mizutani, Satoshi
概要:
Aminopolycarboxylate chelants (APCs) are extremely useful for a variety of industrial applications, including the treatm
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ent of toxic metal-contaminated solid waste materials. Because non-toxic matrix elements compete with toxic metals for the binding sites of APCs, an excess of chelant is commonly added to ensure the adequate sequestration of toxic metal contaminants during waste treatment operations. The major environmental impacts of APCs are related to their ability to solubilize toxic heavy metals. If APCs are not sufficiently eliminated from the effluent, the aqueous transport of metals can occur through the introduction of APCs into the natural environment, increasing the magnitude of associated toxicity. Although several techniques that focus primarily on the degradation of APCs at the pre-release step have been proposed, methods that recycle not only the processed water, but also provide the option to recover and reuse the metals, might be economically feasible, considering the high costs involved due to the chelants used in metal ion sequestration. In this paper, we propose a separation process for the recovery of metals from effluents that contain an excess of APCs. Additionally, the option of recycling the processed water using a solid phase extraction (SPE) system with an ion-selective immobilized macrocyclic material, commonly known as a molecular recognition technology (MRT) gel, is presented. Simulated effluents containing As(V), Cd(II), Cr(III), Pb(II) or Se(IV) in the presence of APCs at molar ratios of 1:50 in H2O were studied with a flow rate of 0.2mL min-1. The 'captured' ions in the SPE system were quantitatively eluted with HNO3. The effects of solution pH, metal-chelant stability constants and matrix elements were assessed. Better separation performance for the metals was achieved with the MRT-SPE compared to other SPE materials. Our proposed technique offers the advantage of a non-destructive separation of both metal ions and chelants compared to conventional treatment options for such effluents. © 2011 Elsevier Ltd.
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| 4.
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論文
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Rahman, Ismail M. M. ; Furusho, Yoshiaki ; Begum, Zinnat A. ; Sabarudin, Akhmad ; Motomizu, Shoji ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
A simple flow-based method was developed for the simultaneous separation of certain transition metal ions (Co, Ni, Cu, Z
…
n, Cd) from aqueous systems, which ions show ecotoxic effects when present at elevated concentrations. A silica-gel-bonded macrocycle system, commonly known as molecular recognition technology (MRT) gel, was used for solid phase extraction (SPE) of the target analytes. The collection behavior of the MRT-SPE system was studied based on pH. Fortified deionized water samples containing 250 ìg L-1 of each of the elements were treated at the flow rate of 1 mL min-1. The collected analytes were then eluted by 3 M HNO3 and analyzed using inductively coupled plasma spectrometry. Detection limits of the proposed technique were in the range of 0.004-0.040 ìg L-1 for the studied metal ions. The validity of this separation technique was checked with spiked 'real' water samples, which produced satisfactory recoveries of 96-102%. The non-destructive nature and highly selective ion-extraction capability of the SPE material are the most important aspects of the proposed method and they are the main focus of this paper. © Versita Sp. z o.o.
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| 5.
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Begum, Zinnat A. ; Rahman, Ismail M. M. ; Tate, Yousuke ; Sawai, Hikaru ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
Ex situ soil washing with synthetic extractants such as, aminopolycarboxylate chelants (APCs) is a viable treatment alte
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rnative for metal-contaminated site remediation. EDTA and its homologs are widely used among the APCs in the ex situ soil washing processes. These APCs are merely biodegradable and highly persistent in the aquatic environments leading to the post-use toxic effects. Therefore, an increasing interest is focused on the development and use of the eco-friendly APCs having better biodegradability and less environmental toxicity. The paper deals with the results from the lab-scale washing treatments of a real sample of metal-contaminated soil for the removal of the ecotoxic metal ions (Cd, Cu, Ni, Pb, and Zn) using five biodegradable APCs, namely [S,S]-ethylenediaminedisuccinic acid, imminodisuccinic acid, methylglycinediacetic acid, DL-2-(2-carboxymethyl) nitrilotriacetic acid (GLDA), and 3-hydroxy-2,2'-iminodisuccinic acid. The performance of those biodegradable APCs was evaluated for their interaction with the soil mineral constituents in terms of the solution pH and metal-chelant stability constants, and compared with that of EDTA. Speciation calculations were performed to identify the optimal conditions for the washing process in terms of the metal-chelant interactions as well as to understand the selectivity in the separation ability of the biodegradable chelants towards the metal ions. A linear relationship between the metal extraction capacity of the individual chelants towards each of the metal ions from the soil matrix and metal-chelant conditional stability constants for a solution pH greater than 6 was observed. Additional considerations were derived from the behavior of the major potentially interfering cations (Al, Ca, Fe, Mg, and Mn), and it was hypothesized that use of an excess of chelant may minimize the possible competition effects during the single-step washing treatments. Sequential extraction procedure was used to determine the metal distribution in the soil before and after the extractive decontamination using biodegradable APCs, and the capability of the APCs in removing the metal ions even from the theoretically immobilized fraction of the contaminated soil was observed. GLDA appeared to possess the greatest potential to decontaminate the soil through ex situ washing treatment compared to the other biodegradable chelants used in the study. © 2012 Elsevier Ltd.
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| 6.
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Hasegawa, Hiroshi ; Rahman, Ismail M. M. ; Egawa, Yuji ; Sawai, Hikaru ; Begum, Zinnat A. ; Maki, Teruya ; Mizutani, Satoshi
概要:
The metal indium termed as 'rare' in recent days due to its increasing demand in the formulations of electronic and ener
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gy-related gadgets and scarce supply resources. Hence, the attempts to recover indium from the secondary resources, such as recycling of the indium abundant waste materials, received increasing research focus. The major indium consumption happens in the form of indium tin oxide (ITO) that used for the fabrication of liquid-crystal displays (LCD). The end-of-life LCD screens, termed as ITO-glass hereafter, are an emerging contributor to the global e-waste load and can be an impending secondary source of indium. The present work introduces a new technique for the treatment of waste ITO-glass using aminopolycarboxylate chelants (APCs) in combination with a mechanochemical treatment process. APCs are capable of forming stable complexes with the indium deposited on the ITO-glass, whereas the rate of recovery was not substantial. The mechanochemical treatment induces the destruction of crystalline structure with which the ITO fragments are attached and facilitate the increased indium dissolution with the chelants. The increase was more prominent followed by a decrease in the cumulative processing time from 24 to 6. h when the vitrified ITO-glass was simultaneously crushed and washed with the chelants. The extraction of indium was better at the acidic pH condition, and it was further intensified when the operating temperature was raised to ≥ 120°C. © 2012 Elsevier B.V.
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| 7.
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Begum, Zinnat A. ; Rahman, Ismail M. M. ; Tate, Yousuke ; Egawa, Yuji ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
The protonation and complex formation equilibria of two biodegradable aminopolycarboxylate chelants {dl-2-(2-carboxymeth
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yl)nitrilotriacetic acid (GLDA) and 3-hydroxy-2,2′-iminodisuccinic acid (HIDS)} with Ni 2+, Cu 2+, Zn 2+, Cd 2+ and Pb 2+ ions were investigated using the potentiometric method at a constant ionic strength of I = 0.10 mol·dm -3 (KCl) in aqueous solutions at 25 ± 0.1 °C. The stability constants of the proton-chelant and metal-chelant species for each metal ion were determined, and the concentration distributions of various complex species in solution were evaluated for each ion. The stability constants (log 10K ML) of the complexes containing Ni 2+, Cu 2+, Zn 2+, Cd 2+ and Pb 2+ ions followed the identical order of log 10K CuL > log 10K NiL > log 10K PbL > log 10K ZnL > log 10K CdL for either GLDA (13.03 > 12.74 > 11.60 > 11.52 > 10.31) or HIDS (12.63 > 11.30 > 10.21 > 9.76 > 7.58). In each case, the constants obtained for metal-GLDA complexes were larger than the corresponding constants for metal-HIDS complexes. The conditional stability constants (log 10 {Mathematical expression}) of the metal-chelant complexes containing GLDA and HIDS were calculated in terms of pH, and compared with the stability constants for EDTA and other biodegradable chelants. © 2012 Springer Science+Business Media New York.
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| 8.
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論文
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Rahman, Ismail M. M. ; Islam, M. Monirul ; Hossain, M. Mosharraf ; Hossain, M. Shahadat ; Begum, Zinnat A. ; Chowdhury, Didarul A. ; Chakraborty, Milan K. ; Rahman, M. Azizur ; Nazimuddin, Mohammad ; Hasegawa, Hiroshi
概要:
金沢大学理工研究域物質化学系<br />The concern over ensuing freshwater scarcity has forced the developing countries to delve for altern
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ative water resources. In this study, we examined the potential of stagnant surface water bodies (SSWBs) as alternative freshwater resources in the densely populated Chittagong metropolitan area (CMPA) of Bangladesh-where there is an acute shortage of urban freshwater supply. Water samples were collected at 1-month intervals for a period of 1 year from 12 stations distributed over the whole metropolis. Samples were analyzed for pH, water temperature (WTemp), turbidity, electrical conductivity (EC), total dissolved solids, total solids, total hardness, dissolved oxygen (DO), chloride, orthophosphates, ammonia, total coliforms (TC), and trace metal (Cd, Cr, Cu, Pb, As, and Fe) concentrations. Based on these parameters, different types of water quality indices (WQIs) were deduced. WQIs showed most of CMPA-SSWBs as good or medium quality water bodies, while none were categorized as bad. Moreover, it was observed that the minimal water quality index (WQIm), computed using five parameters: WTemp, pH, DO, EC, and turbidity, gave a reliable estimate of water quality. The WQIm gave similar results in 72% of the cases compared with other WQIs that were based on larger set of parameters. Based on our finding, we suggest the wider use WQIm in developing countries for assessing health of SSWBs, as it will minimize the analytical cost to overcome the budget constraints involved in this kind of evaluations. It was observed that except turbidity and TC content, all other quality parameters fluctuated within the limit of the World Health Organization suggested standards for drinking water. From our findings, we concluded that if the turbidity and TC content of water from SSWBs in CMPA are taken care of, they will become good candidates as alternative water resources all round the year. © 2010 Springer Science+Business Media B.V.
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| 9.
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論文
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Rahman, Ismail M. M. ; Uddin, M. Ashraf ; Iwakabe Koichi ; Adhikhari, Anath B. ; Majid, M. Abdul ; Hasegawa, Hiroshi
概要:
金沢大学理工研究域物質化学系<br />Viscosities of binary liquid mixtures of butan-2-one with benzene were measured at a number of mole
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fractions at T = (303.15, 313.15, and 323.15) K and atmospheric pressure. The viscometric behavior is discussed on the basis of structural and geometrical effects between the components. In addition, kinematic viscosities were calculated using the UNIFAC-VISCO model. The predicted kinematic viscosities are in good agreement with the experimental ones. © 2011 American Chemical Society.
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| 10.
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論文
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Rahman, Ismail M. M. ; Islam, M. Monirul ; Hossain, M. Mosharraf ; Hossain, M. Shahadat ; Begum, Zinnat A. ; Chowdhury, Didarul A. ; Chakraborty, Milan K. ; Rahman, M. Azizur ; Nazimuddin, M. ; Hasegawa, Hiroshi
概要:
金沢大学理工研究域物質化学系<br />The concern over ensuing freshwater scarcity has forced the developing countries to delve for altern
…
ative water resources. In this study, we examined the potential of stagnant surface water bodies (SSWBs) as alternative freshwater resources in the densely populated Chittagong metropolitan area (CMPA) of Bangladesh-where there is an acute shortage of urban freshwater supply. Water samples were collected at 1-month intervals for a period of 1 year from 12 stations distributed over the whole metropolis. Samples were analyzed for pH, water temperature (WTemp), turbidity, electrical conductivity (EC), total dissolved solids, total solids, total hardness, dissolved oxygen (DO), chloride, orthophosphates, ammonia, total coliforms (TC), and trace metal (Cd, Cr, Cu, Pb, As, and Fe) concentrations. Based on these parameters, different types of water quality indices (WQIs) were deduced. WQIs showed most of CMPA-SSWBs as good or medium quality water bodies, while none were categorized as bad. Moreover, it was observed that the minimal water quality index (WQI m), computed using five parameters: WTemp, pH, DO, EC, and turbidity, gave a reliable estimate of water quality. The WQIm gave similar results in 72% of the cases compared with other WQIs that were based on larger set of parameters. Based on our finding, we suggest the wider use WQI m in developing countries for assessing health of SSWBs, as it will minimize the analytical cost to overcome the budget constraints involved in this kind of evaluations. It was observed that except turbidity and TC content, all other quality parameters fluctuated within the limit of the World Health Organization suggested standards for drinking water. From our findings, we concluded that if the turbidity and TC content of water from SSWBs in CMPA are taken care of, they will become good candidates as alternative water resources all round the year. © 2010 Springer Science+Business Media B.V.
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