• Transactions on Electrical and Electronic Materials
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• v.15 no.2
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• pp.81-86
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• 2014

The process parameter in optimized KOH alkali activation of soft carbon series coke material in high purity was set with DOE experiments design. The activated carbon was produced by performing the activation process based on the set process parameters. The specific surface area was measured and pore size was analyzed by $N_2$ absorption method for the produced activated carbon. The surface functional group was analyzed by Boehm method and metal impurities were analyzed by XRF method. The specific surface area was increased over 2,000 $m^2/g$ as the mixing ratio of activation agent increased. The micro pores in $5{\sim}15{\AA}$ and surface functional group under 0.4 meq/g were obtained. The contents of the metal impurity in activated carbon which is the factor for reducing the electrochemical characteristics was reduced less than 100 ppm through the cleansing process optimization. The electrochemical characteristics of activated carbon in 38.5 F/g and 26.6 F/cc were checked through the impedance measuring with cyclic voltammetry scan rate in 50~300 mV/s and frequency in 10 mHz ~100 kHz. The activated carbon was made in the optimized activation process conditions of activation time in 40 minutes, mixing ratio of activation agent in 4.5 : 1.0 and heat treatment temperature over $650^{\circ}C$.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.4
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• pp.107-114
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• 2007

A study on the removal of heavy metals using alginic acid, a kind of polysaccharides, was performed. Alginic acid adsorbed 480 mg Pb/g dry mass at pH 4, which was about twice as high as uptake capacity of other biosorbents. Isothermal adsorption curve for lead ions was described by the Langmuir model equation and the experimental data well fitted to model equation. The adsorption of lead ions was an endothermic process since binding strength increased with temperature. The effect of alkali metal ions ($Ca^{2+}$ and $Mg^{2+}$) on lead sorption capacity was negligible and most adsorption process was completed in 30min. The uptake capacity of other metals such as, copper, mercury, strontium, and cesium ions using alginic acid was also investigated.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.553-556
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• 2007

We previously reported a 27.12 MHz inductively coupled plasma source at atmospheric pressure for atomic emission spectrometry based on polymer microchip plasma technology. For the PDMS polymer microchip plasma, molecular emission was observed, but no metallic detection was done. In this experiment, a lab-made electrothermal vaporizer (ETV) with tantalum coil was connected to the microchip plasma for aqueous sample introduction to detect metal ions. The electrode geometry of this microchip plasma was redesigned for better stability and easy monitoring of emission. The plasma was operated at an rf power of 30-70 W using argon gas at 300 mL/min. Gas kinetic temperatures between 800-3200 K were obtained by measuring OH emission band. Limits of detection of about 20 ng/mL, 96.1 ng/mL, and 1.01 μ g/mL were obtained for alkali metals, Zn, and Pb, respectively, when 10 μ L samples in 0.1% nitric acid were injected into the ETV.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.969-973
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• 2008

Solvent extraction using a Schiff-base, salen$(NEt_2)_2$, as a chelating agent has been conducted on several water samples to study the determination of trace Cu(II), Mn(II) and Zn(II). Experimental conditions for the formation and extraction of metal complexes were optimized with an aqueous solution similar in composition to the samples. The matrix difference between the sample and standard solutions was approximately matched, and the pH of each sample solution was adjusted to 9.5 with $NaHCO_3/NaOH$ buffer. The concentration of salen$(NEt_2)_2$ was $7.3\;{\times}\;10^{-3}$ mol/L, and the complexes were extracted into MIBK solvent followed by the measurement of AAS absorbance. The potential interference of concomitant ions was investigated, but no interference from alkaline and alkali earth ions was shown in this procedure. The given procedure is precise, as judged from the relative standard deviation of less than 5% for five measured data. The recovery of 93-103% shows that this method is quantitative for such trace metal analysis.

• Bulletin of the Korean Chemical Society
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• v.26 no.6
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• pp.882-886
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• 2005

Copper(II) ion-selective PVC membrane electrode based on 2-mercaptobenzoxazole as a new ionophore and o-nitrophenyl octyl ether (o-NPOE) as plasticizer is proposed. This electrode revealed good selectivity for $Cu^{2+}$ over a wide variety of other metal ions. Effects of experimental parameters such as membrane composition, nature and amount of plasticizer, and concentration of internal solution on the potential response of $Cu^{2+}$ sensor were investigated. The electrode exhibits good response for $Cu^{2+}$ in a wide linear range of 5.0 ${\times}$ 10−.6-1.6 ${\times}$ $10^{-2}$ mol/L with a slope of 29.2 ${\pm}$ 2.0 mV/decade. The response time of the sensor is less than 10 s, and the detection limit is 2.0 ${\times}$ $10^{-6}$ mol/L. The electrode response was stable in pH range of 4-6. The lifetime of the electrode was about 2 months. The electrode revealed comparatively good selectivities with respect to many alkali, alkaline earth, and transition metal ions.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1465-1470
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• 2004

A short and efficient synthesis, solvent extraction and potentiometric measurements of new thiazole-containing naphtho-crown ethers are reported. The naphthalene moiety enhances the ammonium ion selectivity over potassium ion. The selectivity of ${NH_4}^+/K^+$ follows the trend $3\;{\approx}\;2\;>\;1$, indicating that the differences in conformational changes of 2 and 3 in forming ammonium complexes affect little on the resulting ammonium/potassium extraction selectivity ratio. The ammonium ion-selective electrodes were prepared with noctylphenyl ether plasticized poly(vinyl chloride) membranes containing 1-4 the effect of one naphthalene unit introduced on either right (2) or left (3) side of thiazolo-crown ether on their potentiometric properties (e.g., ammonium ion selectivity over other cations, response slopes, and detection limits) were not apparent. However, the ammonium ion selectivity of 1, 2 and 3 over other alkali metal and alkaline earth metal cations is 10-100 times higher than that of nonactin.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.1
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• pp.17-21
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• 2016

Alkali metal fluoride sources (MFs) such as potassium fluoride (KF) have been widely used as a fluoride source in the nucleophilic displacement reaction. However, they have low solubility and nucleophilicity in most of the organic solvents. Bulky fluoride sources such as tetrabutylammonium fluoride (TBAF) were substituted for MFs to improve these properties. However, hygroscopic property of TBAF makes it less convenient for handling as well as its strong basic property can make the side-reaction occur. Recently, novel fluoride sources have been developed to solve these problems. In this paper, we would like to introduce coordinated fluoride sources as a new fluoride sources such as tetrabutylammonium tetra(t-butyl alcohol)-coordinated fluoride, crown ether metal complex fluoride, and various bulky alcohols coordinated fluoride complexes. In particular, bulky alcohol coordinated fluoride source could generated by the controlled hydrogen-bonded of fluoride with alcohols and these fluoride sources have better stability and reactivity with showing low hygroscopic property. The study of these fluoride sources will help to understand the characteristic of [$^{18}F$]fluoride for increasing the radiochemical yield in the [$^{18}F$]radiofluorination.

• Textile Coloration and Finishing
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• v.14 no.5
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• pp.284-293
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• 2002

Nylon 6 and polyester taffeta fabrics are dyed in aqueous medium with vat dyes such as Indanthren Red FBB, Mikethren Blue ACE and Mikethren Blue HR varying the compositions of sodium hydrosulfite and NaOH. Also nylon UMF nonwoven and polyester UMF knitted fabrics are dyed with metal complex and disperse dyes as a reference, and the wash and rubbing fastnesses for these dyes are investigated. In vat dyeing of polyester and nylon taffeta, an optimum composition of sodium hydrosulfite/NaOH is existed at a range of 1∼2wt%/0.2wt%. A good build-up property for Mikethren Blue ACE on nylon 6 UMF nonwoven fabric is shown at high temperature. Vat dyeing of polyester with Mikethren Blue Ace shows a good color shade in a higher temperature, while dyeing with Mitsui Blue HR shows low temperatures. Vat dyes In dyeing of both nylon 6 UMF nonwoven and polyester UMF knitted fabrics have a better wash fastnesses compared with metal complex or disperse dyes.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.394-401
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• 2014

In order to minimize a building energy consumption with ventilation, a development of smart ventilation system is very important. In this study, a dry adsorbent that is main element of smart ventilation system was developed for removing indoor $CO_2$, and evaluate the adsorption performance. Specific surface area, pore characteristic and crystal structure of the modified sorbent was measured to analyze physical properties. From this analysis, it was found that the developed absorbent has a low specific surface area, due to mesopores of substrate was filled with metal contained raw material. Additionally, through analysis of the adsorption properties, the developed adsorbent was shown a adsorption form of mesopore (type IV), which means adsorption amount was rapidly increased at the part of high-pressure. Order to applying for the field, chamber test was performed. Continuous column tests (2,500 ppm) and batch chamber tests ($4m^3$, 5,000 ppm) showed $CO_2$ removal efficiency of 95% and 88% within 1 hour, respectively.

• Bulletin of the Korean Chemical Society
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• v.16 no.3
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• pp.265-269
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• 1995

Complexation of ortho-xylyl-17-crown-5 (X17C5) with alkali metal ions in acetonitrile was studied by 7Li and 23Na NMR spectroscopy. The complex formation constants of X17C5 with LiI, LiSCN, NaI, and NaSCN were determined by investigating the changes in the chemical shifts as a function of the concentration ratio of X17C5 to metal ion. It was found that X17C5 forms 1:1 complex with Li+ and Na+ ions and the log Kf's for the complexation with LiI, LiSCN, NaI, and NaSCN were determined to be 2.88, 2.43, 2.53, and 2.30, respectively. In particular, the kinetics of complexation of X17C5 with Na+ was investigated by the method of 23Na NMR lineshape analysis. Activation energies were determined from Arrhenius plot of the resultant rate constant data to be 25.4 kJ/mol for NaI and 15.1 kJ/mol for NaSCN. Other kinetic parameters were also calculated by employing the Eyring equation. The decomplexation rates measured were 1.82 × 104 M-1s-1 for NaI and 1.50 × 104 M-1s-1 for NaSCN. It is concluded that the decomplexation mechanism is predominantly a bimolecular cation exchange for both cases.