• Rapid Communication in Photoscience
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• v.4 no.3
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• pp.67-69
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• 2015

FTIR spectroscopy has been employed to investigate the variation of anion-water hydrogen bonding in 1-butyl 3-methyl imidazolium tetrafluoroborate ([Bmim][$BF_4$]) ionic liquid caused by addition of organic co-solvents with various polarities. The variation was estimated by probing band shape and intensity of the OH stretching vibration of trace water present in ionic liquid at $3400-3800cm^{-1}$. The presence of polar aprotic co-solvent in ionic liquid dramatically reduces the absorptivity of the OH stretch band, indicating that the co-solvent changes the nature of anion-water hydrogen bond drastically, which might be responsible for the reduction of the viscosity of ionic liquid in the presence of the co-solvent.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2683-2688
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• 2012

The position of the thermodynamic equilibrium for reverse thermochromic spiropyran 6-carboxylates (SP-COOHs) was easily determined in aqueous binary mixtures, such as water-methanol, water-acetonitrile and water-dimethyl sulfoxide. The existence of more than one type of interconvertible species of the ring-opened form of SP-COOH in aqueous binary solvents enables us to evaluate the molar extinction coefficients of the ring-opened species of SP-COOH and to obtain the thermodynamic parameters.

• Bulletin of the Korean Chemical Society
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• v.15 no.9
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• pp.786-791
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• 1994

A simple and rapid sample pretreatment process necessary for determination of metal oxides in water was proposed. Samples were injected into the continuous-flow tube installed inside the microwave oven and the treated samples were cooled before entered to the Ion Chromatography (IC) or Inductively Coupled Plasma (ICP). By coupling this microwave digestion system with IC or ICP, a fully automatic analytical procedures may be easily established. In this study, two different types of digestion methods were considered; the open tubing method (OTM) and the restraint tubing method (RTM). The RTM was proved to be 3 times faster in digestion period and 10 times higher in detection range than the OTM. Validation of proposed sample digestion system was carried out by using an ICP. The results showed that both of continuous-flow methods, the OTM and the RTM were comparable in accuracies with the conventional batch-type vessel digestion method.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.823-828
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• 2011

Characteristics of water separation in a FWKO(Free Water Knok Out) vessel was investigated to remove water from oil-water mixture. Decane, toluene, and asphalt were used as model oils. Preliminary experiments were carried out for decane in a prototype FWKO vessel. Based on the results of preliminary experiments, the prototype vessel was modified and its performance was evaluated by using toluene. The effects of experimental variables on the separation of oil-water mixture were evaluated in terms of separation efficiency. The experimental variables include water cut(water ratio), number of baffles, residence times, and operation temperatures. The optimum conditions of water separation were found to be 0.8 water cut, 3 baffles, 1,200 sec, and $45^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.459-462
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• 2011

In the present work, catalytic activity of basic alumina in water has been demonstrated for the synthesis of poly functionalized pyridines. This strategy has some remarkable advantages, such as use of heterogeneous catalyst in aqueous media, reusability of catalyst and scalable approach.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.356-357
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• 2005

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4244-4246
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• 2011

A simple chromogenic system based on 1-fluoride was developed to determine water content in organic solvent. This system utilized deprotonation and protonation of the anion receptor 1. The water content evaluated from this system gave close value to the real water content in the range of 0 to 0.35% in acetonitrile and 0.2 to 0.5% in DMSO. Therefore, protonation and deprotonation phenomenon from the anion receptor by basic anion could be promising method for water sensing system.

• Analytical Science and Technology
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• v.8 no.4
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• pp.405-410
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• 1995

A study on elemental speciation of trace metals in lake water (Lake Biwa in Japan) has been carried out by a size exclusion chromatography (SEC) / inductively coupled plasma mass spectrometry (ICP-MS) system. Before analysis, the water sample was preconcentrated with a ultrafiltration technique, where the large molecules with molecular weight larger than 10,000 were concentrated. Then the preconcentrated water samples (500-1000 fold) were analyzed by a SEC/ICP-MS system. Most trace metals were found at the UV absorption peaks corresponding to the molecular weights of ca. 300,000 and 10,000-50,000, where trace metals were on-line detected by ICP-MS. The results suggest that many of trace metals exist as the large organic molecules-metal complexes in natural water.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2547-2555
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• 2023

Amberlite IRN-78 resin was incorporated with iron to make a hybrid resin for the removal of silica from the borated water of nuclear power plants. The hybrid resin contained 0.84 wt % iron compounds upon pyrolysis. In batch experiments carried out at room temperature, 1 g of the hybrid resin removed ~60 ㎍ silica from 1 ppm borated water in ~120 min. The efficiency of the hybrid material increased with the resin quantity, decreased with silica concentration, and remained unchanged at different pH values. Freundlich and Temkin isothermal adsorption dominated the silica removal process and followed the pseudo-first-order and intra-particle diffusion mechanism simultaneously. The concentration of the leached iron remained appreciably under the safe limits of 200 ㎍/l during the experiments. This detailed study suggests the use of hybrid resin for the removal of silica from borated water streams and other similar systems.

• Analytical Science and Technology
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• v.33 no.3
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• pp.167-167
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• 2020