• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.226-226
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• 2017

• Journal of Soil and Groundwater Environment
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• v.7 no.3
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• pp.79-84
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• 2002

The optimal operation conditions, including voltage applied, reaction time, distance between electrodes. and electrode material. were investigated for the treatment of soil flushing effluent using electrofloatation. When 3V was applied for 1 hour, 88% oil-water separation efficiency was achieved. In case of 6V and above, 90% efficiencies were achieved. As reaction time and distance between electrodes were longer, separation efficiencies were higher and lower, respectively. Separation efficiencies for different anode materials were copper > aluminum > iron > titanium. It might result from the differences of their electrical conductivities.

• Membrane and Water Treatment
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• v.13 no.4
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• pp.201-208
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• 2022

Emulsion Liquid Membrane (ELM) is a prominent technique for the separation of heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of the components (Surfactant and Carrier) of ELM is a very significant step for its preparation. In the ELM technique, the primary water- in-oil (W/O) emulsion is emulsified in water to produce water-in-oil-in-water (W/O/W) emulsion. The water in oil emulsion was prepared by mixing the membrane phase and internal phase. To prepare the membrane phase, the extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2- ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II). Emulsion Liquid Membrane (ELM) is a well-known technique for separating heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of ELM components (Surfactant and Carrier) is a very significant step in its preparation. In the ELM technique, the primary water-in-oil (W/O) emulsion is emulsified to produce water-in-oil-in-water (W/O/W) emulsion. The water in the oil emulsion was prepared by mixing the membrane and internal phases. The extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2-ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II).

• Journal of Aerospace System Engineering
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• v.11 no.4
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• pp.8-14
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• 2017

In this study, the production of proper emulsion fuel and the evaluation of its rheological stability in various experimental conditions were carried out. The W/O (water-in-oil) emulsion fuel was made using n-decane, pure water, and Span 80 was used as a surfactant. Increments of water volume ratio and fuel temperature were the factors, which boosted the phase separation of the emulsion fuel. Rheological characteristics for different water/oil volume ratio, temperature, and elapsed time after the fuel production were examined. As the water volume ratio in the fuel increased, the behavior of non-Newtonian fluid was observed. Viscosity declined as the fuel temperature increased due to the cohesion of water droplets in the fuel. The effect of elapsed time on viscosity was not severe for lower water ratio. However, gradual decrease of viscosity 3 hours after fuel production, in the case of ratio of 3:7, was clearly observed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1835-1841
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• 2006

Demand of enhanced bilge separation sensor system has been recently increased due to the severe regulation reinforcement of MEPC(Marine Environment Production Committee). Up to date bilge separation sensor has to be extremely accurate and highly reliable. To design and build such a bilge separator. a precise oily water separation level sensor that distinguishes oil from water is critical. Three dimensional simulations have been carried out to figure out the characteristics of capacitive level sensors, which grounds the finding of the parameters required to design the sensors. The parasitic capacitance problem which is inherent to capacitive level sensors has been taken care of. This paper concludes with the future research direction that can be pursued with the newly defined parameters of the capacitive level sensors.

• Journal of Environmental Impact Assessment
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• v.28 no.3
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• pp.332-345
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• 2019

The purpose of the study is to evaluate the treatability of contaminated groundwater with TPH and (or) $Cr^{6+}$. Laboratory scale tests were performed for oil/water separation, dissolved air flotation (DAF), coagulation and precipitation, and filtration with sand and activated carbon respectively. Two times of oil/water separation tests for total 40 minutes of separation or separating time shows 90.2 % of TPH removal rate. In case of DAF test for high TPH sample, the TPH removal rates were not varied significantly by the variation of microbubble size. However, tests for low TPH samples show that TPH removal rate increases as microbubbles are smaller. When coagulant was added to sample for DAF test, TPH removal rate was increased 12.3 %. SS removal rate by DAF was 97.9 % at $16-40{\mu}m$ and it was increased as the size of microbubble is reduced. Tests for coagulation and precipitation were performed to evaluate the removal of $Cr^{6+}$ in groundwater. The increase of $FeSO_4$ dosage increased $Cr^{6+}$ removal rate in the coagulation and precipitation process. As the amount of activated carbon in the filter media increased TPH removal rate in the filtration process. SS removal rate by the filtration was 96.7 % similar to the results of DAF process tests. The filtration process treats TPH and SS. Best design parameters are determined as the size of sand is $425-850{\mu}m$ and the ratio of activated carbon and sand is 50:50.

• Membrane Journal
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• v.6 no.4
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• pp.219-226
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• 1996

Rotary disc ultrafiltration module(RDM) was developed for the separation of oil emulsions. This module was devised to reduce the gel polarization phenomenon by alecoupling the operation pressure and the surface velocity of solution in ultrafiltration(UF) processes. Two-shaft engaged disc type RDM having 20 rotary disc membcanes(UOP, USA) was operated under 85kPa vacuum at $25^{\circ}$C. The pressure drop due to slip flow in the two-shaft RDM was found to be proportional to $(2.5{\omega}r)^{2}$. The pure water flux of two-shaft RDM decreased by 9.95% at the angular velocity of 41.89rad/s compared to the decrease of 3.01% for one-shaft RDM at the same velocity. When the angular velocity was changed from 31.42rad/s to 2.62rad/s, the flux decline for 1% cutting oil in two-shaft RDM was 30.16% that is similar to that of one-shaft RDM. Disc gap of 3mm and 7mm did not show any significant differences in the flux for 1% cutting oil solution. A modified model for two-shaft RDM showed good agreement with the experimental results for the cutting oil solution.

• Journal of Mechanical Science and Technology
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• v.15 no.12
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• pp.1845-1852
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• 2001

This paper deals with the experiment to obtain quantitative information about conditions of the interface between a water drop and surrounding oil. Velocity distributions in very close region of the interface are measured by introducing a new illumination technique and a telecentric lens. It enables precise measurements of velocity distributions in the close region to the interface. Although the measured velocity distributions exhibit strong influence from the solid wall of an experimental tube, the coincidence of inner and outside velocities on the interface is clearly confirmed for the clean interface. The shearing stresses on the interface, which are proportional to the velocity gradient normal to the interface, clearly show conditions of contaminated interface, which can be divided into two parts. From front stagnation point to somewhere near a separation point, the distribution of shearing stresses is well coincide with that of the Hadamard's analytical solution, while the distribution on the latter part of the interface sows quite different feature, which is supposed to be strongly influenced by contamination of the surface.

• Journal of the Korean Society of Safety
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• v.4 no.1
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• pp.15-24
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• 1989

The transport of Chromium(Vl) ion from waste water throughl the liquid surfactant membrane containing tri-n-octylamine as a carrier, was analyzed by a slab model and was investigated through experiments. For the experiment of membrane stability, concentrations of surfactant and liquid parafnn oil were analyzed. Extraction euperiments were carried out to observe the effect of system variables, such as stirring speed, concentration of carrier, and NaOH in internal aqueous phase, and concentrations of H$_2$SO$_4$and initial chromium(VI) ion in external aqueous phase at $25^{\circ}C$. It is concluded that the most stable formation of liquid membrane emulsion was obtained when surfactant concentration is above 3 wt. ％ and liquid parafnn oil concentration is 50 vol. ％. The transport of chromium(VI) ion in bacth extractor increased with increasing carrier concentration, the volume ratio of emulsion to external aqueous phases, and initial concentration of chromium(VI) ion under the optimum stirring speed of chromium(VI) ion below 2 ppm. The theoretical equation on the transport of chromium(Vl) ion agreed well with the experimental results.

• Journal of Soil and Groundwater Environment
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• v.8 no.3
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• pp.56-60
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• 2003

The optimal operation conditions of electrofloatation for oil-water separation of soil flushing effluent including electrolyte and pH were investigated. The reactor (200 ${\times}$ 10 ${\times}$ 15 cm) for the experiment was constructed by using acrylic plate. Diesel concentration was 1,000 mg/L in the 1 % mixed surfactant solution ($POE_5$: $POE_{14}$ 1: 1). Titanium coated electrode was used as cathode and stainless steel electrode as anode. Reaction time was 62 minutes (reaction time: 60 min., flotation time: 2 min.) and voltage was 6 V. The separation efficiency of electrofloatation was improved to 40% by electrolyte addition. Furthermore, NaCl (1N) added as electrolyte was showed enhanced efficiency compared to NaOH (1N). While, the effect of both NaCl and NaOH was sequentially increased in the range of 0.2∼1.0% (0.02∼0.1 M). The equilibrium time was found as 20 min. in the range of 0.4∼1.0% (0.04∼0.1M) for both of them.