• Journal of the Korean Applied Science and Technology
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• v.41 no.1
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• pp.19-26
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• 2024

Recently, separation membranes have been applied to fields such as water supply, sewage treatment, gray water reuse, and air pollution control. Chemical cleaning technology is attracting attention among the methods of reusing these expensive separation membranes. It was found that the separation membrane could be regenerated using chemical cleaning. Specifically, it was found that the use time of the separation membranes regenerated by chemical cleaning was sustainable for more than 1,700 hours. Additionally, it was found that the flux recovery ratio after chemical cleaning was maintained at least 60%. In addition, the flux recovery ratio of HYDREX 4710, an organic membrane cleaner, and 4703, an inorganic membrane cleaner, was 76% and 62%, respectively, showing the highest flux recovery ratio among the chemicals used. Considering that the target raw water of this study is biological secondary treatment water, it was suggested that chemical cleaning could be actively used to regenerate separation membranes in future water treatment.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.185-189
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• 2001

A study on the new active circulation type oil-water separation system including buoyancy type guidance system was carried out in this paper. Oil-water separation system is composed of several oil separation steps. Buoy type oil guiding system was developed based on the difference of buoyance of water and oil. The design speed of this vessel is 25 knots.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.10a
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• pp.39-39
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• 1999

Membrane separation technology has become a more attractive technology on waste water treatment and water recycle in recent years. On this application, membrane does not take main part of treatment, such as decomposition or handling of organic matter in the waste water, but it is very important supporting method in the total system. Activated sludge is most popular method as main part. In the system , membrane works as a separator to obtain clear water after biological treatment, by which the permeate could be released, recycled or applied to further additional treatment, instead of conventional sedimentation, coagulation and sand filtration. We would like to introduce our system cases for waste water treatment and water recycle, in which membrane separation technology works. In most of cases, membranes are applied to solid- liquid separation of activated sludge. Our experiences will be introduced as following items.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.842-846
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• 2016

It's possible for a human to breathe under water, but the amount of dissolved oxygen in the water is small and a large amount of water is necessary to obtain sufficient dissolved oxygen from water. So, large separation system with large water pumps, having large surface areas, and large battery sources are needed. Exhalation gases are used to solve this problem. Theses gases contain some oxygen, nitrogen, and carbon dioxide; they contain less oxygen and more carbon dioxide compared to air. Therefore, reduction of the amount of carbon dioxide is necessary. If exhalation gases are employed appropriately, the separation device can be made more compact. Inlet water mixed with exhalation gases is supplied into the separation device, and dissolved gases are separated from the mixed water as it passes through the device. The inlet part of a typical separation system with a water delivery pump before the membrane module has more than one atmosphere. Hence, a compressor is used to mix the exhalation gases. In this study, the pressure at the inlet due to the use of a suction pump after the membrane module was less than one atmosphere; hence, compressors were not required. Separation characteristics were studied using a separation device without a compressor. The use of exhalation gases led to an increase in the amount of dissolved gases being separated. As the amount of inlet exhalation gases was increased, the separation of dissolved gases was increased as well.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.91-94
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• 2003

In this work, the physicochemical properties for permeant molecules and polyion complex membrane prepared by complexation between SA and chitosan were determined by using molecular modeling methods, and the permeation behaviors of water and alcohol molecules through the PIC membrane have been investigated. In the case of penetrant molecule, the experimental results showed that the prepared membrane was excellent pervaporation performance result in most solution, and the selectivity and permeability of the membrane were dependent on the molecular size, the polarity and the hydrophilic surface of permeant organics. However, the separation behavior of methanol aqueous solution exhibited other permeation tendency with other feed solutions and contradictory result. That is, the membrane were preferentially permeable to methanol over water despite water molecule has stronger polarity and small molecular size than methanol molecule. In this study, the results were discussed from the viewpoint of chemical and physical properties between permeant molecules and membrane in the diffusion state.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1347-1353
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• 2014

It's possible for a human to breathe under water, if dissolved oxygen is effectively used. Fish can stay under water using the gill which extracts dissolved oxygen from water. Water includes small amounts of oxygen, so a human needs larger amounts of water to acquire oxygen enough for underwater breathing. The exhalation gas from a human is another method to get higher amounts of oxygen under water. It mainly composes of oxygen, nitrogen and carbon dioxide. So, if only carbon dioxide is decreased, the exhalation gas has good characteristics for breathing of a human under water. In this paper, composition of the exhalation gas from a human was analyzed using GC. Based on these results, the synthesized gas was prepared and mixed into water which was used for experimental devices to analyze separation characteristics of dissolved gases from water. Experimental devices included a water pump, a hollow fiber membrane module and a vacuum pump. The effects of pressure and water flow on separation characteristics of synthesized gas were investigated. The compositions of gases separated from water using synthesized gas were investigated using GC. These results expect to be applied to the development of underwater breathing technology for a human.

• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.1-5
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• 2001

A study on the new active type oil-water separation system including the oil-water separation system of magnetic film was carried out. Separation system is composed of several active types of circulating oil separation steps and one magnetic film separation step at final stage. At the magnetic separation step, ferrofluid easily forms a weak magnetic mixture with oil, which is from the water by magnetic field gradient. The vessel has been designed to run at the maximum speed of 25 knots. And two typical forms of SWATH and Catamaran have been studied as a new type of oil recovery vessel.

• Toxicological Research
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• v.5 no.2
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• pp.89-96
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• 1989

Rapid and complete epidermal-dermal separation procedure were determined in neonatal rat skin by light microscopic observation and by compairing enzyme activities in the separated epidermis. Microscopic appearance demonstrated the at four different separation procedures used in the study resulted in good separation of epidermis from dermis` heating method (i.e., immersion in 55C water for 30 sec, followed by immersion in 0-4C water) and microwave irradiation for 10 sec were saving time.

• Membrane Journal
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• v.30 no.6
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• pp.359-372
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• 2020

Compared to other oil/water separation methods, oil/water separation membranes have low energy costs and higher performance levels. Superhydrophilicity and underwater superoleophobicity are factors that are most vital in developing effective oil/water separation membrane. In addition, antifouling property and biodegradability are also factors that have to be considered in developing the membranes. In this review, studies which have enhanced the oil/water separation efficiency by modifying the chemistry and morphology of the surface of the membrane are discussed.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.616-622
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• 2001

Split-flow thin (SPLITT) cell Fractionation(SF) is a technique that allows separation of particulates and macromolecules into two fractions. A gravitational SF(GSF) system is constructed and tested for its applicability for separation of dust and ground water particulates. When tested with polystyrene latex particles, experimental data were in good agreements with theory. The 9.8 and 21.4㎛ polystyrene particles were successuflly separated in a continuous mode, where the mixture is continuously fed into the GSF channel allowing separation in a large sacle. The GSF system is successfully applied to continuous separation of dust and ground water particels based on the sedimentation coefficient, which is closely related to the particle size. The separations were confirmed by microscopy and energy-dispersive X-ray (EDX) analysos.