• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.3
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• pp.58-65
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• 2000

Responses to marine oil spills can be classified Into categories; 1) mechanical treatment using booms and skimmers, 2) chemical one utilizing dispersants, 3) controlled in-situ burning of spilled oils. In the present paper, characteristics, history, present issues, advantages and disadvanteges, and future applicability of in-situ burning technology which is nowadays winning much attention are summarized on the basis of a survey of related papers and other resources.

• Journal of the Korean Applied Science and Technology
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• v.28 no.4
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• pp.449-454
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• 2011

This surfactant can be used as a cosmetics and chemical dispersants. The variation of critical micelle concentration(CMC) with temperature for N-eicosyl pyridinium bromide over the range $40^{\circ}C$ to $60^{\circ}C$ has been measured by drop methods. Thermodynamic quantities for micellization of N-eicosyl pyridinium bromide in water have been calculated by polynominal equation.

• Journal of the Korean Ceramic Society
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• v.27 no.5
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• pp.684-692
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• 1990

Ultrafine magnetite powder for the ferromagnetic fluid was prepared by an addition of alkaline solution to the solution containing Fe2+ and Fe3+ ions at 6$0^{\circ}C$. The optimum condition of the magnetite synthesis was delineated by examining such various physico-chemical properties as Fe2+/Fe+3 ratio in the powder, phase characteristics, MHC and $\sigma$max. A new scheme for the steric stabilization of colloidal dispersion was proposed using the concept of the buffer group action for the increased interfacial density of the stabilizing moieties at colloid particle/dispersion medium interface. The proposed concept was successfully applied to the preparation of the kinetically stable kerosinebased ferrofluid using Tween and Span as dispersants. In the dispersion of magnetite particles in a kerosine, Tween(polyoxyethylene sorbitan oleate) acts as a primary stabilizer which provides an anchor group, whereas Span(sorbitan oleate) can be classified as a secondary stabilizer which adsorbs on the surface of magnetite particle through the action of the buffer group. Dispersion studies using various quantities of Tween and Span supported the concept of the buffer group action for increased dispersion characteristics of the kerosine based ferromagnetic fluid.

• Journal of the Korean Society of Safety
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• v.34 no.6
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• pp.22-28
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• 2019

In South Korea, the enact of Korean Coast Guard Act-1 manages physical and chemical oil-dispersants. Oil snare, which is made of polypropylene, is newly added to the aforementioned act, and it has advantage on the ease of recovery compare to other adsorbents. This study synthesized bunker B-oil with diesel-oil and bunker C-oil to perform an adsorption test based on three samples which were manufactured in South Korea. As a result, adsorption test revealed 5.2 g/g more adsorption than the previous results from the act. Additional toluene test revealed that all the samples satisfied 90.0%, however coloured samples could release its pigment on the marine environment. Thus, colorless samples are recommended on the risk management of marine accidents. The study on the basic direction of the calculation of the test items and the standard value for the quality control of the oil snare was also carried out.

• Corrosion Science and Technology
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• v.7 no.5
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• pp.269-273
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• 2008

It is known that the fluoric resin has the most outstanding properties in the extremely acidic environment of high temperature. However, this resin is the thermal hardening type that needs long time heat treatments above $250^{\circ}C$. It's impossible to use in situ in the extremely acidic environment such as a huge FGD ductworks or industrial chemical tanks. Furthermore, even the natural hardening type fluoric coatings which can be hardened less than $120^{\circ}C$ can not be applied to the highly acidic environmental plants because of its chemical resistance. In this study, new fluoric coatings that has excellent thermal resistance, chemical resistance and corrosion resistance has been developed in order to solve above problems and to be applied to the large plant structures in the field. These newly developed coatings are organic and inorganic composite type that have fluoric rubber(100 wt%), fluoric resin(5~50 wt%), oxalates(5~30 wt%), inorganic fillers mixed with plate-type and bulk-type solids(20~150 wt%), hardeners(0.5~5 wt%), and hardening hasteners(0.1~3 wt%). The best chemical and physical properties of these coatings are acquired by variation of adhesive reinforcement agents, dispersants, leveling agents. Mixing ratios of plate-type and bulk-type inorganic fillers influence the thermal properties, abrasive resistance and chemical infiltration properties of coatings. The mixing control is also very important to have homogeneous surface and removing inner voids of coatings.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.656-662
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• 2013

The iron oxide ($Fe_3O_4$) particles in the coolant of the secondary system of a nuclear power plant reduce the heat transfer performance or induce corrosion on the surface of the heat transfer tube. To prevent these problems, we conducted a study to improve the dispersion stability of iron oxide using polymeric dispersant injection in simulated secondary system water. The three kinds of anionic polymers containing carboxyl groups were selected. The dispersion characteristics of the iron oxide particles with the polymeric dispersants were evaluated by performing a settling test and measuring the transmission, the zeta potential, and the hydrodynamic particle size of the colloid solutions. Polymeric dispersants had a significant impact on the iron oxide dispersion stability in an aqueous solution. While the dispersant injection tended to improve the dispersion stability, the dispersion stability of iron oxide did not increase linearly with an increase in the dispersant concentration. This non-linearity is due to the agglomerations between the iron oxide particles above a critical dispersant concentration. The effect of the dispersant on the dispersion stability improvement was significant when the dispersant concentration ratio (ppm, dispersant/magnetite) was in the range of 0.1 to 0.01. This suggests that the optimization of dispersant concentration is required to maximize the iron oxide removal effect with the dispersant injection considering the applied environments, the iron oxide concentration and the concentration ratio of dispersant to iron oxide.

• Journal of Environmental Health Sciences
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• v.39 no.4
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• pp.360-368
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• 2013

Objectives: Phthalates are used in a large variety of products including as coatings of pharmaceutical tablets, film formers, stabilizers, dispersants, emulsifying agents, and suspending agents. They have been the subject of great public concern in recent years. The extensive uses of this material have attracted attention and issues regarding its safety have been raised. Methods: In this study, three types of phthalate skin permeation were studied using matrixes such as ointments, creams and lotions in vitro. The absorption of phthalate diesters [Dimethyl phthalate (DMP), Di-n-propyl phthalate (DPP) and Di-n-pentyl phthalate (DNPP)] using film former has been measured in vitro through rat skin. Epidermal membranes were set up in Franz diffusion cells and their permeability to PBS measured in order to establish the integrity of the skin before the phthalates were applied to the epidermal surface. Results: Absorption rates for each phthalate ester were determined and permeability assessment made to quantify any irreversible alterations in barrier function due to contact with the esters. Types of phthalate in vitro experimental results quickly appeared in the following order DMP > DPP ${\geq}$ DNPP. Conclusions: In the experimental results, lotion> cream> ointment, and the permeation rate of lotion with a great amount of moisture was the fastest. Skin permeation rate is generally influenced by the chemical characteristics of a given chemical, such as molecular weight and lipophilicity. As the esters became more lipophilic and less hydrophilic, the rate of absorption decreased.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.06a
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• pp.237-239
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• 2011

최근 국제해사기구(International Maritime Organization, IMO)는 "극지를 운항하는 선박에 대한 안전기준(Polar Code)"를 제정하여 결정하기로 하였으며, 2012년까지 완료하여 법제화하기로 하였다. 이는 최근의 극해 지역의 연속적인 사고의 심각성에 대한 대비책의 일환이다. 2004년도에 알라스카 앞바다에 침몰한 Selendang Ayu 는 6600만 톤의 콩, 170만 리터의 연료유와 55,564 리터의 MDO 및 다른 오염물질을 바다에 유출하였다. 이는 주변의 동물들에게 심각한 영향을 끼쳤고, 아직까지도 유출되어진 오염물질들을 완전히 처리하지 못한 상태이다(Arctic marine shipping assessment, Arctic council 2009.). 즉, 기름이 유출을 하면 방재시설이 다른 육상에서 오기 전까지는 상당히 오랜 시간 동안, 사고 지역 주변을 오염시키게 되며, 유빙이나 극한의 온도는 방재 작업을 더욱 힘들게 한다. 본 연구에서는 극해와 같은 해역에서 기름이 유출 하였을 때에 대응하는 방법, 즉 현존하는 기계적인 복구 방식, 점화식 처리 방식 과 유처리제 방식을 소개하고, 그에 대한 국제규정 및 기술 발전 동향에 대해서도 설명한다.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.520-524
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• 2004

As a feasibility study for the application of carbon nanotubes to the treatment of environmental pollutants, the adsorption characteristics of humic acid on carbon nanotubes has been investigated. The dispersion features of carbon nanotubes in aquatic environment were investigated by measuring the variation of their electrokinetic potentials with pH, and the effects of some dispersants on their dispersion features were also examined. Under the experimental conditions, humic acid was observed to mostly adsorb on nanotubes within a few minutes and reach the equilibrium state within about one hour. The adsorption features of humic acid on nanotubes were found to follow the Freundlich model better than the Langmuir Model. Humic acid adsorbed on carbon nanotubes endothermically and the change of enthalpy in adsorption reaction was estimated to be ca. 18.37kJ/mol at standard state. The entropic change in adsorption reaction for humic acid was ca. 0.0503kJ/mol at standard state and the activation energy for adsorption was also estimated based on the change of rate constants with temperature. FT-IR investigations showed that the functional groups such as alcohol, ester, and aromatics existing in the chemical structure of humic acid might work as the bridge in its adsorption on nanotubes.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.113-118
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• 2021

The International Maritime Organization (IMO) has confirmed a global limit of 0.5 % for sulfur in fuel oil used on board ships with effect from January 1, 2020. Among various alternatives to respond to these regulations on sulfur content in fuel oil, such as LNG ships, SOx scrubbers, and very-low-sulfur fuel oil (VLSFO). VLSFO is preferred owing to its low investment costs. As more ships are expected to use VLSFO, VLSFO spills are expected to increase. In particular, when the seawater temperature is below the pour point of VLSFO, VLSFO solidifies when it is spilled, which makes controlling spills difficult. In this study, six types of VLSFO produced in Korea and one type of high-sulfur fuel oil (MF380) were compared in terms of the dispersibility of dispersants according to the seawater temperature conditions. The results confirmed that the six type of VLSFO did not satisfy the domestic standards for dispersant rate (60 % or more for 0.5 min, 20 % or more for 10 min). Morever, the dispersant rate of the six types of VLSFO was low compared with that of the high-sulfur fuel oil. The results of this study are expected to be used to set the direction of dispersant control in the case of VLSFO spills.