• 자원리싸이클링
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• 제2권4호
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• pp.27-32
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• 1993

제강더스트 중에 미량으로 함유되어 있는 갈륨을 분리 회수하는 프로세스를 연구하였다. 2.25mol/l-$H_2SO_4$ 침출에의하여 38mg/l의 갈륨을 함유하는 수용액을 얻었다. 이 침출액 중에서 1000배 량의 철과 아연이 함유되어 있다. 침출액 중의 갈륨은 철(III)이온을 철(II)이온으로 환원하고, pH 조정한 후, 아미노카르본산형 관능기를 가진 킬레이트 수지를 이용하여 흡착 농축하였다. 1.5mol/l-$H_2SO_4$에 의한 용리액을 칼럼에 재공급하고 재농축하여, 3.0mol/l-HCl을 이용하여 용리하였다. 용리액 중의 갈륨은 13g/l의 농도를 나타내었다. 갈륨의 정제는 용매추출법에 의하여 정제하였다. 추출제로는 TOMAC(tri-n-octhylmethylammonium chloride)을 사용하여 순수한 갈륨 정제액을 얻었다.

• 폴리머
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• 제34권5호
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• pp.450-453
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• 2010

Iron(III) p-toluenesulfonate(FTS)를 개시제로 한 pyrrole의 중합에서 용액 중합법(LPP)과 기상 중합법(VPP)으로 제조된 PPy 박막의 전기/광학적 특성 및 표면구조를 비교하였다. LPP에 비해서 VPP 방법으로 제조된 PPy 박막은 우수한 전기적 특성을 보여주었다. 표면 특성분석을 이용하여 제조된 PPy 필름의 표면 모폴로지와 표면저항과의 상관관계를 검토하였다. VPP 방법으로 제조된 PPy 박막의 표면이 LPP로 제조된 것보다 평탄하였다. VPP를 응용한 잉크젯 프린팅과 소프트 리소그래피를 사용하여 미세 패턴된 PPy 박막을 효과적으로 제조할 수 있었다.

• 한국환경보건학회지
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• 제17권1호
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• pp.120-128
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• 1991

Saccharomyces cerevisiae was immobilized by incubating iron oxides with calcium alginate, and by polyacrylamide entrapment to use repeatedly for the conversion of glucose to ethanol. Magnetic and non-magnetic immobilized yeast and polyacrylamide immobilized yeast were compared with the native yeast a batch-fermentation of ethanol from glucose. Three kinds of immobilized yeast tended almost identically, having ethanol productivity as well as the final yield about the same to what was found for the native yeast. The long-term operational stability of three kinds of immobilized yeast were significant difference according as immobilized yeast activation or non-activation before ethanol fermentation. In the non-activation they lost their activity of fermentation rapidly in the beginning stage an slower at a later stage. On the other hand, in the activation with nutrient media, their activities were increased to some extent and stable in the later stage. The cell count of three kinds of immobilized yeast after activiation by incubating nutrient media, increased by a factor of about 45 to 48, whereas the fermenting capacity increased by a factor of 174 to 178. In the prearation of immobilized biocatalysts, magnetic matter does not seem to have any adverse affect on the properties of the microorganism. The immobilized biocatalysts by utilizing magnetic matter have some advantages, especially in application of viscous media or insoluble particle-containing media, for this work was linked with microbial utilization of environmental wastes and elimination of envirnmental pollutant.

• Journal of Magnetics
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• 제20권4호
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• pp.371-376
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• 2015

Magnetite nanoparticles were synthesized by adding excess ammonium hydroxide to a solution of iron (II) and (III) chlorides. The surfactants of oleic acid and Span 80 were applied in sequence to the magnetic particles as a combined stabilizer, and poly-${\alpha}$-olefin (PAO) 30 or 60 was used as the liquid base with a low or high viscosity, respectively. The ferrofluids were prepared with the concentrations of 200, 300, 400, and 500 mg/mL, and characterized by density, dispersion, magnetization, and viscosity. The density of the fluids increased proportionally to the concentration from 0.98 to 1.27 g/mL and 1.01 to 1.30 g/mL with PAO 30 base and PAO 60 base, and the dispersion stability was 77-95 and 81-74% for the PAO-30 and PAO-60-based fluids, respectively. The observed saturation magnetization values of the PAO-30 and PAO-60-based ferrofluids were 16 to 42 mT and 17 to 41 mT with the concentration increase in the range 200-500 mg/mL, respectively, depending upon the content of magnetic particles in the fluid. The viscosity variation of the PAO-30 and PAO-60-based ferrofluids in the temperature range $20-80^{\circ}C$ was the least with the concentrations of 400 and 300 mg/mL, respectively.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권3호
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• pp.88-94
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• 2016

The simultaneous biodegradation between MTBE (Gasoline additives) and BTEX (Benzene, Toluene, Ethyl-benzene, o-Xylene, m-Xylene, p-Xylene) was achieved within a competitive inter-relationship, with not only electron accepters such as nitrate, sulfate, and iron(III) without oxygen, but also with electron donors such as MTBE and BTEX. Preexisting indigenous microorganisms from a domestic sample of gasoline contaminated soil was used for a lab-scale batch test. The result of the test showed that the biodegradation rate of MTBE decreased when there was co-existing MTBE and BTEX, compared to having just MTBE present. The growth of indigenous microorganisms was not affected in the case of the MTBE treatment, whereas the growth of the microorganisms was decreased in combined MTBE and BTEX sample. This may indicate that an inhibitor related to biodegradation when BTEX and MTBE are mixed will be found. This inhibitor may be found to retard the anaerobic conditions needed for efficient breakdown of these complex carbon chain molecules in-situ. Moreover, it is also possible that an unknown competitive reaction is being imposed on the interactions between MTBE and BTEX dependent on conditions, ratios of mixture, etc.

• Membrane and Water Treatment
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• 제7권6호
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• pp.495-505
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• 2016

Mesoporous MCM-41 was deposited on an inexpensive disk shaped ceramic support through hydrothermal technique for ultrafiltration of $Fe^{3+}$ from aqueous solution. The ceramic support was fabricated using uni-axial compaction technique followed by sintering at $950^{\circ}C$. The characteristics of MCM-41 powder as well as the composite membrane were examined by X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), porosity and pure water permeation test. The XRD result revealed the good crystallinity and well-resolved hexagonally arranged pore geometry of MCM-41. TGA profile of synthesized MCM-41 zeolite displayed the three different stepwise mechanisms for the removal of organic template. The formation of MCM-41 on the porous support was verified by FESEM analysis. The characterization results clearly indicated that the accumulation of MCM-41 by repeated coating on the ceramic disk directs to reduce the porosity and pore size from 47% to 23% and 1.0 to $0.173{\mu}m$, respectively. Moreover, the potential of the fabricated MCM-41 membrane was investigated by ultrafiltration of $Fe^{3+}$ from aqueous stream at various influencing parameters such as applied pressure, initial feed concentration and pH of solution. The maximum rejection 85% was obtained at applied pressure of 276 kPa and the initial feed concentration of 250 ppm at pH 2.

• 한국응용과학기술학회지
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• 제28권3호
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• pp.335-344
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• 2011

The pearlesent pigment has received attention in a diversity of fields like cosmetics, inks, paints and so on. Ferric Ferrocyanide, one of the nano sized pearlescent pigment, is a kind of surface modification pigment that covers a metal oxidized substance or a coloring agent with uniform thickness. Characteristics of pearlescent pigment are various interference color, intense gloss effect and a three-dimensional effect. We synthesised the pearlesent pigment that ferric ferrocyanide can be deposited on the titania/mica surface by hydrothermal synthesis method. The process parameters are concentration of precursor, controlling pH and reaction temperature. The optimun conditions is that amount of iron(III) chloride hexahydrate is 3.1 wt% and amount of potassim ferrocynide trihydrate is 3.6 wt% in the started pH 4.5 at $70^{\circ}C$. The coating rate and coating efficiency of ferric ferrocyanide was about 1.47 % and 96.7 %, respectively. The synthesised pearlesent pigment was characterized by SEM, XRD, FT-IR and EDS.

• 대한화학회지
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• 제19권6호
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• pp.454-462
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• 1975

금속의 착물을 첨가제로 사용하여 햇빛에 의한 고분자 물질의 분해를 빠르게 하고자 하였다. 첨가제는 햇빛의 자외선에 의해 들뜬상태가 되어 공기중의 산소를 들뜬 단일상태로 만들어 준다. 들뜬 산소는 고분자의 골격에 카르보닐기나 히드록실기와 같은 작용기를 만들어 주며 동시에 골격을 끊어준다. 이러한 작용기는 미생물에 의해 공격받기 쉬우므로 고분자물질은 점점 저분자 물질로 되어 분해된다 적외선 스펙트럼으로 이러한 작용기들의 생성을 측정하였으며, 점성도의 측정과 비교하여 이러한 기들의 생성이 분자량의 감소와 비례함을 알았다. 첨가제의 종류를 바꾸어 가며 그 효과를 비교함으로써 350${\sim}$400nm의 자외선에서 센 charge-transfer band를 가지는 금속착물이 효과가 좋으며 특히 철의 디티오카르밤산 착물과 그와 유사한 구조의 착물이 좋은 효과를 보여줌을 알았다.

• 한국식품영양학회지
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• 제26권3호
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• pp.515-525
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• 2013

This study was performed to investigate the characteristics of nutrient intake according to metabolic syndrome in Korean elderly. Data on 1,200 elderly (men 545, women 655) over 65 years was obtained from the Korea National Health and Nutrition Examination Survey 2010. The subjects were divided into metabolic syndrome (MetS) and normal groups based on NCEP-ATP III guidelines and by applying the Asia-Pacific definition with waist circumference. The prevalence of MetS was 48.9% in all subjects, 35.6% in men and 58.9% in women, respectively. All nutrient intake was significantly lower in MetS than normal subjects, except iron, vitamin A, carotene, and retinol. In the carbohydrate: protein: fat (C:P:F) ratio, MetS showed a higher rate for carbohydrate, but a lower rate for protein and fat than normal. MetS was lower in calcium, vitamin B1, and vitamin C by the nutrient adequacy ratio than normal. Mean adequacy ratio of MetS (0.69) was lower than that of the normal group (0.72). These results demonstrated that undernutrition, not excess intake of specific nutrients - energy, fat, or cholesterol was associated with the risk for MetS in Korean elderly with MetS. Therefore, it is recommended to have a healthy dietary pattern with diverse nutrients for the prevention of MetS.

• Journal of Magnetics
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• 제11권3호
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• pp.115-118
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• 2006

Co-ferrite nanoparticles have been synthesized by the decomposition of iron(III) acetylacetonate, $Fe(acac)_3$ and Co acetylacetonate, $Co(acac)_2$ in benzyl/phenyl ether in the presence of oleic acid and oleyl amine at the refluxingtemperature of $295^{\circ}C$/$265^{\circ}C$ for 30 min. before cooling to room temperature. Particle diameter detected by PSA can be turned from 4 nm to 20 nm by seed-mediated growth and reaction conditions. Structural and magneticcharacterization of Co-ferrite were measured by use of HRTEM, SAED (selected area electron diffraction), XRD and SQUID. The as-synthesized Co-ferrite nanoparticles have a cubic spinel structure and coercivity of 20 nm $CoFe_{2}O_{4} nanoparticles reached 1 kOe at room temperature and 18 kOe at 10 K.