• 전기화학회지
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• 제7권3호
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• pp.148-154
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• 2004

Nonactin을 이온 운반물질(ionophore)로, poly(vinyl chloride) (PVC) 또는 polyurethane (PU)을 지지체로, 그리고 bis(2-ethylhexyl)adipate을 가소제로 사용하여 제작한 암모늄이온 선택성전극의 성능을 비교한다. PU-전극의 검출한계를 PVC전극에 비해 더 낮게 제작할 수 있는 것을 제외하고는 PVC전극이 PU전극에 비하여 그 성능이 우수하였으며 이를 설명하기 위하여 AFM 형상과 임피던스 측정 등을 하였다. PU-전극이 PVC에 비하여 이온 이동에 대한 저항이 더 큰 것으로 보아 더 단단한 막을 형성하여 더 낮은 검출 한계를 가지며 수명이 긴 전극으로 발전시킬 수 있을 것으로 보인다.

• 방사성폐기물학회지
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• 제20권2호
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• pp.193-207
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• 2022

Thermodynamically, TRUO_x, REO_x, and SrO_x can be chlorinated using ammonium chloride (NH₄Cl) as a chlorinating agent, whereas uranium oxides (U₃O₈ and UO₂) remain in the oxide form. In the preliminary experiments of this study, U₃O₈ and CeO₂ are reacted separately with NH₄Cl at 623 K in a sealed reactor. CeO₂ is highly reactive with NH₄Cl and becomes chlorinated into CeCl₃. The chlorination yield ranges from 96% to 100%. By contrast, U₃O₈ remains as UO₂ even after chlorination. We produced U/REO_x- and U/SrO_x-simulated fuels to understand the chlorination characteristics of the oxide compounds. Each simulated fuel is chlorinated with NH₄Cl, and the products are dissolved in LiCl-KCl salt to separate the oxide compounds from the chloride salt. The oxide compounds precipitate at the bottom. The precipitate and salt phases are sampled and analyzed via X-ray diffraction, scanning electron microscope-energy dispersive spectroscopy, and inductively coupled plasma-optical emission spectroscopy. The analysis results indicate that REO_x and SrO_x can be easily chlorinated from the simulated fuels; however, only a few of U oxide phases is chlorinated, particularly from the U/SrO_x-simulated fuels.

• Journal of the Korean Wood Science and Technology
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• 제12권2호
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• pp.10-19
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• 1984

The $3{\times}3{\times}30$ ($cm^3$) sized lumbers of Populus alba-grandulosa L. were treated with four fire-retardant solutions of ammonium sulfate, monoammonium phosphate, diammonium phosphate and aluminium chloride for 1, 15, 30, and 60 minutes and 1, 3, and 7 days. Thereafter they were air-dried and burned at high temperature about $1,800^{\circ}C$ and for short time of five minutes. This study estimated the relationship between absorbed chemical amounts and rate of weight loss or residual bending strength of these burned lumbers. The results were as follows: 1) In absorption amount of fire-retardant chemicals, diammonium phosphate showed the largest, aluminium chloride the smallest, but monoammonium phosphate and ammonium sulfate showed similar level. 2) The absorption amount of chemicals was decreased with the increase of specific gravity in the same species except aluminium chloride. 3) The rate of weight loss was decreased as the absorption amount of chemicals increased, especially monoammonium phosphate was most effective. 4) The MOR value of the residual bending strength was increased as the absorption amount of chemicals increased and especially monoammonium phosphate showed the most efficient effect. 5) Aluminium chloride showed more striking increase of MOR value of residual bending strength with the increase of absorption amount than any other chemical, therefore its MOR value was similar to the maximum MOR value of the most effective monoammonium phosphate. 6) The correlation between weight loss and MOR value of the residual bending strength was negative and aluminium chloride showed the most striking negative relation, but the others showed similar trends. 7) The correlation between work to proportional limit and absorption amount of chemicals was positive and the degree of increase in work to proportional limit was most in aluminium chloride, and the next, in monoammonium phosphate and diammonium phosphate in turn. 8) The correlation between work to maximum load and absorption amount of chemicals showed positive and diammonium phosphate revealed the best result and aluminium chloride showed better results than other two chemicals.

• 대한화학회지
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• 제19권4호
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• pp.225-232
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• 1975

용리액의 pH변화에 따른 몰리브덴산과 텅스텐산의 용리곡선과 이들 산의 분리조건을 얻었다. 이 용리곡선으로부터 이들 산의 중합반응의 평형상수를 크롬산과 중크롬산의 중합반응의 결과와 비교하여 계산했고 분리조건을 pregnant 용액 분리에 적용했다. 이때 얻은 이들산의 중합평형상수 값은 다음과 같다. $7MoO_4^{2-}+8H^+{\longleftrightarrow}Mo7O_{24}^{6-}+4H_2O K=4{\times}10^{53},$$6WO_4^{2-}+7H^+{\longleftrightarrow}HW_6O_{21}^{5-}+3H_2O K=3{\times}10^{54}.$ 이온 교환크로마토그라피를 이용하여 프레그난트용액중의 탄산염을 분리하는 데는 pH8의 0.2M 염화나트륨 용액을 사용했고 몰리브덴을 분리하는데는 pH5의 0.05M $Na_2SO_4+0.5M NH_4Cl$ 혼합용액을, 텅스텐을 분리하는데는 pH 10의 0.5M 염화암모늄 용액을 단계적으로 사용하여 정량적으로 분리했다. 이때 텅스텐은 염화암모늄 용액을 용리액으로 사용했기 때문에 직접 APT(Ammonium para-tungstate)형태로 얻어졌다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.107-110
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• 2003

Reduction of nitrate by zero valent iron (Fe$^{0}$ ) has been previously studied, but the proper treatment for the by-product of ammonium has not been reported. However, in terms of nitrogen contamination, ammonium may be regarded as another form of nitrogen contaminants since it can be oxidized to nitrate again under aerobic conditions. This study is focused on simultaneous removal of nitrate and its by-product of ammonium, with the ZanF (Zeolite anchored Fe), a product derived from zeolite modified by Fe(II) chloride followed by reduction with sodium borohydride. Batch experiments were performed without buffer at two different pH condition with ZanF, iron filing, Fe(II)-sorbed zeolite, and pure zeolite to estimate the nitrate reduction and the ammonium production. At higher pH, removal rate of nitrate was reduced in both ZanF and iron filings. ZnF removed 60 % of nitrate at initial pH of 3.3 with no production of ammonium, while iron filing showed equivalent production of ammonium to the reduced amount of nitrate. In terms of nitrogen contamination, ZanF removed about 60 % and 40 % at initial pH of 3.3 and 6, respectively, while iron filing presented negligible removal against total nitrogen including nitrate and ammonium.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1465-1470
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• 2004

A short and efficient synthesis, solvent extraction and potentiometric measurements of new thiazole-containing naphtho-crown ethers are reported. The naphthalene moiety enhances the ammonium ion selectivity over potassium ion. The selectivity of ${NH_4}^+/K^+$ follows the trend $3\;{\approx}\;2\;>\;1$, indicating that the differences in conformational changes of 2 and 3 in forming ammonium complexes affect little on the resulting ammonium/potassium extraction selectivity ratio. The ammonium ion-selective electrodes were prepared with noctylphenyl ether plasticized poly(vinyl chloride) membranes containing 1-4 the effect of one naphthalene unit introduced on either right (2) or left (3) side of thiazolo-crown ether on their potentiometric properties (e.g., ammonium ion selectivity over other cations, response slopes, and detection limits) were not apparent. However, the ammonium ion selectivity of 1, 2 and 3 over other alkali metal and alkaline earth metal cations is 10-100 times higher than that of nonactin.

• Journal of the Korean Wood Science and Technology
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• 제43권5호
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• pp.672-681
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• 2015

As a part of abating the formaldehyde emission of amino resin-bonded wood-based composite panels, this study was conducted to investigate hydrolytic stability of urea-melamine-formaldehyde (UMF) resin depending on various hydrolysis conditions and hardener types. Commercial UMF resin was cured and ground into a powdered form, and then hydrolyzed with hydrochloric acid. After the acid hydrolysis, the concentration of liberated formaldehyde in the hydrolyzed solution and mass loss of the cured UMF resins were determined to compare their hydrolytic stability. The hydrolysis of cured UMF resin increased with an increase in the acid concentration, time, and temperature and with a decrease in the smaller particle size. An optimum hydrolysis condition for the cured UMF resins was determined as $50^{\circ}C$, 90 minutes, 1.0 M hydrochloric acid and $250{\mu}m$ particle size. Hydrolysis of the UMF resin cured with different hardener types showed different degrees of the hydrolytic stability of cured UMF resins with a descending order of aluminum sulfate, ammonium chloride, and ammonium sulfate. The hydrolytic stability also decreased as the addition level of ammonium chloride increased. These results indicated that hardener types and level also had an impact on the hydrolytic stability of cured UMF resins.

• 한국염색가공학회지
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• 제32권4호
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• pp.265-273
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• 2020

In this study, octadecyldimethyl(3-triethoxy silylpropyl)ammonium chloride (ODDMAC) incorporated with Polyethylene terephthalate (PET) fabrics with different environmental conditions such as various temperature and time intervals. First, ODDMAC (15 weight %) was dissolved in ethanol. Then PET fabrics immersed in the ODDMAC solution at 25 ℃ for 10 minutes and dried at 80 ℃ for 5 minutes. The dried PET/PDDMAC fabrics carried out for curing process out at 110 ℃ ~ 190 ℃. The treated PET/ODDMAC has examined the surface and side coating properties through SEM analysis and elemental analysis. PET/ODDMAC fabric washed with water up to 50 times and studied the durability of the materials. It was confirmed that the treated PET fabric also exhibited good water repellency. In addition, the antimicrobial activity against the gram-positive bacteria Staphylococcus aureus and gram-negative bacteria Escherichia coli were studied by the disc diffusion method on the treated fabric.

• Animal Bioscience
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• 제35권4호
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• pp.631-637
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• 2022

Objective: Surface disinfection is important in the proper running of livestock farms. However, disinfection of farm equipment and facilities is difficult because they are made of different materials, besides having large surface areas and complex structures. 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (Si-QAC) is a quaternary ammonium salt-based disinfectant that attaches to various surfaces by forming covalent bonds and maintains its disinfecting capacity for a considerable time. Our aim was to evaluate the potential use of Si-QAC for disinfection of farm equipment and facilities. Methods: The short- and long-term antimicrobial and antiviral effects of Si-QAC were evaluated in both laboratory and farm settings using modified quantitative assessment method based on the standard operating procedures of the United States Environmental Protection Agency. Results: Si-QAC was highly effective in controlling the growth of the Newcastle disease virus and avian pathogenic Escherichia coli. Electron microscopy revealed that the mechanism underlying the disinfection activity of Si-QAC was associated with its ability to damage the outer membrane of the pathogen cells. In the field test, Si-QAC effectively reduced viral contamination of surfaces of equipment and space. Conclusion: Our results suggest that Si-QAC has great potential as an effective chemical for disinfecting farm equipment and facilities. This disinfectant could retain its disinfection ability longer than other commercial disinfectants and contribute to better farm biosecurity.

• 자원리싸이클링
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• 제30권6호
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• pp.3-11
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• 2021

본 연구에서는 소듐바나데이트 수용액에 염화암모늄을 첨가하여 암모늄메타바나데이트를 침전시킬 때, 암모늄메타바나데이트의 용해도와 암모늄이온의 분해율이 침전반응에 미치는 영향을 알아보았다. 침전온도와 수용액 pH가 증가함에 따라 암모늄 이온의 분해율이 증가하였으며 45 ℃에서 수용액 pH 9.3일 때 분해율은 81% 이상으로 pH 8일 때와 비교하였을 때 약 4배 정도 증가하였다. 그러므로 침전 반응에 큰 영향을 미치는 침전온도와 수용액 pH 두 인자를 고려하여 침전반응을 수행한 결과, 침전온도가 증가함에 따라 침전속도가 증가하였으나 35 ℃ 이상에서는 침전온도의 영향이 크지 않았다. 침전반응 속도론적 고찰을 통하여 얻은 침전반응의 활성화 에너지는 42.3 kJ/mol이었다. 이와 같은 연구를 통하여 암모늄메타바나데이트의 용해도를 고려하였을 때 침전온도는 낮을수록 바나듐 회수율에 유리하였다. 또한 암모늄 이온의 분해를 고려하였을 때 수용액의 pH는 낮을수록 유리하나 pH 8 이하에서는 소듐폴리바나데이트가 침전되며 바나듐 산화물의 순도 저하가 야기될 수 있었다.