• 자원리싸이클링
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• 제28권5호
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• pp.42-50
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• 2019

본 연구에서는 바나듐을 회수하기 위하여 수용액의 바나듐과 염화암모늄 침전반응에 관하여 고찰하였다. 바나듐 함유 수용액 pH 9.2 ~9.4에서는 결정구조가 [$NH_4VO_3$]인 암모늄메타바나데이트가 침전되었고, 바나듐 함유 수용액의 pH를 황산으로 조절하면 결정구조가 [$(NH_4)_2V_6O_{16}$]인 암모늄폴리바나데이트가 침전되었다. 암모늄폴리바나데이트[$(NH_4)_2V_6O_{16}$]는 바나듐 함유 수용액 pH 2에서는 침전온도 $80{\sim}90^{\circ}C$에서, 그리고 수용액 pH 6 ~ 8에서는 침전온도 $40^{\circ}C$에서 침전되었다. 또한 수용액 pH 2인 산성 영역에서 99% 이상의 침전률을 얻기 위해서는 수용액의 바나듐 함량이 3,000 mg/L 이상은 되어야 하며, 침전온도는 $80^{\circ}C$ 이상으로 유지해야 한다. 알칼리 영역에서 암모늄메타바나데이트를 침전시킬 때, 바나듐 함량은 10,000 mg/L 이상 그리고 침전온도는 $40^{\circ}C$로 유지해야 침전률을 높일 수 있었다. 알루미늄은 수용액의 바나듐 함량 및 pH에 상관없이 거의 침전이 일어나지 않았으나, 철 성분은 염화암모늄과 반응하여 암모늄 자로사이트 형태로 침전되며, 따라서 바나듐의 회수율을 높이기 위해서는 Fe 성분을 우선적으로 제거해야만 한다.

• Environmental Engineering Research
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• 제11권4호
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• pp.173-180
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• 2006

Autotrophic nitrogen removal and its microbial community from a laboratory scale upflow anaerobic sludge bed reactor were characterized with dynamic behavior of nitrogen removal and sequencing result of molecular technique (DNA extraction, PCR and amplification of 16S rDNA), respectively. In the experiment treating inorganic wastewater, the anaerobic granular sludge from a full-scale UASB reactor treating industrial wastewater was inoculated as seed biomass. The operating results revealed that an addition of hydroxylamine would result in lithoautotrophic ammonium oxidation to nitrite/nitrate, and also hydrazine would play an important role for the success of sustainable nitrogen removal process. Total N and ammonium removal of 48% and 92% was observed, corresponding to nitrogen conversion of 0.023 g N/L-d. The reddish brown-colored granular sludge with a diameter of $1{\sim}2\;mm$ was observed at the lower part of sludge bed. The microbial characterization suggests that an anoxic ammonium oxidizer and an anoxic denitrifying autotrophic nitrifier contribute mainly to the nitrogen removal in the reactor. The results revealed the feasibility on development of high performance lithoautotrophic nitrogen removal process with its microbial granulation.

• 한국표면공학회지
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• 제55권3호
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• pp.156-163
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• 2022

An ammonium ion with a size and charge similar to that of potassium can bind to valinomycin, which is used as an ion carrier for potassium, and cause a meaningful interference effect on the detection of potassium ions. Currently, there are few ion sensors that correct the interference effect of ammonium ions, and there are few studies that specifically suggest the mechanism of the interference effect. By fabricating a SPCE-based potassium ion-selective electrode, the electromotive force was measured in the concentration range of potassium in the nutrient solution, and the linear range was measured to be 10^-5 to 10^-2 M, and the detection limit was 10^-5.19 M. And the interference phenomenon of the potassium sensor was investigated in the concentration range of ammonium ions present in the nutrient solution. Therefore, a data-based analysis strategy using deep learning was presented as a method to minimize the interference effect.

• 한국세라믹학회지
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• 제43권10호
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• pp.635-639
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• 2006

Dispersion behavior of the slurries consisted of Pb or Bi-based glass frits, which are used for the fabrication of green sheet as PDP front panel transparent dielectric, was examined in non-aqueous solvent system. Measurements of sedimentation height and viscosity were conducted to determine proper dispersion condition in the various solvent and dispersant system. Azotropic compound and ethyl acetate were used as the solvent and ammonium-type dispersant was applied to the slurries. All slurries were dispersed well in azotropic solvent system involving 20$\sim$50 vol% ethyl acetate at 2$\sim$3 wt% dispersant content. Especially, dispersion behavior was notably improved in the addition of ethyl acetate in the Bi-based frit slurry.

• 분석과학
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• 제16권3호
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• pp.198-205
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• 2003

쿠페론은 nitrosophenylhydroxylamine의 ammonium salt로서 흡착촉매 벗김법 (AdCtSV)에서 리간드의 역할을 하고 동시에 촉매 역할을 한다고 알려져 있다. 순환 전압전류법을 이용하여, 1 mM 인산염 완충용액에서 오스뮴-쿠페론 착물의 전기화학적 행동을 살펴보았다. 오스뮴 정량의 최적 조건은 1 mM 인산염 완충용액 (pH 6.0), 0.1 mM 쿠페론의 용액에서 주사속도는 100 mV/s 이었다. 이 조건에서 농도 변화에 따른 선형 주사 전압곡선의 환원 봉우리 전류변화를 이용하여 얻은 오스뮴의 검출 한계 ($3{\sigma}$)는 $1.0{\times}10^{-7}M$이다.

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.645-651
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• 2005

• 한국환경과학회지
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• 제20권1호
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• pp.119-126
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• 2011

In this study, reaction model and reactions rate accelerated by o-iodosobenzoate ion(IB$^{\ominus}$) on hydrolysis reaction of p-nitrophenyl valate(NPV) using ethyl tri-octyl ammonium mesylate(ETAMs) for quaternary ammonium salts, the phase transfer catalysis(PTC) reagent, were investigated. The effect of IB$^{\ominus}$ on hydrolysis reaction rate constant of NPV was weak without ETAMs solutions. Otherwise, in ETAMs solutions, the hydrolysis reactions exhibit higher first order kinetics with respect to the nucleophile, IB$^{\ominus}$, and ETAMs, suggesting that reactions are occurring in small aggregates of the three species including the substrate(NPV), whereas the reaction of NPV with OH$^{\ominus}$ is not catalyzed by ETAMs. Different concentrations of NPV were tested to measure the change of rate constants to investigate the effect of NPV as substrate and the results showed that the effect was weak. This means the reaction would be the first order kinetics with respect to the nucleophile. This behavior for the drastic rate-enhancement of the hydrolysis is referred as 'Aggregation complex model' for reaction of hydrophobic organic ester with o-iodosobenzoate ion(IB$^{\ominus}$) in hydrophobic quarternary ammonium salt(ETAMs) solutions.

• 자원리싸이클링
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• 제27권2호
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• pp.48-54
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• 2018

강염기성 음이온 교환 수지인 Amberlite IRA 402와 AG 1-X8로 염화암모늄용액에 함유된 금(III)의 이온교환을 회분식 실험으로 조사했다. 두 수지 모두 염화암모늄용액에서 금(III)을 잘 흡착했으며, AG 1X-8이 Amberlite IRA 402보다 우수한 금(III) 흡착거동을 보였다. AG 1-X8 수지의 금(III)의 흡착은 Langmuir 등온흡착과 잘 일치했고 흡착용량은 355 mg/g이었다. AG 1X-8에 흡착된 금(III)은 과염소산으로 세출할 수 있으며, 과염소산의 농도 증가에 따라 세출률이 증가하였다.

• 한국자기공명학회논문지
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• 제6권2호
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• pp.132-141
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• 2002

$^1H$ nuclear magnetic resonance (NMR) relaxations have been investigated in ammonium sulfate $((NH_4)_2SO_4)$ power at temperatures ranging form 102 K to 440 K. There is a bottleneck in the spin-lattice relaxation between the nuclear spin system and the hindered rotation of ammonium ions, which is certified by measuring the relaxation according to the initial condition of the spin system. For temperatures below 318 K the $^1H$ spin-lattice relaxations have double-exponential behaviors with the exponent, n, having a value 2>n>1 initially and n=l after a long time. Above 318 K not only is the relaxation exponential initially with exponent n=1, but it is a single-exponential over the entire time, resulting in one $T_1$ value. The two types of $NH_4^+$ ions have different activation energies for hindered rotation, $E_a^1=0.27{\pm}0.02eV$ and $E_a^11=0.12{\pm}0.0eV$, in the ferroelectric phase.

• 융복합기술연구소 논문집
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• 제5권2호
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• pp.43-48
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• 2015

Deep eutectic solvents (DESs) are now broadly understood as a new kind of ionic liquid (IL) because they exhibit many characteristics and properties similar with ILs. The DESs made of quaternary ammonium salt blended with one of hydrogen bonding donor (HBD) compounds behave as ILs even at very low temperature. In this study, properties such as density, viscosity, surface tension, conductivity, and electrochemical behavior of DESs were reported and their applications were reviewed. Study on DESs has been drawn attention on application in metal finishing, but these solvents can be used in a variety of synthesis, and their potentials have been demonstrated in various areas. DESs are expected to offer applicability by extending the types of salts and hydrogen bond donor mixtures.