• Journal of the Korean Chemical Society
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• v.29 no.2
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• pp.121-128
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• 1985

The electrochemical reduction of uranyl ion in aqueous basic media has been examined by d. c. polarography, differential pulsed polarography and cyclic voltammetry. From voltammograms obtained in uranyl solutions containing 0.1M sodium bicarbonate, either with or without the same amounts of sodium tripolyphosphate it is concluded that the first wave corresponds to the reduction of $UO_2^{2+}$ to $UO_2^+$. It is assumed that the uranyl ion undergoes appreciable hydrolysis in these media. The hydrolysis product $UO_2OH^+$ from $UO_2^{2+}$ is not reduced at the first wave, but is reduced at the second wave together with $UO_2^+$. The diffusion current was found proportional to the uranyl concentration in a range between $7.5 {\times} 10^{-4}$ and $3.75 {\times}10^{-3}$M.

• Journal of the Korean Electrochemical Society
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• v.3 no.2
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• pp.69-71
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• 2000

Redox-active calix[4]arenes with carboxylic acid and disulfide groups were prepared and spontaneous deposition on silver and gold surfaces was observed. Owing to their unusual structure, the calix[4]arenes exhibit selective affinity fur alkaline earth metal ions in aqueous media. When annular ionophores are immobilized on the surface, voltammetric and spectroscopic studies show the entrapment of metal ions. Furthermore, it was possible to reversibly capture and remove the ions using strong chelating agents such as ethylenediaminetetraacetic acid (EDTA).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.5221-5231
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• 2010

The complex formation from Ni(II) ion and 2-(2-Hydroxyethylamino)-2-(hydroxymethyl)-1,3-propanediol(Monotris) in aqueous solution at $25^{\circ}C$ and at ionic strength of 0.10M has been studied potentiometrically. In the Monotris(L) comlex $NiL^{2+}$, hydroxyl oxygen atom as well as the amine nitrogen of the ligand are coordinated to the Ni(II) ion.. The complex $NiL^{2+}$ undergoes further dissociation as the pH is increased forming triply deprotonated dinuclear complex $Ni_2L_2H_{-3}^+$.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.243-243
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• 2003

무기 나노 입자와 유기물간의 균일한 화학적 결합으로 제조된 나노 구조형 재료는 수많은 용도에 부응할 수 있는 기계적, 전기적 및 광학적 특성을 설계, 제조하는데 유용한 방법으로 사용되고 있다. 이중 화학적 습식 졸-겔 공정은 나노 구조형 유/무기 하이브리드 재료 제조에 매우 효과적인 방법으로 알려져 있으며 내부식성 금속 코팅막, 내 스크래치 코팅막 제조에 활용되고 있다. 그러나 무기 나노 졸 입자와 유기물과의 매개로 작용하는 커플링제와의 하이브리드 과정에 대한 정보는 극히 조금 알려져 있다. 본 연구에서는 알루미나 나노 졸과 GPS((3-glycidoxypropyl-triethoxysilane)와의 하이브리드 생성 과정을 이온 전도도 측정으로 관찰한 결과를 보고하고자 한다. 알루미나 나노 졸은 Al(NO$_3$)$_3$.9$H_2O$ 수용액에 NH$_4$OH를 가하여 침전물을 얻고 여과 및 수세하여 졸 입자의 함량이 약 5 wt%가 되게 이온교환수와 해교제인 초산을 소량 가하여 10$0^{\circ}C$에서 약 50시간 열처리하는 방법으로 제조하였다. 알루미나 졸 입자와 GPS와의 결합 과정을 reactor FT-IR로 시간에 파라 연속적으로 분석하여 그 반응 경로를 이온 전기전도와 비교하여 논의 될 것이다. 아래 그림 1은 알루미나 나노 졸에 GPS를 첨가한 후 시간에 따라 얻어진 이온 전기전도도를 나타낸 그림이다.

• Resources Recycling
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• v.27 no.5
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• pp.9-13
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• 2018

The equilibrium constant of a chemical reaction is related to the standard Gibbs free energy change. Since equilibrium constant is defined as the ratio of the activities of the chemical species, it is necessary to consider the non-ideal behavior of the solutes as ionic strength of the solution increases. In this paper, the derivation of Debye-$H{\ddot{u}}ckel$ limiting law and its modification by which the activity coefficient of an ion can be calculated was explained. Moreover, the method to obtain the activity coefficient of an ion from the experimentally determined mean activity coefficients of an electrolyte was explained.

• Journal of the Korean Chemical Society
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• v.31 no.6
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• pp.503-508
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• 1987

The protonation constants of 3,4 : 9,10-dibenzo-1,12-diaza-5,8-dioxacyclotetradecane $(NenOenH_4)$ and stability constants of its transition metal complexes have been determined by the potentiometric titration in 1 : 1 dioxane-water mixture with 0.1 ionic strength at $25^{\circ}C.$ For a given anion system, the stabilitv constants of the complexes are in the order of $Mn^{2+}<\;Co^{2+}\;< Ni^{2+}\;<\;Cu^{2+}\;>\;Zn^{2+}$, which accords with the Williams-Irving series.

• Journal of the Korean Chemical Society
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• v.29 no.2
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• pp.137-143
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• 1985

Construction of a liquid membrane type of cupric ion selective electrode and its application to the potentiometric titration have been studied. A liquid ion-exchange membrance was prepared by extracting Cu(II) in aqueous solution into 1-(2-pyridylazo)-2-naphthol/nitrobenzene. A Ag/AgCl internal reference electrode was dipped into the aqueous reference solution of $1.00 {\times} 10^{-3}M\;Cu(NO_3)_2$ buffered with HAc-NaAc buffer solution, which was in contact with the nitrobenzene extract. The electrode showed the nernstian response to Cu(II) in the concentration range from $1.00{\times} 10^{-6}$ to $1.00{\times} 10^{-3}$M. The most suitable ion-exchanger concentration in the liquid membrane was $1.00{\times} 10^{-4}$M. The selectivity coefficients of the electrode for the various metal cations were investigated. The electrode was applied to the potentiometric titration of Cu(II) with EDTA.

• Analytical Science and Technology
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• v.11 no.5
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• pp.386-393
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• 1998

A new analytical luminescence method for the $Dy^{3+}$ ion was studied using the luminescence enhancement by the treatment of the o-phenanthroline on the TLC plate. Compared to the specific emission intensities of the ion in water solution, if the ion solution is spotted on the TLC plate, the luminescence intensities were extremely enhanced. There was additional enhancement effect of the luminescence intensities of the ions on the TLC plate, if the ion on the TLC plate is treated with o-phenanthroline. Based on the luminescence enhancement, the detection limit was improved by more than 4 order of magnitude compared to that of solution sample. The dynamic ranges and correlation coefficients of the calibration curves near the detection limit were 102 order and ~0.99, respectively. The energy-transfer mechanism was explained for the theoretical back ground of the luminescence enhancement.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.726-730
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• 2019

The removal of calcium ions using zeolite to solve problems of the CaCO₃ manufacturing process using cement kiln dust was investigated. To do so, a modified zeolite was employed and experiments were conducted to select the optimal zeolite type considered the binding cation and structure, evaluate the removal performance of calcium ions, the influence of the type and concentration of the modifying solution, and the removal selectivity when K coexists. Among five zeolites, 13X zeolite was found to have the best calcium ion removal performance, and it was confirmed that the removal performance was enhanced when KCl was used as a modifying solution instead of NaCl. This study is expected to be the basis for the solution of carbonation process and high concentration of KCl recovery technology.

• Analytical Science and Technology
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• v.23 no.6
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• pp.560-565
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• 2010

Perchlorate ion ($ClO_4^-$) has been widely used as oxidizing agent in military weapon system such as rocket and missile fuel propellant. So it has been challenging to remove the pollutant of perchlorate ion. nanoscale zero valence iron (nZVI) particles are widely employing reduction catalyst for decomposition of perchlorate ion. nZVI particles has increasingly been utilized in groundwater purification and waste water treatment. But it have strong tendency of aggregation, rapid sedimentation and limited mobility. In this study, we focused on reduction of perchlorate ion using nZVI particles immobilized in alginate polymer bead for stabilization. The stabilized nZVI particles displayed much greater surface area, and much faster reaction rates of reduction of perchlorate ion. In this study, an efficient way to immobilize nZVI particles in a support material, alginate bead, was developed by using $Ca^{2+}$ as the cross-linking cations. The efficiency and reusability of the immobilized Fe-alginate beads on the reduction of perchlorate was tested at various temperature conditions.