• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1526-1530
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• 2009

Solvent extraction reaction of Zn(II) by Alamine336 from strong HCl solution up to 10 M was identified by analyzing the data reported in the literature. The equilibrium constant of this reaction was estimated by considering the complex formation between zinc and chloride ion. The necessary thermodynamic parameters, such as equilibrium constant for the formation of complexes and the interaction parameters, were evaluated from the thermodynamic data reported in the literature. The following solvent extraction reaction and the equilibrium constant was obtained by considering the activity coefficients of solutes present in the aqueous phase with Bromley equation. $Zn^{2+}\;2Cl^{-}\;+\;R_3NHCl_{org}\;=\;ZnCl_3R_3NH_{org},\;K_{ex}\;=\;6.33\;{\times}\;10^2$ There was a good agreement between measured and calculated distribution coefficients of Zn(II).

• 한국주조공학회지
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• 제25권1호
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• pp.36-39
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• 2005

The thermodynamic analysis of deoxidation in molten coppyr by Fe has been made. Equilibrium oxygen solubility saturated with FeO in Cu-Fe-O system has been derived without and with consideration of the solute interaction between Fe and O. The derived relationship of oxygen contents with Fe has been compared with the experimental results done by Kulkarni and the minimum oxygen solubility could be predicted by a simple first order interaction method, Wagner model.

• Korean Chemical Engineering Research
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• 제47권6호
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• pp.755-761
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• 2009

일반적으로 비등점의 차이가 큰 물질들은 그 물리적 성질의 차이로 인해 혼합물에서 비이상적인 상거동을 보이며, 이러한 혼합물의 상거동 특성을 이해하기 위해서는 정확한 실험적 데이터가 필요하다. 본 연구에서는 재순환 평형조가 포함된 기-액 상평형 장치를 사용하여 10, 30, 60 kPa에서 톨루엔과 크레졸 혼합물에 대한 정압 기-액 평형 실험을 행하였다. 측정한 기-액 평형 데이터는 NRTL과 UNIQUAC 모델식을 이용하여 잘 적합할 수 있었으며 Gibbs/Duhem 식에 근거한 열역학적 건전성 테스트를 수행하여 실험결과의 건전성을 확인하였다. 한편, 혼합물의 과잉몰부피를 측정하여 Redlich-Kister 다항식으로 나타내었다.

• 공업화학
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• 제21권3호
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• pp.295-300
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• 2010

1-propanol과 bromochloromethane 혼합물은 공비점의 형성이나 큰 휘발성 차이 때문에 실제 증류탑이나 흡수탑 등의 단위 공정에서 효율적이고 경제적인 운전이 쉽지 않다. 이처럼 비이상성이 큰 혼합물을 효과적으로 다루기 위해서는 혼합물에 대한 기-액 평형 등의 열역학적인 정보가 필수적이다. 본 연구에서는 재순환 기-액 평형장치를 이용하여 일정 압력 하에서 30 kPa에서 70 kPa까지 1-propanol과 bromochloromethane 혼합물의 기-액 평형을 측정하였으며 얻어진 실험 데이터를 UNIQUAC과 NRTL 모델식을 이용하여 상관하였고 과잉 Gibbs 에너지와 활동도 계수를 추산하였다. 또한 Gibbs/Duhem식에 근거한 열역학적 건전성 테스트를 수행하였고 진동 밀도계를 사용하여 이성분계의 과잉 몰부피를 측정하였으며 그 결과를 Redlich-Kister다항식으로 상관하였다.

• Corrosion Science and Technology
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• 제3권5호
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• pp.198-208
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• 2004

Although there has been no general agreement on the mechanism of primary water stress corrosion cracking (PWSCC) as one of major degradation modes of Ni-base alloys in pressurized water reactors (PWR's), common postulation derived from previous studies is that the damage to the alloy substrate can be related to mass transport characteristics and/or repair properties of overlaid oxide film. Recently, it was shown that the oxide film structure and PWSCC initiation time as well as crack growth rate were systematically varied as a function of dissolved hydrogen concentration in high temperature water, supporting the postulation. In order to understand how the oxide film composition can vary with water chemistry, this study was conducted to characterize oxide films on Alloy 600 by an in-situ Raman spectroscopy. Based on both experimental and thermodynamic prediction results, Ni/NiO thermodynamic equilibrium condition was defined as a function of electrochemical potential and temperature. The results agree well with Attanasio et al.'s data by contact electrical resistance measurements. The anomalously high PWSCC growth rate consistently observed in the vicinity of Ni/NiO equilibrium is then attributed to weak thermodynamic stability of NiO. Redox-induced phase transition between Ni metal and NiO may undermine the integrity of NiO and enhance presumably the percolation of oxidizing environment through the oxide film, especially along grain boundaries. The redox-induced grain boundary oxide degradation mechanism has been postulated and will be tested by using the in-situ Raman facility.

• Bulletin of the Korean Chemical Society
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• 제7권6호
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• pp.448-453
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• 1986

Two contributions to the activation barrier of the $S_N2$ reaction, intrinsic and thermodynamic, are discussed in connection with the predictive power of various rate-equilibrium relationships. It has been shown that the PES models can only give correct predictions of changes in structure and energy of the transition state if the activation barrier is dictated by the thermodynamic factor. We concluded that the identity and dissociative $S_N2$ reactions are dominated by the intrinsic component while associative $S_N2$ reactions are predominantly of thermodynamic controlled. Thus in the former cases, the PES models fail, whereas in the latter cases predictions based on the intrinsic factor, the quantum mechanical models, fail. Finally in a general case of equal contributions by thermodynamic and intrinsic factors, the $SN_2$ reaction proceeds by a synchronous process with zero net charge on the reaction center, for which predictions of substituent effects will be the same as for the intrinsic control case.

• 청정기술
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• 제20권3호
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• pp.290-297
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• 2014

본 연구에서는 활성탄을 사용하여 coomassi brilliant blue G (CBBG)염료를 흡착하는데 필요한 흡착평형과 흡착동역학 및 열역학 파라미터들에 대하여 조사하였다. 등온흡착평형관계로 부터 Langmuir 식과 Freundlich 식의 분리계수를 평가하여 활성탄에 의한 CBBG의 흡착조작이 유효한 처리방법이 될 수 있음을 알았고, Dubinin-Radushkevich 식으로부터 흡착공정이 물리흡착공정임을 알았다. 흡착공정에 대한 동력학적 해석을 통해 흡착반응은 유사이차반응속도식이 유사일차반응속 도식에 비해 일치도가 높은 것으로 나타났으며, 입자내확산이 흡착공정의 지배단계임을 알았다. 유사이차반응속도식을 적용한 열역학적 해석을 통해 평가된 엔탈피 변화값(406.12 kJ/mol)으로부터 흡착공정이 흡열반응으로 진행됨을 알았다. 또한 엔트로피 변화값(1.66 kJ/mol K)은 흡착공정의 무질서도가 증가한다는 것을 나타내었다. 온도가 올라갈수록 자유에너지 값이 감소하는 경향을 보인 것은 활성탄에 대한 CBBG의 흡착반응은 온도가 올라갈수록 자발성이 높아지는 것으로 판단되었다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.60-61
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• 2006

In this contribution, we attempted a theoretical analysis on the validity of the widely-accepted idea that rough and singular surfaces can coexist in a crystal at equilibrium. By manipulating the Cahn and Hoffman capillarity vector, the conclusion that a crystal at equilibrium should be composed either of singular surfaces or of rough ones was reached.

• Membrane and Water Treatment
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• 제5권4호
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• pp.295-304
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• 2014

Adipic acid (hexane-1,6-dioic acid) is one of the most used chemical in industrial applications. This must be separated from any environmental contaminant. In this study, adipic acid separation from wastewater by adsorption method onto Perlite or Perlite + Mn or Perlite + Cu composites was investigated. Adsorption of Adipic acid was investigated in terms of equilibrium, and thermodynamic conditions. For thermodynamic investigations the experiments carried out at three different temperatures (298 K, 318 K, 328 K). In the equilibrium studies, 2 g of perlite and its composites were determined as the optimal adsorbent amount. Freundlich and Langmuir isotherms were applied to the experimental data. Freundlich isotherms for all temperatures used in this work gave some deviations with R square values under 0.98 where as Langmuir isotherm gave good results with R square values upper 0.99 at different temperatures. As a result of thermodynamic studies, adsorption enthalpy (${\Delta}H$), adsorption entropy (${\Delta}S$), and adsorption free energy (${\Delta}G$) have been calculated for each adsorbents.

• 한국세라믹학회지
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• 제49권1호
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• pp.11-18
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• 2012

The characteristic features of solid oxide fuel cells are reviewed from the viewpoint of the thermodynamic variables to be developed inside cells/stacks particularly in terms of gradients of chemical potential, electrical potential and temperature and corresponding flows of air, fuel, electricity and heat. Examples of abrupt destruction of SOFC systems were collected from failures in controlling their steady flows, while continuous degradation was caused by materials behaviors under gradients of chemical potentials during a long operation. The local equilibrium approximation has been adopted in NEDO project on the durability/reliability of SOFC stacks/systems; this makes it possible to examine the thermodynamic stability/reactivity as well as mass transfer under the thermodynamic variable gradients. Major results of the NEDO project are described with a focus on degradation/deterioration of electrolyte and electrode materials.