• 분석과학
• /
• 제28권5호
• /
• pp.341-346
• /
• 2015

In order to understand the counter anionic effects in a non-aqueous vanadium redox flow battery (VRFB), we synthesized four types of electrolyte salts (1-ethyltriethamine tertafluoroborate, [E-TEDA]⁺[BF₄]⁻, 1-ethyltriethamine hexafluorophosphate, [E-TEDA]⁺[PF₆]⁻, 1-butyltriethylamine tertafluoroborate, [B-TEDA]⁺[BF₄]⁻, and 1-buthyltriethamine hexafluorophosphate [B-TEDA]⁺[PF₆]⁻) by counter anion exchange reaction after the SN₂ reaction. We confirmed the successful synthesis of the electrolyte salts [E-TEDA]⁺[Br]⁻ and [B-TEDA]⁺[Br]⁻ via ¹H-NMR spectroscopy and GC-mass analysis before the counter anion exchange reaction. The electric potential of the vanadium acetylacetonate, V(acac)₃, as an energy storage chemical was shown to be 2.2 V in the acetonitrile solvent with each of the [E-TEDA]⁺[BF₄]⁻, [E-TEDA]⁺[PF₆]⁻, [B-TEDA]⁺[BF₄]⁻, and [B-TEDA]⁺[PF₆]⁻ electrolyte salts. In a non-aqueous VRFB with a commercial Neosepta AFN membrane, the maximum voltages reached 1.0 V and 1.5 V under a fixed current value of 0.1 mA in acetonitrile with the [E-TEDA]⁺[BF₄]⁻ and [E-TEDA]⁺[PF₆]⁻ electrolyte salts, respectively. The maximum voltage was 0.8 V and 1.1 V under a fixed current value of 0.1 mA in acetonitrile with the [B-TEDA]⁺[BF₄]⁻ and [B-TEDA]⁺[PF₆]⁻ electrolyte salts, respectively. From these results, we concluded that in the non-aqueous VRFB more of the [PF₆]⁻ counter anion than the [BF₄]⁻ counter anion was transported onto the commercial Neosepta AFN anion exchange membrane.

• 한국환경과학회지
• /
• 제9권3호
• /
• pp.261-266
• /
• 2000

A kinetic study for nitrate removal by anion exchange resin was performed using continuous column reactors. Kinetic approach from the packed bed showed the reaction rate constant k$_1$ was 0.07~0.17 $\ell$/mgㆍhr and maximum exchange quantity q$_{o}$ was 27.75~31.81 mg/g. The results from the continuous column well agreed with that from the batch reactor. An economic analysis of the water treatment plant by anion exchange resin with a regenerating system was performed to design plant and process. Based on the treatment of 20 mg/$\ell$ nitrate-contained wastewater of 10,000 gallons per day to 2 mg/$\ell$, total capital cost and total annual cost are estimated to be 836 million wons and 211 million wons, respectively.y.

• 한국산학기술학회논문지
• /
• 제3권3호
• /
• pp.194-197
• /
• 2002

이온교환은 액체상 이온과 고체상 이온간의 화학반응이며 연수 및 탈염공정, 특정물질의 제거 및 회수, 토양을 통한 이온성 물질의 이동에서 널리 이용되고 있다. 이온 선택도는 원자가가 높을수록, 수화반경이 작을수록 증가한다. 본 연구는 평형 이온교환에서 결정된 이온 선택도가 칼럼 이온교환에 적용되는 가를 조사하였다. 음이온 교환수지에 대한 이온 선택도 순서는 OH/sup -/ < F/sup -/ < HCO/sup -/ < Cl/sup -/ < Br/sup -/ ≤ NO₃/sup -/ < SO₄/sup 2-/ 이였으며, 음이온 칼럼교환에서도 동일하였다. 또한 바탕 양이온의 전하가 낮을수록 이온교환이 빠르게 진행됨을 알 수 있었다.

• Nuclear Engineering and Technology
• /
• 제46권1호
• /
• pp.93-100
• /
• 2014

The paper deals with the application of radio isotopic non-destructive technique in the characterization of two industrial grade anion exchange resins Indion GS-300 and Indion-860. For the characterization of the two resins, $^{131}I$ and $^{82}Br$ were used as tracer isotopes to trace the kinetics of iodide and bromide ion-isotopic exchange reactions. It was observed that the values of specific reaction rate ($min^{-1}$), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log $K_d$ were calculated as 0.328, 0.577, 0.189 and 19.7 respectively for Indion GS-300 resin, which was higher than the respective values of 0.180, 0.386, 0.070 and 17.0 calculated for Indion-860 resins when measured under identical experimental conditions. Also at a constant temperature of $40.0^{\circ}C$, as the concentration of labeled iodide ion solution increases 0.001 M to 0.004 M, the percentage of iodide ions exchanged increases from 75.16 % to 78.36 % for Indion GS-300 resins, which was higher than the increases from 49.65 % to 52.36 % compared to that obtained for Indion-860 resins. The overall results indicate that under identical experimental conditions, Indion GS-300 resins show superior performance over Indion-860 resins.

• 한국재료학회지
• /
• 제28권11호
• /
• pp.633-639
• /
• 2018

In anion exchange membrane fuel cells, Pd nanoparticles are extensively studied as promising non-Pt catalysts due to their electronic structure similar to Pt. In this study, to fabricate Pd nanoparticles well dispersed on carbon support materials, we propose a synthetic strategy using mixed organic ligands with different chemical structures and functions. Simultaneously to control the Pd particle size and dispersion, a ligand mixture composed of oleylamine(OA) and trioctylphosphine(TOP) is utilized during thermal decomposition of Pd precursors. In the ligand mixture, OA serves mainly as a reducing agent rather than a stabilizer since TOP, which has a bulky structure, more strongly interacts with the Pd metal surface as a stabilizer compared to OA. The specific roles of OA and TOP in the Pd nanoparticle synthesis are studied according to the mixture composition, and the oxygen reduction reaction(ORR) activity and durability of highly-dispersed Pd nanocatalysts with different particles sizes are investigated. The results of this study confirm that the Pd nanocatalyst with large particles has high durability compared to the nanocatalyst with small Pd nanoparticles during the accelerated degradation tests although they initially indicated similar ORR performance.

• 전기화학회지
• /
• 제25권2호
• /
• pp.69-80
• /
• 2022

고순도 수소생산을 위한 음이온 교환막 수전해는 양성자 교환막 수전해 시스템에서 사용되는 기존 귀금속 촉매 대신 저렴한 비귀금속 기반 촉매를 사용하여 차세대 녹색 수소 생산 기술로 많은 관심을 받고 있다. 하지만 음이온 교환막 수전해 기술은 개발 초기 단계이기 때문에 음이온 교환막 수전해의 핵심 요소인 음이온 교환막, 이오노머, 전극지지체 및 촉매에 관한 연구 수행이 필요하다. 그 중, 현재 촉매 분야에서 진행되고 있는 연구들은 기개발된 알칼리용 반쪽전지 촉매를 음이온 교환막 시스템에 적용하는 방향의 연구가 진행되고 있으며 적용된 촉매는 낮은 활성도와 내구성의 문제점을 가진다. 이에 본 총설은 알칼리성 매질에서 비귀금속 기반 촉매를 사용하여 산소발생반응 및 수소발생반응을 촉진시킨 촉매 합성 기술을 제시하였다.

• Journal of Nuclear Fuel Cycle and Waste Technology
• /
• 제1권1호
• /
• pp.57-63
• /
• 2013

Natural green rust (GR) can retard the migration of anions through geological media because it has a Layer Double Hydroxyl (LDH) structure with a positive charge. In this study, the sorption behaviors of anions such as selenite ($Se(IV)O{_3}^{2-}$), selenate ($Se(VI)O{_4}^{2-}$), and iodide ($I^-$) onto green rusts with different structures, i.e., GR($Cl^-$) and GR($CO{_3}^{2-}$), were investigated by conducting batch sorption experiments in an anoxic condition. Experimental results showed that selenite was mostly sorbed onto GR($CO{_3}^{2-}$) and then partly reduced to metal selenium, Se(0). However, little selenate and iodide was sorbed onto GR($CO{_3}^{2-}$) while some iodide was sorbed onto GR($Cl^-$). It is presumed from the experimental results that the major sorption mechanism of $SeO{_3}^{2-}$ and $I^-$ onto green rusts is the anion exchange reaction with the anions existing in the interlayer of the rusts. Green rust, therefore, can play an important role in the retardation of anions migrating through deep geological environments owing to its LDH structure with a high anion exchange capacity.

• 한국수소및신에너지학회논문집
• /
• 제33권6호
• /
• pp.715-722
• /
• 2022

Pt-Fe/carbon black nanocatalysts were prepared by spontaneous reduction reaction of Platinum(II) acetylacetonate and Iron(II) acetylacetonate in a nucleophilic solvent and they were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analyzer (EDS), thermogravimetric analyzer (TGA), transmission electron microscopy (TEM), Brunauer, Emmett and Teller (BET) surface area analysis and anion exchange membrane (AEM) water electrolysis test station. The distribution of the Pt and Fe nanoparticles on carbon black was observed by TEM, and the loading weight of Pt-Fe nanocatalysts on the carbon black was measured by TGA. Elemental ratio of Fe:Pt was estimated by EDS and it was found that elemental ratio of Pt and Fe was changed in the range of 1:0 to 0:1, and the loading weight of Pt-Fe nanoparticles on the carbon black was 5.95-6.78 wt%. Specific surface area was greatly reduced because Pt-Fe nanocatalysts blocked the pores. I-V characteristics were estimated.

• Bulletin of the Korean Chemical Society
• /
• 제3권2호
• /
• pp.66-70
• /
• 1982

The question of the bicyclohomoaromatic stabilization and destabilization is examined. The chemistry of bicyclo(3.2.1)octa-3,6-dienide anion has been studied on order to test these concepts. The bicyclooctadienide anion is shown to be stable delocalized ion which undergoes a facile proton-deuterium exchange reaction. The solvolysis of bicyclo(3.2.1)octa-3,6-dienyl p-nitrobenzoate is much slower than the monoene analog. We have made direct observation of the bicyclooctadienyl and octenyl cations by $^{19}F$-nmr spectroscopy, and were able to demonstrate that the bicyclooctadienyl cation was bishomoantiaromatic.

• 자원리싸이클링
• /
• 제31권6호
• /
• pp.25-35
• /
• 2022

본 연구는 겔 타입의 음이온교환 수지를 이용하여 바나듐과 텅스텐 이온의 흡·탈착 거동과 분리조건을 규명하였다. 용액의 초기산도에 따른 흡착실험에서 바나듐은 강산성 및 강염기성에서 흡착률이 현저히 낮아지며, 텅스텐은 강염기성에서 흡착률이 낮게 나타났다. 반응온도의 상승은 흡착반응속도 및 최대흡착량의 증가에 영향을 주었으며, 텅스텐은 최대흡착량에 미치는 영향이 미미하였다. 이온교환 수지에 대한 바나듐과 텅스텐의 흡착등온실험은 두 이온 모두 Langmuir 흡착등온식에 적합하였으며, 텅스텐의 경우 폴리옥소메탈레이트화 되어 이온 간의 결합이 이루어져 다분자층 흡착의 형태가 나타나 Freundlich 흡착등온식에도 적합한 것으로 나타났다. 두 이온교환 수지 모두 유사 2차 반응속도모델에서 잘 모사되었으며, 탈착용액의 종류에 따른 바나듐과 텅스텐의 탈착특성에서 바나듐은 HCl 수용액 및 NaOH 수용액 모두 탈착이 이루어 졌으며, 텅스텐은 HCl 수용액에서 탈착이 전혀 이루어지지 않아 탈착공정을 통한 두 이온의 분리가 가능하였다. 탈착반응은 반응 개시 후 30분 이내에 평형에 도달하였으며, 90% 이상 회수가 가능하였다.