• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.579-584
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• 2005

The 3-[(2-furylmethylene)amino]-2-thioxo-1,3-thiazolidin-4-one (FTT) was used as an excellent ionophore in construction of a $Zn^{2+}$ PVC-based membrane sensor. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride), 62% nitrobenzen (NB), 3% FTT and 5% sodium tetraphenyl borate (TBP). This membrane sensor shows very good selectivity and sensitivity towards $Zn^{2+}$ over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The membrane sensor revealed a great enhancement in selectivity coefficients for $Zn^{2+}$ ions, in comparison to the previously reported $Zn^{2+}$ membrane sensors. Theoretical studies also showed the selective interaction of TFF and $Zn^{2+}$ ions. The proposed membrane sensor exhibits a Nernstian behavior (with slope of 29.3 ${\pm}$ 0.3 mV per decade) over a wide concentration range (1.0 ${\times}$ $10^{-6}$-1.0 ${\times}$ $10^{-2}$) with a detection limit of 8.5 ${\times}$ $10^{-7}$ M (52 ng mL$^{-1}$). It shows relatively fast response time, in the whole concentration range ($\lt$ 20 s), and can be used for at least 10 weeks in a pH range of 3.0-7.0. The proposed membrane sensor was successfully used in direct determination of $Zn^{2+}$ ions in wastewater of industrial zinc electroplating companies, and also as an indicator electrode in titration with EDTA.

• Elastomers and Composites
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• 제47권2호
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• pp.129-140
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• 2012

본 연구에서는 현실적으로 실현가능한 플라스틱 제품의 재활용률을 산정하기 위하여 PVC프로파일에 대한 물질흐름도를 작성하는 것을 목적으로 연구가 수행되었다. 이를 위해 합성수지 및 제품별 생산 현황 조사, 폐기물 발생 및 재활용 현황 조사, 재활용 실태 현황 조사, 제품별 물질흐름 검토를 거쳐 내구성 플라스틱의 발생부터 폐기까지의 조사를 실시하여 물질흐름도를 작성하였다. 제품별 재활용이 가능한 비율을 산정한 결과, PVC바닥재와 PVC프로파일의 경우 국내에서 사용된 제품의 내수량의 합이 525,448톤이고, 폐기물 배출량은 105,853톤으로 나타났다. 재생제품과 재활용원료의 생산량 합계는 76,004톤으로 제품의 내수량에 대비하면 2009년 의무량 8.5%에 비교하여 연구를 통한 재활용량은 추정량 14.46%로 산출되었다. 향후 각 품목의 연도별 사용량은 해당제품의 생산량이 현재와 크게 차이가 없을 것으로 가정하고 연도별 생산량에 대입한 후 5~20년 뒤의 물질수지도를 작성한 결과, 재활용률은 지속적으로 상승하여 바닥재 및 프로파일은 2013년에 20% 수준의 재활용률에 도달될 것으로 예측되었다.

• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1418-1422
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• 2006

In this work the construction of a novel poly(vinyl chloride) membrane sensor based on 2,2'-dianiline disulfide (DADS) as a neutral carrier, o-nitrophenyloctyl ether (NPOE) as a plasticizer and sodium tetraphenyl borate (NaTPB) as an anionic site with unique selectivity towards Tm(III) ions is reported. The electrode has a linear dynamic range between $1.0\;{\times}\;10^{-6}$ and $1.0\;{\times}\;10^{-2}$ M, with a nice Nernstian slope of 19.5 ${\pm}$ 0.3 mV per decade and a detection limit of $4.0\;{\times}\;10^{-7}$ M at the pH range of 4.8-8.5. It has a very fast response time (<15 s) in the whole concentration range, and can be used for at least 4 weeks without any considerable divergence in the electrode potentials. The proposed sensor revealed comparatively good selectivity with respect to most common metal ions, and especially lanthanide ions. It was used as an indicator electrode in the potentiometric titration of Tm(III) ions with EDTA and in direct determination of concentration of Tm(III) ions in binary mixtures. It was also applied in determination of fluoride ions in mouth wash preparations.

• Advances in Energy Research
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• 제7권1호
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• pp.21-34
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• 2020

Energy storage devices have received a keen interest throughout the world due to high power consumption. A large number of research activities are being conducted on electrochemical double layer capacitors (EDLCs) because of their high power density and higher energy density. In the present study, an EDLC was fabricated using natural graphite based electrodes and ionic liquid (IL) based gel polymer electrolyte (GPE). The IL based GPE was prepared using the IL, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (1E3MITF) with the polymer poly(vinyl chloride) (PVC) and the salt magnesium trifluoromethanesulfonate (Mg(CF₃SO₃)₂ - MgTF). GPE was characterized by electrochemical impedance spectroscopy (EIS), DC polarization test, linear sweep voltammetry (LSV) test and cyclic voltammetry (CV) test. The maximum room temperature conductivity of the sample was 1.64 × 10^-4 Scm^-1. The electrolyte was purely an ionic conductor and the anionic contribution was prominent. Fabricated EDLC was characterized by EIS, CV and galvanostatic charge discharge (GCD) tests. CV test of the EDLC exhibits a single electrode specific capacitance of 1.44 Fg^-1 initially and GCD test gives 0.83 Fg^-1 as initial single electrode specific discharge capacitance. Moreover, a good stability was observed for prolonged cycling and the device can be used for applications with further modifications.

• Bulletin of the Korean Chemical Society
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• 제26권1호
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• pp.38-42
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• 2005

Bis(2-methylbenzaldehyde)butane-2,3-dihydrazone(TDSB) was used as new N-N Schiff's base which plays the role of an excellent ion carrier in the construction of a La(III) membrane sensor. The best performance was obtained with a membrane containing, 30% poly(vinyl chloride), 60% benzyl acetate, 6% TDSB and 4% sodium tetraphenyl borate. This sensor reveals a very good selectivity towards La(III) ions over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The proposed electrode exhibits a Nernstian behavior (with slope of 19.8 mV per decade) over a wide concentration range (1.0 ${\times}$ 10$^{-5}$-1.0 ${\times}$ 10$^{-1}$ M). The detection limit of the sensor is 7.0 ${\times}$ 10$^{-6}$ M. It has a very short response time, in the whole concentration range ($\sim$5 s), and can be used for at least twelve weeks in the pH range of 3.0-9.4. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of a La(III) solution, with EDTA. It was also successfully applied in the determination of fluoride ions in three mouth wash preparations.

• 한국표면공학회지
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• 제47권2호
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• pp.57-62
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• 2014

The biogas holder is composed of an outer membrane and an inner membrane which are subject to outdoor exposure and gas exposure respectively. The influence of weathering conditions on the photo-degradation of a biogas holder was investigated. Tests were performed under three different methods - outdoor exposure tests (Seosan, Arizona), accelerated tests (Xenon-are lamp) with the outer-membrane of biogas. Moreover, the changes in the aging process were monitored using color difference, gloss, the contact angle and an optical microscope. Changes in physical properties, such as decrease reduction in gloss, decrease in the contact angle, increase in color difference were observed in the aging process. The comparison between membrane 3B, 4B and membrane 5B under xenon-arc were discussed. Membrane 5B was very sensitive to ultraviolet (UV) ray. There were many difficulties in the outdoor exposure test due to acid rain, dust, and stain resistance.

• Advances in environmental research
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• 제5권3호
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• pp.201-211
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• 2016

Laboratory tests were conducted to evaluate the performance of waste rubber shreds in leachate collection layer of engineered landfills. The study found that waste rubber shreds layer in combination with a gravel layer can be of potential use in landfill drainage system. To study the performance, conventional gravel along with waste rubber shreds were used in different combinations (with total layer thickness = 500 mm) as leachate collection media. For the laboratory study poly vinyl chloride (PVC) pipes were used. The size range of waste rubber shreds used were 25 mm to 75 mm in length and width = 10 to 20 mm. The gravel size used in the leachate collection media is 10 mm to 20 mm size. Performance study of 7 Test Cols. with different combinations of waste rubber shreds and gravel bed thickness were studied to find out the best combination. The study found that the Test Col.-3 having waste rubber shreds thickness = 200 mm and gravel layer thickness = 300 mm gave the best results in terms of percentage removal in various physicochemical parameters present in the leachate. Further to find the best size rubber shreds three more Test Cols - 8, 9 and 10 were constructed having the rubber shreds and gravel layer ratio same as that of Test Col.-3 but having rubber shreds width = 10 mm, 15 mm and 20 mm respectively. Based on the results obtained using Test Cols. 8, 9 and 10 the study found that smaller size rubber shreds gave bests results in terms of improvement in various leachate parameters.

• Bulletin of the Korean Chemical Society
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• 제14권1호
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• pp.123-127
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• 1993

New lipophilic Crown-4 compounds of 16-membered rings containing furan (neutral carrier,I), tetrahydrofuran (neutral carrier,II) and lithium complex of the latter (neutral carrier,III) have been synthesized and tested as the active sensors for lithium ion in poly(vinyl chloride) (PVC) membrane electrode, in the presence and absence of an anion excluder, tetrakis(4-chloro-phenyl)borate (KTClPB), 2-nitrophenyl phenyl ether (NPPE), tris(2-ethylhexyl)phosphate (TEHP), o-nitrophenyl octyl ether (NPOE), dioctyl adipate (DOA), bis(2-ethylhexyl)adipate (BEHA), di-n-octylphenyl phosphonate (DOPP) were used as plasticizing solvent mediators. The electrode response function had a nearly Nernstian slope of 54-61 mV per decade (25$^{\circ}$C) within the concentration range of $10^{-1}-10^{-4}$ M LiCl and the detection limits for all electrodes were ca. $5{\times}10^{-4}$ M. The response time of the electrode was faster at the higher lithium concentration and the response of the electrode was stable for longer than 6 months. The sensor membranes exhibit improved response times and increased lifetimes as compared to the system described earlier.

• 폴리머
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• 제29권6호
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• pp.536-542
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• 2005

로크웰 경도시험 조건 중에서 시간과 관련이 있는 인자들이 경도측정 결과에 미치는 영향을 연구하였다. 대상 소재는 PE, PP PVC, PMMA이었으며 압입속도, 시험하중 유지시간, 그리고 계기판독 시점 등을 중심으로 시험한 결과 탄성이 큰 소재일수록 이들 인자들의 영향을 크게 받는 것으로 나타났다. 시험에 소요되는 시간 등을 고려하였을 때 최적 시험 조건은 각기 4, 15, 15초 이었으며 이 기준에 따라 순회 비교시험을 실시하였다. 순회 비교시험 결과 고분자소재의 경도를 제대로 측정하려면 부가하중을 제하하고 나서 계기판독 시점인 15초의 시간을 유지할 수 있는 기능이 중요한 것으로 나타났다. 황동 기준편으로 경도시험기를 간접 검증하는 것만으로는 탄성 회복력이 좋은 고분자 소재의 특성 때문에 경도 측정값의 신뢰도를 보증할 수 없는 것으로 나타났다.

• Bulletin of the Korean Chemical Society
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• 제27권6호
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• pp.835-840
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• 2006

Dimethyl 1-(4-nitrobenzoyl)-8-oxo-2,8-dihydro-1H-pyrazolo[5,1-a]isoindole-2,3-dicarboxylate has been used as an ionophore and o-nitrophenyloctyl ether as a plasticizer in order to develop a poly(vinyl chloride)-based membrane electrode for calcium ion detection. The sensors exhibit significantly enhanced response towards calcium(II) ions over the concentration range $8.0{\times}10^{-7}\;1.0{\times}10^{-1}$ M at pH 3.0-11 with a lower detection limit of $5.0 {\times}10^{-7}$ M. The sensors display Nernstian slope of 29.5 ${\pm}$ 0.5 mV per decade for Ca(II) ions. Effects of plasticizers, lipophilic salts and various foreign common ions are tested. It has a fast response time within 10 s over the entire concentration range and can be used for at least 2 months without any divergence in potentials. The proposed electrode revealed good selectivity and response for $Ca^{2+}$ over a wide variety of other metal ions. The selectivity of the sensor is comparable with those reported for other such electrodes. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of a Ca(II) solution, with EDTA.