도금 폐수 중 유가 금속 회수를 위한 이온교환섬유의 상용화기술

유성식 ( Seong-sik You ) 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.4

On the basis of 200 ppm of Ag and 120 l/h of feed flow rate, we built a pilot plant of an ion exchange fiber system having an double tube type ion exchange chamber with strong base ion exchange fiber (FIVAN A-6) which was designed to replace fibers easily and to eliminate the need for a fixture. The following results were obtained for the double tube type of ion exchange fiber system with an ion exchange capacity of 4.6 meq/g for Ag. The adsorption process was operated in the range of 40~90 l/h after confirming the effect of the flow rate and, pH did not affect formation of complex ion of Ag in the range of pH 7~12. In the case of backwash process, the recovery rate of Ag was tested in the range of 60~120 l/h and comparative experiments were carried out using NaOH, NH₄Cl, and NaCl as the chemicals for backwash. Although the desorption time was shortened at higher concentration, the desorption efficiency per mol was lowered. Therefore, it was confirmed that the desorption time and the concentration should be well balanced to operate economically. The desorption pattern of the backwash process is slower than the adsorption process and takes a lot of time. The results showed that the Ag adsorption ratio was 99.5% or more and the Ag recovery ratio was 96% or more, and commercialization was possible.

격자모델에 근거한 상태방정식을 이용한 이성분 혼합물의 삼상궤적의 계산

유성식 (정),이철수 (정) ( Seong Sik You,Chul Soo Lee ) 한국화학공학회 1991 춘계학술발표논문집 Vol.- No.-

등온 미세열량계를 이용한 n-Hexane-알칸계 이성분 혼합물 및 NaOH/Water/Ethanol계의 과잉 엔탈피 측정 및 계산

최인규,유성식,Choi, In Kyu,You, Seong-sik 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.5

화학공정에서 증류 또는 추출 등 분리 장치의 설계 및 조업에 있어서 혼합물의 평형데이터는 필수적이다. 이들 평형데이터는 실험을 통해서 얻거나 알려진 이성분 매개변수를 이용하여 모델에 의한 계산으로 얻을 수 있다. 일반적으로 이들 매개변수를 구하기 위해서 기-액, 액-액 등의 상평형 실험 데이터를 주로 이용하지만, 본 연구에서는 보다 간편한 방법으로서 흐름형 미세열량계를 이용하여 혼합물의 과잉엔탈피 실험데이터를 얻고, 이 데이터를 이용하여 여러 이론들의 매개변수를 구하고자 하였다. 더불어, 알칸계의 경우 탄소의 사슬길이와 엔탈피 그리고 이성분 매개변수간의 관계를 알아보고자 하였으므로 n-hexane + alkane (n-pentane, n-heptane, n-octane, n-dodecane)계들에 대해서 298.15 K에서 과잉엔탈피를 측정하였으며, 이 실험데이터로부터 Wilson, NRTL, UNIQUAC의 매개변수를 구하였다. 또한, 다양한 분야에 적용 가능한 전해질 계의 상호작용 및 회합현상에 대한 기본정보를 과잉엔탈피 실험 데이터들과 기존 이론을 이용하여 얻고자 하였다. 우선은 기초적인 실험으로서 NaOH/Water/Ethanol 계에 대한 과잉 엔탈피를 측정하고, electrolyte-NRTL(eNRTL) 이론을 이용하여 응용성을 검토하고자 하였다. Equilibrium data of the mixture is essential in the design and operation of separation equipment such as distillation or extraction in chemical processes. These equilibrium data can be obtained through experiments or by calculations using the known binary parameters and the thermodynamic models. Generally, to obtain these parameters, phase equilibrium experimental data such as gas-liquid and liquid-liquid are used. In this study, the excess enthalpy of the mixture was measured using the flow type microcalorimeter which is a simpler method than phase equilibria experiments, and the parameters of various theories were obtained by using this data. In order to investigate the relationship between carbon chain length, enthalpy and binary parameters in the alkane system, excess enthalpies for the n-hexane + alkane (n-pentane, n-heptane, n-octane and n-dodecane) were measured at 298.15 K and the banary interaction parameters of Wilson, NRTL, and UNIQUAC were obtained from the experimental data. In addition, we wanted to obtain basic information on the interaction and association phenomena of the system including electrolyte applicable to various fields by using the excess enthalpy experimental data and the existing theory. First, we investigated the excess enthalpy for the NaOH / Water / Ethanol system as a basic experiment and examined the applicability using the electrolyte-NRTL (eNRTL) theory.

고분자 용액의 상평형

유기풍 (정),유성식 (정),이철수 (정) ( Ki Pung Yoo,Seong Sik You,Chul Soo Lee ) 한국화학공학회 1992 춘계학술발표논문집 Vol.- No.-

알긴산 나트륨을 이용한 유산균 캡슐화의 상업화 공정 개발

김지연 ( Jiyeon Kim ),유성식 ( Seong-sik You ) 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.3

We aimed to develop commercialization process of encapsulation which is superior in productivity compared to existing methods by using sodium alginate. Also, in the same process, sodium alginate with chitosan was used to encapsulate lactic acid bacteria with the same process and then the viable cell counts of the two encapsulated lactic acid bacteria were compared. As a test result of the fluidized drying process developed by the present researchers, it was found that the drying time was shortened by 15 to 20 hours compared to the freeze drying method, but the number of viable lactic acid bacteria was about 75% as compared with freeze drying. However, considering the cost and time of drying, it can be confirmed that the commercialization process is possible by the fluidized bed drying method. When the number of viable cells of Ca-alginate capsule and Chitosan-alginate capsule were compared, it was confirmed that there were about 1×10⁹ or more bacteria in the former and about 1×10³ in the latter. The lactic acid bacterium capsules prepared by the present technique were stable for 96 hours or more at pH 4.65 and 6.01, but disappeared within 1 hour at pH 7.07 and 8.35. This suggests that the disintegration of lactic acid bacteria can be easily occurred in small and large intestine.

순수한 미리스틴산 및 팔미틴산과 그 혼합물의 초임계 이산화탄소에 대한 용해도

조용상(Yong Sang Cho),유성식(Seong Sik You),이철수(Chul Soo Lee) 한국화학공학회 1993 춘계학술발표논문집 Vol.- No.-

이온성 액체를 이용한 dodecanethiol로 안정화된 금속 나노입자 합성

이영은 ( Young Eun Lee ),이성윤 ( Seong Yun Lee ),유성식 ( Seong Sik You ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.5

Nanoparticles have received significant attention because of their unusual characteristics including high surface area to volume ratios, Thiol ligand have been used as stabilizers of metal nanoparticles since Brust et al. They reported the preparation method of ligand capped metal nanoparticles by protecting the nanoparticles with a self-assembled monolayer of dodecanethiolate. In this method, volatile organic compounds (VOCs) were used as sovents. This study was carried out to replace these VOCs with room temperature ionic liquids (RTILs). We used two type of ILs to prepare metal nanoparticles. One is a hydrophobic IL, [BMIM][[PF6] (1-Butyl-3-methylimidazolium hexafluorophosphate) purchased from IL maker, C-Tri from Korea and the other one is a hydrophilic one, [BMIM][Cl] (1-Buthy-3- methylimdazolium chloride) sinthesized by us. In the case of preparing Ag and Au nanoparticles using [BMIM][Cl], we didn`t use phase transition reagents and ethanol because it has hydrophilic property and preparing Au, Ag nanoparticles using [BMIM][[PF6] the method is as same as Brust et al.`s except using [BMIM][[PF6] instead of organic solvent because it has hydrophobic property. FT-IR and UV-vis, TEM, TGA analysis have been used in an attempt to determine the particle size and verify functional groups. The particle size obtained from TEM was very similar to those obtained by Brust et al. This is a clear example of ligand capped metal nanoparticles prepared using ionic liquids. And the experimental result demonstrated ionic liquids can act as a highly effective medium for the preparation and stabilization of gold and silver metal nanoparticles.

철 기반 촉매의 Fischer-Tropsch 합성에서 γ-Al₂O₃/SiO₂ 혼합 지지체 조성의 영향

민선기 ( Seon Ki Min ),노성래 ( Seong-rae No ),유성식 ( Seong-sik You ) 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.3

Fischer-Tropsch synthesis is the technology of converting a syngas (CO+H₂) derived from such as coal, natural gas and biomass into a hydrocarbon using a catalyst. The catalyst used in the Fischer-Tropsch synthesis consists of active metal, promoter and support. The types of these components and composition affect the reaction activity and product selectivity. In this study, we manufactured an iron catalyst using γ-Al₂O₃/SiO₂ mixed support (100/0 wt%, 75/25 wt%, 50/50 wt%, 25/75 wt%, 0/100 wt%) by an impregnation method to investigate how the composition of γ-Al₂O₃/SiO₂ mixed support effects on the reaction activity and product selectivity. The physical properties of catalyst were analyzed by N₂ physical adsorption and X-Ray diffraction method. The Fischer-Tropsch synthesis was conducted at 300 ℃, 20bar in a fixed bed reactor for 60h. According to the results of the N₂ physical adsorption analysis, the BET surface area decreases as the composition of γ-Al₂O₃ decreases, and the pore volume and pore average diameter increase as the composition of γ-Al₂O₃ decreases except for the composition of γ-Al₂O₃/SiO₂ of 50/50 wt%. By the results of the X-Ray diffraction analysis, the particle size of α-Fe₂O₃ decreases as the composition of γ-Al₂O₃ decreases. As a result of the Fischer-Tropsch synthesis, the CO conversion decreases as the composition of γ-Al₂O₃ decreases, and the selectivity of C1-C4 decreases until the composition of γ-Al₂O₃ was 25 wt%. In contrast, the selectivity of C5+ increases until the composition of γ-Al₂O₃ is 25 wt%.

초임계 이산화탄소를 이용한 미세전자기계시스템의 식각, 세정, 건조 연속 공정

민선기 ( Seon Ki Min ),한갑수 ( Gap Su Han ),유성식 ( Seong-sik You ) 한국화학공학회 2015 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.53 No.5

The previous etching, rinsing and drying processes of wafers for MEMS (microelectromechanical system) using SC-CO2 (supercritical-CO2) consists of two steps. Firstly, MEMS-wafers are etched by organic solvent in a separate etching equipment from the high pressure dryer and then moved to the high pressure dryer to rinse and dry them using SC-CO2. We found that the previous two step process could be applied to etch and dry wafers for MEMS but could not confirm the reproducibility through several experiments. We thought the cause of that was the stiction of structures occurring due to vaporization of the etching solvent during moving MEMS wafer to high pressure dryer after etching it outside. In order to improve the structure stiction problem, we designed a continuous process for etching, rinsing and drying MEMS-wafers using SC-CO2 without moving them. And we also wanted to know relations of states of carbon dioxide (gas, liquid, supercritical fluid) to the structure stiction problem. In the case of using gas carbon dioxide (3 MPa, 25 oC) as an etching solvent, we could obtain well-treated MEMS-wafers without stiction and confirm the reproducibility of experimental results. The quantity of rinsing solvent used could be also reduced compared with the previous technology. In the case of using liquid carbon dioxide (3 MPa, 5 oC), we could not obtain well-treated MEMS-wafers without stic- tion due to the phase separation of between liquid carbon dioxide and etching co-solvent(acetone). In the case of using SC-CO2 (7.5 Mpa, 40 oC), we had as good results as those of the case using gas-CO2. Besides the processing time was shortened compared with that of the case of using gas-CO2.

방열 아크릴 점착제의 제조를 위한 개질 알루미나의 효과

오지환(Ji-Hwan Oh),강신혜(Sinhye Kang),리시앙수(Li Xiangxu),노성래(Seong-Rae No),유성식(Seong-Sik You),조을룡(Ur-Ryong Cho) 한국고분자학회 2016 폴리머 Vol.40 No.5

용액중합을 통해 합성한 아크릴 점착제에 실란커플링제로 전처리한 알루미나(30, 60, 90 wt%)를 혼합하여 열전도성 복합체를 제조한 후 접착특성 및 열전도도를 조사하였다. 접착특성은 180° 박리강도, 유지력 및 초기점착력을 측정하였고, 열전도도는 laser flash 법을 이용하여 측정하였다. 박리강도와 초기점착력은 알루미나의 함량의 따라 감소하였고, 유지력은 향상되는 경향을 보였으며, 열전도도는 크게 향상되었다. 전처리한 알루미나를 사용한 점착테이프는 전처리하지 않은 알루미나를 사용한 것에 비해서 상대적으로 점착력이 낮아지며, 열전도도는 10% 가량 향상되었다. 이는 커플링제로 인하여 점착제 매트릭스와 알루미나 필러 사이의 계면결합이 증가한 것으로 추정된다. 개질된 90 wt%의 알루미나를 포함한 경우 열전도도는 0.242 W/mK 값을 나타내어 알루미나를 포함하지 않은 점착테이프에 비해 크게 향상됨을 확인할 수 있었다. Thermal conductive acrylic pressure sensitive adhesives (PSA) were synthesized by solution polymerization. The adhesive was mixed with (30, 60, 90 wt%) alumina (Al) pretreated by silane coupling agent. Adhesion properties of the PSA/Al composites were investigated by measuring peel strength, holding power, and initial tack. Thermal conductivity was measured by a laser flash analyzer. Peel adhesion and intial tack decreased with the alumina content, and holding power tended to increase. Adhesion properties of adhesive tape using modified alumina decreased compared with using pristine alumina, and thermal conductivity was increased by 10%. It was confirmed that the interfacial bonds between the PSA and the modified alumina increased because of silane coupling agent. Thermal conductivity of adhesive sheet containing 90 wt% modified alumina as filler was 0.242W/mK, which was significantly improved compared to pure PSA sheet.