Editor’s Choice

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Editor’s Choice

NEWS & INFORMATION FOR CHEMICAL ENGINEERS, Vol. 33, No. 5, 2015 … 637 Editor's Choice

Korean Journal of Chemical Engineering, Vol.32, No.9, 1713-1719, 2015

Integrated fabrication-conjugation approaches for biomolecular assembly and protein sensing with hybrid microparticle platforms and biofabrication

- A focused minireview

Sukwon Jung and Hyunmin Yi

Abstract - Controlled manufacturing of polymeric hydrogel microparticles is crucial, yet challenging, for rapid and sensitive detection of biomacromolecules in biodiagnostics and biosensing applications. Our approach is an integrated fabrication-conjugation strategy utilizing a simple and robust micromolding technique and biofabrication with a potent aminopolysaccharide chitosan as an efficient conjugation handle for high-yield bioorthogonal conjugation reactions. We present a concise overview of our recent findings in the controlled fabrication of shape-encoded or core-shell structured microparticles consisting of poly(ethylene glycol) (PEG) and short single-stranded (ss) DNA or chitosan, and their utility in the covalent conjugation and nucleic acid hybridization-based assembly of target ssDNAs, proteins and viral nanotemplates. Particularly, two novel routes to achieve substantially improved protein conjugation capacity and kinetics are presented from our recent reports: tobacco mosaic virus (TMV) as a high capacity nanotubular template and polymerization-induced phase separation (PIPS) of pre-polymer droplets for controlled core-shell structure formation. We envision that our fabrication-conjugation approaches reported here, combined with our current and future endeavors in improved fabrication and design of controlled structures with chemical functionalities, should permit a range of manufacturing strategies for advanced functional microscale materials and platforms in a wide array of applications.

Microbial bioremediation processes for radioactive waste

Changhyun Roh, ChanKyu Kang, and Jonathan R Lloyd

Abstract - Microbial processes can affect the environmental behavior of priority radionuclides, and understanding these reactions is essential for the safe management of radioactive wastes and can contribute to the remediation of radionuclide- contaminated land. Underlying mechanisms that can control radionuclide solubility in biogeochemical systems can range from biosorption and biomineralization process, through direct (enzymatic) and indirect redox transformations. The mechanisms of enzyme-mediated reduction of problematic actinides, in principal, uranium (U), but including neptunium (Np), plutonium (Pu) and Americium (Am), are described in this review. In addition, the mechanisms by which the fission products technetium (Tc), cesium (Cs), and strontium (Sr) are removed from a solution by microorganisms are also described. The present review discusses the status of these microbiological processes, and the potential for cost-effective and scalable in situ remediation of radioactive waste.

New α-Zn

2

V

2

O

7

/carbon nanotube nanocomposite for supercapacitors

Nulu Venugopal and Woo-Sik Kim

Abstract - This study synthesized α-Zn2V2O7 nanopowders using a hydrothermal approach followed by annealing treatment. The resulting powders were then mixed with multi-walled carbon nanotubes and electrochemically characterized as new nanocomposite electrodes for supercapacitors. The structure and surface morphology of the powders were characterized by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. Plus, the capacitive behavior of the composite electrodes was evaluated by cyclic voltammetry and galvanostatic charge-discharge

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638 … NICE, 제33권 제5호, 2015

cycles in different molar aqueous KCl solutions. The α-Zn2V2O7/multi-walled carbon nanotube composite electrodes were prepared using three different ratios and screened for their use in supercapacitors. As a result, the α-Zn2V2O7/ multi-walled carbon nanotube composite electrode with a 1 : 2 ratio was identified as the best electrode with a specific capacitance value of 44.8 F g−1 in 0.5M KCl. Notwithstanding, all the tested composite electrodes demonstrated an excellent cycle stability and showed a less than 4% change in their specific capacitance values when compared to the initial values.

Recent advances in development of biomass pretreatment technologies used in biorefinery for the production of bio-based fuels, chemicals and polymers

Young Hoon Oh, In Yong Eom, Jeong Chan Joo, Ju Hyun Yu, Bong Keun Song, Seung Hwan Lee Soon Ho Hong and Si Jae Park

Abstract - Biochemical conversion of biomass into biofuels, biochemicals, and biopolymers has attracted much interest throughout the world in terms of biorefineries. Lignocellulosic biomass is one of the most plentifully available biomass resources on the earth. It is composed of three main biopolymers - cellulose, hemicelluloses, and lignin, all of which are cross-linked to each other to resist degradation by enzymes and microorganisms resulting in so-called biomass recalcitrance. The biorefinery process typically consists of three steps: pretreatment, hydrolysis, and fermentation. Energy and cost efficiency of biorefinery is predominantly dependent on how to produce inexpensive sugars from complex cell wall component of lignocellulosic biomass by overcoming biomass recalcitrance. There have been tremendous efforts to develop effective biomass pretreatment technologies for obtaining the highest yield of fermentable sugars from biomass feedstocks at the lowest cost. The present review discusses various pretreatment technologies to understand how to effectively break down biomass into fermentable sugars that are eventually used for microbial fermentation to produce biomass-based fuels, chemicals, and polymers.

Fischer-Tropsch synthesis on Co-Al

2

O

3

-(promoter)/ZSM5 hybrid catalysts for the production of gasoline range hydrocarbons

Jae-Hong Ryu, Suk-Hwan Kang, Jin-Ho Kim, Yun-Jo Lee and Ki-Won Jun

Abstract - The Fischer-Tropsch synthesis (FTS) reaction was investigated for the direct production of gasoline range hydrocarbons (C5-C9) from syngas on Ru-, Pt- and La-promoted Co-Al2O3/ZSM-5 (Si/Al=25) hybrid catalysts prepared by co-precipitation method in a slurry. The hybrid catalysts were characterized by BET surface area, XRD, H2-TPR and NH3- TPD analyses. Their physicochemical properties were correlated with the activity and selectivity of the catalysts. The promoted Co-Al2O3-(promoter)/ZSM-5 hybrid catalysts were superior to the unpromoted Co-Al2O3/ ZSM-5 catalyst in terms of better C5-C9 yield. In particular, the Co-Al2O3-Pt/ ZSM-5 hybrid catalyst exhibited the highest catalytic activity with a low C1 and olefin selectivity and a high C5-C9 selectivity. It could be due to not only a higher value for the reduction degree by H2-TPR, but also assigned to weak acidic sites of a low temperature desorption peak by NH3-TPD.

Removal characteristics of Cd(II) ions from aqueous solution on ordered mesoporous carbon

Linhang Lu, Haibo Zhao, Lu Yan, Guowei Wang, Yulin Mao, Xin Wang, Kai Liu, Xiufang Liu, Qian Zhao and Tingshun Jiang

Abstract - Ordered mesoporous carbon (CMK-3) was synthesized using SBA-15 mesoporous molecular sieve as a template and sucrose as carbon source. The materials were characterized by XRD, TEM and N2 physical adsorption technique. The resulting CMK-3 was used as adsorbent to remove Cd(II) ions from aqueous solution. The effect of pH,

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NEWS & INFORMATION FOR CHEMICAL ENGINEERS, Vol. 33, No. 5, 2015 … 639 contact time and temperature on adsorption process was investigated in batch experiments. The results showed that the removal percentage could reach ca. 90% at the conditions of initial Cd(II) ions concentration of 20 mg/L, dose of 20mg, pH 6.5, contact time of 3h and 293K. Langmuir and Freundlich models were employed to describe the adsorption equilibrium.

The kinetics data were described by the pseudo-first-order and pseudo-second-order models, respectively. The adsorption isotherm was well fitted to the Langmuir model, and the adsorption process was well described by the pseudo-second-order kinetic model.

Korean Chemical Engineering Research, Vol.53, No.4, 412-416, 2015

고분자전해질 연료전지 구동 중 수소투과도 측정

Measurement of Hydrogen Crossover During PEMFC Operation

정재진, 정재현, 김세훈, 안병기, 고재준, 박권필

Abstract - 고분자 막 성능 평가 및 내구성 평가에 이용하기 위해 고분자전해질 연료전지(PEMFC) 구동 중에 수소 크로스오버측정이 필요하다. 수소 크로스오버 측정 시에 불활성 기체 대신에 공기를 cathode에 공급하면서 기체 크로마토그래프로 수소 농도를 cathode 출구에서 분석하였다. PEMFC 구동 중 고분자 막을 통과한 수소는 cathode에서 산소와 반응해 불활성 가스를 공급할 때에 비해 수소 농도가 감소하였다. cathode 공기 공급 유량이 증가하면 수소 농도가 감소했고, 셀의 온도와 습도, 압력이 증가하면 cathode의 수소 농도는 증가했다. 일반적인 PEMFC 구동 조건에서 120 mA/cm² 전류밀도에서 수소농도는 약 5.0 ppm이었다.

초임계유체를 이용한 고삼으로부터 Genistein의 추출

Extraction of Genistein from Sophora flavescens with Supercritical Carbon Dioxide

한창남, 강춘형

Abstract - 본 연구에서는 초임계 이산화탄소를 용매로 사용하여 고삼으로부터 genistein을 추출하였다. 공용매와 추출 온도 및 압력 등에 따른 추출효율을 측정하였으며, 공용매로 메탄올과 에탄올을 사용하여 200 bar에서 300 bar의 압력범위와 35 ℃와 50 ℃의 온도범위에서 연구를 수행하였다. 조건에 따라 서로 다른 genistein의 추출효율을 보였으며, 특히 높은 압력과 높은 온도에서 가장 높은 추출효율이 관찰되었다. 또한 메탄올이 에탄올보다 더욱 효과적인 공용매 특성을 보였으며 농도가 높을수록 추출효율도 증가하였다. DPPH 라디칼 소거 활성을 측정하여 고삼 추출물의 항산화 활성을 비교하였다.

중성 영역 구리 화학적 기계적 평탄화 공정에서의 작용기에 따른 부식방지제의 영향성 연구

Study on the Effects of Corrosion Inhibitor According to the Functional Groups for Cu Chemical Mechanical Polishing in Neutral Environment

이상원, 김재정

Abstract - 금속 배선형성 재료가 구리로 대체됨에 따라 다마신(damascene) 공정이 도입되었고, 과증착된 구리를 화학적 기계적 평탄화(Chemical Mechanical Polishing, CMP) 방식을 통해 제거하는 구리 화학적 기계적 평탄화 공정이 필요하게 되었다. 본 연구에서는 중성영역 구리 화학적 기계적 평탄화 공정용 슬러리의 구성 요소 중 하나인 부식 방지제에 아 미 노 기 ( - N H2) 와 카 르 복 실 기 ( - C O O H ) 를 부 착 시 켜 그 에 따 른 영 향 성 을 확 인 하 고 자 하 였 다 . 1H-1,2,4-트리아졸(1H-1,2,4-triazole)을 기준 부식방지제로 선정하여 식각속도, 제거속도 및 화학적 식각력을 측정한 결과 아미노기는 높은 구리 식각 능력을 보여주는 반면, 카르복실기는 부식방지제 효과가 증대되어 기본 부식방지제보다 낮은 식각 능력을 보여주었다. 이는 높은 제거속도가 필요한 1차 구리 화학적 기계적 평탄화 공정에는 아미노기가, 높은 구리 제거속도/식각속도 비를 필요로 하는 2차 구리 화학적 기계적 평탄화 공정에는 카르복실기가 적합하다는 결론을 보여준다.