• Korean Chemical Engineering Research
• /
• v.45 no.5
• /
• pp.415-423
• /
• 2007

Photocatalytic water splitting (PWS) is the most promising technology to produce $H_2$ energy directly from renewable water and solar light. In spite of the remarkable progress made in the last decade, there are still many technical challenges remaining particularly in finding new photocatalytic materials with high efficiency and durability. This article discusses the application of nanocomposite materials in search of new photocatalytic materials for solar hydrogen production from water. It has been demonstrated that smart combination and modification of known materials and functions could be fruitful approach for the purpose.

• Journal of Environmental Science International
• /
• v.16 no.5
• /
• pp.641-647
• /
• 2007

The phase transfer catalysis(PTC) reagent, ethyl tri-octyl ammonium bromide(ETABr), strongly catalyzes the reaction of p-nitrophenyi diphenyl phosphinate(p-NPDPIN) with benzimidazole(BI) and its anion($BI^{\theta}$). In ETABr solutions, the dephosphorylation reactions exhibit higher first order kinetics with respect to the nucleophile, BI, and ETABr, suggesting that reactions are occuring in small aggregates of the three species including the sub-strate(p-NPDPIN), whereas the reaction of p-NPDPIN with $OH^{\theta}$ is not catalyzed by ETABr. This behavior for the drastic rate-enhancement of the dephosphorylation is referred as 'aggregation complex model' for reaction of hydrophobic organic phosphinates with benzimidazole(BI) in hydrophobic quarternary ammonium salt(ETABr) solutions.

• Journal of Energy Engineering
• /
• v.14 no.2 s.42
• /
• pp.133-139
• /
• 2005

An activated carbon-photo catalysis hybrid system is proposed for the treatment of VOC produced from paint booth. and its VOC removal performance is experimentally evaluated. Activated carbon tower is designed on the basis of the adsorption characteristics of toluene. Photocatalytic system is designed as the series of $TiO_2/SiO\_2$ fluidized bed reactor and $TiO_2$-coated filters. The present activated carbon-photo catalysis hybrid system shows the VOC removal efficiency within $75\~100\%$ under different VOC species and concentrations.

• STI Policy Review
• /
• v.4 no.2
• /
• pp.19-40
• /
• 2013

The Association of Southeast Asian Nations (ASEAN) achieved relatively rapid economic growth over the past decade. Sustainable growth among member states, however, is put into question due to macroeconomic challenges, political risk, and vulnerability to external shocks. Developed countries, in contrast, have turned into less labor-intensive technologies to further expand their economies. In this paper, we review the science, technology, and innovation (STI) policies and statuses of the scientific and technological capabilities of the ASEAN member countries. Empirical results based on STI indicators (R&D spending, publications, patents, and knowledge economy indices) reveal considerable variation between the science and technology (S&T) competence and effectiveness of STI policies of ASEAN members. We have categorized nations into clusters according their situations in their S&T productivity. Under the Korean Innovation Model, Cambodia, Laos, Myanmar, and Brunei are classified as being in the institutional-building stage, while Malaysia, Thailand, Indonesia, the Philippines, and Vietnam in the catch up stage, and Singapore in the post-catch up stage. Finally, policy prescriptions on how to enhance the S&T capabilities of the developing ASEAN countries, based on the South Korea development experience, are presented.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.4
• /
• pp.600-603
• /
• 2007

The effect of a water-miscible ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate $([BMIM][BF_4])$, on the horseradish peroxidase (HRP)-catalyzed oxidation of 2-methoxyphenol (guaiacol) with hydrogen peroxide $(H_2O_2)$ was investigated. HRP maintains its high activity in the aqueous mixtures containing various concentrations of the ionic liquid and even in 90% (v/v) ionic liquid. In order to minimize the effect of solution viscosity on the kinetic constants of HRP catalysis, the enzymatic reactions in the subsequent kinetic study were performed in water-ionic liquid mixtures containing 25% (v/v) ionic liquid at maximum. As the concentration of $[BMIM][BF_4]$ increased for the oxidation of guaiacol by HRP, the $K_m$ value increased with a slight decrease in the $K_{cat}$ value: The $K_m$ value increased from 2.8 mM in 100% (v/v) water to 22.5mM in 25% (v/v) ionic liquid, indicating that ionic liquid significantly weakens the binding affinity of guaiacol to HRP.

• Journal of Korean Society on Water Environment
• /
• v.36 no.2
• /
• pp.153-163
• /
• 2020

Magnetic separation technology is an efficient and environmentally friendly technology. Compared with the traditional wastewater treatment technology, the magnetic separation technology has its unique advantages and characteristics, and has been widely applied in the field of wastewater treatment. In particular, the emergence of superconducting magnetic separation technology makes possible for high application potential and value. In this paper, which through consulting with the literatures of Korea, Chinese, United States and other countries, the magnetic separation technology applied to wastewater treatment was mainly divided into direct application of magnetic field, flocculation, adsorption, catalysis and separation coupling technology. Advantages and limitations of the magnetic separation technology in sewage treatment and its future development were also studied. Currently, magnetic separation technology needs to be studied for additional improvement in processing mechanism, design optimization of magnetic carrier and magnetic separator, and overcoming engineering application lag. The selection, optimization and manufacturing of cheap magnetic beads, highly adsorbed and easily desorbed magnetic beads, specific magnetic beads, nanocomposite magnetic beads and the research of magnetic beads recovery technology will be hot application of the magnetic separation technology based on the magnetic carriers in wastewater treatment. In order to further reduce the investment and operation costs and to promote the application of engineering, it is necessary to strengthen the research and development of high field strength using inexpensive and energy-saving magnet materials, specifically through design and development of new high efficiency magnetic separators/filters, magnetic separators and superconducting magnetic separators.

• Applied Chemistry for Engineering
• /
• v.30 no.6
• /
• pp.652-658
• /
• 2019

Direct hydrazine fuel cells (DHFCs) have been considered to be one of the promising fuel cells because hydrazine as a liquid fuel possesses several advantages such as no emission of CO₂, relatively high energy density and catalytic activity over platinum group metal (PGM)-free anode catalysts. Judging from plenty of research works, however, regarding key components such as electrocatalysts as well as their physicochemical properties, it becomes quite necessary to understand better the underlying processes in DHFCs for the long term stability. Herein, we highlight recent studies of DHFCs in terms of a systematic approach for developing cost-effective and stable anode catalysts and electrode structures that incorporate mass transport characteristics of hydrazine, water and gas bubbles.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.9
• /
• pp.1371-1378
• /
• 2004

A porous stainless steel (SUS) as a substrate of silica composite membranes for hydrogen purification was used to improve mechanical strength of the membranes for industrial application. The SUS support was successfully modified by using submicron Ni powder, $SiO_2$ sols with particle size of 500 nm and 150 nm in turns. Silica top layer was coated on the modified supports under various preparation conditions such as calcination temperature, dipping time and repeating number of dipping-drying process. The calcination temperature for proper sintering was between H ttig temperature and Tamman temperature of the coating materials. Maximum hydrogen selectivity was investigated by changing dipping time. As repeating number of dipping-drying process increased, permeances of nitrogen and hydrogen were decreased and $H_2/N_2$ selectivity was increased due to the reduction of non-selective pinholes and mesopores. For the silica membrane prepared under optimized conditions, permeance of hydrogen was about $3\;{\times}\;10^{-5}\;cm^3{\cdot}cm^{-2}{\cdot}s^{-1}{\cdot}cmHg^{-1}$ combined with $H_2/N_2$ seletivity of about 20.

• Environmental Engineering Research
• /
• v.13 no.2
• /
• pp.51-65
• /
• 2008

The increasing demand for energy in the near future has created strong motivation for environmentally clean alternative energy resources. Microbial fuel cells (MFCs) have opened up new ways of utilizing renewable energy sources. MFCs are devices that convert the chemical energy in the organic compounds to electrical energy through microbial catalysis at the anode under anaerobic conditions, and the reduction of a terminal electron acceptor, most preferentially oxygen, at the cathode. Due to the rapid advances in MFC-based technology over the last decade, the currently achievable MFC power production has increased by several orders of magnitude, and niche applications have been extended into a variety of areas. Newly emerging concepts with alternative materials for electrodes and catalysts as well as innovative designs have made MFCs promising technologies. Aerobic bacteria can also be used as cathode catalysts. This is an encouraging finding because not only biofouling on the cathode is unavoidable in the prolonged-run MFCs but also noble catalysts can be substituted with aerobic bacteria. This article discusses some of the recent advances in MFCs with an emphasis on the performance, materials, microbial community structures and applications beyond electricity generation.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.3
• /
• pp.809-814
• /
• 2011

A method based on the TMS derivatives and acidic hydrolysis was developed for the simultaneous determination of free and conjugated steroidal hormones in surface water. A silylation of five natural and two synthetic steroidal hormones was achieved with N-methyl-N-(trimethylsilyl) trifluoroacetamide/$NH_4I$ (1000:3) under catalysis of dithioerythritol for 60 min at $80^{\circ}C$. TMS derivatives of the steroid hormones containing multifunctional groups offer a single derivative product under this condition. The accuracy of the analytes was in the range of 87 to 110% at a concentration of 20 and 50 ng/L with relative standard deviations of less than 10%. The method detection limit was in the range of 0.01 to 0.02 ng/L for surface water. Natural steroidal hormones were detected in a concentration range of 0 to 1.03 ng/L in free form and 0 to 14.6 ng/L in conjugated form, respectively. We found that most of the natural hormonal steroids exist in conjugate forms (43 to 100%) in river water.